Thursday, December 22, 2016

The Crash That Made Your Airplane Safer

Terrain is now displayed on primary flight displays
Enhanced GPWS display showing terrain (in green)

Any airplane crash is a tragedy, but in the investigation following a crash, it is always hoped that something can be learned which will aid in the prevention of a future crash. Commercial aviation is now one of the safest modes of transportation available, but it has only become this way through dogged investigation of aircraft accidents and the application of lessons learned. Such was the case of American 965.

On December 20, 1995, American 965, a 757-200, crashed in the mountains of Colombia while enroute to Cali. 151 passengers and eight crew were killed while five passengers survived the impact. The investigation into the crash concluded that the primary cause was a navigational error made by the flight crew resulting in terrain impact.

There were, however, some unique aspects of this accident which highlighted contributing factors. One of these was found to be several errors in the aircraft's navigational computer database which led the crew astray.  Also unique to this accident investigation was the method in which investigators were able to reconstruct the events which led to the crash. As it happened, one of the 757's flight navigation computers was found in the wreckage with its internal battery and volatile memory still intact. 

This allowed investigators to reconstruct electronically what the aircrew saw as they were descending through the mountainous terrain that night in Colombia. This finding revealed the true cause of the errors that were made by the flight crew which had until then eluded investigators. And this, in turn, directed investigators to the errors in the onboard database.

Increasing reliance on automation meant that aircrews were becoming more dependent on onboard electronic systems used for navigation rather than on the printed paper charts and radio beacons which had been the mainstay of airborne navigation since the dawn of aviation. Uncritical trust in this system, however, turned out to be deadly.

The aftermath of this crash resulted in new safety systems that are now installed on virtually all commercial airliners to aid in terrain avoidance as well as new procedures to be used with automated aircraft navigation systems.

Let's take a closer look at the causes of this accident and some of the changes resulting from the investigation.

Where is it Taking Us?

Alfonso Bonilla Aragón International Airport, which serves Cali, lies in a valley with mountainous terrain rising to over 12,000 ft on either side of the north-south running Cauca Valley. The arrival path of AA965 had the aircraft descending through this valley to pass over the airport and then reverse course to land to the north.

At some point though, the controller, who had no operable radar due to terrorist activity, offered the crew a straight-in approach to land to the south on the north-south runway. The crew accepted this clearance but were now high on profile without the turn around to lose the excess altitude. Thus they were expediting their descent with the aircraft's speed brakes being extended.

There was also some confusion in the instructions given to the crew by air traffic control with the aircrew finally asking to proceed directly to a radio beacon near the airport. This beacon, really just a radio transmitter, was named "Rozo NDB". It is here where a database error and a lack of situational awareness caused problems.

The paper charts which the crew was using listed the Rozo beacon by its identifier as the letter "R". That meant that typing that identifier into the computer should have caused the aircraft to fly to the Rozo beacon straight down the valley. The database installed in the aircraft, however, had an error and differed from the paper charts the crew was using, The identifier of the Rozo beacon in the electronic database was "ROZO" and not the letter "R" as the crew believed.

Thus when the crew typed in "R", the aircraft turned left towards another beacon located 130 miles to the east in Bogota named "Romeo". This beacon actually did have its identifier listed as "R" in the electronic database. This turn to the east took the aircraft directly into the mountains on the east side of the Cauca Valley.

Maintain Situational Awareness

If the above description is confusing for you to read, imagine what was going through the minds of those pilots as they tried to sort out where they were and why their airplane was mysteriously turning when it should've been going straight south to the runway. It took the crew about a minute to sort out that the airplane shouldn't be turning and another minute to start a turn back to safety. But even though they eventually got terrain warnings and had started an emergency climb, they had descended too far into the mountains and hit a ridge at an elevation of about 8900 ft.

One of the prime directives of aviation, drilled into all pilots from the beginning of their careers, is to maintain situational awareness. This means knowing what is going on around you at all times. It is a fundamental skill in aviation. This crew was set up by a database error, but should have had an idea that any turn off their course down the valley was ill advised. They should also have known that they had descended below the altitude of the mountains bordering the valley.

One of the luxuries that US based airlines enjoy is a first rate air traffic control system which is unparalleled in not only maintaining traffic separation, which is their main objective, but also in providing terrain avoidance. They're so good at it in fact, that it is easy for pilots to become complacent about the need to always be vigilant about terrain if for no other reason than they (and their passengers) will suffer the consequences of any such complacency.

The same, unfortunately, cannot be said for many countries without the superb infrastructure found in most first world countries. While most controllers are excellent at what they do, the Colombian controller had no radar with which to warn American 965 that they were in danger. It is the pilot's sole responsibility to maintain awareness of any terrain clearance problems.

Not in Vain

The story does not end here. The fallout from this accident was wide ranging. The database error which led the pilots to make a wrong turn into the mountains prompted a thorough review of the navigational databases which are used by commercial aircraft, including safeguards to ensure that the information printed on charts matches that in navigational databases. Flight crew procedures were also changed to ensure that a "common sense" check of any computer commands were made before those commands were executed in the navigation computers.

It also became apparent that faster and more capable computers coupled with GPS receivers would be able to provide a whole new level of protection against controlled flight into terrain (CFIT). Ever since the crash of Eastern Airlines 401 into the Florida everglades in 1972, commercial aircraft have had a system installed that is known as the Ground Proximity Warning System (GPWS). Pronounced "jip whiz", this system warns pilots of approaching terrain through a downward looking radio altimeter. 

GPWS is the source of the electronically generated "PULL UP" command you may have heard in movies or when the system is tested at the gate. The limitation of this system is that there is no way to reliably warn pilots of very rapidly rising terrain as the system can only look straight down at what is directly below the airplane. In fact, the GPWS system on American 965 did warn the pilots of danger but not until it was too late.

Enhanced GPWS

A new system called Enhanced GPWS has since been designed to use a database of all the terrain an aircraft is expected to encounter either regionally or globally. When coupled with GPS location, this system can give pilots enough warning to avoid any possible terrain conflicts well in advance of encountering any high terrain. It generates a terrain map on the primary flight display. This display looks somewhat like an old fashioned topographic map but terrain is displayed in green, yellow, or red depending on the height of the terrain in relation to aircraft altitude.

The system is proactive and will also generate cautions and warnings based on the current aircraft trajectory and any terrain that may be a danger. Pilots are warned well in advance of any projected terrain encounters. The system finally gives pilots real time feedback on exactly where they are in relation to high terrain, a problem which has always plagued aviation.

Aviation is safer now than at any time in history but this is no accident. Many accidents are caused by carelessness or complacency on the part of crews or maintainers, but occasionally something is learned that materially affects the safety of the entire industry. American Airlines 965 was a tragedy for everyone aboard that fated airliner as well as for their friends and families, but at least in this one case, real changes were made which will make a recurrence of this accident much less likely.

The next airplane trip you take will also be safer because of lessons learned from the crash of American 965.

Addendum: Counterfeit Parts and Aircraft Design

Two other issues were brought to light in the aftermath of American 965. One that was highlighted was the existence of an international network of counterfeit aircraft parts as some of the parts from the wreckage began to show up on the black market. Aircraft parts are built to exacting and expensive standards, so an incentive exists for unscrupulous actors to sell counterfeit and stolen parts. Parts with serial numbers from AA 965 did make their way into this network.

A second issue was that of cockpit design. When the pilots realized that they were near the terrain, they initiated an emergency climb, but neglected to retract the speedbrakes which they had been using to descend. Because the aircraft hit the ridge only a few hundred feet below the summit, speculation was made as to whether the speed brakes should automatically retract when the throttles are pushed up and whether doing so would have saved the aircraft. Some aircraft have this feature while others do not, but highlighting the issue should make pilots aware of the potential problem.

Friday, December 02, 2016

How Does an Airliner Run Out of Fuel?

LaMia 2933 ran out of fuel

While the investigation into the crash of the LaMia RJ-85 airliner in Columbia is still ongoing, it is becoming apparent that the aircraft ran out of fuel. Investigators at the crash site noted that there was no post-crash fire or fuel spillage. Other evidence suggesting fuel starvation is that photos of the fan blades on the engines appear to show them to be mostly intact. A spinning engine often throws its blades upon impact suggesting that the engines were not operating.

Other significant factors affecting this flight were the length of the leg, an arrival delay imposed due to another emergency aircraft, and the status of the pilot as a part owner of the charter airline. Also of note is that the first officer was on her first flight as a commercial pilot.

How Much Fuel Did They Need?

Any airline will be subject to the regulations of the country in which they are based, but most countries' rules conform to guidelines published by the International Civil Aviation Organization (ICAO). ICAO rules state that any aircraft must have enough fuel to travel to its destination and any alternate airport plus an additional 45 minutes for reserve. The investigation will determine if the LaMia aircraft departed with sufficient fuel.

Remember, though, that winds aloft, weather, payload, and even temperature can affect the fuel range of any airplane. There is no hard and fast mileage number to apply. The investigation will need to reconstruct all the planning data that the LaMia pilots had.

Two Ways to Run Dry

The first and perhaps most common way to run out of gas is due to simple human error. This can result in an aircraft being mis-fueled or having an erroneous fuel reading due to a bad gauge. Call it inadvertent...when it gets quiet while still airborne, the pilots may be surprised the most. This can take multiple errors by fuelers, mechanics, or pilots who can be extremely inventive in finding ways to circumvent procedures designed to catch fuel errors, but it has been known to happen.

The second way to run out of fuel is to have a lapse of judgement, or what we in aviation call airmanship.

This Has Happened Before

Part of the essence of being a pilot in command of a commercial aircraft means internalizing the fact that 1) you're on your own and 2) that everyone aboard is depending on you. Of course you aren't literally on your own as you have resources such as your first officer, air traffic control, and dispatch, but no one will be there to hold your hand or pull your chestnuts out of the fire if things go wrong. The nature of the job means that you will be made, in some way or another, to own the decisions you make.

Keeping your eye on your fuel state is one of those "Aviation 101" things that every pilot gets pounded into them from day one. Running out of gas is something you just don't do if you're aware of the two precepts above. It is rare but it happens.

In 1978, a United Airlines DC-8 crashed outside of Portland, Oregon after running out of fuel. The pilots had become preoccupied with a bad gear indication and flew around until the fuel ran out. The engineer was not assertive enough to communicate the plane's dire fuel state to a distracted captain. As the engines quit, the captain implored the engineer to "keep them running". He forgot that it was his job to land before the fuel ran out.

Again in 1990, an Avianca Boeing 707 crashed after running out of fuel on approach to New York's JFK airport killing 74 passengers and crew. The cause was determined to be a language barrier and misunderstanding by the crew in communicating their fuel state to air traffic control. Specifically, air traffic controllers will not give priority handling to any aircraft unless the word "emergency" is used. The Avianca crew did not use that term and ran out of fuel after extensive traffic delays.

In both of these cases, the pilot in command failed to take appropriate actions to land before the fuel ran out. It really doesn't matter what air traffic control says or what state the landing gear are in. It would've been better to belly in or to disregard controller instructions than to crash. Making uncomfortable choices between two potentially unpleasant options is a big part of being a pilot.

Was This Careless Flying?

While the investigation is far from complete, a picture is beginning to emerge. LaMia, which only owned this one aircraft, was known to be one of the cheapest charter operators available for hire in the region. A takeoff delay also meant that a potential refueling stop was not available due to the closure of that field. It also turns out that the pilot in command was a part owner of the company who may have let financial concerns cloud his judgement. 

Lastly, his copilot, Sisy Arias, was on her first ever commercial flight as a pilot. This is important because in her very inexperienced state, she may not have been aware of the fuel situation nor was she likely to intervene even if she was.

There's an old aviation aphorism floating around which states that the definition of a superior pilot is one who uses their superior judgement (proper fuel planning) to avoid situations requiring their superior skill (doing a night dead-stick landing into mountainous terrain). 

Aviation is a profession that calls for strict adherence to unmalleable rules. Behaving recklessly is bad enough, if that is indeed what happened here, but the real tragedy is in betraying the trust of your passengers and crew.

Monday, October 17, 2016

NTSB Attributes Design Flaw and Pilot Input for Crash at LaGuardia

Back in March of last year, a Delta MD-88 slid off the runway in a snow storm at LaGuardia. The aircraft was heavily damaged but there were no injuries. I wrote about that incident here.

To recap, the aircraft landed in really lousy visibility during a snowstorm and slid off the side of the runway and almost into Flushing Bay. While the approach and landing were normal, the aircraft drifted off the left side of the runway after landing, eventually hitting the airport perimeter fence and coming to a rest on the berm that borders the airport and the water.

Since the winds were not particularly strong, my first guess was that the problem might have been a braking problem, but that was not the case. The NTSB recently concluded their investigation of the incident and have blamed the accident on an obscure directional control characteristic of aircraft with tail mounted engines known as "rudder blanking" along with the pilot's reaction to that effect. The full accident report can be found here.

Design Flaw

Inherent in the design of turbine powered aircraft with tail mounted engines and thrust reversers is an effect known as rudder blanking. Shortly after touchdown, pilots command the thrust reversers open using levers located on the throttles. On the MD-88, the aircraft involved, baffles actually close over the exhaust of the engines and redirect the thrust to the sides and forward of the engine. This redirected thrust helps to slow the aircraft.

The problem with this configuration is the location of the engines on the rear fuselage near the tail of the aircraft. The redirected thrust also has the effect of reducing the relative wind over the vertical stabilizer and rudder. Reducing the air over the rudder reduces its effectiveness. The reduced rudder effectiveness combined with the crosswind allowed the aircraft to depart the left side of the runway and to hit the boundary fence.

Boeing (which purchased McDonnell Douglas, the manufacturer of the MD-88) was aware of the flaw and recommended that reverse thrust was not to be used at full power during landing. Boeing recommended a further restricted use of reverse thrust when landing on a runway "contaminated by clutter" which is aviation-speak to mean a buildup of snow or slush.

Here's an excerpt from the Flight Operations Bulletin published by Boeing:

Due to the geometry of the MD-80 thrust reversers, the exhaust gas efflux pattern will, at certain rollout speeds and EPR settings, interfere with the free-stream airflow across the rudder surfaces. This will result in partial “rudder blanking”; with a resultant reduction in directional control authority. As rudder effectiveness is more critical on wet or slippery surfaces, “rudder blanking” becomes a concern above a reverse thrust level of 1.3 EPR. Normal dry runway maximum reverse thrust power is 1.6 EPR [emphasis in original].

Will the Brakes Stop the Airplane on the Runway?

Another concern of the crew was the "braking action" on the runway. This is also aviation-speak to mean the slipperiness of the pavement. The crew had heard reports that the braking had been reported as "fair" which meant that they would not have been able to stop the aircraft on the runway and would have needed to divert. Later on in the flight, the braking action had been reported as "good" by another airliner and the crew made the decision to continue.

The problem with braking action reports by other aircraft is that they are highly subjective. Some pilots make the determination by how many times their anti-skid cycles during a landing. Others use different criteria and each aircraft can respond differently to the same conditions. One pilot's "fair" report can easily be another's "good".

Weather and runway reports from the airport itself indicated that the runway was covered with 1/4 inch of wet snow. The runway had recently been swept, but by the time Delta 1086 landed, it was already white in appearance from new snowfall.

So you can see that as a minimum, this crew was concerned that they didn't have much room for error on this landing.

The Friction Measuring Trucks Were Parked

As far as the actual condition of the pavement, airport authorities have been using friction measuring equipment for decades. So what was the actual friction measurement at the time Delta 1086 landed? No one knows. Due to bureaucratic ambiguity and confusion between FAA directives and the New York Port Authority, the Port Authority elected to not use either of the two trucks it had available to measure runway surface friction.

From a bureaucratic point of view this makes perfect sense as you can be held liable for inaccurate or missing reports if your policy was to collect them. Change your policy to keep the trucks parked and you're off the hook. This works best for bureaucrats sitting in heated offices, but not so well for passengers landing in a snowstorm. But it's completely legal.

On the Edge of Safe

So in essence, the story so far is that the aircraft landed in 1/4 mile of visibility in a snowstorm on an extremely short runway bounded on three sides by water with an essentially unknown slickness of the pavement.

As a reminder, a quarter mile of visibility is 1320 feet and a touchdown speed of 140 kts is about 236 feet per second. This gave the pilot about five and a half seconds of time between seeing the runway and landing on it. And according to the flight recorder, the touchdown was well within the landing zone and on speed.

What happened next was measured in seconds. Here's the synopsis from the NTSB report:

During a postaccident interview, the captain stated that, as he was lowering the airplane’s
nose to the ground after main gear touchdown, he moved the thrust reversers to idle and then “one knob width on the reverser handle” to obtain Delta’s target setting of 1.3 engine pressure ratio (EPR).16 FDR data showed that engine reverse thrust exceeded 1.3 EPR between 3 and 4 seconds after main gear touchdown (with the left engine exceeding 1.3 EPR before the right engine) and was advancing through 1.6 EPR immediately after the nose gear touched down. FDR data showed that the EPR value exceeded 1.6 for 5 seconds, reaching maximum EPR values of 2.07 on the left engine and 1.91 on the right engine between 6 and 7 seconds after main gear touchdown. Engine power decreased after this point, and the thrust reversers were stowed at 1102:25 (7.5 seconds after deployment, 9 seconds after main gear touchdown, and 2,500 feet from the runway threshold) at an EPR value of 1.8 on the left engine and 1.6 on the right engine. At that time, the airplane’s groundspeed was 93 knots. 

In plain-speak, the pilot used reverse thrust in excess of the recommended amount for a total of five seconds and then stowed the reversers. The aircraft started to drift left at six seconds after touchdown, or three seconds before the reversers were stowed. This meant that it was in the three seconds between the time the aircraft started to drift and the time the reversers were stowed that the problem occurred.

To further complicate the landing, the aircraft by this time had slowed to 93 knots. At this speed the rudder itself loses effectiveness as there is not enough air moving over the surface to keep the aircraft on the runway. Other than the rudder, directional control of an aircraft on the ground is obtained through the use of nosewheel steering and differential braking. Both of these were used but were not effective enough to get the aircraft under control.

No Win Situation

Pilots are goal oriented people. We like to get the job done. But we are also called upon to get the job done correctly and are tasked with being the final arbiters of safety. To this end, we are given the tools and the criteria to use those tools correctly. But when some of the supposedly objective information we have turns out to be highly subjective and incomplete, the process becomes a crapshoot.

In my view, these guys were set up. They were told that if the braking was "good" they could land, but if it was "fair" they'd go for a swim. So for a few seconds the pilot overcompensates with too much reverse thrust and they nearly go swimming anyway. Another MD-88 had landed minutes before and had no problem while also exceeding reverse thrust limits. These guys just got hit with an unlucky gust of wind.

The whole idea of risk management is to make sure that the operation does not become a crapshoot. Had these pilots diverted when the "system" said they could make it safely and other airplanes were landing, they'd be questioned by their chief pilot and ridiculed by their passengers. Now they're probably wishing they had diverted. A three second and immediately corrected deviation from SOP during extreme conditions should not result in a major accident.

In the appendix to the accident report, board member Robert Sumwalt, himself a retired airline pilot, had this to say about the situation facing the captain:

As a former airline pilot for over 20 years, I’m confident saying that having to limit reverse thrust on a relatively short, slippery runway is counter-intuitive: When you need it the most, you have to use it the least.

So the next time your pilot diverts or goes around when others are landing, you will be frustrated or angry that you don't get to your meeting or home on time. Don't be. The guy or gal up front is trying to get you where you're going, but also trying to keep you alive.

Addendum: A Few Words about the The NTSB

I'm going to take a moment to say a few words about the NTSB. Good words. The NTSB in my view is a national treasure. They are staffed with a group of smart and thoughtful professionals who take the time to get to the bottom of the accidents they investigate. And while they don't have any real regulatory power to force changes, nor do they make economic cost-benefit assessments of their various proposals, their recommendations often serve as signposts to be disregarded by industry and regulators at their peril.

Delta is the Best!

Here's an amusing comparison from a Delta captain of block hours, revenue, and profits at the big four carriers that I found on a pilot forum...

Delta is THE BEST...

...Just ask them! A Delta Pilot's perspective on how the big 4 measure up.


Hello all, me again, with more numbers to share. As of late we've been all up in arms
about the status of negotiations. And somewhat displeased and confused by the rumors of
what's happening inside the MEC and perhaps even in a panic by the NMB parking us. No
doubt these are all depressing things for the average line pilots.

Well, relax a second. I'd like to take a moment of your time to give you some numbers
that will lift up your spirits and make you proud to be a DELTA pilot working for a truly
good company. Ironically, my numbers will also expose a number of lies our boss, the
company and DALPA are trying to sell us.

The Steve Dickson LIE - If you have attended a meeting recently in which our boss, a good
guy by most accounts, has briefed us about the status of the company - you will have
heard him say that the company needs improved productivity from the pilots. He has said
to me directly, that we are the least productive pilots in the industry. That our average
block hours per pilot per month are well below our competitors and that we must make
improvements to remain competitive. If you look at the data from MIT, at first, his
statement appears to have some validity.


Let's look at the big three and half airlines for comparison. They are American, United,
Delta and Southwest. The first three are similar in size and SW is about 60 percent of
the other's size. According to MTI, the average pilot flies...

> 46.9 hours per month at American
> 40.2 hours per month at United
> 43.1 hours per month at Delta

And - those energizer bunny guys at SWA...

> they fly 57.8 hours per month (Whooah!)

[data based on 2015 total annual block hours flown, divided by total pilots, divided by
twelve months]

Okay - first little lie. We're not the least productive, by the above data we are number
three and United is dead last. Clearly lazy bastards with too much quality of life
(remember this statement). But - geeze, those SWA boys and girls are kicking everyone
else's asses in productivity. How do they do it? I can see Management is dying to ramp us
to that level of efficiency... but is it really?

Block hours flown is not a complete picture. A better picture is how much revenue each
company pulls in with their annual block hours. So - let's compare annual block hour
generation first. In 2015...

> American with 12,363 pilots flew 3,478,489 total block hours
> Delta with 11,476 pilots flew 2,966,095 total block block hours
> United with 11,128 pilots flew 2,687,068 total block hours

Again - American, averaging 46.9 per month seems to have a clear lead among the big
three, but fucking SWA, wow...

> Southwest with a mere 7,457 pilots flew 2,587,191 block hours (almost equal to
united) - [could it be their taxi speeds?]

Clearly the Managements of the bigger three want to know SWA's secret and salivate over
the thought of driving us to such high levels of productivity. Look at SWA, you guys can
do just as good!

On a side note, Dickson's least productive guys delivered the second highest amount of
block hours to their company last year.
But - this is a rather meaningless number without looking at the revenue the block hours
generated. Revenue generated per block hour is important because it is an excellent
indicator of comparative fleet capacity effects on money generation. And of the big
three, Delta has the least wide bodies, and SWA has none.


In 2015 the big three and half generated the following total revenues:

> American's 3.478 million block hours delivered 41.084 billion $.
> Delta's 2.966 million block hours delivered 40.704 billion $.
> United's 2.687 million block hours delivered 37.864 billion $.
> And SWA's 2.587 million block hours only got 19.820 billion $.

Stated another way - as in dollars per block hour, a measure of efficiency of the
operation, it looks like this.

> SWA earned $7,661 per block hour flown.
> American earned $11,811 per block hour flown.
> United earned a whopping $14,091 per block hour flown.

Wait a minute, weren't those United guys the lazy goofs who only flew 40.2 hours per
month? Aren't they less productive than everyone else? Why isn't this lining up with
Steve Dickson's accusations? Liar... Oh, and what about Delta.

> Delta earned $13,723 per block hour flown.

Hey! Don't we have the second lowest average block hours flown per month per pilot? Yet
we produced the second highest amount of revenue per block hour of all the airlines.
Could that mean that there is less a correlation of block hours flown to revenue than
fleet capacity per hour flown to revenue? And doesn't more hours mean less quality of
life? Those poor rabbits at SWA are running hither and dither working way harder than
anyone else yet barely generating half the total revenue. Could there be a problem with
an all narrow-body fleet mix. Could there be a correlation with United having the most
wide bodies being able to produce the most revenue with the least effort, perhaps even
having a better QOL than us Delta guys? I'd say yes.

The good news fellow Delta pilots, by this measure we are in second place among the
airlines. But wait...there's more. Revenue is just one measure of a company's
productivity. Each airline is unique for its expenses, so let's look at how good they are
making money, not in terms of revenue, but in terms of profits.


You have revenue and then expenses and what's left is profit. This is the REAL measure of
pilot productivity. Not total work generated but rather total profits generated by equal
work. Since each company is different in size and make up, and in it's total block hours
flown, we have to go one step further and look at how much profit each pilot generates
for its company per year, all things being equal, that means per block hour. Alright -
let's see who has the best business model going.

In 2015...

> SWA generated 3.479 billion in profits. That works out to $1,344 and 70 cents per
block hour flown. As it takes two pilots to fly a block hour, each pilot at SWA generates
$672.35 in profits per block hour flown.

> American generated 4.668 billion in profits. That is $1,341.96 per block hour and
$670.98 in profits per pilot per block hour.

> United generated 4.219 billion in profits. That is $1,570.12 per block hour and
$785.06 per United pilot per block hour.

And what about the home team? Dickson's "least productive" pilots in the
industry? The ones who are third in average block hours flown and only second in revenue
generated? The one's Management MUST have become more productive lest the competition
bury us? The one's DALPA is bending over backwards to rob QOL from in order to meet the
company's needs???

Yeah, what about us Delta line guys and gals?

> Delta generated an amazing 7.157 billion in profits last year.

That is $2,412 and 94 cents per block hour, which is 53.7 percent better than the
powerhouse United gang and almost double the others.

THAT - is a whopping $1,206.47 in profits per pilot per block hour flown.


Ladies and gentlemen, fellow Delta pilots, esteemed comrades, despite our in fighting,
our fears, and management's lies and distortions...


Take pride - wear your orange, fight for what you deserve!

(Mr. Dickson - take your lack of productivity message and ditch it. DALPA, negotiate us
what we are truly worth).

J.D. Webster
7ER Capt. C4

Thursday, September 22, 2016

What's Up with the Rollercoaster Takeoffs from Orange County?

If you've ever had the pleasure (or perhaps the terror) of taking off in a commercial plane from Orange County's John Wayne airport, you'll know that it is a takeoff unlike any other. Just seconds after liftoff, you will feel your stomach drop as the airplane does a very abrupt pushover. This pushover, similar to what you might feel on a rollercoaster or perhaps a hilly backcountry road, will make you light in your seat. You might even feel yourself being restrained by your seatbelt.

The next thing that you will notice is that the sounds in the cabin will change. Specifically, they will get much quieter. The roar of the engines that accompanies all takeoffs will diminish dramatically. You will sense that the nose of the aircraft has dropped significantly. The incline, or what pilots call the "deck angle" will have gone from the usually steep angle used for most takeoffs, to one that is barely distinguishable from level flight. And all this will seem to be happening much too close to the ground.

Finally, you may become aware of an annoying thumping that you feel in your chest. Don't worry, that's only your heart pounding.

You may think that this is over...and wonder if there's enough time to squeeze a goodbye text to your loved ones before plunging into the Pacific ocean. But you should rest easy. You are not going to die (at least not today). What you have just experienced is known as a noise abatement takeoff. They occur hundreds of times weekly at John Wayne and are an FAA approved and in fact government mandated maneuver. That's right; pilots and airlines will be fined if they don't perform this type of takeoff.

So why, you may ask, are you being subjected to an experience that should probably be featured at the nearby Disney theme park? Well, as I mentioned above, noise. Noise and of course politics. For John Wayne airport is the only airport which mandates such a drastic noise reduction profile. And as legend has it, the Duke himself, the airport's namesake, had a hand in getting those restrictions put in place.

The departure path from John Wayne airport flies almost directly over Newport Beach. And as you may know, Newport Beach is a very well-heeled community. And while I'm not going to make judgements on wealth accumulation, one thing wealthy people are good at is getting things done. Starting with the arrival of the first turboprops and jets in the 1970s, community activism followed soon thereafter. Eventually lawsuits were filed and the restrictions were put in place.

Why Orange County?

John Wayne Airport dates back to 1923 when a landing strip was first opened by a man named Eddie Martin to host a flying school. Then known as Martin Field, Orange County assumed ownership in 1939 with the airport becoming to be known as Orange County Airport. The name was changed to John Wayne Airport in 1979 in honor of actor John Wayne, a nearby resident, upon his death.

Noise restrictions at the airport date back to 1985 when a local group representing residents who lived under the departure path sued the county. The resulting settlement implemented noise regulations and curfew requirements which remain in force today. Noise meters are deployed along the departure path to measure the sound footprint of each departing aircraft. Those restrictions are unique in being some of the first of their kind, and also just about the only of their kind.

In 1990, Congress, fearing that many localities could eventually hamstring the growth of aviation by implementing their own patchwork of noise restrictions, passed the Airport Noise and Capacity Act which outlawed curfews at airports. John Wayne was grandfathered in, however, due to the original lawsuit being filed in 1985.

Why the Rollercoaster?

So knowing why airplanes have to fly quietly, you may be wondering about the "how". And specifically, you might be wondering why airliners don't just use less thrust from the get-go instead of the roar followed by the pushover and silence. Without getting too technical about takeoff performance, much of it comes down to the runway length at John Wayne airport, or to be more specific, the lack of runway length.

The longest runway at John Wayne is less than 6000 feet long. At a scant 5701 feet to be precise, it is one of the shortest runways if not the shortest runway in the nation from which large commercial aircraft fly.

It is the nature of gaining flying airspeed in a very short distance which necessitates the full power takeoff. Once airborne, but before the flaps are retracted, the aircraft reaches a "cutback" altitude of about 800 ft. It is here where the engines are throttled back either manually or by the auto-throttles to a thrust which meets the minimum required climb gradient of about 2.5%. Less thrust also means a shallower climb angle, hence the pushover.

Once beyond the noise sensitive area, or about six miles after takeoff, the aircraft resumes its normal climb profile using full climb thrust.

Is It Dangerous?

I suppose that depends on your definition of the word dangerous. Any time you monkey around with large power changes on a turbine engine, you increase the odds of something going wrong. In fact, many engine failures occur not on initial thrust application such as takeoff, but rather on a large thrust reduction. That said, the odds of that ever happening are infinitesimal. Still, it isn't unknown for engines to fail as was dramatically illustrated by the uncontained engine failure on a Southwest Airlines 737 several weeks ago. Infinitesimal odds, but not zero.

So no, it isn't dangerous in the conventional sense of the word. Avoiding flights out of Orange County to avoid takeoffs using this procedure would be silly. And likely more dangerous as a longer commute up the freeway to LAX would definitely expose you to more absolute danger in your car. Of course, the safest course of action is to hide under the bed which still won't protect you from meteorites...or dust bunnies.

So when you do get on that airplane leaving the OC, be sure to get a window seat on the left side of the airplane which gives the best views of Catalina, relax and enjoy the ride. But don't put your arms in the air and scream as if on a real rollercoaster. People will stare.

Monday, September 19, 2016

Flying to Cuba on One Engine

Flying to Cuba on One Engine
Brian Hall (center) and his Bonanza in Havana

This past August saw an important landmark in aviation history with the first scheduled commercial flight between the US and Cuba taking place in nearly fifty years. On August 31st, a JetBlue Airbus flew from Ft Lauderdale to Santa Clara, Cuba with 150 passengers, journalists, and dignitaries. JetBlue is one of six US airlines which won approval to fly direct routes from the US to Cuba.

As historic as that occasion was, an equally historic flight took place earlier in 2015. Scooping the first scheduled commercial flight by over a year, was the first flight of a private civilian aircraft to Cuba from the US. On January 15 of last year former Air Force C-130 pilot and businessman Brian Hall flew his Beech Bonanza from Fort Myers, Florida to Havana. Flying under the rules of Part 91, Hall's flight was the first flight of this type in over fifty years.

Hall is hoping to start a new ferry service called CubaKat between Florida and Cuba. He flew to Havana to discuss business details with his Cuban employees and government officials. He might be considered a serial entrepreneur as he is currently the CEO of a marine engineering company and has had a hand in starting or running everything from ferry services to an airline to an energy services company and consultant services.

Flying to Cuba on One EngineWhile travel to Cuba for tourism is still not permitted under current rules, other reasons for travel such as cultural exchange are permitted. In addition to his proposed ferry service, Hall also spoke to Cuban officials during his visit about starting airline service between cities in Cuba itself. There is apparently a need for intra-island air transportation and Hall seems to be in the right place at the right time to capitalize on business opportunities in Cuba. He is proposing to start service using Cessna Caravans to deliver passengers and cargo.

Well as it turns out, Hall was a student pilot in my flight at the 98th Flying Training Squadron at Williams AFB in Phoenix, Az, nearly thirty years ago. The 98th trained students to fly the T-37 primary jet trainer while on their way to become Air Force pilots. After graduation from undergraduate pilot training, Hall went on to pilot C-130 Hurricane Hunter aircraft before leaving the service to start his career as a businessman.

The Road to Cuba

I was able to catch up with him about a week ago and ask him how his path led him to make history flying a single engine aircraft to Cuba.

He told me that his fascination with Cuba came from his grandparents who had often vacationed on the island. They would tell stories of their travels which captivated him. Many years later, he was able to arrange a retreat to Cuba for some family members and from that point on was hooked. He has since been back to Cuba many times on cultural exchange trips, though always having to travel by chartered aircraft.

In December of 2014, President Obama announced a restoration of full relations with Cuba thus ending decades of stalemate and embargo with the island nation. Hall knew that this was his opportunity to get in on the ground floor with the establishment of ferry service between Cuba and Florida. His CubaKat venture, which will use large catamaran ferries carrying up to 200 passengers, is still awaiting final government approval to begin operations.

In the meantime, Hall saw an opportunity to make a historical flight. He actually owns two aircraft, a single engine Bonanza and a twin engine Baron. And while the general rule for overwater flying is that more engines are better, Hall said he had insurance problems with taking the Baron to Cuba. As a result, he had to take his single engine 1953 Bonanza for the 217 mile journey to Havana.

While many pilots fly single engine aircraft to the Caribbean islands, Hall said that the one concession he made was to wear his life vest rather than to just have it available. The last thing a pilot wants to be doing if forced to ditch in a small aircraft, is to simultaneously fly the plane and make a distress call while figuring out how to don a life vest.

While planning for his flight, he did contact the US Immigration and Customs service who for some bureaucratic reason or another informed him that he couldn't make the flight as he had planned. It had something to do with Miami being the only approved airport for flights from Cuba. Being steeped in the culture of entrepreneurial risk taking, he found that it was in fact easier to beg forgiveness than to ask permission and had no trouble upon his return to the states.

Lacking the Basics

Hall told me that the actual mechanics of flying to Cuba were rather routine. The Cuban controllers were all perfectly gracious, spoke good English and his flight to Havana was uneventful. It was upon arrival that he realized that Cuba has a ways to go as far as aviation infrastructure is concerned. Routine expectations such as tie-downs and chocks, available at most US airports, were notably lacking. They also didn't have fuel, which might have been a problem had he not had the foresight to carry enough fuel for a round trip.

Since his first trip, Hall has been back to Cuba in his own plane three times. He says that the lack of overall infrastructure to handle the tsunami of Americans expecting to visit the island will be a brake on the tourism industry once the tourism ban is eventually lifted. Hall told me that one of his employees requested that he bring a toilet seat along on his next visit. It took two visits as the first one he brought was oval when a circular one was required.

Hall also mentioned that travellers to Cuba should not forget to bring enough cash to cover their expenses while visiting as there are almost no ATMs on the island. The Cubans, for their part, seem to be catching on that there is money coming along with their new island visitors. On one of his latest trips, a new $40 departure tax was levied which hadn't been mentioned or collected before. Of course you must pay if you wish to take off.

Cuba is His Passion

Even though the regulatory hurdles Hall faces to get his CubaKat venture going can be a real headache, he doesn't plan on quitting the island anytime soon. He's there to stay in one fashion or another. His motto is that if a businessman isn't earning, then he's learning. And Brian Hall, Air Force pilot turned entrepreneur turned Cuba evangelist seems to have enough passion and energy to do plenty of both.

Thursday, September 08, 2016

Is Aviation Automation Killing Us?

Is Aviation Automation killing us?

"When we design our systems, we need to assign appropriate roles to the human and technological components. It is best for humans to be the doers and technology to be the monitors, providing decision aids and safeguards."

 - Captain Sully Sullenberger

The past week has seen several high profile aviation incidents come to light. The first one was a preliminary accident report on the crash and fire which destroyed an Emirates Boeing 777 in Dubai last August. The second was the release of the final report by the Australian Transport Safety Bureau (ATSB) regarding an AirAsia Airbus A330-300 enroute from Sydney to Malaysia last year which suffered navigation and other system failures as the result of erroneous input by the pilots during preflight.

The Emirates crash tragically took the life of a responding fireman, while the AirAsia incident caused no injuries but did result in a diversion. Each incident had the potential for great loss of life, though. The improper use of automation can be implicated in both the Emirates and AirAsia events. Let's take a look at each of these and see if we can draw some parallels.

Emirates 521

The crash report on the Emirates flight, released by the General Civil Aviation Authority (GCAA) of the UAE details that the approach was flown by the captain. The autopilot was disconnected for the landing while the autothrottles remained engaged. The aircraft experienced a longitudinal wind component which changed from a headwind of 8 kts to a tailwind of 16 kts during the approach. As a result of the decreasing performance wind shift, the aircraft made a long touchdown.

An automatic system on the Boeing warned the crew about the long touchdown, and a decision was made to go around. So far so good. Going around rather than accepting a long landing due to shifting winds is the correct decision.

What happened next wasn't so good. The nose was raised, the flaps were reset and the gear were retracted, but go-around power was not added until three seconds before the aircraft impacted the runway with the gear partially retracted. The post crash fire destroyed the aircraft entirely.

Adding power during a go-around is...or should be, instinctual. It's considered aviation 101, or rather it used to be. Today's highly automated aircraft, however, all employ autothrottles which automatically advance themselves when the "Takeoff-go-around" or TOGA button is pushed. This is how go-arounds are performed on automated aircraft.

The 777, however, has a feature which disables the TOGA button after touchdown. This makes sense as you don't want the throttles to advance after landing in case of accidentally touching the TOGA button. After a normal landing, that is. There are times when a rejected landing, or go-around, occurs after touchdown. The reasons vary, but a landing can be rejected any time until the thrust reversers are deployed, even after the gear touch down.

This is what happened to the Emirates 777. It touched down, and then attempted a go-around without adding power. Questions remain as to whether or not the captain actually engaged the TOGA button but in any case, the captain should have manually pushed up the throttles for the go-around or ensured that the autothrottles automatically advanced.

Why would he not do that? Easy. It's called negative conditioning or negative training. Go-arounds are routinely practiced in all airline simulator training programs, but go-arounds after touchdown are practiced much less frequently. Over time, muscle memory will expect the autothrottles to advance themselves during a normal go-around as they always do.

Put a pilot in a highly dynamic situation such as a windshear landing, and then perhaps throw in a non-routine distraction such as the automatic runway length warning, and voila, muscle memory takes over and the throttles don't get pushed up. Automation, which is supposed to make flying easier and safer, might have helped make a crash such as this inevitable.

AirAsia X 223

On March 15 last year, an AirAsia A330 suffered multiple inflight malfunctions of  its navigational display systems rendering the aircraft incapable of either continuing to its destination in Malaysia, nor of returning to its origination point of Sydney due to low ceilings. The aircraft eventually landed uneventfully in Melbourne, which had clear weather.

Subsequent investigation revealed that the pilots made a data entry error during their pre-flight checks consisting of a single digit error in programming the aircraft's location.

Modern navigation systems on today's commercial aircraft are capable of guiding an airplane to a spot on the other side of the globe with accuracy down to several feet. But in order to know where to go, the computers on the airplane first have to know where they are. 

Part of the preflight process is to enter in the aircraft's current location in the form of a latitude and longitude. The pilot entering this data made some sort of fat finger error which resulted in the actually entered position being thousands of miles away from the Sydney airport. So after the aircraft departed, discrepancies between where it actually was and where it believed it was caused the computers to crash resulting in a nearly complete failure of the navigational system.

After identifying  and while attempting to fix the problems with the navigation systems, the crew compounded their problem by cycling two of their three flight computers to off and back on. This incorrect procedure resulted in the loss of other primary flight displays and rendered the aircraft incapable of flying even a simple approach back to Sydney necessitating the diversion to Melbourne.

Even after arrival at Melbourne, the aircraft had to make several attempts at a completely manual landing without the benefit of either the autopilot nor autothrottles. There is little doubt that flying a highly automated aircraft left the pilot's manual flying skills in a somewhat rusty state, which is completely expected.

Automation: Friend or Foe?

Automation of commercial airliners is with us to stay. It provides many benefits and economies but there are problems with its deployment which contributes to accidents and incidents such as these. The old aphorism which states that computers just allow humans to make mistakes faster and with more efficiency certainly applies here. 

Over reliance on automation is also well known to cause a deterioration in manual stick and rudder piloting skills, which go unmissed until they are needed. The crash of Asiana 214 in San Francisco several years ago was a perfect example of this.

But as Captain Sully warned in the quote above, automation is best deployed as an enhanced decision making tool, not something which a bored human being should be tasked to sit and watch, as it is today.

Wednesday, September 07, 2016

How I Raised Four Amazing Children as the Husband of an Airline Pilot

The Captain...with progeny

I, no we, my wife and I, have four amazing kids. No, seriously, they are. I couldn't possibly be biased, but I'll let you judge:

Marlon, the oldest, (not their real names) recently graduated as an officer from one of the service academies where he was a collegiate swimmer, and is now in training with a special forces unit. He was offered a pilot training slot but turned it down to go into special forces (a subject for a future post).

Bronwyn has recently returned from a two year dance school in Canada and is embarking upon her career as a professional modern/jazz dancer. Genevieve, my third, is also a cadet at a US service academy and in her sophomore year studying operations research, while Poppet, my youngest, is a high school senior sorting out her options. She is finding out that being a National Merit Scholar semifinalist means a mailbox full of Ivy League promotions on a daily basis.

So they're awesome kids, and what's more is they're really nice people, which in my book counts for more than their accomplishments.

But I am not going to be shy about taking at least some of the credit here because my wife, their mother, abandoned the family. At least weekly. Oh, she would always eventually come home only to fly out the door in a week or so leaving me alone with an infant and three toddlers for days on end.

She's not a bad person either, but she is an airline pilot. Part of her job description is to be gone. And she wasn't only gone for her three to four trips a month, but for many weeks of time every time her airline decided to send her to train on a new aircraft.

I've Got the T-Shirt

Short of actually giving birth to these children, there wasn't a single child rearing function that I was not required to master. They're 15,16 and 19 months apart so for a short while we had four in diapers. Did you know that a running clothes dryer can calm a crying baby in seconds? No, not in it, but rather on it where the changing table was. And I bet you didn't know that a bungee cord stretched from a bedroom door across the hall to the bathroom door is an excellent means to corral a toddler who won't stay in bed.

When giving baths, be sure to buy the cheapest conditioner available and then use about half the bottle per child per bath to ease the brushing of hair tangles. Learning how to apply drywall texture can also be a useful skill you will need to repair downstairs water damage from bath time. And doubling the recipe for hamburger helper, otherwise known as "Daddy goulash", leaves enough food to put in their thermos for a tasty and nutritious school lunch the next day!

Now I know that many of the stay at home dads and all of the moms reading this are thinking "So what? You're not doing anything that I haven't done." And you would be right. But to give credit where due, remember no one applauds the dancing bear for dancing well, but rather for being able to dance at all! The kids turned out OK, so I figure we must've done something right. What exactly that was, I have no idea, but there are a few clues. Here are my best guesses.

Full Disclosure

For full disclosure, I am also an airline pilot. My wife, Sandy, and I were both Air Force pilots which is where we met. Sandy flew transport aircraft in Desert Storm and left the military shortly afterward to start her airline career. She has flown numerous aircraft over a 20+ year career to include the 747 and is currently flying the 777 on international routes.

I have also been flying commercially for about 26 years, but after leaving active duty, I found a job in the Air Force Reserve. As a "weekend warrior", I flew the C-5 jumbo transport concurrently with my airline job until retiring from the military in 2002.

Can You Juggle?

The nature of being an airline pilot (or flight attendant) means that you can't bring work home. Once you park the jet and set the brake, you're free. This means that while you are home, you are one hundred percent home. There are no business calls to take, emails to answer or projects due on Monday.

Over the years, I've met quite a few "industry couples" trying to raise a family. The entry of women into the piloting ranks as well as men into the flight attendant ranks means that more "assortative mating" is occurring. This is a fancy way of saying that there are more pilot-pilot couples and flight attendant-flight attendant couples.

Each couple has to decide for themselves how they are going to structure their family life. Sometimes this involves one person giving up their career to be a full time parent while the other becomes the sole breadwinner. Where both parents keep working, as we did, an important decision has to be made. Will they both be gone at the same time or will they fly opposite schedules?

Both of these options have their advantages and disadvantages. We tried both and then settled on flying opposite schedules. We figure that after almost 30 years of marriage, we probably have maybe 10 years of time actually spent together. (We may have accidentally stumbled on another secret of a long and happy marriage!)

As far as the couples who choose to be away at the same time, both parents being away simultaneously can be made much easier with the help of a grandparent or other adult family member willing to help out. Many couples make these sorts of arrangements.

Who's This Person with Our Children?

For others who wish to fly the same schedule, but without the benefit nearby family, hiring a nanny is required. This is how we started. We found a lovely older woman through an agency and made arrangements for her to live in while we were both away. When Barb, our nanny, started, we had two children aged 7 and 22 months.

We quickly found out that we were profoundly uncomfortable with the arrangement. Barb was loving and warm, but we simply realized that we just didn't know her that well. I think we both came to this conclusion one night when talking on the phone while we were both on a trip. Sandy was in Medford, Oregon and I was in perhaps St Louis. We never had any reason to believe that Barb wouldn't take good care of our children, but we still wondered whether she would get up in the night to comfort a crying baby. And that was that.

We learned that we were expecting again soon afterwards. Two babies later and after Sandy returned to work, we started flying opposite schedules and haven't looked back. It's not quite as harsh as it sounds though. We'd typically fly perhaps three trips passing in the night and then enjoy a week off together. Airline schedules can be flexible and we had the ability to occasionally give away trips for some time off.

 Effectively Single Parent

So we ended up raising our kids as serial single parents. I can't be certain, but I think the kids learned some independence from this arrangement. Each of us had our own parenting style to which the kids had to adapt. But unlike real single parents, the parent who happened to be home at the time was, as I mentioned, completely available and involved. In a sense, the kids were the only full time residents in our house with Mom and Dad coming and going.

As the kids got older, they had to by necessity take more responsibility for their own activities. Telling Dad for instance that a form was due with a check for some activity did little good if when by the night before it was due, Dad was away and Mom was the parent on duty. I have little doubt as well that the kids used our part time status against us in ways we can only imagine.

As technology bridged the physical communications gap, keeping the travelling parent in touch with family life became much easier. In the days before cell phones we paid for our own personal "800" number which would ring at the house. Later on we used cell phones to call home, but now we mostly use video links such as Facetime or Skype. We would occasionally sit in on family meals and homework time as a disembodied head on the iPad, even from overseas.

We even took a stab at homeschooling for a few years after becoming disenchanted with our local schools. I could write pages on that experience alone, but I'll just say it was hectic, tiring and totally worth the effort. We eventually moved and put the kids back in public school.

High Expectations and Priorities

One thing we never lost sight of in the chaos of a dual airline career was the importance of family priorities. We always had sit down dinners at a set time and tightly controlled TV time. I think that children need guardrails and routines. Even though my wife and I would run the house somewhat differently, the kids knew that our priorities were the same.

Being kids of airline employees, our children have become adept at navigating air travel and have travelled extensively by themselves, even to overseas destinations. When it came time to look for colleges, we told our kids that we were in for half the cost and that we'd buy a car for whoever got a free ride through scholarships. I may end up buying three cars.

So that's it. When we started this journey, we had no contact with other parents who had done this and we more or less made it up as we went along. It worked out but I think our key to success was to keep focused on the important things.


Thursday, September 01, 2016

So How Do Jet Engines Work and Why Would One Blow Up?

Southwest Airlines engine failure

This past week a Southwest Airlines 737 suffered a very dramatic engine failure while on a flight from New Orleans to Orlando. It appeared as if the entire front of the engine came off judging from pictures taken from inside the cabin. The aircraft also suffered a rapid decompression which was most likely due to debris from the engine striking and puncturing a hole in the fuselage. Considering that the time of useful consciousness (TUC) at 31,000 feet is only one to two minutes, the crew did an outstanding job of prioritizing their emergency action responses and safely recovering the aircraft into Pensacola.

On September 8th last year a British Airways 777 aborted its takeoff from Las Vegas after its left engine failed and burst into flames. The entire left side of the aircraft was engulfed in flames by the time emergency responders were able to put the fire out. Again, thankfully, no one was injured. The aircraft was later repaired and returned to service.

So in these two high profile incidents, jet engine failures caused very dramatic and potentially life threatening damage to commercial airline flights. But how do jet engines work in the first place and what would make one blow up? Is there any way to make engines safer or are these types of mechanical failures just something with which we'll have to learn to live?

Suck Squeeze Bang Blow

Modern turbine aircraft engines are simultaneously simple in operation, yet highly complex precision machines. Their operation, which can be simplified into the title of this paragraph, consists of four elements. Air is first drawn into the front of the engine and is next compressed by a series of blades rotating on a center spool. 

This compressed air is then combined with fuel sprayed into the combustion chamber and ignited. The resulting flow of hot expanding gas flows over turbine blades also connected to the center spool and then exits at high speed providing thrust. The turbine blades provide power for the compressor blades and the process repeats.

The earliest jet engines were known as "pure turbine" engines where all the air from the inlet went through the hot section. Since then, large fans have been employed where only some of the air goes into the hot section but most of the thrust is created by the fan and bypassed around the core of the engine. High bypass engines are now the standard on airliners though pure turbines are still used on military aircraft.

And that's it. Conceptually quite simple and very few moving parts. 

What Could Go Wrong?

The truth is that because jet engines have so few moving parts in comparison to other types of engines, there is very little actually to go wrong. The problem is that when things on a jet engine do go south, they can make a big mess as seen in the two above mentioned incidents.

As far as the central operation of the compressor-turbine assembly is concerned, metal fatigue and subsequent failure are the primary culprits. Investigation of the BA 777 incident revealed that the spool in the high pressure section of the compressor had failed and parts of the compressor spool and blades were subsequently thrown through the engine case and cowling.

A similar metal failure was implicated in the crash of United 232 back in 1989 which claimed 111 lives. Thankfully, advanced metallurgy and inspection technologies make these types of problems quite rare.

The speculation of what caused the failure of the Southwest Airlines engine ranges from mechanical failure of the fasteners which keep the structure attached to possible failures of the engine anti-icing system which is located in that area. An NTSB investigation is ongoing,

Simple and Yet Complex

While the operating principles of jet engines are simple, many of the technologies used to make them work are quite complex. The metallurgy used in building the fan and compressor blades is state of the art. These structures are mostly made of titanium which while being extremely strong and flexible is notoriously difficult to cast. Titanium castings are required to be forged in a vacuum as any air can induce impurities resulting in cracks in the metal. Newer technology engines now use composite materials in fan blade construction while retaining titanium for the leading edges of the blades.

The tolerances required inside the fan and compressors of jet engines are extremely fine. Modern jet engines even have what is known as an ablative coating around the primary fan which is designed to wear away as the fan blades expand through heating. This keeps the gap between the fan and its housing as small as possible for efficiency.

As you might imagine, any solid object which is ingested by a jet engine can cause havoc. Any damage to the compressor section of a modern jet engine can cause what is known as a compressor stall which is a major disruption in airflow. When the airflow is disrupted, the fire can go out or be severely restricted. This is how Sully and his passengers ended up in the Hudson river courtesy of a flock of Canadian geese.

I should add a note about all the auxiliary components that, while not central to the operation of a jet engine, are attached to the engine in what is known as an accessory drive unit. It is located either beneath or on the side of the engine yet inside the cowling. Things like hydraulic pumps for the flight controls, generators, and fuel control units are driven through a drive shaft powered by the main turbine. Problems with these components may or may not result in engine failure depending on the affected component and the nature of the failure. 

In Conclusion

Modern turbine engines are models of efficiency and simplicity. They are highly reliable power plants and yet, like any machine, subject to occasional failure. That they fail so infrequently given the extreme conditions in which they operate is a testament to their design and upkeep.

Wednesday, May 25, 2016

Does Falling Asleep at the Controls Make You a Bad Pilot?

A Delta 767 gets intercepted by Greek F-16s after comm loss.
Delta 767 and Greek F-16s in formation.

Not necessarily, though it might very well make you a dead pilot if you were in a single pilot aircraft such as an F-16 or Cessna. But as far as airliners go, if the pilots take a snooze at altitude with the autopilot flying, the airplane stays on course and airspeed. Falling asleep is a physiological incident which can be due to many different reasons, but one thing it is not, is a moral failing. Let me explain.

In a recent event over Greek airspace, a Delta Airlines 767 flying a charter for the US military entered Greek airspace and did not check in with air traffic control. The Greeks then launched two F-16s which intercepted the airliner about 40 minutes after it entered into Greek airspace. Shortly after the intercept, the aircraft reestablished communications with air traffic control and proceded onto its destination of Kuwait.

There have been some unsubstantiated reports in Greek media that the fighter pilots saw the airline pilots unresponsive in their seats. The reports also claim that it was calls from the flight attendants who noticed the intercept which alerted the pilots to the situation.

Delta, for its part, reported that the aircraft couldn't make contact with Greek controllers after their handoff from a previous sector. That's plausible, though losing communications in an extremely busy part of the world for 40 minutes does seem unlikely. Maybe 5 or 10, but 40 is more difficult to swallow.

They Want You to Lose Communication

A little known fact is that many jurisdictions around the world actually love it when an airliner from a wealthy nation flies into their airspace without making contact. They then get to launch an intercept or search and rescue (SAR) forces and then send the bill to whoever has the deepest pockets. That would be Delta and the US government in this case.

Notice that it only took 18 minutes from the time the airliner entered Greek airspace to the launch of the fighters. There are rumors around that Greece itself is in some financial straits. They're smelling a payday. Sure there are legitimate reasons to intercept a comm-out airliner in today's crazy terrorist besotted world, but money also makes a good motivator as well. Win-win I suppose.

At any rate, any pilots worth their salt flying in this part of the world must know that going comm-out while crossing a flight identification region (FIR) boundary while bound for the Middle East will not be good.

So what other reason might there be?

They Were Snoozing (Maybe)

The nature of this job is many days and time zones away from home, back side of the clock flying, lousy diet, and hotel beds which only get the straw changed every other year. I jest about the straw beds, but I often feel like I've slept on one as my back will let me know when trying to roll out of bed. 

My point is that getting a reasonable amount of sleep on the road is a serious challenge, and that is if everything goes right. A noisy or inop air conditioner, maids knocking on the door early in the morning after a late night arrival or my personal favorite, hammer drills in a nearby room from construction crews can make a good night of sleep nearly impossible.

Even though most airlines have good fatigue policies which allow pilots to decline a flight with no sanction, there is no guarantee that halfway through a flight which you felt fine to start that you won't simply find it impossible to keep your eyes open. This can be in the middle of the day, perhaps right after lunch while sitting on the sunny side of the jet.

Do you do what you can to prevent this? Sure. Get up and stretch, get a cup of coffee, or take a restroom break. Even after all that you might still be droopy. So it is by far from implausible that this happened to both of the guys or gals up front.

Are They in Trouble?

No, they are not. As I mentioned above, falling asleep is a physiological incident and not a moral failing. There will be no scene from 12 O'clock High with Gregory Peck chewing out a guard who has fallen asleep at his post. What will happen is the crew will fill out various safety and fatigue reports (if that indeed is what happened) and life will go on. And if it was merely a case of lost comm, mostly the same thing will happen.

Their reports will go into a safety database where de-identified safety data will hopefully guide any policy changes which need to be made. Yea, that may be somewhat idealistic, but the point is the crew will live to fly another day.

And as I always brief to my copilots, I never want to wake up and find them sleeping! (Just kidding!)

Sunday, May 22, 2016

Egyptair 804

Egyptair 804 was lost over the Mediterranean Sea
Egyptair A320

Egyptair 804 disappeared over the Mediterranean Sea last week. The aircraft, an Airbus A320, was carrying 56 passengers and 10 crew when it vanished from radar screens at about 2:30 am local time (00:30Z). There were no survivors.

While recovery of the wreckage is underway, the only other notable factor concerning the accident was a flurry of automated maintenance messages received from the aircraft shortly before its disappearance.

The system, known as Aircraft Communications Addressing and Reporting System (ACARS), is used to send data messages about the operational and mechanical status of an airliner to the company for various uses. For instance, when you bring up the arrival status of your flight on your phone, that exact arrival time is derived from data sent over ACARS. The system also sends maintenance status reports to help track the mechanical status of the aircraft and also to alert ground maintenance personnel of impending problems.

This system sent the following messages:

00:29Z 2200 AUTO FLT FCU 2 FAULT
00:29Z 2700 F/CTL SEC 3 FAULT
no further ACARS messages were received.

These messages indicate that smoke was detected by the lavatory and avionics smoke detectors and that the window heat computer detected an overheat condition. The avionics bay is an area below the cockpit where most of the aircraft's computers and radios are located. What these messages mean when taken together is anyone's guess. They could possibly indicate the presence of an onboard fire or might only indicate multiple erroneous inputs from a failure of the reporting system.

At this point no determination can be made about the nature of the malfunctions or their origins. This will no doubt have to wait until the data and voice recorders are recovered. This recovery effort is underway.

Saturday, May 14, 2016

How to Dodge a Thunderstorm and Not Spill Your Coffee

Very few aircraft will survive an encounter with one of these big guys
They have big teeth too!

Well it's spring. It is a time when, according to Tennyson, a young man's fancy lightly turns to thoughts of love. Being an old grizzled coot firmly in the grip of matrimony for more than a score of years now, my fancy begrudgingly turns instead to the spring return of every pilot's nemesis, the thunderstorm.

I fondly recall a time years ago while sitting in Air Force ground school in Lubbock, Texas. The instructor drew a shape on the board and asked us students to identify the shape. It looked like the state of Texas which some brave soul ventured to point out. The instructor corrected him with a shouted "NO". "That," he exclaimed, "is an airborne emergency!"

His meaning was that flying in the state of Texas in the spring meant doing battle with, or rather attempting to avoid doing battle with the towering giants which would daily sweep across the panhandle. Because even today, with all of our technology and shiny fast moving flying machines, there is still virtually no airplane that can survive a thunderstorm penetration. And I'm including everything from fighters to helicopters to especially airliners in this category.

But wait, you cry! How about those hurricane hunter planes? Aren't hurricanes worse than thunderstorms? Actually no, they're not. At least not in an airplane. A hurricane can certainly muss your hair while airborne, but they are mostly lower altitude phenomena and have limited vertical development. There may be thunderstorms embedded in a hurricane which the hunter aircraft are careful to avoid, but overall, nothing on earth can match the fury of a well developed hammer-headed storm reaching to over 50,000 ft.

Ok, but can't we just fly over them? No, again. Most airliners can only climb up to the low 40s whereas I mentioned above, a large storm can easily reach to 50k. Even should the storm be a "smaller" one and top out in the 30s, the area above the storm can be quite turbulent as the storm grows and should hail get ejected out of the top of one of these babies, that's exactly where you'll find it. So no, going over a developing cumulonimbus is never a good idea. It is always best to avoid a storm laterally.

Wandering into one of these bad boys will easily make the top of your list of worst things to happen in an airplane. The gusts from violent up and down drafts will produce severe turbulence and the volume of rain your engines will swallow can easily put the fire out. An encounter with hail will scratch your shiny paint job just microseconds before it permanently bashes your radome and the leading edges of your wings into a very non aerodynamic shape. And that is if your windshield doesn't shatter.

Thunderstorms are to be avoided at all cost.

Houston to Chicago

Our trip had us returning from an international destination to be followed by the last leg to Chicago. Then we were done. My F/O lived in base so he was just going home while due to the late arrival time, I was going to the crash pad to be followed by an early morning flight home. We parked the jet at the international terminal, cleared customs and went to look for some dinner before meeting another jet in the domestic terminal. My F/O was diverted away from the automated kiosk into the longer line to an agent for some reason so I'd catch up with him later.

My big decision now became where to eat. The oriental place is good but expensive, while the Mexican place had a long line. I opted for Subway. Nothing like living on airport food. The other option is to carry a food bag, which many crew members do, but an international flight means no fresh food can pass. Little wonder that so many airline pilots are fat. (That's my story, and I'm sticking to it!)

I made a quick trip by the pilot lounge and then went to the gate to meet the incoming aircraft. We were supposed to push at 8:00 pm but the board said the flight was expected out at 8:25. It pulled into the gate dutifully at 7:50 meaning that this was planned for a 35 minute turn. We used to do these in as little as 15 or 20 minutes, but the planes are bigger and people are slower and carry more stuff to stow, hence the 35 minute turn.

Weather Reroute

The reason I stopped by the pilot lounge was to get a wifi signal to update the weather app on my iPad. The company spent a ton of money to give us all iPads with a comprehensive weather app. The only problem is that it's useless without a wifi connection, and we're not allowed to use the onboard wifi. This makes the whole thing quite useless for weather. Rumor has it that this will change soon but I'm not holding my breath.

What I did see during my brief lounge visit was that a large system of thunderstorms was camped out just east of the Mississippi river valley, stretching from perhaps eastern Arkansas up to southern Michigan. I guessed that this meant that we were not going to be flying the most direct route. It turns out I was correct.

When I got the flight plan, it showed that we were going to take a very circuitous route to Chicago. We were routed north over Oklahoma City and then to Omaha followed by Fort Dodge, IA at which point we'd make a turn to the east. I don't know if our dispatcher came up with this route by himself or whether it was given to him by air traffic control, but it was what we were given.

What we were also given was a ton of fuel. The normal route should take about two hours, but this roundabout route was going to be 2+45. The 737 burns about five thousand pounds an hour, plus we have to have our required reserves of 45 minutes of extra gas. On top of that we had gas for two alternates listed as Detroit and Columbus, and also extra fuel in case we had to hold. All of that fuel added up to about 27 thousand pounds.

Now it has been said that the only time you've got too much fuel on board is if you are on fire. While true, having too much fuel when you're trying to land on a short runway in bad weather can be a problem as well. More gas means a heavier airplane. And the Chicago weather was forecast to be ok for our arrival, but thunderstorms were threatening. Another limitation is our structural landing weight limit. There is an upper weight limit for landing that must be met. Carrying too much fuel might put us above that limit in which case we'd have to burn it off or divert. 737s cannot dump fuel like many other aircraft.

The dispatcher put a note on the release to pump us up to 29 thousand pounds if other limits were met, but come push time, the extra fuel never showed up. I was fine going without it as we were planned to land with 12 thousand pounds, about double what we normally have on landing.

Off We Go!

After a last minute runway change requiring new takeoff data, we blasted off at about 8:45. The sun had set and there was a beautiful blue orange glow to the west. Also visible was a rather large storm several hundred miles distant. It turned out to be over central Texas but we could see it perfectly from Houston. Air traffic control stopped our climb at 37,000 feet, 2000 feet shy of our planned 39,000 ft. I assumed that this was due to other traffic conflicts.

My hat is off to the controllers who must not only keep all the airplanes separate, but who must also thread all their traffic through a constantly shifting map of storms. As an additional challenge, their radar systems do not show weather very well. They rely upon pilots to tell them where they can and cannot go. It's crazy, but I have apps on my phone that have better weather readouts than that.

We watched the lights of the Dallas Metroplex go by followed by Ok City and Kansas City off to our right. Prior to getting to Omaha we were cleared to cut the corner to Fort Dodge. It was at this point that things started getting funky. We were first cleared one arrival over Joliet, and then quickly by another arrival farther to the north. Finally, the controller just gave us a northeasterly heading and a descent.

Storms were approaching Chicago from the west and were closing the normal arrival routes. Controllers have to get very creative when this happens. We were lucky that our arrival was so late as the traffic flows were diminished. Had this happened during peak arrival times, we would likely have held or diverted. The new plan was to take us in north of the city, over the lake and south to Midway. The controller's challenge was to get us across the arrival traffic going into O'Hare. For this he had us expedite our descent to below their arrivals.

I was also thinking about my possible options should Midway get hit by a storm. One of our alternates, Columbus, was already being hit by a storm but Detroit was still good. Since we were only a few miles south of Milwaukee by this point, I checked the weather there. Their visibility was only 1/8th of a mile which made that not a great choice. Behind us, though, was Minnie which had good weather.

Like a quarterback, you're always keeping an eye on your open receivers while you avoid the linebackers.

Smooth as Butter!

We got fussed at several times to expedite our descent below the O'Hare arrival corridor. The problem is that to increase descent, one must increase airspeed by pointing the nose lower. We were also getting the poop knocked out of us by turbulence, and our turbulence airspeed is only 280 kts. So we do the best we can to get down without beating ourselves or our passengers up too much.

Once we were below the bumps and over the lake we broke out of the weather and everything smoothed out. We were given a turn to the south and enjoyed a beautiful view of downtown Chicago from the north which we almost never see. After passing downtown we were given a vector to the downwind to runway 4R at Midway. 

Abeam the airport the controller cut us loose and cleared us for the visual. This rarely happens any more and I used the opportunity to hand fly the approach just like we always did in years gone by. Off went the autopilot and autothrottles. My flying skills may get a little rusty when using all the magic day after day, but the rust knocks right off and I rolled out on glidepath right at a thousand feet fully configured.

The aviation gods smiled upon me because I had one of the best touchdowns at Midway that I've had in a long time. The runways are short, so you normally just try to not land long and accept whatever kind of touchdown you can manage.

Well, we taxied clear, contacted ground and the company to let them know we were there, and of course, as day follows night, after a long day and delays, we have to hold out for our gate. Then we get assigned another gate, then back to yet a third gate, and then we wait for marshallers to guide us in. The important point here to remember is that if you shut down an engine, you will then likely be required to turn into your running engine. Think of trying to turn left on ice when only your left rear tire is turning. It doesn't want to go.

Anyway, we get it shut down, I even get a compliment about the landing, and then it's off to the crash pad for about four hours of shuteye before my flight home. Well as they say, it's hard work, but it still beats working for a living.

Dodging thunderstorms for fun and profit