Air France Flight 447 report

[Skwinty]

And yet there are many who tout the Tomahawk as an excellent trainer. Just don't spin them.

Given the right condition any aircraft can crash and burn, Cessnas are no exception.

Wrt to the unreliable 172 fuel gauges. Does this not give the pilot extra motivation to verify the fuel load and configuration before taking off?

Once again, let me re-iterate my position, there are many factors the influence a pilots judgement and pilot error is usually mitigated by many other issues.

Unless of course the crash was intentional. There been a few of those instances.

Sent from the far side

 

[LondonJohn]

Late model Cessna 172's are renowned for having fuel gauge issues. If you hang around amateur pilot forums you'll see lots of discussions about it.


Preflight doesn't include scanning the fuel tanks with your x-ray vision...

Yes, it's only a particular date variant of 172s that have this problem. And it is a massive problem, which Cessna has subsequently addressed. Unfortunately, there are still plenty of aircraft out there with the problem. And I've flown at least two of them.

As you've already pointed out, the issue is that the aircraft has a single fuel gauge, and no facility for gauging the fuel load in each separate wing tank. And if the aircraft is less than half-fuelled, it's virtually impossible to visually inspect the tanks for relative quantities. Therefore, the optimum scenario for a looming problem is if, say, the left wing tank is 2/3 full and the right tank is 1/3 full - with the fuel gauge therefore reading 1/2 full. The aircraft is therefore unbalanced to start with, but not dangerously so. But if one takes of with this fuel load, using the right wing tank to draw fuel, it won't take long to fully drain the right tank, leaving the left tank 2/3 full and the right tank empty. The fuel gauge will read 1/3 full, but the aircraft will now be unbalanced to the point of potential danger.

As I mentioned before, a decent way to alleviate the chance of this happening is to fuel up to at least 3/4 capacity if one is going to make a flight of any significant duration. This minimises the chance of creating a dangerous imbalance, and in addition of course it's good practice to switch fuel tanks every 15 mins or so when in level cruising flight.

 

[Sideroxylon]

You don't like reading for comprehension do you.

It's the training I don't like.



Sent from the far side

I think your highlighted sarcasm was rather clear.

 

[LondonJohn]

But they passed their training. How do you find the person who is going to panic?

The training is supposed to include the elements of scenarios where it's possible to make a reasonable assessment of the propensity to panic. Of course, in training - especially in a simulator - it's almost impossible to inject any real jeopardy into any scenario. But skilled instructors and assessors can spot the warning signs of propensity to panic even in reduced-stress scenarios.

And anyhow, very few pilots who get full certification do manage to get that far with a propensity to panic or get disproportionately stressed in an emergency situation. In the vast majority of cases where pilots (those who survive accidents) subsequently claim not to have heard/seen auditory/visual warnings on the flight deck, they are simply not telling the truth. The truth is that they did hear/see the warnings, but for a variety of reasons - ego being perhaps the biggest one - they chose to ignore or minimise them.

If there's one thing that can be taken away from accidents like AF447, I think it's that still more research is needed into human factors in aircrew. I'd say that commercial pilots have a higher proportionate streak of stubbornness and egotism in them than the public at large, and that in some cases this can translate into real - and fatal - problems in emergency scenarios. I believe that commercial passenger aircraft flight crews should undergo more rigorous psychiatric assessments, and they should be pushed to psychological limits in training to get the best indication to their "grace under pressure".

I'm reminded of the legendary SAS training course techniques, where, in one exercise, they would tie applicants blindfolded to a railway line (under the guise of a "terrorist/hostage" scenario or similar), then have a locomotive come down the line. The instructors would then feign panic at the situation going wrong ("Oh my god! There's a train coming! Untie the guy now! Abort the training exercise!" sort of thing), and they would observe the reactions of the applicant tied to the tracks. What they wanted was for the applicant to take measured, rational steps to free himself from his bindings, and to calmly call for assistance. What they didn't want to see was the applicant screaming in blind panic and pulling uselessly at the bindings. Of course, unbeknown to the applicant, he had been tied to the track just beyond a points junction, and the locomotive would pass onto a parallel track at the last moment. Many an applicant was weeded out through this exercise.....

 

[Skwinty]

Londonjohn, are you stating the certain Cessnas have 2 tanks and no selector - isolation valve.

The sensible choice to make when setting off is to select both tanks for fuel feed to the engine. It is in fact part of the preflight checklist.

Again, what is your source as to the limits of wing tank fuel imbalance being disasterous.

Sent from the far side

 

[LondonJohn]

Londonjohn, are you stating the certain Cessnas have 2 tanks and no selector - isolation valve.

The sensible choice to make when setting off is to select both tanks for fuel feed to the engine. It is in fact part of the preflight checklist.

Again, what is your source as to the limits of wing tank fuel imbalance being disasterous.

Sent from the far side

No, you're misunderstanding. There's a selector valve and switch. There are no individual gauges to indicate the levels in each separate tank.

At cruising altitude, with relatively low demand for fuel, it's improper and illogical to draw fuel from both tanks simultaneously. The recommended procedure at cruising altitude is to switch to single tank feed. You are confusing the issue here: the problems rarely (if ever) occur at take-off or during ascent to cruising altitude. They typically occur after, say, 45 minutes of level cruising.

Of course, if one were to remember to alternate tanks every 5 minutes (say), then the problem could never occur, barring a faulty fuel gauge (although that's a different problem altogether). But pilots often forget to perform this manual function at such relatively frequent intervals - and it's then that problems can occur.

My main point was that if the aircraft has been taxied out with significantly different fuel levels in each tank, it's very hard for the pilot to know this: all (s)he sees is the overall fuel quantity. And if, by chance, the pilot selects the lower-quantity tank when at altitude, then neglects to switch tanks at frequent intervals, then a situation can occur where the aircraft becomes dangerously unbalanced. That's why, in my opinion, it's safer not to take out this variant of aircraft with much less than 3/4 fuel load: if the aircraft is fuelled to at least this level, it's far less likely that any unbalancing problems will occur down the line in cruising flight. And on top of that, of course, it's important to force oneself to remember to alternate tanks regularly.

 

[LondonJohn]

I think your highlighted sarcasm was rather clear.

In some threads, his response would have put him in a lot of trouble

He does seem to have a pretty deep-held antipathy towards Airbus, particularly in regard to its level of flight computerisation. Perhaps he should contact Boeing, who have incorporated much of Airbus's pioneering commercial avionics and computerisation into their new 787 Dreamliner. Indeed, in many respects, the Dreamliner goes much further down the computerisation route than any Airbus: for example, all the flight control surfaces are purely electrically controlled rather than hydraulically, and these electric servos/actuators are all governed by computers.

 

[rwguinn]

The simulator may have covered unreliable airspeed indication but does not simulate recovery from a high altitude stall.The simulator does not have the data for this and no pilot want's to actively gather the data.

You're missing the point--no pilot in the simulator even got TO the high-altitude stall...

 

[Fine]

I've found this thread interesting reading, though I have only a casual familiarity with the incident. So instead of offering my theory on the cause of the crash I want to ask a couple questions.

In reading the transcript of the cabin conversations, it's clear the the pilot and copilot became aware of the gravity of the situation. ("We've got no control over this aircraft.") So shouldn't the passengers have been notified of an impending crash? If I were a passenger I wouldn't want the crash to come as a surprise. Is failure to notify the passengers of the emergency another pilot error?

And was the crash survivable? We always read that there were no survivors. Or were there? Wikipedia ---as I recall---has a diagram of the recovered plane, illustrating which seats were found with the passengers in place, and which seats were found vacant. Does anyone know the status of the seatbelts on those vacant seats........were some of those seatbelts found open?

///

 

[a_unique_person]

No one could have survived.
I think the pilots had their hands full with other things.

 

[Justinian2]

Yup - it's a well-documented phenomenon. But as I pointed out in my reply to the same post, if the pilot(s) is/are so panicked that this phenomenon is a genuine factor, then this in itself indicates that they do not have the requisite psychological qualities to be flying commercial aircraft carrying freight or human cargo.

When my car goes into a slide on glare ice during the winter, I just automatically turn the wheel into the slide and mentally look for an escape route - like a snow bank. I don't have time to get nervous and never do.

However, on a free fall that lasts five minutes on a plane being bounced around by a violent storm with alarms going all around and people talking, I would probably be exhausted by the time of impact.

Perhaps the flight simulator should have flunked the copilot for pulling up on the air stick under all conditions. I'll bet he pulled up on the side stick during the simulations too. Just as I turned into the slide naturally and without thinking, the copilot probably did the same thing with his side stick. Either that, or he was trying to crash the plane for insurance reasons.

 

[richardm]

which seats were found with the passengers in place, and which seats were found vacant. Does anyone know the status of the seatbelts on those vacant seats........were some of those seatbelts found open?

It wouldn't indicate any survivors anyway - most passengers don't keep their seatbelts fastened during a long flight. Although having said that, with the amount of bouncing around the aircraft would have been doing, perhaps they would have done.

 

[Justinian2]

I've found this thread interesting reading, though I have only a casual familiarity with the incident. So instead of offering my theory on the cause of the crash I want to ask a couple questions.

In reading the transcript of the cabin conversations, it's clear the the pilot and copilot became aware of the gravity of the situation. ("We've got no control over this aircraft.") So shouldn't the passengers have been notified of an impending crash? If I were a passenger I wouldn't want the crash to come as a surprise. Is failure to notify the passengers of the emergency another pilot error?

And was the crash survivable? We always read that there were no survivors. Or were there? Wikipedia ---as I recall---has a diagram of the recovered plane, illustrating which seats were found with the passengers in place, and which seats were found vacant. Does anyone know the status of the seatbelts on those vacant seats........were some of those seatbelts found open?

///

Good point. The speed of impact was 75 knots. The landing was tail first. Planes have landed on water under similar situations. Perhaps if the surface wasn't rough they could have made a water landing and stayed floating for awhile.

If they were still in thier seats, it seems like they might have been alive at impact only to be drowned by inrushing water.

 

[rwguinn]

Good point. The speed of impact was 75 knots. The landing was tail first. Planes have landed on water under similar situations. Perhaps if the surface wasn't rough they could have made a water landing and stayed floating for awhile.

If they were still in thier seats, it seems like they might have been alive at impact only to be drowned by inrushing water.

That was the forward speed. Vertical was in the realm of 100-120 mph...

 

[I Ratant]

The simulator may have covered unreliable airspeed indication but does not simulate recovery from a high altitude stall.The simulator does not have the data for this and no pilot want's to actively gather the data.

.
When we were doing the P3 Operational Flight Trainer for the USN way back when at Link, we got all the data Lockheed had... one flight report by the pilot John Christiansen said..."Full power stalls... no sane person would try this."
Some things are really outside the box of normal flight.
Many years later John let me fly the P3C prototype for awhile to get a feel for the flight control system, which as we simulated it was unacceptable to him, although it met all the system's engineering requirements.
Many simulator engineer disparage pilot's response to simulators, BTW.
John was right!
That enormous plane was a delight to fly! I was even able to detect the autopilot's inputs.. which I had him turn off.
Loved that airplane!

 

[I Ratant]

...he had been tied to the track just beyond a points junction, and the locomotive would pass onto a parallel track at the last moment. Many an applicant was weeded out through this exercise.....

.
Or sliced and diced, if the train didn't get switched...

 

[Justinian2]

That was the forward speed. Vertical was in the realm of 100-120 mph...

They were at 10,000 feet at 2:13:32 and at 0 feet at 2:14:28. They descended 2 miles in one minute. Roger your vertical speed calculation! I'm surprised any of the fuselage survived that impact - except the fuselage over the wings.

Ten thousand feet in 56 seconds corresponds to a verticle descent rate of 126 mph. Vectorially adding the forward velocity to that produces an even higher velocity. Interestingly enough, that calculation produces a net velocity of 147 mph - landing speed.

 

[LondonJohn]

.
Or sliced and diced, if the train didn't get switched...

If I recall correctly, the points had been welded so that they could guarantee the loco would divert onto the other track.

It's very important to elite combat units to try to ascertain how their soldiers will behave/act in situations of extremely high stress or personal jeopardy/danger. I think that - albeit to a lesser extent - airlines and air industry regulators should make similar efforts to ascertain how flight crews - who potentially hold the lives of hundreds of people in their hands - react in similar situations. Don't get me wrong - I'm not suggesting that they start tying blindfolded pilots to railway lines! But I do think that they should examine ways of introducing some higher element of stress and jeopardy into the training and certification processes of commercial airline pilots. In addition to weeding out applicants who panic or go to pieces in such a situation, it's also a useful way of training even those who pass such a test. It's possible to have fruitful post-test discussions about what happened, how the applicant responded, and what the applicant could learn for the future if (s)he is placed in a real-world extreme situation.

 

[rwguinn]

If I recall correctly, the points had been welded so that they could guarantee the loco would divert onto the other track.

It's very important to elite combat units to try to ascertain how their soldiers will behave/act in situations of extremely high stress or personal jeopardy/danger. I think that - albeit to a lesser extent - airlines and air industry regulators should make similar efforts to ascertain how flight crews - who potentially hold the lives of hundreds of people in their hands - react in similar situations. Don't get me wrong - I'm not suggesting that they start tying blindfolded pilots to railway lines! But I do think that they should examine ways of introducing some higher element of stress and jeopardy into the training and certification processes of commercial airline pilots. In addition to weeding out applicants who panic or go to pieces in such a situation, it's also a useful way of training even those who pass such a test. It's possible to have fruitful post-test discussions about what happened, how the applicant responded, and what the applicant could learn for the future if (s)he is placed in a real-world extreme situation.

All training is not on the simulator.
I take it you have never sat with a n examination/check pilot who is going to up-or-down-check your every move, utterance, and perspiration bead? I am told it is about as stressful as anything that can occur in reality (I've never gotten quite that far--always out of money before I licensed.)

 

[LondonJohn]

They were at 10,000 feet at 2:13:32 and at 0 feet at 2:14:28. They descended 2 miles in one minute. Roger your vertical speed calculation! I'm surprised any of the fuselage survived that impact - except the fuselage over the wings.

Ten thousand feet in 56 seconds corresponds to a verticle descent rate of 126 mph. Vectorially adding the forward velocity to that produces an even higher velocity. Interestingly enough, that calculation produces a net velocity of 147 mph - landing speed.

The extreme deceleration forces acting on the aircraft as it hit the water would have instantly killed everyone on board. But, mercifully, it's very unlikely that any of the passengers had any indication of their impending doom. The aircraft had remained in a nose-up attitude, and the vertical acceleration was almost certainly very slight (and would have been close to zero in the minute before the impact). If one is descending at a constant velocity, one has no forces acting on the body, and the descent is not noticeable without reference to external fixed points or instrumentation of some sort. It's exactly the same principle as descending (or ascending) in a fast elevator. You feel forces on the body at the beginning of the descent (or ascent) as the elevator is accelerating downwards (or upwards). But as soon as the elevator reaches its operating velocity, to the occupants inside it feels the same as if the elevator were completely static.

So, given the weather, the nighttime, the constant downward vertical speed in the lead-up to the impact, and the nose-up attitude of the aircraft, it's highly likely that none of the passengers had any idea that the aircraft was falling out of the sky and heading rapidly towards the ocean below. If there's any crumb of consolation from this tragic incident, it's this (coupled with the fact that death would have been instantaneous and painless - the deceleration forces would have caused immediate and instantly fatal internal trauma, even if the passenger was belted tightly into the seat.)