Pitch controls airspeed?

[Gabriel]

So they are sitting there, at a great stall attitude, and watching their airspeed decay AND ARE OBVIOUSLY AWARE OF IT.

Then the stick shaker goes off.

Then the stick pusher goes off.

Then they override it by over-pulling-up the stick pusher.

Then the stick pusher goes off a second time.

Then they override it by over-pulling-up the stick pusher again.

Then the stick pusher goes off a third time.

Then they override it by over-pulling-up the stick pusher again.

Then the stick pusher goes off a 4th time.

Then they override it by over-pulling-up the stick pusher again.

But they let the aircraft stall.

Fixed.

[Gabriel]

MCM,

First, I don't disagree with you saying that, from a practical POV, in the final approach you use thrust for speed and pitch for altitude.

I've said it from post 1. I agree 100% with you that your explanation is correct. What I've said is the "thrust controls altitude and pitch elevator controls airspeed" is just another way of explaining the same thing.

No matter what explanation you use, and no matter if it's in a 747 or a C-152, in each case there is only ONE combination of elevator and throttle input that will take you from speed A to speed B while keeping the same descent slope, and only ONE combination that will take you from descent slope A to descent slope B while keeping the same speed.

None of "elevator = speed, throttle = altitude" and "elevator = altitude, throttle = speed" is an absolute truth, but rather "tools" to help explain some things in different ways.

The closest to the reality (but not exactly THE reality) is that elevator controls AoA and throttles control power/thrust.

In any case, a change in only speed, only vertical speed, or both, all require a coordinated use of elevator and thrust. And IMNSHO the pilots, at any level, should understand not only what combination works in each case but how and why. And I'm sorry but, while I'm sure you and most do, I have the strong feeling that more than I wanted to don't. These are quotes from instructors or very experienced pilots, said to me (and 3we knows about one of these):

"The Tomahawk doesn't have so nice handling characteristics to fly with a tailwind because of it's T tail"

"The Cessnas are more stable than the Pipers because of the high wing, where the weight hangs from the lift"

"You must be careful when turning to downwind because the airspeed will go down as the plane catches-up the wind"

(With me in the right seat of the Grumman Tiger and, seeing we were way high and fast during final approach with a clean wing, asked if he wanted me to drop some flaps) "No, the flaps on this plane are very effective, they increase the lift a lot, which will make things worse" (He also rejected my suggestion to go-around, we stopped in the stopway of a 3000+ ft runway)

I know there were many more, but these are the ones that come off the head now.

About Austral (not Air Austral), I'm not questioning that it's hard to recognize which instrument is failing, and that then it's not that easy to hold altitude and speed based on pitch and thrust. BUT PLANES STALL AT AN AoA, AND AN AIRPLANE THAT IS FLYING STRIGHT AND LEVEL WITH 2deg ANU IS NOT ANYWHERE REMOTELY CLOSE TO STALL, and yes, I expect a professional crew to notice that before extending the slats at cruise. The CVR showed that they were not trying to determine what instrument was the wrong one, they just said "speed down, increase thrust, still down, ask for lower, they said hold on, no matter, go down anyway, speed still going down, about to stall, pumps and slats, oh shit".

Again, I don't criticize them for not flying thrust and pitch, not even for not being quick enough to recognize the airspeed failure, but for calling a stall when ALL CUES, with the only exception of airspeed, were that the plane was nowhere close to stall (2deg ANU, altitude steady, VS steady, no buffet, no stick shaker, no mushy control forces, the plane flying perfectly normal and behaving perfectly normal and reacting perfectly normal to all the pilot inputs, except IAS)

No, I have not flown in real IMC and have no instrument rating, so I might be forgiven those mistakes, which I doubt I would have made anyway (on the other hand, I would have probably been a victim of spatial disorientation and ended in a graveyard spiral 178 seconds after entering IMC)

[3WE]

Originally Posted by 3WE
So they are sitting there, at a great stall attitude, and watching their airspeed decay AND ARE OBVIOUSLY AWARE OF IT.

Then the stick shaker goes off.

Then the stick pusher goes off.

Then they override it by over-pulling-up the stick pusher.

Then the stick pusher goes off a second time.

Then they override it by over-pulling-up the stick pusher again.

Then the stick pusher goes off a third time.

Then they override it by over-pulling-up the stick pusher again.

Then the stick pusher goes off a 4th time.

Then they override it by over-pulling-up the stick pusher again.

But they let the aircraft stall. [end Gabe's modifications of 3WE's rant]

Fixed

1. All previous 3WE rants X 100,000 Why/How in the hell do you stall a plane when the attitude and airspeed is "screaming" imminent stall and the stall horn and the stick shaker is "screaming imminent" stall and you have 39,000 feet of excess altitude, and you are sitting there talking about your attitude and decaying airspeed, rant rant rant rant rant rant rant. (sorry, but geez!).

2. They didn't know that airplanes with tail-mounted engines tend to flame out when stalled???????

3. They did not have ATC clearance to descend, and if they had descended without clearance, ATC could ask for written explanations, thus calling attention to the fact that they were flying in an unprofessional manner, and then they lose their jobs??????

4. They were they hoping and praying that against all odds, that MAYBE....MAYBE it would hang on and not stall????

5. OR....were they simply idiots.

6. I suppose all of the above or any number of combinations of above are valid reasons too.

Sorry..... MCM if you have any thoughts that Gabe or I missed, I would be interested in hearing them.

[Praehapt Bubtah]

"You must be careful when turning to downwind because the airspeed will go down as the plane catches-up the wind"

Wow, I never thought of this. I read that stalls happen when you fly too slow. And given that you slow down to land, if you turned into a tailwind, I see that you would lose airspeed and might stall. YIKES

[Gabriel]

Wow, I never thought of this. I read that stalls happen when you fly too slow. And given that you slow down to land, if you turned into a tailwind, I see that you would lose airspeed and might stall. YIKES

Exactly what book are you reading to learn to fly?

Anyway, drop it and read this one. It's freely available on-line and by far the best resource I've found so far (and the only one written for pilots that has no important conceptual errors):

See how it flies

That is, if you really want to understand how all this stuff work.

[MCM]

3WE,

I started to write an explaination of some of the issues surrounding these types of crashes... but this is one of those accidents that just leaves you amazed.

I am an avid supporter of pilots not being blamed (for obvious reasons ), with "pilot error" usually being a cop-out to not go into the background in sufficient detail.

On this occasion, however, what can you say.
The contributing factors -

- The culture of the airline was probably one. (I can go into more detail if you need it, but I think you probably understand the concept of the culture making a decision have a certain bias behind it).

- The fact in normal service the crew had quite possibly not operated the aircraft in a performance - limited way, and so were not as familiar as they should have been with the issues surrounding speed and climb to limiting altitudes.

The way they flew the aircraft prior to even climbing to FL410 is "interesting", and shows the state of mind... they had an empty aircraft, and they were going to have fun with it. Quite large RUDDER deflections, high positive (and below 1) g manoeuvres... they were out to have fun. They had a stick shaker activation early in the flight, and it didn't "put the wind up them" sufficiently to stop them doing it again. State of mind.

Why did they stay at FL410 when they realised that they couldn't maintain it? Good question, however based on the other decisions they had made during the flight I can't see why you could expect them to start making the correct decisions then. They "should" have just started a descent, and why they didn't... I can only put down to inadequate training, and the current state of mind.

They continued to make questionable decisions and take poor courses of action right until the crash.

All you can do is investigate why the crew felt that treating the aircraft in that manner was appropriate. My guess is that the "culture" of the airline lead to it.

One saving grace is that I firmly believe that had the flight had passengers on board, it would never have happened, as the crew only took the actions that they did because it was just them.

[Gabriel]

I am an avid supporter of pilots not being blamed (for obvious reasons ), with "pilot error" usually being a cop-out to not go into the background in sufficient detail

I agree. Human error can be a link in the chain of events that lead to an accident, but it can never be a root cause.

A root cause always need a corrective action. What's the corrective action for human error? To tell the human not to err? That wont work. Humans make mistakes period. The only way would be to get rid of the human at once, and that's not possible and will never be (some human will have to design the engineer-less software that will design the pilot-less plane).

The design (of the airplane, of the procedure) should be fairly design proof. It's not? Then it's a design problem, not a pilot error.

The training should be such that pilots will not make so many severe mistakes in a row to overwhelm the mistake-proof design. It is not? Training problem.

The culture should be such that only adherence to the procedures and playing on the safe side is acceptable. It is not? Culture problem.

Pilot selection and continuous evaluation should be such that those that just aren't good or willing enough to deal with the task are kept away from flying. It is not? Recruitment and flight department problem.

You can't blame a bad pilot for being bad.

Now, what about a good pilot that is well trained within a good culture and passes always with A grades, but then just decides to do stupid things that he knows are stupid and officially unacceptable?

That for me is not an "error" or "mistake". It's willful misbehaviour, and many times criminal negligence. You CAN blame a pilot for that.

One saving grace is that I firmly believe that had the flight had passengers on board, it would never have happened, as the crew only took the actions that they did because it was just them.

I agree with that: They would have not pulled high and below Gs during the climb, and they would have not deviated from their filled flight plan to play the 410 club. BUT... what if...

They were once flying at 370 and were asked by ATC to climb to 410?
Or they encountered a widshear that makes the stickshaker go off?
Or had a Colgan-like stickshaker during the approach?
Would they have been up to the stack?
I'm not so confident.

[3WE]

Thanks for your coments MCM.

One other thing I have said about this crash. I really do not blame the pilots for having a little fun.

A "race to FL410" is not all that bad of a "game". The skill to nail a maximum rate of climb airspeed....working with ATC to see how the cards will fall, can you get there faster than anyone else in the company....and getting a plane to 410 where apparently it may not have the power to "get there well" is an interesting challenge.

Amazingly enough, Barry Schiff in an AOPA pilot magaizine once mentioned getting a block altitude in passenger-loaded L-1011, letting the speed build and then achieving a 6000 fpm climb. I have to believe he did this with high levels of gentleness- I am sure it takes VERY little to get a plane load of passengers upset.

So, "having a little fun" with the plane is not a problem. (I'm not so sure that negative G's are ok- that could really mess up a galley! As seen on Airplane, spilling all the coffee is a TOTAL air disaster, and a time to panic!). Don't get me wrong- I know the plane can take negative G's, but it does seem like a magical line you shouldn't delibarately cross when it ain't your airplane! Trying to see how fast you can climb (gently), and some rudder waggle- no foul....

Anyway, I'll TRY to shut up....even though, yes after they lost power, they were most incompetent in restart procedures, and overflew a couple of suitable landing fields (although I don't know that the weather was suitable for a power-off landing in their "defense").

Gabe and I have a little debate going on the flapless DC-9 crashes- In those cases I have a little bit of forgiveness for the pilots pulling up too much. He has somewhat less forgivenes- although we see each others point.

[MCM]

Yeah, having "fun" with an aircraft can be ok, depending on how you do it.

Letting speed build up and then doing 6000fpm is not inappropriate if it is handled correctly, and it can be a perfectly smooth manoeuvre. It is something that is also done for operational reasons... in fact I usually end up doing it every second day of flying due to a particular SID design.

They did not to do that.. they pulled up so hard that they hit, what was it... about 2.8g, and triggered the stall warning. That is irresponsible in an aircraft of that size. So too is stamping on the rudders to "wiggle" the tail. The aircraft is NOT designed for that sort of behaviour. Sure, it is strong enough to resist it (most of the time), but it is not the intent of the aircraft and so you shouldn't be doing it. The deflection they got it up to was really quite high.

So there is "responsible" fun, and irresponsible fun.

[Praehapt Bubtah]

I was reviewing this thread for old times sake and see that MCM never really answered 3WE's comments about the Pinnacle CRJ thread.

[MCM]

What specifically didn't I address?

I thought I had covered it off pretty well.

[AJ]

I was reviewing this thread for old times sake and see that MCM never really answered 3WE's comments about the Pinnacle CRJ thread.

Are you kidding? The responses have been extremely informative!