Machinbird

Actually not. Agreed that if you are flying, it is your problem to solve right now. Later, if you are still among the living, it becomes someone else's problem.

But the causative factor is really a problem in control design that can be overcome by the control design engineers.

If you blame yourself for the problem (when you find it) and don't write it up, it won't get fixed. As long as the maintenance folks have not changed the way the aircraft flies by ill-advised maintenance, the problem belongs with the certifying authority and the guys and girls with slide rules.

BOAC

Actually a 'PIO' has little to do with the aircraft and a lot more to do with the 'P', and hence its name. I don't think 'writing it up' will work!

"I induced a PIO - aircraft u/s"

CONF iture

But the BUSS has not been designed to exit a fully developed stall. BUSS is not the solution either to unreliable speed indication above 25000 feet. Would the AF447 crew have attempted to select all ADRs OFF passing FL250 in order to activate the BUSS ... ? What would have been the BUSS indication ? Is it designed for 45 deg of AoA ?
I have some doubt about the BUSS ... but I have never experienced it in the simulator.
A more simple AoA indicator could be a better option maybe ...

ChrisJ800

Glider PIO's can be due to CG out of range, eg someone accidentally leaving a ballast weight in or in my case on one flight, a loose trim tab that moved every time I moved the elevator. Too fwd a CG can lead to you running out of elevator authority and too rear can lead to too twitchy elevator!

infrequentflyer789

A simple AoA indicator already is an option, I believe. Just not one that many airlines seem to specify.

And if the final report recommends AoA inidcator be mandatory, it won't be the first to do so. Maybe one day the regulators will act on it.

Organfreak

@stepwilk
I have, I did. All of them. Thoroughly.

A33Zab

As you said the BUSS is activated by switching off all 3 AirData sources, this action will also force the flight control Alternate Law.
Its advised to not use it above FL250 because theres the assumption there is sufficient altitude to recover an UAS.

From the FCTM:
‐ At high altitude, typically above FL 250, the cases of unreliable speed situation are mostly a
temporary phenomenon: They are usually due to contamination of the pitots, by water or ice,
in particular meteorological conditions. In-service experience shows that such a contamination

typically disappears after few minutes, allowing to recover normal speed indications.

It comes with an ECAM drill...then the question is:
Would the AF447 crew had followed the drill passing FL250?

The yellow AOA indicator line [Current AOA] would have been at the bottom of the SLOW side of the scale.



It is based on Inertial data instead of AirData and always available as long IRs not failed, since the AOA is now also available when AirData is not (e.g. CAS <60Kts) the stall warning would not have silenced.

Maybe, but the AOA limit (in Alternate and Direct Law) is a function of MACH, Speedbrake and Flap/Slat settings.
Then a crew needs to know its limits for MACH/CONFIG or the bug needs to be automated and that will make it more than just a simple indicator.

BTW The BUSS is not adopted for use of Speedbrake

mono

Far simpler is a table in the QRH to cross refer to and select AOA in the AIDS ALPHA parameter call up menu.

Birdstrike737

RE:

a. the stall warning trigger threshold "cooks off" at a LOWER AoA and remains silent at deep-stall AoA's (i.e. any attempt to stick fwd [and thus lower the nose] triggers a quite deterrent aural stall warning – so any prudent pilot unstalling actions are thwarted).

>>Bonin: 'But I have been pulling back on the stick all the way for a while.'
>>Dubois: 'No, no, no, don't climb.'
>>Robert: 'Ok give me control, give me control.'
>>Dubois: 'Watch out you are pulling up.'
>>Robert: 'Am I?'

Perhaps "prudent pilot unstalling actions" are thwarted by the automation, but I don't see any prudent pilot unstalling actions here TO THWART!

Also, although I fly Boeing and am thus not familiar with the Windows Vista flight control system of more "advanced" aircraft, I wonder: did the pilot have authority over pitch trim, or was that removed from his crib like a dangerous toy also?

cats_five

The usual cause of PIO landing a glider is insufficient airbrake.

HazelNuts39

Is that inertial data + raw AoA, or does the BUSS not use AoA vane angle at all?

CONF iture

A33Zab,

First, thanks for the documentation as the information on the BUSS is IMO seriously insufficient. A video animation for anyone who operates such equipment should be readily available ...

If I get you right, the green - red scale is fixed on the PFD, green always in the middle. Only the Current AoA line is moving.
Now, is it possible for the AF447 scenario, that the Current AoA line would not have been visible at the bottom of the SLOW side of the scale as the CAS was already well below VLS, and the red lower area is for a CAS above VLS ?

The QRH leaves no latitude at all - It is a 2 cases scenario - Either you're above FL250, either you're below.
If above, you're good for a 4 pages QRH procedure ...

A33Zab

For the BUSS it is Inertial Data + the AOAi (Indicated AOA) which IMO is identical as what you call the 'Raw AOA'.

VGCM66

All three were clueless. Bonin flew that plane into a stall condition, not on purpose but it doesn't matter really except that he did. Robert became more preoccupied/obsessed on giving the controls back to the captain instead of taking charge of the airplane and the situation. The captain arrived too late and the plane had already stalled and time-left was fast becoming shorter.

I can accept that only the captain had received the training to escape stall conditions but that doesn't mean the other two didn't know/hear/read/test about them. How can you get an air pilot license without completely know about airplane stalls? How could they possibly ignore the First time "Stall + Calvary" warning? Not the second or third one or even less the 70+ time. How one pilot, after hearing the warning for the first time asked: What is that? and the other one didn't reply?

How do three professional pilot lose sight of altitude until 28,000ft were gone-by? Then another 6,000ft? Then, at less than 4000ft, one of them realized the possibility of death.

BOAC

- I sincerely hope you are wrong!

bubbers44

Every airline I flew with all pilots knew how to fly as well as the captain. I know things have gone downhill but hope not too far..

bubbers44

Not being able to tell your crew to push the SS down because you are stalled is an obvious fix but they probably wouldn't have known how to do it. They seemed to not understand the fundamentals of stall recovery. Push down. Works every time. At least for me.

CONF iture

I was looking at the FCOM and things are described a bit differently :

So that yellow line stays in the middle and probably and hopefully the GREEN area with the target speed (GREEN triangle) remains visible at the top of the scale whatever the current stall speed/AoA is.

For the Red SLOW area :
Those checked on the 380 probably know more as the BUSS seems to be standard equipment.

DC-ATE

Hey, bubbers44.....maybe they were from the "school" where they were taught that if you pull back, you go up, and if you pull further back, you go down !!!

before landing check list

No, obviously they were NOT from that school. But they should have been.