[Closed] AirAsia aircraft 'stalled', apparently.

Phil,

As I mentioned above, high altitude stall recovery requires a subtly different technique to low altitude recovery. We're trained in both as are most UK operators, I'm sure.

Jamba,

A high alt stall should be recoverable. Low alt stall will depend on how much altitude you have available, reaction time, weight etc. But in essence, you should be able to recover from them all within reason. The key is to recognise the symptoms of the approaching stall and never get there in the first place. I'm lucky in having stalled aircraft countless times as a student and instructor on basic and high performance types at all sorts of altitudes. Many pilots are given a commercially-driven training package (we all like cheap fares don't we?) and have had limited exposure of the joys of stalling.

A storm cell might (if you've climbed to a level where your margins are reduced-"Coffin Corner") bring on a stall situation very rapidly. That's why, especially given the intensity of the storm as featured in the press, [i]climbing[/i] to avoid a storm cell isn't a great idea. Plus some very active storms will exceed the Max Altitude of most aircraft.

Better to give them respectful lateral separation, ideally >20nm.

@mikertroid, how much of a dive would you have to put the plane in at high altitude? Proper nose down, rapid descent, screaming passengers or more gentle?

mikertroid - good to know.

Bob,

At height and if you've got it fully stalled it could be in the region of 40-45° ND (all depends on the conditions of the day etc). You pitch until the symptoms stop so there's no actual number you're aiming for unless you're using AoA gauges.

It's very easy to go back into the stall if you try to regain pitch too soon and if you give it full thrust due to the pitch up effect of under slung engines. You'd get a few screams for sure and you'd lose a few thousand feet. But you wouldn't (unless flying over Everest) hit the deck.

Many pilots are given a commercially-driven training package (we all like cheap fares don't we?) and have had limited exposure of the joys of stalling.

We did loads of stall training in both powered and glider aircraft as cadets and actually stall turns in powered craft are a cool and easy-to-master aerobatic move.

I found flying by instruments more difficult than flying on feel and actually in gliders we were specifically discouraged from using instruments.

One tactic we used to use in powered craft was having two cadets up in the air together and doing a mock dogfight or just a "follow the leader". Once you're concentrating on the other aircraft the control systems come much more easily; you fly by feel and reaction rather than looking at instruments.

Crazy-legs

That's great that you've had that experience. Many Airline Pilots don't.

Stall turn isn't a stall however. It's a misnomer. However you can stall (and spin) off them if you don't get it right!!

I'm still bemused by the general, knee jerk reaction to these events - blaming the pilots.

If the Air France Aurbus did not have faulty pitot heads ( which I believe the manufacturer was fully aware of), then the crew's limitations wouldn't have been so painfully exposed.

So let's take a step back - if those pitot heads didn't ice up, would the aircraft have crashed?

It's so, so easy to pontificate from the safe comfort of a computer keyboard.

Trek

I'm sure they were placed in a grim situation. I don't think anyone in the industry mocks them. However there was nothing wrong with the aircraft that prevented its continued flight.

The pitot heads iced up, then started working again once they had de-iced. Not sure that constitutes faulty.

torsionalake, they gave duff information - how much more faulty do you want?

Mikertroid, I agree there was nothing preventing continued, safe flight, if the crew knew and recognised what was going on.
But they didn't. Again, I'm just emphasising that if the aircraft had worked perfectly that night, the crew wouldn't have been placed in such a situation.

Trek

They had the picture in front of them. Throughout the majority of the event and during the stall the instruments were perfectly fine. Even during the moments when the photos were blocked they didn't act appropriately. Why??

The fact that they chose not to believe them is the baffling aspect.

It's akin to a rally driver applying in turn steering inputs mid-skid.
A very sad event.

Mikertroid, I agree there was nothing preventing continued, safe flight, if the crew knew and recognised what was going on

I know in the Air France Concorde crash BA put all the variables into the simulator including all the things that were wrong before take off and it flew fine as long as you didn't shut down a working engine while on the ground while taking off (something you absolutely do not do). Pretty sure they did the same with 447.

Mikertroid, I consider myself luck to fly a Boeing, so can't pretend to fully understand the mysterious workings of an Airbus.
But I can't accept that the aircraft was fully functional - it wasn't.
I'm as baffled as you to the crews' reaction - but again, if the aircraft was fully functional, that wouldn't have been exposed.

The A320 can be stalled in normal law if sufficiently unsuitable environmental factors can be found. It's incredibly easy to get into a secondary stall during the recovery at high altitude and needs a large and sustained forwards input to recover.

That Air Canada story is good, especially the foot note regarding the techs sent to repair it!

Trek,

I prefer Lockheed but actually recent events have proved how good the Bus is, in terms of Flight Control. Another thing I learnt from a friend who runs an aircraft scrappage company is that the bus wing is the strongest in the industry. We compared a 320 with a 727 and L-1011 (Queen of the skies) and the Bus was seriously beefy in comparison. Something that surprised me. They've scrapped a few 74s too. Quite surprisingly reassuring! German engineering I guess....

I'd be seriously worried if a professional pilot told me he couldn't cope with a blocked pitot tube...

Trek,

I prefer Lockheed but actually recent events have proved how good the Bus is, in terms of Flight Control. Another thing I learnt from a friend who runs an aircraft scrappage company is that the bus wing is the strongest in the industry. We compared a 320 with a 727 and L-1011 (Queen of the skies) and the Bus was seriously beefy in comparison. Something that surprised me. They've scrapped a few 74s too. Quite surprisingly reassuring! German engineering I guess....

I would, however, be seriously worried if a professional pilot told me he couldn't cope with a blocked pitot tube...

Just so I can understand... how many actual real life pilots are contributing to this?

2.5. I double post for max effect.....

2.5. I double post for max effect.....

So you guys all think the ability to average the stick inputs is a good design choice? I'm just curious, I've only flown a glider and two light aircraft (one each, all). And loads of GraphSims F/A-18 Hornet sim.

As an Engineer ................ Locheed were a nightmare !

But a dream to fly.

I think there are pros and cons with the side stick idea. Dual input is a no-no but you have a takeover button that you use instead.

I think the Bus vs Boeing thing comes down to the fact that the Bus designers are all about function, whereas Boeing injects a bit of passion in there too.

The Hudson pilot was an ex fighter pilot and active glider pilot. That helped a lot.

That pilot did a great job, no question - however one big advantage over the Air France situation is that he'd have had external points of reference to confirm what his instruments were telling him. In crashes like the Air France one it seems to often be the case that the instruments are saying one thing but the pilot thinks he's experiencing something different i.e. thinks he'd descending when in reality he's climbing.

Always interesting discussions when these things happen especially in forums not specifically aviation related.

I've been a Engineer working on aircraft for 40 years now..... about 25 years ago we were subjected to a new type of learning of " Human Factors " where it was realised that if the current ( then ) accident rate continued , there would be a hull loss each and every week , based on the huge growth of Civil Air Transport,all this in spite of the advances in technology ...........(the most effective of these has been GPWS , which dramatically reduced the instances of CFIT Controlled Flight into Terrain ) The alarming statistic was that the Human performance was the biggest factor in accidents and where the biggest reduction had to take place....something that did happen otherwise we would witness many many accidents still.

We all are shocked when a big loss of life accident happens , such as Air Asia , but have to put accidents into context....remember that hundreds of thousands of flights take place every day, all which arrive safely.
Both Boeing and Airbus have good products which safely traverse the skies day in, day out , although they differ in the way they approach certain aspects of Flight control.

Ref the AF447................. that aircraft stalled and failed to recover over something like 3 minutes.... IIRC the co-pilot kept the sidestick nose up despite it not working..... if only they had tried something else and lowered the nose, regained flying speed and started to overcome the problems they were in.