AirAsia Flight Missing - 155 on board

[Peanut]

Sounds like they found the cockpit voice recorder today, as well.

http://news.yahoo.com/divers-retriev...--finance.html

[gargamel]

I've always noticed that AirAsia is the only airline that I fly that is never delayed. Out of the dozens of flights I've taken with them over then past few years, zero were delayed for any reason. I don't know if that means that they were willing to fly in weather that other airlines were not and/or that they were doing less airplane maintenance or if it was just a coincidence, but I found it interesting that, for the first time ever with them, my flight last week was delayed by about an hour.

[FlamesAddiction]

Originally Posted by gargamel

I've always noticed that AirAsia is the only airline that I fly that is never delayed. Out of the dozens of flights I've taken with them over then past few years, zero were delayed for any reason. I don't know if that means that they were willing to fly in weather that other airlines were not and/or that they were doing less airplane maintenance or if it was just a coincidence, but I found it interesting that, for the first time ever with them, my flight last week was delayed by about an hour.

West Jet is like that to a degree as well. They seem to take off even when Air Canada delays their flights. A couple of years ago when West JEt had that near miss in Kelowna due to weather, Air Canada had already delayed their flights.

[Acey]

Originally Posted by FlamesAddiction

West Jet is like that to a degree as well. They seem to take off even when Air Canada delays their flights. A couple of years ago when West JEt had that near miss in Kelowna due to weather, Air Canada had already delayed their flights.

Specifically in Kelowna - WestJet can land when Air Canada and everybody else can't, because they have better navigation equipment that allows them to operate in lower visibility. Click here for more info on that if you so desire.

Having said that, it goes both ways. I've seen days in Calgary where WestJet just scrubs everything and AC or Jazz will try to fight through it. The idea sometimes is to take a big hit on one day so you're not also completely screwed the next day. For example, say today the weather is great all across the country, but tomorrow there's a huge blizzard forecast in Montreal. Among several others, WestJet will axe your Calgary - Montreal flight today despite the great weather because WestJet is based here in Calgary, and it does them no good to have 7 airplanes stranded in Montreal that can't go anywhere tomorrow morning.

Airline scheduling is far more complicated than most people understand, and it's all about the big picture.

[FlamesAddiction]

The voice recording indicates that there were no signs of terrorism nor signs of a mid-air explosion.

http://www.cbc.ca/news/world/airasia...ding-1.2917456

When asked if there was any evidence from the recording that terrorism was involved, Hananto said: "No. Because if there were terrorism, there would have been a threat of some kind."

"In that critical situation, the recording indicates that the pilot was busy with the handling of the plane."

[Flabbibulin]

Curious to see how similar it ends up being to the Air France Airbus crash.

Question for those that understand these things- If the theory about stalling because they ascended too quickly is true, wouldn't a stall at that altitude give them plenty of time to recover? Possible, like Air France, that they didn't know they were in a stall?

[Ryan Coke]

Yes there is plenty of time to recover from a stall at that altitude. As to the why, if that is indeed what occurred here, then that is really the question.

[FlamesAddiction]

Originally Posted by Ryan Coke

Yes there is plenty of time to recover from a stall at that altitude. As to the why, if that is indeed what occurred here, then that is really the question.

Correct me if I am wrong, but to recover from a stall, you basically need to dive the plane at a pretty steep angle to gain enough speed, then slowly level the plane to regain lift...

That would take a lot of balls.

[Flabbibulin]

Originally Posted by FlamesAddiction

Correct me if I am wrong, but to recover from a stall, you basically need to dive the plane at a pretty steep angle to gain enough speed, then slowly level the plane to regain lift...

That would take a lot of balls.

Have read the transcripts from AF 447 a few times- they basically didn't realize they were in a stall until the last second when there wasn't enough altitude to perform this maneuver.

[Acey]

Originally Posted by Flabbibulin

Have read the transcripts from AF 447 a few times- they basically didn't realize they were in a stall until the last second when there wasn't enough altitude to perform this maneuver.

Yeah and it was pitch black in the middle of the ocean, you have zero visual reference. If you think your instruments are lying to you, or don't know they're lying to you, things can get ugly pretty quickly.

The other thing is, and Ryan Cooke can speak more to this as he is a pilot - recovering from a stall is counter-intuitive at times, similar to the way people over correct when spinning on the highway. You're falling out of the sky so reflexively you pull up, but you need to get more air over the wings by decreasing the angle of attack, accomplished by pushing the column (sidestick, in this Airbus' case) down.

The computers in the Airbus are not supposed to let you enter a stall condition either, technically. So there's a lot more info to come out on this.

[ken0042]

I seem to recall one of the recent crashes was caused by conflicting controls on a fly by wire plane like the Airbus. (Air France possibly.) In that one pilot was pushing down to gain forward speed and lift, and the other was pulling back. The FDR showed the conflicting actions were cancelled out by the computer. Does anybody know if that has been addressed? (Is it even a "mechanical" issue? Is it a training/co-operation issue?)

[Dan02]

Originally Posted by ken0042

I seem to recall one of the recent crashes was caused by conflicting controls on a fly by wire plane like the Airbus. (Air France possibly.) In that one pilot was pushing down to gain forward speed and lift, and the other was pulling back. The FDR showed the conflicting actions were cancelled out by the computer. Does anybody know if that has been addressed? (Is it even a "mechanical" issue? Is it a training/co-operation issue?)

The A320 has a SIDE STICK PRIORITY button over each sidestick that, when pressed and held down, prevents the other sidestick controller's inputs from "counting." If the Captain (or other FO) had pressed this button, the junior FO's inputs would have been ignored.

In addition, according to the FCOM, if the two sidesticks are operated simultaneously, a "DUAL INPUT" audio voice message is sounded every 5 seconds indicating that conflicting inputs are being made. Not sure if this message shows up in the transcript (it's possible that it doesn't sound when in alternate law), but if it did sound, it would have been a clue that the junior FO was fighting the senior FO's inputs.

Source: CCM Airlines A320 FCOM rev. 3, section 1.27.40, page 3.

[Ryan Coke]

As for the recovery from the stall, yes you have to pitch the nose down to regain speed. At lower altitudes when max thrust is applied you have so much engine power you can effectively power out of the stall with very minimal nose down, so minimal loss of altitude.

At altitude (let's say above 30000') you have dramatically less engine thrust available due to the thinner air. So to recover from a deep stall you have to pitch down more and trade altitude for airspeed. So yes it can be more of a challenge, and anything affecting the recognition of the stall will make it harder to properly recover (such as air France).

I have run scenarios in the simulator with a deep stall from 40000' simulating what occurred with the air France A330, getting descent rates of greater than 10000 feet per minute, but it was still recoverable within several thousand feet (can't remember exactly now but certainly less then 5000'). If recovery was initiated at a lower altitude, it would actually take less altitude to complete the recovery to level flight.

I could write a few pages on the nuances of the air France crash and how Airbus automation contributed to it, as well as pilot training and experience, but I'll leave it here for now .

[FlamesAddiction]

Originally Posted by Ryan Coke

As for the recovery from the stall, yes you have to pitch the nose down to regain speed. At lower altitudes when max thrust is applied you have so much engine power you can effectively power out of the stall with very minimal nose down, so minimal loss of altitude.

At altitude (let's say above 30000') you have dramatically less engine thrust available due to the thinner air. So to recover from a deep stall you have to pitch down more and trade altitude for airspeed. So yes it can be more of a challenge, and anything affecting the recognition of the stall will make it harder to properly recover (such as air France).

I have run scenarios in the simulator with a deep stall from 40000' simulating what occurred with the air France A330, getting descent rates of greater than 10000 feet per minute, but it was still recoverable within several thousand feet (can't remember exactly now but certainly less then 5000'). If recovery was initiated at a lower altitude, it would actually take less altitude to complete the recovery to level flight.

I could write a few pages on the nuances of the air France crash and how Airbus automation contributed to it, as well as pilot training and experience, but I'll leave it here for now .

This might be a stupid question, but outside of the simulator, has the stall recovery method been tested a lot in the field by passenger aircraft?

You never really hear about stall situations where disaster was averted. It leads me to believe that stall that are recovered from are either rare or just not considered news worthy.

As someone in the aviation industry, do you ever hear about real life events of high altitude aerodynamic stalls like the ones you described?

[BigNumbers]

They are very, very rare - You don't hear about them as they are pretty much unheard off with modern commercial airliners.... The computers pretty much make them impossible to do (eg: computer stops stall scenarios before they can happen with pitch adjustment, thrust, etc).

The only time it comes up is when the computers (usually the instruments) fail. My rudimentary understanding of the Air France crash was that the instruments iced up, so the pilots didn't know they were in a stall, and nor did the computers (as they rely on the same instruments as the pilots). As it was pitch black over the ocean, the pilots had no visual reference, so.... stall.

A real pilot can of course explain how wrong my layman's understanding is

[stazzy33]

Originally Posted by Ryan Coke

I could write a few pages on the nuances of the air France crash and how Airbus automation contributed to it, as well as pilot training and experience, but I'll leave it here for now .

Would you? I would really enjoy reading that haha.

[Burninator]

Originally Posted by stazzy33

Would you? I would really enjoy reading that haha.

Here is a length Vanity Fair article about it.

http://www.vanityfair.com/business/2...ight-447-crash

[Bigtime]

There is a somewhat "famous" crash in the aviation community about 2 pilots that were ferrying an empty CRJ back to another airport. They decided to take her up above the certified altitude and caused both engines to stall out. They then proceeded to crash it on an interstate if I am remembering correctly.

Here is a link to all the stupid they did:

http://en.m.wikipedia.org/wiki/Pinna...es_Flight_3701

[automaton 3]

Will be interesting to hear the dialogue from the cockpit voice recorder, but some very early indications of a stall:

“The plane, during the last minutes, went up faster than normal speed … after then, it stalled. That is according to the data from the radar,” Jonan said.


A source familiar with the investigation’s initial findings told Reuters last month that radar data appeared to show Flight 8501 made an “unbelievably” steep climb before it crashed, possibly pushing it beyond the Airbus’ limits.


http://www.theglobeandmail.com/news/...ticle22532807/

[burn_this_city]

Sounds like AF447 all over again.