Another Fatal Stall From 38,000 Feet

[sardak]

The Indonesian KNKT, their version of the NTSB, released the final report today of Air Asia Flight 8501 that crashed into the Java Sea on December 28, 2014.

The aircraft entered a stall at 38,000 ft and the aircrew was unable to recover. The last data on the flight data recorder showed the plane with an airspeed of 132 kts, pitch 20° up, angle of attack of 50° up, rate of descent of 8,400 ft/min at a radar altitude of 118 feet. At one point the plane was descending at at a rate of 20,000 fpm nose up. The stall horn was sounding during the entire descent.

This is very similar, including the altitude when the plane stalled, to what happened with Air France 447 in 2009.

Related to the recent CAP Talk thread on "Guarding the Controls," the report notes that the FDR shows the captain tried to take control away from the first officer who was flying, but never verbalized his effort. Adding to the confusion was the captain's repeated command to "pull down." The FO's side-stick controller was pulled back (cows get smaller) most, if not all, of the descent.

KNKT report: http://kemhubri.dephub.go.id/knkt/ntsc_home/ntsc.htm

The "Guarding the Controls" thread: http://captalk.net/index.php?topic=20472.0

The last of several threads on AF 447, which discussed CRM: http://captalk.net/index.php?topic=19309.0

Mike

[Live2Learn]

http://www.bbc.com/news/world-asia-34972263  BBC had this to say.  The rudder circuit had 23 identical electrical malfunctions in the previous 12 months, and four on the accident flight.  It's sad, but apparent that neither high quality maintenance nor pilot CRM were part of the corporate culture for that airline.  The Airbus side stick control feel and lack of interconnectedness also contributed to the accident similarly to AF 441. 

Though human pilots are likely to become relicts of a previous age within even our lifetimes - and possibly just a few short years, I hope human factors will continue to build kinesthetic feedback into the [fly by wire/drive by wire/robotic assist] technology as long as humans are in the cockpit.  I've not flown an Airbus, but my airline pilot friends tell me they are a very different machine from Boeing products or any GA aircraft because of the very pervasive automation.  One Airbus pilot friend said he frequently hears his peers say keeping track of automation is the most challenging part of their jobs.

[PHall]

I find it "interesting" that the rudder control fault didn't show up on the Fault Logs of the Flight Control System.
Especially since they had 22 repeats.....
After about repeat 3 or 4 the Military would have grounded this jet until the cause was found and corrected.
Flight Control faults are taken very seriously in Military Aviation.

[scooter]

In jet world there is a this place called the  "coffin corner". That's where the airplane stalls no matter what the indicated air speed. It is not too hard to get there in a jet at high altitude. Pilots are passengers along for the ride if they dont recognized this soon enough. The result can be fatal. Sad story of airmanship if this is the case.

It is even in the Cessna world of performance but you would really need to work at it to get there. It would also be bad airmanship.

[Live2Learn]

It is even in the Cessna world of performance but you would really need to work at it to get there. It would also be bad airmanship.

A stall occurs when the smooth airflow over the airplane's wing is disrupted, and the lift degenerates rapidly. This is caused when the wing exceeds its
critical angle of attack. This can occur at any airspeed, in any attitude, with any power setting.    So sayeth the Airplane Flying Handbook (FAA-H-8083).

[xray328]

I'd love to have this....

Icon A5 - Angle of Attack

https://www.youtube.com/watch?v=2wlvpJLcf-A