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  • 33

Pilots Disabled Critical Computers Moments Before AirAsia Crash

Submitted
 
The pilots of AirAsia Bhd. Flight 8501 cut power to a critical computer system that normally prevents planes from going out of control shortly before it plunged into the Java Sea, two people with knowledge of the investigation said. The action appears to have helped trigger the events of Dec. 28, when the Airbus Group NV A320 climbed so abruptly that it lost lift and it began falling with warnings blaring in the cockpit, the people said. All 162 aboard were killed. The pilots had been… (www.bloomberg.com) More...

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preacher1
preacher1 16
They probably had to disable them in order to get their hands on the aircraft and fly it, otherwise they would have had to fight the computer and whatever upset they had. When will Airbus realize that sometimes a pilot has to fly a plane.
spatr
spatr 2
Actually, they probably turned off the FACs because they were getting erroneous readings, or they were trying to eke out a little more climb but the slow speed protections were overriding them (which means the plane was attempting to prevent a stall and the pilots shut the computer down and stalled the plane themselves). When I see that the plane climbed over 5000 feet in under 30 seconds, I'm thinking they were caught in a major updraft. I fly the 320 and I'll say that even the lightest loaded 320 wouldn't do that at FL320. Even disconnecting the AP and pulling full back would only do that for a few seconds before the low speed protection kicked in. If they turned the FACs off there would have been no protection and a stall would have occurred.
preacher1
preacher1 2
I really don't know of anything, commercial wise, that wood. Those are fighter jet numbers.
mht9876
mht9876 2
If the pitot tubes iced over it would cause all kinds of warnings on the flight deck. To me it seems like a repeat of Air France 447. Only this time the crew started messing with FAC's instead of flying the airplane with basic power settings and attitude control.
chalet
chalet 1
If the pitot tubes iced over then the pilots wre not getting any correct readings from the HSI, altimeter, speed, rate of climb (or descend), AOA, etc. and without these they probably stalled and dropped down without knowing what was going on. To me this was an accident similar to AF447





sparkie624
sparkie624 1
Minor correction here.. The AOA was still working so they would have had conflicting information... As far as the HSI indications, that is not a product of Pitot Static... HSI is for Horizontal Situation Indicator that will either come from the Gyros, AHRS Computer, IRS, or INS systems. If the Pitot only was iced and not the static, the Airspeed would have gradually increased with pressure altitude. If it was the other way around and the Static being frozen then the altitude would drop with airspeed, which would continually increase with altitude... If they thought they were going too fast and trying to climb then they would have stalled... If the stall warning was going off at the same time then they were getting conflicting information and would not have known what to do, and since stall had one vote and the other 3 showed going too fast they would have following the voting and said that the stall warning was in failure. I have not seen the FDR data yet, and the CVR Data released is sketchy at best, so until all the data is out it is hard to tell...
chalet
chalet 1
Thanks for the corrections, now prior to the release of the FDR and CVR data what would be your theory about the conflicting information, what cause that awful situation, and secondly what would have been the correct actions to take control of the aircraft and save the lifes of so many souls on board.
sparkie624
sparkie624 1
I am still leaning towards another Air France 447 with the Pitot Icing. That is very probably with the fact that they airspeed was indicating so fast, so they were climbing to slow it down... In the process the only working system (Stall Warning) went off, and crew thought it was a failed system and ignored it. They knew one system had to be failed, and they chose the wrong system. Once climbing and not slowing down, they should have figured out that the Airspeed was incorrect and corrected, but by then it was too late.... This is all in my personal opinion and not based on public facts.
chalet
chalet 1
I am also leaning towards a repeat AF447 which suffered multi false readings due to Pitot tubes freezing, wasn't it.
sparkie624
sparkie624 1
That is the one...
joelwiley
joel wiley 0
I wonder how much of the FDR data will be publicly released.
sparkie624
sparkie624 1
Ugh... Probably not much... They do not want to make the flight crews look too bad...
nasdisco
Chris B 1
I'm with you on the updraft causation since the Climb was first reported. I'm also sure that Airbus has run simulations with that data to evaluate loads. Would expect Boeing to do the same thing.
dtw757
mike SUT 1
I can't see anyone purposely turning off FACs to eke a little more speed out of the aircraft. I wonder if they didn't fly into the core of a CB, exceed the angle of bank limits and go into Direct Law on the aircraft, thereby losing all stall protections and g limit protections. I have a couple of thousand hours in both the A320 and 330, and as you well know, when it is Direct Law, it is squirrely, and easy to overcontrol with that ridiculous little stick. (Back on Boeings now).Add the uncertainty of turbulence and anxiety from that sudden climb....recipe for disaster. It will be interesting to read the CVR report if it is released.
spatr
spatr 1
If the FACs were sensing an overspeed they would command a nose up attitude. The crew could have been trying to eliminate that. However, the checklist solution isn't to shut the FACs off (they are just reacting to the data they recieve) it's to isolate what air data computer (pitot or static source)is malfuncioning. Although, I think something worse was going on here, hence the 5000' climb in under 30 seconds. A malfuntioning FAC/ELAC/SEC or ADC would not give a loaded A320 that kind of performance.
joelwiley
joel wiley 1
as you say, if it is released. Likewise the FDR.
WtfWtf
WtfWtf 1
Can the protection protect against a 6000fpm up or downdraft?
usad
usad 1
Doesn't appear that it did...does it! Hence, they pulled the breakers. 10,000 fpm for 30 seconds will not give you much time to make effective decisions.
WtfWtf
WtfWtf 2
That was mY point.. Spatr made it sound like pulling the breakers caused the stall.. I call BS on that because the plane isn't physically capable of climbing at that rate either way.
WtfWtf
WtfWtf 1
However I should note that I see his point.. If it were in the downdraft then it would keep trying to point the nose down as to prevent a stall..
sparkie624
sparkie624 0
Pulling the CB by itself did not cause the stall, but even so, it is obvious that they were side tracked by another issue and forgot one simple fact..."FLY THE PLANE"... I think that the lack of CRM played a big roll here.
preacher1
preacher1 4
bentwing60
bentwing60 1
No!!!
ColinSeftel
Colin Seftel 2
Here's another news report which mentions that the aircraft had previously experienced problems with its FAC. Also that the Captain was out of his seat just before the crash:
http://www.reuters.com/article/2015/01/31/us-indonesia-airplane-idUSKBN0L404E20150131
sparkie624
sparkie624 1
Good info. thanks for sharing.... Not sure what would be so urgent that they would have to reset a CB, but in my training as a Maintenance Controller, Crews in flight are NEVER to reset a CB unless specifically stated to do so in the FOM, and under NO circumstances would be permitted to pull one in flight... I have been asked via ACARS and BAT Phone for CB resets and I always tell them to call me on the ground... I cannot give that info over the phone... Sometimes depending on the circumstances I will give them a CB to reset and tell them specifically not to reset it until after landing and to give me a call... I am not going to say what many of them do.

[This poster has been suspended.]

sparkie624
sparkie624 2
The one in the Captains imagination list.
abowland
Andy Bowland 1
You can(might) get from Direct law back to Alternate law if you reset the ELAC's. Circuit breaker reset? I don't know, maybe it was a last effort to regain control. My computer reset table allows for ELAC's to be reset inflight, but one at a time and via the pushbutton not a circuit breaker. Also, the reset table allows for other systems to be reset via a circuit breaker during flight or on the ground--fire is not required. I would say most system resets involve pulling a circuit breaker, I'm not clear on your "FIRE" comment. Also AirBus doesn't always necessarily have a checklist to follow if you are trying to get on the ground, once the ECAM actions are done it is not mandatory to use the COM.
7Deuceman
7Deuceman 2
How many thousands of pounds does a fly by wire system save versus the cable and yoke system of yesteryear? What if Boeing goes to an all fly by wire cockpit?

I kinda miss that old reliable 727 right about now.
sparkie624
sparkie624 2
I have to agree with you... The old cables are heavy, and there is probably a substantial weight savings, but I too like the 727 and the old 737's alike... Too me from a maintenance stand point the old technology is more solid... As a maintenance controller, I cannot tell you how many times that I have fixed a plane by just simply turning it off and back on.... I call it the "Microsoft Maneuver"... The ole [CTRL] [ALT] [DELETE] ... Sarcastically speaking, I have more than once blamed Microsoft for writing the Operating system for much of the avionics in the planes today.
preacher1
preacher1 1
787 is FBW as well as part of the 777. The new 777X is supposed to be FBW. It will be interesting to see how it progresses. I am like you, cable and yoke did give you a feel. They say, and I haven't flown them, that Boeing put resistance in there so a pilot wouldn't lose that feel, idk.
dek7nrt
Having flown numerous international flight operations in wide body aircraft, into areas of severe, even extreme tropical weather that had developed after departure, trying to avoid the storm by extending our route to circumnavigate the area was our best and safest option, often times that option was not practicable, leaving the only alternative to try to "top" the storm, and climb to a clear altitude, which statistically, was highly improbable. Some storms had tops near 70,000 feet, 45 to 50,000 feet being average. Attempting this action was fraught with danger. As most experienced pilots are aware, severe thunderstorms have extreme conditions of rapid vertical movement of columns of atmosphere, both ascending and descending at prodigious rates at times exceeding ten thousand feet a minute, and far greater on occasion, Had this crew attempted to out climb the approaching storm, they could have encountered these conditions, especially if they were climbing within the last several thousand feet before climbing clear above and historically much violence and severe conditions could be in the final two to four thousand feet before climbing clear, and still in a very serious situation until well clear of the storm.Some reports indicate the crew had established an extreme rate of climb, far exceeding the capabilities of the aircraft parameters, it would appear the crew entered into an area of this extreme weather that they were unable to cope with and in some last desperate attempt to get to a safe altitude either pushed or were pushed to the limits of operation for the aircraft, far exceeding design limits, both operational and structural causing the aircraft to enter a regime of flight outside the envelope of normal operations and suffered catastrophic lost of control that resulted in a uncontrollable and fatal crash of the aircraft. Intentionally or unintentionally disconnecting vital aircraft control systems, contributed to the disaster, especially if intentional. It would indicate a desperate attempt by the crew to try everything before giving up control. Most crews "fly" the aircraft until structural failure or impact
OnTheHorizon
Tony Smith 2
There needs to be an increased emphasis on the dangers of CB and TS in training. As Honeywell and Rockwell Collins both put in their weather radar manuals, onboard weather radar is to be used for thunderstorm avoidance, NOT penetration. Two years ago a series of pop up TS's swept through STL. Tower on liveatc.net called an MB alert, loss of 30 knots. An American and Southwest both said they'd sit and wait. And 10 minutes later both took off safely in calm winds. More of that attitude would be good either on the ground or at 35000 ft.
abowland
Andy Bowland 2
Airbus has an OEB (Operation Engineering Bulletin) that says turn off 2 of the 3 ADIRS in order to get the plane into Alternate Law. And you do it via the ADIRS to allow the flight computers (FAC, ELAC, SEC) to continue to provide information to each other and to the logic of Alternate Law. Because Alternate Law still provides high and low speed stability, yaw damping and load factor limitations. But when you turn off the computer that is calculating and providing that data you completely lose that information, so it's kind of like a double failure when it only needs to be a single failure.

Disclaimer: I hope based on the information the pilots had they chose the best course of action at that time.

The Airbus ECAM will lead you down the wrong path very quickly, and only if you remember the OEB will it get done.
captoso
WTF happened to Pilots flying airplanes instead of computers.
sparkie624
sparkie624 1
RVSM is the biggest reason... 1000' vertical separation.
joelwiley
joel wiley 1
Automation and fuel efficiency among others
mpmt06
Mark Thomas 1
Terribly unfortunate! Hard to imagine that they couldn't have got the nose down at all to get out of the stall, especially from 37000 feet, that's an awfully long way to fall! Do you think the engines were turning when they hit the water? Obviously I'm not a pilot so forgive my ignorance here but how do those hurricane hunter guys fly their planes through weather and come out the other side? Media seems quick to blame the pilots here, I don't think ANY statement should be made until the report comes out.
preacher1
preacher1 2
HH has full power and knows what is ahead of the and hence prepared. These guys knew wx was ahead but not really how bad. I think updraft got them, taking them up, and causing the stall and then got slam dunked coming down. No way in heck except by divine providence to get out of something like that.
spatr
spatr 1
Amen to that, Preacher. Stall recoveries at altitude are hard enough, let alone stall recoveries in the middle of a cell.
preacher1
preacher1 3
With such unpredictable air, it's like I said, divine providence. My personal rule of thumb was that if I couldn't overtop it by 5 grand, I'd try and go around it. At the time, I think that was rule of thumb that AA used and we tried to stay with them. One thing I always had was good wx.
skittel
skittel 1
Thats my thoughts...once you hit an updraft, the downdraft side of it isnt too much later...and trying to pull out of a 6000fpm downdraft would be impossible or at least cause a stall.. I personally dont like the whole fly by wire..complicated technology (think of the algorithms needed to fly these airbus within a certain envelope) is more susceptible to bugs and failure imho.
bentwing60
bentwing60 1
Too many whistles and bells and when they all go off at once the result is not an asset to the flight crew. The last generation GA jets I fly give occasional extraneous TAWS or TCAS alerts that drive you nuts. Throw in a stall warning or config. horn and see how well you can concentrate on separating the wheat from the chafe. I have flown with a very diverse group of pilots in my GA career and I hate to admit it but more than a couple have displayed a lack of systems knowledge in older airplanes that tells me they would be typeable but clueless in an Airbus. I suspect my experience is not unique. I am not commenting on this crew, I wasn't there, but if you are going to build airplanes designed by Rhodes scholars, maybe its time to get Rhodes scholars to fly em. If you could afford them!
preacher1
preacher1 4
Bells and whistles have long been associated as being problems of Airbus and they can be overwhelming. They are now prevalent on a lot of equipment but moreso on the Bus. I like your Rhodes Scholars comment up here. There are guys out there that swear by the bus and some swear at it. All the flap has sort of died down over the last year or so but it was a standing joke for awhile that the Airbus was designed by programmers and good ideas that had no application in the real world.
bentwing60
bentwing60 2
I like that last line. Airbus seems as hellbent on getting rid of pilots as Obama is on getting rid of taxpayers. One day they will look up and say "Where did everybody go"!
sparkie624
sparkie624 1
Ditto... Well said
preacher1
preacher1 1
LOL, and agreed
WtfWtf
WtfWtf 1
If something was severely messed up with the computers and or FBW (lightning strike maybe?) combined with storm drafts, then how do you know if they even had any elevator control in the first place? We'll have to wait and see.
patpylot
patrick baker 1
this is deceptive writing, done by someone with zero instrument stick time, wrongly suggesting that pilots need autopilots in operation to be able to control flight. I have disengaged autopilot on occasion when weather conditions were severe, and that is what happened here. I have flown light aircraft without autopilot where I had to use continuous inputs to keep the gages in good behavior. Big aircraft can also be flown this way from time to time. I disengage when the weather gets crappy and look for a way out of the situation, if one presents itself. Otherwise, buckle down and ride. Needle/ball is the way to fly .
777300ERJapan
Jim Quinn 1
10000 Ft/min of course it stalls
virtualcboy
Rob Miller 1
Another loss of an Airbus due to pilot-induced, high altitude stall, in heavy thunderstorms? Can anyone say Air France 447? When will Airbus finally realize the benefits of a shaker stick, and move away from Alternate Law and allowing competing inputs from pilots???
sparkie624
sparkie624 0
To pull power to a system like that is not good... There is no reason for crews to be pulling CB's in the air for any reason and on the ground should only be done so under the guidance of Maintenance. Doing this to a Vital Part of the aircraft system is a good way to pay the ultimate cost.
preacher1
preacher1 2
Regardless of what they were doing, this is out of the story and one hellacious understatement"
"You don't pull the circuit breaker unless it was an absolute emergency. I don't know if there was one in this case, but it is very unusual." When you are climbing that fast, you have a problem, regardless of what you call it.
joelwiley
joel wiley 1
That the aircraft went into an unstable condition from which it did not recover is a given. I wonder if the condition was unrecoverable or if there was a solution that the crew failed to find in time. Maybe pulling the CBs was an indication they were to the point of working in plokta mode. Maybe the report will clarify this somewhat.
sparkie624
sparkie624 0
In the FOM there is NO procedure or reason in any kind of emergency for a crew member to pull a CB in flight unless it is particular-ally noted in the FOM... There was nothing there that would have fixed the problem and furthermore with the plane in the air moving the box could have never reset and come back on line properly... The plane needs to be still during that kind of action....

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