Go Back  PPRuNe Forums > Flight Deck Forums > Rumours & News
Reload this Page >

Air Asia Indonesia Lost Contact from Surabaya to Singapore

Rumours & News Reporting Points that may affect our jobs or lives as professional pilots. Also, items that may be of interest to professional pilots.

Air Asia Indonesia Lost Contact from Surabaya to Singapore

Old 5th Feb 2015, 15:05
  #3061 (permalink)  
 
Join Date: Oct 2013
Location: Tree
Posts: 222
Thanks for your input. I don't think they did either.
Sop_Monkey is offline  
Old 5th Feb 2015, 15:56
  #3062 (permalink)  
 
Join Date: Jun 2009
Location: Germany
Age: 67
Posts: 782
post 3061 - RetiredF4
Quote:
And if the full forward stick does not lead to the desired reaction, feed in manual trim.

Quote Ventus
What good would that do ? If "the system" wants 1g, if you trim the THS nose down, won't it just keep feeding in up elevator to counter you, until it is finally full up ? By that stage you will have far more THS nose down trim than is healthy. Might you then be in a worse place than from whence you came ?
ventus45 is offline
The system wants, what is demanded by the SS position. Therfore the positioning of the SS to nose down is the first priority. If that works, than fine, but if it does not work fast enough, than the trim most probably is already all the way up.

If we look back to the documented stall accidents we know, that most crews were reluctant to do that in an appropriate way. The ND input was not present at all, was not far enough nose down, not long enough down or accompanied by noseup inputs averaging in an overall nose up input. This inapropriate SS handling may command a loadfactor value greater than the one present while descending in a stalled attitude. The consequence is that the flight computers may drive the elevators and in turn the THS trim to full nose up position.

As long as the elevators are nose up from neutral, the trim will not move afaik despite the SS nose down position. As the certification requirement is -1 and +2.5g, I assume that a full nose down SS input would not deliver more than 0 G (i could not find a reference with the applicable loadfactor demands in relation to the SS position). A controlled manual trim input would assist the SS input and not counter it.

In A320 series the THS trim might have stopped depending on the law reconfiguration, and it might only be available in mechanical mode.

But is there time for error and try?
As I said before, follow the procedure, which says under step 2.b
" Nose down pitch trim .......as needed.
RetiredF4 is offline  
Old 5th Feb 2015, 17:23
  #3063 (permalink)  
 
Join Date: Feb 2015
Location: Alternate places
Age: 72
Posts: 97
RetiredF4;
http://www.pprune.org/rumours-news/5...#post8855181As long as the elevators are nose up from neutral, the trim will not move afaik despite the SS nose down position. As the certification requirement is -1 and +2.5g, I assume that a full nose down SS input would not deliver more than 0 G (i could not find a reference with the applicable loadfactor demands in relation to the SS position). A controlled manual trim input would assist the SS input and not counter it.
I concur. Experiments with the A330 sim, (understand the arguments re sim "duplication of stall" and "no-data", etc.), demonstrated that the THS followed SS position; full-ND SS brought a -13 THS setting (the result of an extended NU SS), to approximately -2, recovering the stall in about 45" with a height loss of about 15,000ft. Manual rotation of the trim wheel forward could only help.

IIRC from the Perpignan accident report, the THS stops trimming with a stall warning. I would have to consult the report again to see if a comment or recommendation regarding the use of manually setting the THS would have provided conditions for recovery - they didn't have much altitude to start with...
FDMII is offline  
Old 5th Feb 2015, 19:25
  #3064 (permalink)  
 
Join Date: Jul 2009
Location: Not far from a big Lake
Age: 77
Posts: 1,458
On the flip side, I 'spect if one rolled in full nose down manual trim for recovery, one would have a tiger-by-the-tail when and if the stall broke at some 30 or so degrees nose low and accelerating with a limiting 2.5 g available.
Yep, I agree. You would ideally like to dial in a 300 knot trim setting, and only if you absolutely needed it to break a stall would you go to a lower trim setting. But them you better have PNF primed to dial it back pronto as soon as the airspeed begins to accelerate past 200 knots.

Probably better to rock the aircraft out of the stall than to dial in those last few nose down units. More than likely, it would be a quicker and more positive recovery.
Machinbird is offline  
Old 6th Feb 2015, 02:15
  #3065 (permalink)  
 
Join Date: Jan 2004
Location: Beach Bum
Posts: 20
Smile 8501

Flaps extension below 20000 or speed brake is the only way to recover
Tested in the sim .. No other inputs will change the turbulent flow .. Perhaps trimming the THS but at 15000 fpm highly unlikely given the severity of emergency and unreliable speed compunded by adr aural warninge and messages . Switching off adr"s and extending the flaps below 20000 and speed brakes , trying to fly pitch n power or BUSS is the only way to recover
Not registered is offline  
Old 6th Feb 2015, 04:40
  #3066 (permalink)  
 
Join Date: Apr 2008
Location: cowtown
Posts: 78
Being in a stalled aircraft in turbulence is no fun ,Being in a stalled iced laden aircraft in turbulence in IMC is time to get the QRH prayer mats out.
If you are brave/dumb enough to go into a 50,000 foot CB you will probably be iced up as well and the aircraft deep stall recovery techniques practiced in the sim may not work .
It may need a combination of tail plane ice stall recovery techniques combined with gentle yaw and roll induced by gentle application of rudder to get the gravity working in the right direction to give you relative airflow without overloading the wing or control surfaces.
Keep in mind that any aircraft when it is iced up can be a wobbly thing to control ,and you may encounter some un-commanded pitch ,roll and yaw changes to the attitude that can be confusing .
fitliker is offline  
Old 6th Feb 2015, 07:53
  #3067 (permalink)  
 
Join Date: Jun 2009
Location: Germany
Age: 67
Posts: 782
Quote:
On the flip side, I 'spect if one rolled in full nose down manual trim for recovery, one would have a tiger-by-the-tail when and if the stall broke at some 30 or so degrees nose low and accelerating with a limiting 2.5 g available.

Quote Machinbird
Yep, I agree. You would ideally like to dial in a 300 knot trim setting, and only if you absolutely needed it to break a stall would you go to a lower trim setting. But them you better have PNF primed to dial it back pronto as soon as the airspeed begins to accelerate past 200 knots.

Probably better to rock the aircraft out of the stall than to dial in those last few nose down units. More than likely, it would be a quicker and more positive recovery.
Rolling the trim to a normal cruise setting or take off setting initially would aid in the recovery and should cause no harm. The change of trim is not instantaneous and the elevators are still controlled by the Flight computers to achieve the loadfactor commanded by the SS. Hence when the AOA comes down to below stall value and the speed builds up, the trim is in the correct range. Imagine what would happen, if the trim would still be in full nose up position at the point of recovery? By increasing speed it gets more effective and kicks the aircraft back into a secondary stall.

MB, i know what you mean by rocking the aircraft out of stall, but i estimate the success rate of a comercial pilot in doing so very low. Same for extending something to change the airflow. Those are last ditch maneuvers with uncertain outcome. Using the rudder without the dampers active or in a degraded mode and no limiter working might brake off the tail.

In AF447 Bonin was occupied by the bank angle, while a healthy bank angle would have helped him to bring the nose down and get the speed back. Anytime the bank angle was greatest, the nose came down, and anytime he managed to level the wings the nose came up again.

The fast jet drivers in an out of control recovery (Spin is different) know not to deal with aileron or rudder inputs until the nose is below the horizon and the speed is building up, only then it is time to correct the attitude by rolling to the nearest horizon. In a comercial aircraft it might be necessary to control the bank angle within a given limit like 45 or 60, but i see no point to level the wings as long as the aircraft is still in high AOA. The High AOA is not a bank angle problem, it is a pitch against flight path problem. That is a point where the new stall recovery procedure is not clear about at least not to my sense of thinking.

If all that normal procedural stuff does not work, then it might be the time to go into test pilots territory and try something outside of the procedure.

Last edited by RetiredF4; 6th Feb 2015 at 09:19.
RetiredF4 is offline  
Old 6th Feb 2015, 11:01
  #3068 (permalink)  
 
Join Date: Mar 2002
Location: Seat 0A
Posts: 7,859
I 'spect if one rolled in full nose down manual trim for recovery, one would have a tiger-by-the-tail when and if the stall broke at some 30 or so degrees nose low and accelerating with a limiting 2.5 g available.
I don't think so. 30 nose down pulling at not even 2g starting at say 150KIAS with no power would probably result in another stall, not a wing-ripping-off mega overspeed... The drag at 200KIAS pulling the equivalent of a 60 bank turn is going to require a fair bit of power. You will obviously have to trim back but it wouldn't be a problem in my view.
Capn Bloggs is online now  
Old 6th Feb 2015, 12:02
  #3069 (permalink)  
 
Join Date: Oct 2013
Location: Tree
Posts: 222
We still have the speed/air brakes on this type of aircraft do we not? Or is it a case the computer inhibits the A/B to reduce speed because it's automatic for landing only??
Sop_Monkey is offline  
Old 6th Feb 2015, 16:42
  #3070 (permalink)  
 
Join Date: Jun 2009
Location: California
Age: 50
Posts: 201
And Mmo testing.
It's not clear to me that anything less than ejector seats would be an reliable means of escape, particularly if the pilots/engineers were experiencing +/- a couple of g.
I have seen 'Bus test pilots claim that the orange suits and parachutes were mostly a box-ticking exercise.
With a hatch forward of the engines there is a risk of the test pilot causing foreign object damage to the engines! Or would you wait for them to spool down
xcitation is offline  
Old 6th Feb 2015, 16:42
  #3071 (permalink)  
 
Join Date: Dec 2014
Location: Schiphol
Posts: 335
One of the pilots had just been recovered

Basarnas has just announced that one of the pilots has been recovered. The pilot was still strapped in his seat. The seat was close to the cockpit. And the cockpit apparently only 20 m (instead of first reported 500 m) from the main fuselage. It is not clear if its the captain or his F/O.

NTSC already reported earlier that the captain was seated on the left and the F/O on the right.

Last edited by A0283; 6th Feb 2015 at 16:56.
A0283 is offline  
Old 6th Feb 2015, 18:02
  #3072 (permalink)  
 
Join Date: Jan 2015
Location: Solar system
Posts: 14
SPD LIMIT

Most probable scenario is :

Captain resetting the FAC's =

Loss of the A/P

Red "SPD LIMIT" appeared on both PFD's speed scale

F/O get confused and tought "SDP LIMIT" is an overspeed warning and thus

pulled up sharply... stalled...
Stabilo31 is offline  
Old 6th Feb 2015, 18:04
  #3073 (permalink)  
 
Join Date: Oct 2013
Location: Tree
Posts: 222
In other words, lack of appropriate training.
Sop_Monkey is offline  
Old 6th Feb 2015, 19:22
  #3074 (permalink)  
 
Join Date: Mar 2014
Location: Clinton WA
Age: 71
Posts: 74
Pushing over

Uncle Fred: Even having been exposed to some of this training in the sim, I did not really take to heart what it would be like to have to push over that much at 350 and how I would have to be fighting what the body would be telling me not to do.

I know that there are a LOT of posts as far (agreement is probably going too far) to the effect that pushing forward, or anything less than 1.00 positive G is uncomfortable, unfamiliar, non-intuitive, and frowned on by management. But it seems pretty clear that poster opinion agrees that there are circumstances when this action is appropriate and even immediately mandatory. I am excluding airframe G limits and myriad possible computer interactions for the moment because they mislead away from the fact that lack of comfort or familiarity is not an excuse for not doing the right thing. If one never ever practices something but thinks that carrying it around in their head as an intellectual trivia bit for use in extreme situations will be sufficient come the need, the success rate is going to be low. And while evident on the FDR might be plain, they why probably will not at all be apparent on the CVR.

I can't help recalling that WWII German pilots got themselves out of a lot of nasty spots by pushing over. Written about later the reason given was always German fuel injection capability over American carburetor incapability. But it wasn't mentioned that pushing also offered the benefit of being counter-intuitive.

I've spent enough time hanging from a seat harness to know that in addition to the brain drain resulting from all the mixed up kinesthetic sensations, control touch inverted or even in positive sub 1 G can be a much different animal depending on one's personal fright curve. And I have to say that the idea that there are a lot of airline pilots out there with no clue whatever about those differences is alarming if not frightening. Granted it may never be needed, but the idea that a pilot would not only be uncomfortable but also would have no interest in pursuing those aspects of flight outside the norm is not preparedness norm I have always expected of pilots who got farther along than I did. Intellectual knowledge does not equal knowledge plus kinesthetic preparedness. What one is not willing to explore out of cautious self preservation will eventually come as a pop quiz in less than propitious circumstances.
Leightman 957 is offline  
Old 6th Feb 2015, 19:46
  #3075 (permalink)  
 
Join Date: Oct 2013
Location: Tree
Posts: 222
On the 320/330 aircraft, are the inboard and outboard spoilers able to be deployed independently?

I ask this as "splitting the spoilers" is an excellent solution to pitch problems on some swept wing aircraft I have operated. For example a jammed stabilizer. To lower the nose, outboard spoilers can be inhibited and the required amount of inboard spoiler can be applied for the required results.

This maybe a possible solution to getting the AoA reduced in a stalled condition if all else fails and as a last resort.
Sop_Monkey is offline  
Old 6th Feb 2015, 21:05
  #3076 (permalink)  
 
Join Date: Aug 2008
Location: Vendee
Posts: 138
Leightman,

Perhaps you might have misunderstood my post or else (probably the case) I did not write clearly enough. I would most definitely push over into negative g territory if needed to recover the aircraft. What I was alluding to is that RetiredF4 brought forth some food for thought in that even if we have done UAS training in the sim, that it is worthwhile to ponder and fix in our mind that what we have to do is something that we might not have done for years.

Many of us on these threads have been lucky enough to have flown aircraft that will gladly enter this territory and therefore are familiar with the sensations. I count myself among those lucky as do you. I will also admit however, that it has been a number of years (decades now?) since I have done so. Should I be faced with the prospect of a UAS at FL350 with rapidly decreasing airspeed I will do what is necessary to try to recover. I just need to remind myself, as did another poster, that doing so at night, at high altitude, in bad weather/IMC, is going to take very deliberate and conscious effort--including actions that might feel to be a bit outside the comfort zone. F4 was talking about pilots in fighter lead in (probably flying BFM) in what I assume to be day VMC. Even then he notes that they were reluctant to push too much. What does that say about the rest of us?

I would hope that none of us would sit there and watch a bad situation deteriorate even further but recent history is proving me wrong on that count. Training is of course the key but what I was drawing from F4's remarks was that even then it is going to be a lot different than it is in the sim.
Uncle Fred is offline  
Old 6th Feb 2015, 21:38
  #3077 (permalink)  
 
Join Date: Mar 2014
Location: Clinton WA
Age: 71
Posts: 74
Clarification

Thanks for the clarification UF, but I think I understood what you meant. It may well have been me who was unclear. I have less concern about older pilots who came up through the ranks flying more kinds of AC than with the descriptions posted elsewhere here about the more recent crop of fast tracked new kids who took a different, more 'streamlined', and much less varied route working from small to heavy aircraft. Pilots I've known flew for fun on their time off, often in rag and stick or a wide range of other contraptions, some of which had almost no knobs. I think their curiosity made them better pilots. In any event I'd rather have one of them up front.

Last edited by Leightman 957; 6th Feb 2015 at 23:17. Reason: Clarified
Leightman 957 is offline  
Old 6th Feb 2015, 22:13
  #3078 (permalink)  
 
Join Date: Oct 2005
Location: Classified
Posts: 315
Originally Posted by xcitation View Post
Why not program in an automated stall recovery
Now this is interesting. The consensus in this thread so far is that pilots have become too dependent on automation.

If pilots have become too dependent on automation, the solution is to add more automation? All that does is exacerbate the problem. It's a vicious circle.
Radix is offline  
Old 6th Feb 2015, 22:31
  #3079 (permalink)  
 
Join Date: Aug 2014
Location: Kemi,Finland
Age: 65
Posts: 68
Radix,not all the pilotage is here. Most would like to keep it as simple as possible,-but sure,have the benefits the automation can bring about. Humanly logical automation might be the words we are after.
Naali is offline  
Old 6th Feb 2015, 22:46
  #3080 (permalink)  
 
Join Date: Dec 2006
Location: Florida and wherever my laptop is
Posts: 1,328
Originally Posted by Radix View Post
Now this is interesting. The consensus in this thread so far is that pilots have become too dependent on automation.

If pilots have become too dependent on automation, the solution is to add more automation? All that does is exacerbate the problem. It's a vicious circle.
Perhaps all that is needed is not so much an automated stall recovery so much as automatics sensing approach to stall and stall not making things worse. For example as the aircraft approaches stall the THS could stop trimming nose up, if the pilot wants more nose up then he can manually dial it in. Perhaps _at_ the stall, and you can get there in Normal law if you zoom climb into it at high cruising levels, the THS could motor to neutral; again the pilot could stop it manually if necessary. Had the THS motored to neutral in the AFR447 case the aircraft would probably have pitched nose down and might have been recovered.
Ian W is offline  

Thread Tools
Search this Thread

Contact Us - Archive - Advertising - Cookie Policy - Privacy Statement - Terms of Service - Do Not Sell My Personal Information

Copyright 2018 MH Sub I, LLC dba Internet Brands. All rights reserved. Use of this site indicates your consent to the Terms of Use.