Artistic Licence or ?
 

I am a little confused by Blankbox's post ( the graphic therein). As far as I knew 8501 had requested a weather diversion to port which was initiated some time before experiencing the zoom climb. As far as I knew, the attitude of the A/C was still in left bank ( or some facsimile) until reaching apogee. Am I wrong ? The graphic shows a turn to starboard, before the zoom and that is news to me. Anyone ? .

Global

The Indonesians have a large offshore oil & gas sector that works subsea all the time - they probably know as much about it as anyone else and the kit they've deployed looks better than most countries could come up with

The pictures of the radome show some marks & evidence that lightening strike & radome separation shouldn't be discounted.....if it had indeed been blown off by such a strike it would have had an interesting disruptive affect too on the sensors that measure AOA & pitot static pressures ...

Lightening in this region is some of the strongest I have ever seen.

Here's a video of divers getting right up close to the fuselage. You can get an appreciation of how difficult it is for the recovery team to enter the fuselage and search for bodies given the poor visibility and limited sunlight reaching down to that depth. On top of that, you have a tangled web of wreckage, metal fragments, cables and wires to deal with. The footage also shows what appears to be the top of the left wing (with spoiler still deflected up) where the over wing emergency exits are.

The Radome also has a split at the very front, which could have let air pressure build up inside the dome... just a few psi over pressure could cause it to pop its rivets.

WINGS OFF ??
 

LEIGHTMAN TODAY @ 15:50 SAID " When we think of wings being pulled off by aerodynamic loads, and how relatively easy that is,'

Relatively easy ?? Suggest you review your comment- its not easy with a maintained airplane. As to surviving water impact, the load direction with forward motion is mostly fore to aft- sort of like a water ski. The engines come off probably at the pylons which leaves the inboard mostly intact as shown.

RE video in #2575

The wing spoilers appear to be deployed. Would deployed spoilers remain up after the aircraft coming apart like this? Or are they just floating freely, as their is no pressure in the hydraulic lines?

I would also image that water impact, regardless of entry angle or velocity would cause damage to the radome, including cracking, paint being delaminated due to "denting", separation of the radome etc.

Are the marks really indicative of a lightenting strike? Could they just be the paint being craked where there was an impact? Looks much like a car bumper that has been impacted and the paint becomes cracked/crazed due to deformation of the underlaying structure...

Radome
 

The radome is held on with screws, not rivets. This allows maintenance access to the weather radar equipment (dual R/T, antenna drive, flat plate, etc.).

If there is a strong current from the rear end, possibly. Due to gravity it should be closed by now. Even with hydraulics fully intact, after some weeks external forces push it where they want to. Anyway remarkable that the spoilers are intact.

Radome
 

FYI radome has a hinge on his upper side and is maintained closed by two latches (approx. 4 and 8 o'clock).

despegue:There is no need to put the aircraft in DIRECT LAW. One just have to take TWO ADRs OUT and put it in ALTERNATE LAW.

In ALTERNATE LAW the aircraft will obey your inputs and the pilot will be able to steer from any unusual attitude, keeping the required information to fly the aircraft away from overspeed protection, as well as low speed. The protections in ALT LAW may be overridden while maintaining structural integrity. (Load Factor).

Load factor
 

Previously limited by physically hardening the pitch axis on the yoke. With FBW it's just implemented in computers (ELAC's, PRIM's,...)

Alternate law and load protection??
 

" The protections in ALT LAW may be overridden while maintaining structural integrity. (Load Factor)"

So in other words one cannot ' bend ' the airplane no matter what ( unless somehow HAL allows direct control "

IMO that is a logic flaw. I posted earlier about a China 747 in 1985 that had an engine failure, went into a major spiral dive, and was recovered- and still flew - but it was severly bent with estimated 5G loads during pullout. Wings were bent up permanently sever inches at tips, who knows how much during flight. Part of horiz stabilizer was torn away.. plane landed safely, and was repaired and put back into service. Structural limit load test the wings on a 747 go several feet above top of fuselage at 2.5 to 3 G equivalent ..

Alternate law limits would have prevented that- and plane and passengers would have been swimming with the fish . .

see China Airlines Flight 006 - Wikipedia, the free encyclopedia

and the official report can be found

" here were two serious injuries on board: a fracture and laceration of a foot, and an acute back strain requiring two days of hospitalization. The aircraft was significantly damaged by the aerodynamic forces. The wings were permanently bent upwards by 2 inches (50 mm), the inboard main landing gear lost two actuator doors, and the two inboard main gear struts were left dangling.[1] Most affected was the tail, where large outer parts of both horizontal stabilizers had been ripped off. The entire left outboard elevator had been lost along with its actuator, which had been powered by the hydraulic system that ruptured and drained."

Now about load protection ??

http://www.airdisaster.com/reports/ntsb/AAR86-03.pdf

http://www.airdisaster.com/reports/ntsb/AAR86-03.pdf

BTW early in the 707 commercial introduction a 707 went into a spiral dive cuz autopilot kicked out at night, nobody minding the store. Luckily they recovered, but wings were permanentely bent..

Load protection would have done What ??

It appears that this can't be fixed with technology. :cool:
Back to our thread, it's a good bet that in this accident, Air Asia Indonesia, the pilots were indeed minding the store and trying to resolve their difficulty with the weather they were encountering.

IndonesianTempo AirAsia Plane Often Experiences Trouble, Former Pilot Says | Economy & Business | Tempo.Co :: Indonesian News Portal - 'Former Garuda Indonesia pilot Capt. Shadrach M. Nababan, said -based on its logbook data - that the Airbus A320-200 serving AirAsia flight QZ8501 had experienced problems as much as nine times on its auto rudder trim limiter flight control in 2014.
Three days before crashing on December 25, 2014, flight QZ8501 experienced a 'return to apron' twice, according to Shadrach.
Flight QZ8501's last transmission were revealed by the Transportation Minister Ignasius Jonan in a meeting with the Transport Commission Legislature on Tuesday, January 20, 2015, saying that the aircraft tried failed gain altitude and stalled before vanishing from Soekarno-Hatta's ATC (Air Traffic Control) radar. The plane attempted to climb from 32,000 feet to 37,000 feet between 06:17 to 06:17:54 am (Western Indonesian Time).
At 6:17:54, the plane stalled from 37,000 feet to 36,000 feet in six seconds, and to 29,000 feet in 31-seconds. At 6:18:44 am, the plane vanishes from ATC radar.
Shadrach explained that commercial planes are not allowed to do any extreme climbs in the air because it does not have the same power as fighter jets.'

SAMPUBLIUS:

Your post raises some thoughts.

Why are Airbus machines designed with such load protection?

Are they built like Boeings?

Would an A330 survive in the above circumstances if full control were allowed?

Is there a related problem: I'm getting the impression that when things go seriously amiss, will the computers try to hang on too long, and in the process make such extreme inputs, that when they finally drop and hand control back, things are already much further gone than they should be?

Is there a related problem ?
 

auraflyer


Auraflyer - In a word - Yes

What we have is the reverse of the Sourcerer and the Apprentice.

In normal life, when the Apprentice screws up, the Master Tradesman has to perform the rectification, and the apprentice gets a kick up the arse and "learns".

What we now have, in the bus philosophy, is the system is the annointed Master Tradesman, that is so much smarter, quicker, better, and all knowing, than the apprentice pilot.
When the Master Tradesman screws up, makes a mess, then compounds it into a bigger mess, and then gives up, it throws it all back onto the apprentice pilot with the instruction:-
"OK son, let's see how much you have learned so far. Show me how to fix this problem, and save our arses, before we loose the contract."

Put bluntly, the real responsibility for these "make it worse - then give up and kick off" automation facilitated needless disasters - should be laid fairly and squarely where it belongs - at the front door of the mentoring and sponsoring certification authouity - La Direction de l'Aviation Civile.

Thanks, Aguadalte,

That is what I meant, haven't flown Airbus since 2003.

Except that on the 'Bus, with one engine out you are still in Normal Law with full protections in place, and the plane would not have rolled into the spiral dive to begin with...

Simply losing one engine on a 747 should not result in total loss of control by the crew and a 5g 30,000ft plunge. Once he took manual control, the Captain made several basic mistakes and nearly killed everyone on board. That is completely unacceptable.

If anything, China Airlines 006 further supports the Airbus design philosophy.

Since icing can affect all IAS probes at the same time, thus nullifying cross-checking, it would make sense to have GPS crosschecking for errors implicit in rapid changes in IAS. If IAS changes unexpectedly and GPS does not then a warning could be issued re suspected icing. It's just another bit of filtering software that perhaps needs to be written.

maybe we just need hotter pitot tubes and vanes

oh, and even without GPS, if you are level at cruise power settings, there is a good chance you are making cruise indicated airspeed.

I want all those who are NOT pilots to know that we train, when we are very early in our pilot training how to deal with loss of indicated airspeed, for what ever reason...

In the larger planes, we actually have a piece of paper in our POH which gives power setting, pitch attitudes and other things which could be used IN LIEU of indicated airspeed...even offering things like this if we LOSE THE RADOME for some reason or another.

I love all the advice from non pilots or engineers, but the best thing I could ever offer to an aircraft designer is the term: KISS

KEEP IT SIMPLE STUPID

but it seems that modern planes have done just the opposite.

That's what the Airbus A330 company pilots thought when they pulled a engine back to simulate a failure with one hyd system shut down. It did not go so well for them.

Amen to that. It has been my argument since 20 years.
Being called a Airbus enemy for so long, i only opposed the stated above. It would take a minor programming change to rectify the system. But it would admit something ...... and therefore we will cynically witness another Airbus c-u.

Did you notice the absence of the usual Airbus lobby-suspects' trivial contributions on here? It's getting ever more difficult to find excuses for the system with the similarity of these accidents.

But you have pointed out the real responsible body in your contribution.

Raising the Fuselage part 3
 

So, it looks like the latest plan is to skip the floatation bags and just winch it up.

Raising the Fuselage part...
 

So last word is they may have 6 meters secured.

Quite simply, the investigators KNOW what happened by now. The fact that there has been exactly ZERO airworthiness directives sent our to Airbus Operators would suggest that we can almost rule out Structural / Equipment failures and are more likely looking at a mishandled event. Investigators probably just trying to figure out what to pin on airbus to shift some of the blame much like the ASIANA investigation which concluded that the pilots were duped into crashing by a 'hard to understand' autothrottle.

SAMPUBLIUS, auraflyer and Gretchenfrage.

Your concerns about load protections on Airbus have been repeatedly raised ever since features of Airbus FBW have become known, about a year or two before first A320 entered service. They have being pointedly ignored by aeronautical powers that be ever since. There are at least two possible explanations for this:

1) there is a worldwide conspiracy started by Airbus and involving all of the aviation authorities that accept the Airbi to be of airworthy design (that means all of them!). This conspiracy is very stealthy, no one has ever managed to prove its existence yet it is so powerful it suppresses data on every incident where overstressing the aeroplane saved the day so perception is there was none and whistelblowers are sidelined to anonymous fora.

2) whoever proposes that 2.5G with 50% reserve is too low for transport category aeroplanes combined with FCS actively maintaining the limit has no clue about certification criteria, structural design of the transport category aeroplane or operations of them - provided they really believe what they write - and everybody who is somebody in aviation is right to ignore that contributions as their notions represent acts of spectacular ignorance. There really is not any accident where transport aeroplane could be realistically saved by being built stronger instead of not getting it her into mess in the first place.

Your pick.

Transport category aeroplanes have to withstand 3.75 G at MTOW, clean, without damage or plastic deformation. For the time being, I'll leave it at this to solicit some entertaining responses.

Dynasty 6 accident happened near the end of cruise. They were lucky to be light yet with enough fuel in wings.

Loss of engine on FBW Airbi does not degrade control laws. Alpha protection would prevent the stall and bank protection would prevent the spiral dive.

Speaking of devil.

Flight QZ8501: Investigator says crash report won?t include black box data | Malaysia | Malay Mail Online


So it doesn't look like there will be an official explanation anytime soon as to what happened.

3 attempt abandoned
 

Latest I hear is they may not raise the fuselage and the ships involved may be recalled. No additional bodies have been recovered.

edit: ships were recalled.

Sorry, engineer here!
 

The GPS speed question that keeps on getting asked ad nauseam usually only gets half the answer it deserves.
With many apologies to those who know this well, IAS is INDICATED Air Speed. If a plane climbs at constant IAS then, due to the decreasing air density, its actual air speed will increase progressively. This is good, because if the speed didn't increase then the lift would decrease.
IAS is an exceptionally useful parameter, GPS speed in itself is doubly useless because it is:- 1) not airspeed, and, 2) requires desnity information and calculation to be of any use.
But GPS height data could be useful, in this engineer's opinion.

Recovery Called Off
 

27Jan15 1700 hk
QZ8501 recovery operation called off: Indonesian military - Channel NewsAsia

JAKARTA: The Indonesian military on Tuesday (Jan 27) called off efforts to recover the wreckage of an AirAsia plane that crashed into the Java Sea last month after failing for several days to lift the fuselage.

"All of our forces are being pulled out," said Rear Admiral Widodo, a navy official overseeing the search and rescue operation. "The operation has been ongoing for 30 days so the joint team has pulled out," he said. "We apologise to the families of the victims. We tried our best to look for the missing victims."

The 787 supplies a back up IAS derived from AOA and inertial system should you lose all pitot's. The GPS takes over altitude. A very nice feature.


p.s the GPS/FMC ground speed indicator is always a vital tool for handling unreliable airspeed especially if you still have wind data.


The vital difference with Boeing is that there are no control FBW inputs to overspeed/underspeed. (Only trim inhibit) This means any failure is passive and Boeing want the pilot to have control over the aircraft not the other way around.


I am losing count of the number of airbus incidents of altitude climb/bust due to transitory overspeeds.


Throttles that don't move/ sidesticks cancelling each other out with inputs not visible to the other pilot/ FBW system that commands pitch manoeuvres without the autopilot..........The airbus design philosophy counters not helps piloting ability and awareness especially when its needed most with out of the ordinary occurrences.

Rudder Problems?
 

I'm surprised that no-one has commented on the report above by 757SP5 at http://www.pprune.org/rumours-news/5...ml#post8841170 about rudder problems with this aircraft.

Apparently Could 'auto rudder trim limiter flight control' problems be the key to this crash?

Sorry to see the wreckage is now to be abandoned, but I guess there is a trade off between the risk to recovery team members and any benefit that might result from their efforts.

Agree,how many times did Airbus aircraft safety systems avoided a disaster due to crew.....

Airspeed determination
 

Failures in airspeed measurements seem to be increasingly implicated in aircraft upsets.

Rather than relying on pitot-based airspeed measurement, a number of contributors have suggested GPS-based approaches (which are unsuitable, as discussed).

As a back-up, could a fuselage-embedded mini-RAT type system work - an air-driven impeller (probably rather smaller than the cooling fan in your PC)?

Or perhaps even an acoustic system: a simple hull-mounted microphone which detects airspeed-derived noise? Frequency tuning or filtering could avoid interference from engine-derived noise.

Deanm - good observation.

Building on that, why not incorporate GPS data as a fall back, in the event of a pitot head icing up, the FMS advises that there is a mismatch between GPS/Pitot speeds and does nothing pending pilot acknowledgement.

Descent to a lower level at this stage gives more speed margin whilst reducing a stall scenario, the secondary effect of pitot head icing is loss of awareness and subsequent loss of control (in some cases).

Just thinking about being in heavy turbulence/wind shear at night with no speed awareness and close to speed margins gives me the sweats.

Prevention is better than cure.

Each of those is still subject to icing. You need sensing from something that does not involve air that's moisture laden. A combination of inertial reference and GPS can compute a probable wind until you get out of icing conditions. There is no simple solution.

It is already being done - only a matter of time before the 'bus has it too