Turkish Airliner Crash

[MathFox]

It is simply strange that the plane was allowed in the air with a "temperamental" altimeter hooked up to its hands free landing system. Surely that calls for some intensive soul-searching at Turkish Airlines...

[...]

Is there some logic to this that I am missing? What would a pilot be trained to do in these circumstances?

I can appreciate that it might be easy to miss detecting that the plane was loosing air speed until it was too late, but how do you end up relying on a piece of equipment that you know is faulty and not notice that it is failing you? I'm not getting it.

You assume that the defect was written down in the logbook... According to the AEI (international organisation of Airline mechanics) that does not always happen. (Commercial interests.) Published rumour (link in Dutch: http://www.luchtvaartnieuws.nl/news/?ID=29843 ) says that the two previous known failures were not written up in the plane's logbook.     

[joeyb747]

Wow. Thats amazing. Blows my mind actually. I've seen logbook entries like "Captains seat uncomfortable. Please change cushion." Trivial stuff. Why were these malfunctions not noted?? Thats what I don't understand. 

[MathFox]

joeyb747, you've got some good questions for the investigation. I am pretty sure that the OVV investigation will take a look into maintenance practices and procedures.

[joeyb747]

joeyb747, you've got some good questions for the investigation. I am pretty sure that the OVV investigation will take a look into maintenance practices and procedures.

Thanks!
We can only hope they will...

You know what they say about the FAA(or governing body in witch ever country the aircraft is operated):
Policies are written in the blood of their passengers...simply meaning, it takes a major disaster before they will change a policy.

I heard that somewhere...just can't remember where...

[toogd]

If the log books are blank regarding earlier malfunctions in this case, the implications are scarier than I care to even think about!

[joeyb747]

If the log books are blank regarding earlier malfunctions in this case, the implications are scarier than I care to even think about!

Indeed!!

[empiredude]

I just cannot believe they would have been using faulty radaralt if they had known it was malfunctioning - I would simply be ridiculous if it weren't so tragic...

on the other hand I also cannot believe they missed to note this in the A/C logbook - I mean you're supposed to note every stupid little thingy that wasn't working perfectly normal - and I'm no pilot, but a faulty radar altimeter causing the autothrottle to go idle for landing too early sounds like something pretty severe to me... and that apparently happened twice (!) within 25h...

just don't get it, should've never ever ever happened...

by the way, is there some official investigation report available on the internet somewehere?

[MathFox]

So far the best official report (in Dutch) is http://www.onderzoeksraad.nl/docs/rapporten/Persverklaring_4_maart_09.pdf and in English http://www.onderzoeksraad.nl/docs/rapporten/Press_statement_4_March_GB.pdf

If there are new reports they'll most likely be listed on:
http://www.onderzoeksraad.nl/en/index.php/onderzoeken/onderzoeksraad-start-onderzoek-crash-turkish-airlines-op-schiphol/

[iskyfly]

by the way, is there some official investigation report available on the internet somewehere?

No. The investigation is not complete. It will take 6 - 9 months.

Right now the only official releases are statements of facts leading up to the accident.

[empiredude]

thanks for the links to the report!

I know the whole redundancy issue has been discussed before - but just in general, shouldn't on a airplane every vital function be back-uped? I mean why is the A/T not in general configured to use both radio-alts no matter what?
just out of curiosity, how does airbus handle the subject? do their A/T also only use one radio alt to measure the distance to the ground? (I really don't wanna start some boing vs. airbus discussion!!! just wondering if this A/T configuration is standard (and if so, why?) or not...)

[joeyb747]

thanks for the links to the report!

I know the whole redundancy issue has been discussed before - but just in general, shouldn't on a airplane every vital function be back-uped? I mean why is the A/T not in general configured to use both radio-alts no matter what?
just out of curiosity, how does airbus handle the subject? do their A/T also only use one radio alt to measure the distance to the ground? (I really don't wanna start some boing vs. airbus discussion!!! just wondering if this A/T configuration is standard (and if so, why?) or not...)

If I'm correct here, the autothrottle is simply linked to the autoland system. It can obviously be used without autoland being activated for cruise and all other phases of flight. The crew of this particular flight was performing a single channel autoland, witch defaults to the left, or #1, Rad Alt.  If a dual channel autoland was being executed, the autopilot would have sensed a discrepancy between the two Rad Alts, and disconnected the autopilot. At witch point, the crew would have had to shoot the ILS "old school", using the autopilot with APPR and IAS Speed Hold mode engaged until they obtained visual contact with the runway environment.

So to answer your Q, it can be connected to both Rad Alts, if the right mode is selected.

As far as differences between Airbus, Boeing, Douglas, Tupolov, or any other manufactureer, I am not totally sure on that...

[empiredude]

hmm I get your point, but why question would more be like "whether or not it is necessary (or "good" or "reasonable") to perform a procudure only "single channel" - only relying on one radioalt instead of both?" I mean there are always at least two radio altimeter on board -  why not use them both (if both are working) in no matter what situation? just for backup reasons - and to detect discrepancies between two instruments...
this would of course be an issue more concerning the aircraft manufacturors than the crew...

[joeyb747]

Aircraft perform single channel autolands everyday. 99.99% of those are uneventful. I understand your point. Use all the redundancy at your disposal. I'm not sure why they were doing a single. There are only three people who can answer that...unfortunately, they are not available for comment...

[speker]

I have come across to below explanations regarding initial report on the CVR-FDR findings ;

Pilots recognised the left altimeter foult at 7000 feet during approach

Due to foulty functioning left altimeter, pilots engaged the autothrottle systems to the rigth controls (at first officer side)
Although the systems should have been commanded by the right altimeter, foulty left altimeter continued processing foulty data to the systems. (due to a software mistake by boeing)
 
Due to the heavy traffic , air control requested the plane to start landing approach from distance 8.69 km & 600 m altitude. (it is said in the report that healthy approach figures should have been 11.47 km & 1000m.) 

Auto throttle cut the gas.  Pilots did not recognised initially as they were fast already.  (landing checklist was going on)
Shacker system automatically activated (as the speed was decreased) by warning the pilots & shaking the controls & increasing throttle. But since the autothrottle still was on, the throttle was back to idle again.

Pilots manually maximized the throttle, but it was too late unfortunately.



does these info makes sense & enlight ? (sorry if I made any translation mistake)

[iskyfly]

(due to a software mistake by boeing)
 

says who?

[speker]

two Turkish newspapers says that they sourced these info from Dutch officials.

http://www.haberturk.com/haber.asp?id=133865&cat=110&dt=2009/03/12

http://arama.hurriyet.com.tr/arsivnews.aspx?id=11190593

also they gave the voice decoding in written.

latest words were : throttle officer throttle !!! (by the senior first officer sitting behind the captain & student first officer (who was landing).

[joeyb747]

A software error?? In only one radio altimeter? Seems a little far fetched to me. Seems like there would be more then one airplane experiencing these types of issues.

Quote from speker:
"Auto throttle cut the gas. Pilots did not recognised initially as they were fast already.  (landing checklist was going on)"

I know I referenced the possibility that the crew was distracted by something, and was not watching what the airplane was doing way earlier in this thread. But to be distracted by something as routine as a landing checklist?? Usually the pilot not flying reads the checklist, and the other monitors the airplane and what it's doing. The also had a third person, an instructor none the less, in the cockpit. I find it real hard to believe that a landing checklist would distract an experienced crew of three to the point that they would not be paying attention the the performance of the aircraft.

Not to say that isn't what happened. It very well may be...I just have a hard time stomaching that. Just my opinion...