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TK B738 Crash At Amsterdam - Part 7  
User currently offlineHB-IWC From Indonesia, joined Sep 2000, 4507 posts, RR: 72
Posted (5 years 7 months 3 weeks 1 day 18 hours ago) and read 29297 times:

As part 6 of this discussion has reached its critical length, please continue the discussion in this new thread.

Previous installments:

Part 1

Part 2

Part 3

Part 4

Part 5

Part 6

214 replies: All unread, showing first 25:
 
User currently offlineDRAIGONAIR From Netherlands, joined Oct 2000, 708 posts, RR: 5
Reply 1, posted (5 years 7 months 3 weeks 1 day 18 hours ago) and read 29319 times:

The retard mode is a mode that moves the throttles to idle just 30/40ft above the ground to enable the plane to flare. So if the throttles are in the retard mode and you want to give power and let go, the throttles go back to idle. TOGA button would have helped go around.
If the Auto Throttles are off, the retard mode will also be removed and you will be able to give power manually (A/T was left on)

Nick



cheers
User currently offlineLexer From Italy, joined Sep 2005, 160 posts, RR: 0
Reply 2, posted (5 years 7 months 3 weeks 1 day 18 hours ago) and read 29133 times:

Thanks Gorgos and Draigon. I then understand that retard mode prevents a quick power-up (with A/T on).

User currently offlineGorgos From Greece, joined Dec 2007, 232 posts, RR: 0
Reply 3, posted (5 years 7 months 3 weeks 1 day 18 hours ago) and read 29143 times:

LIVE

http://www.nos.nl/journaal24/wmv.html


User currently offlinePW100 From Netherlands, joined Jan 2002, 2506 posts, RR: 12
Reply 4, posted (5 years 7 months 3 weeks 1 day 18 hours ago) and read 29207 times:

Live feed of offiicial findings . . . :

* Dutch Safety Safety Board: Safety Alert to Boeing:
*** Recommend to review Fligth Manual B737: if radio altimeters are inop, autothrottles and autopilot must not be engaged;



* 9 casualties;
* 80 wounded, 28 still in hospital;
* TK 1951 ETA 10.40
* No problems until last moment;
* 3 qualified pilots in cockpit;
* 1st officer flying the aircraft;
* TK1951 received landing clearance, no delay in approach, direct approach;
* Autopliot engaged during approach;
* DFDR and CVR in good condition;
* at 1950 ft, LH radio altimeter step change read out from 1950 ft to -8ft;
* this faulty altitude was also reported to autothrottle;

* CVR: crew saw altimeter discrepancy;
* Crew did not see this discrepancy as problem, and lowered gear as gear warning was activated due to -8 ft radio alt;
* As a result, autothrottle went into retard mode at 1950 ft rather than 50 ft due to faulty radio altimeter read out;
* Aircraft slowed to stall speed;
* Aircraft flight controls [autothrottles] thought airplane was above runway and went into "flare mode";

* At 450 ft stall warning /stick shaher activated;
* power was increased immediately [!] [TOGA?], but power increase was too late to continue flight;


* identical problem with LH radio altimeter happened twice before on this airplane in last eight flights;
* that data was still on DFDR, as it had 25 hrs upto crach of recorded information;

* Landing gear and engines broke off at impact as designed;
* due to high power setting engines flew forward by 250m at impact separation;

* investigation will now focus on radio altimeter, and relation/logic with autothrottle system;
* runway was not [very well] visable to crew;

* Dutch Safety Board will lead investigation;
* Several other parties will support investigation [NTSB, Boeing, CFM internaional, Turkish authorities, ;

* Good words for justice department, especially in isolating area around airplane;
* Safety Board and Jutice Department back on same frequency;
* Main objective of investigation is fact finding and improve safety;
* Justice department will limited access to data, to protect "whistleblowers";

* radio altimeter fault is only technical fault found so far;

* No indications of ATC faults;
* No indications of [wake-]turbulence;
* Too early to tell if crew made mistakes;
* All members of invetsigation team are on same line of thinking
* Not yet known where the 2 previous occurances of LH radio Alt happened
* LH radio Alt not considered flight critical component, as function can be taken over manually by crew;
* No conclusions on TK maintenance activities and procedures;

* Aircraft will be recovered this week;



to be continued . . .

[Edited 2009-03-04 05:20:38]

[Edited 2009-03-04 05:24:51]

[Edited 2009-03-04 05:28:25]

[Edited 2009-03-04 05:29:09]

[Edited 2009-03-04 05:30:07]

[Edited 2009-03-04 05:33:27]

[Edited 2009-03-04 05:42:08]


Immigration officer: "What's the purpose of your visit to the USA?" Spotter: "Shooting airliners with my Canon!"
User currently offlinePatches From United States of America, joined Aug 2000, 293 posts, RR: 0
Reply 5, posted (5 years 7 months 3 weeks 1 day 18 hours ago) and read 29069 times:

whats the dude saying in the news conference?

User currently offlineDeaphen From India, joined Jul 2005, 1427 posts, RR: 1
Reply 6, posted (5 years 7 months 3 weeks 1 day 18 hours ago) and read 29040 times:



Quoting Patches (Reply 5):
whats the dude saying in the news conference?

PW100 above is translating.

Nitin



I want every single airport and airplane in India to be on A.net!
User currently offlineStevAAn From Netherlands, joined Mar 2007, 44 posts, RR: 0
Reply 7, posted (5 years 7 months 3 weeks 1 day 18 hours ago) and read 28919 times:

Investigation will from now focus on the altimeter discrepancy and interface to the throttles.
edit: nevermind pw100 was way ahead of me.

[Edited 2009-03-04 05:14:18]


747
User currently offlineKL577 From Netherlands, joined Oct 2006, 776 posts, RR: 0
Reply 8, posted (5 years 7 months 3 weeks 1 day 18 hours ago) and read 28836 times:



Quoting PW100 (Reply 4):
* identical problem with LH radio altimeter happened twice before on this airplane

Actually twice in the past eight flights (which are still recorded on the FDR)


User currently offlineLexer From Italy, joined Sep 2005, 160 posts, RR: 0
Reply 9, posted (5 years 7 months 3 weeks 1 day 18 hours ago) and read 28768 times:

PW100, Tks for the summary

[Edited 2009-03-04 05:45:36]

User currently offlineStevAAn From Netherlands, joined Mar 2007, 44 posts, RR: 0
Reply 10, posted (5 years 7 months 3 weeks 1 day 18 hours ago) and read 28774 times:

Another thing that surprises me is that the problem of discrepancy in the altimeters did occur 2 times before the crash happend according to what is said on the conference.


747
User currently offlineEMA747 From United Kingdom, joined Jun 2006, 1171 posts, RR: 1
Reply 11, posted (5 years 7 months 3 weeks 1 day 18 hours ago) and read 28568 times:



Quoting KL577 (Reply 8):
Quoting PW100 (Reply 4):
* identical problem with LH radio altimeter happened twice before on this airplane

Actually twice in the past eight flights (which are still recorded on the FDR)

On this aircraft?

From reply 4 - LH means Left Hand?

What should the radio alt have read?

If the A/T went into retard mode does this mean the A/P thought it was doing an autoland?



Failing doesn’t make you a failure. Giving up and refusing to try again does!
User currently offlinePHKLM From Northern Mariana Islands, joined Dec 2005, 1198 posts, RR: 2
Reply 12, posted (5 years 7 months 3 weeks 1 day 18 hours ago) and read 28572 times:



Quoting EMA747 (Reply 11):
On this aircraft?

Yes

Quoting EMA747 (Reply 11):
From reply 4 - LH means Left Hand?

Yes

Quoting EMA747 (Reply 11):
What should the radio alt have read?

1950ft ASL

Quoting EMA747 (Reply 11):
If the A/T went into retard mode does this mean the A/P thought it was doing an autoland?

No, it was just being commanded to do so by the altimeter


User currently offlineDeaphen From India, joined Jul 2005, 1427 posts, RR: 1
Reply 13, posted (5 years 7 months 3 weeks 1 day 18 hours ago) and read 28497 times:



Quoting EMA747 (Reply 11):

What should the radio alt have read?

1950 feet.

Quoting EMA747 (Reply 11):
If the A/T went into retard mode does this mean the A/P thought it was doing an autoland?

Yes, as mentioned above, the computer thought they were just a few feet above the runway.

Nitin



I want every single airport and airplane in India to be on A.net!
User currently offlineStevAAn From Netherlands, joined Mar 2007, 44 posts, RR: 0
Reply 14, posted (5 years 7 months 3 weeks 1 day 18 hours ago) and read 28490 times:



Quoting EMA747 (Reply 11):

Left hand altimeter read -8 ft , while the right one read 1950 ft.

1950 was probably the correct reading.



747
User currently offlinePHKLM From Northern Mariana Islands, joined Dec 2005, 1198 posts, RR: 2
Reply 15, posted (5 years 7 months 3 weeks 1 day 18 hours ago) and read 28411 times:



Quoting Deaphen (Reply 13):
Yes, as mentioned above, the computer thought they were just a few feet above the runway

AFAIK autoland is not equal to auto-thrust, the former was not applicable, whereas the latter partially caused this crash.


User currently offlineEMA747 From United Kingdom, joined Jun 2006, 1171 posts, RR: 1
Reply 16, posted (5 years 7 months 3 weeks 1 day 18 hours ago) and read 28349 times:



Quoting Deaphen (Reply 13):
Quoting EMA747 (Reply 11):
If the A/T went into retard mode does this mean the A/P thought it was doing an autoland?

Yes, as mentioned above, the computer thought they were just a few feet above the runway.

I don't have much detailed knowledge of real world 737 flying but don't the both A/Ps need to be engaged to get the A/T to do something like an autoland and retard?

Quoting StevAAn (Reply 14):
Left hand altimeter read -8 ft , while the right one read 1950 ft.

1950 was probably the correct reading.

Why did the crew think it was not a problem? That's a big difference in feet.



Failing doesn’t make you a failure. Giving up and refusing to try again does!
User currently offlineDeaphen From India, joined Jul 2005, 1427 posts, RR: 1
Reply 17, posted (5 years 7 months 3 weeks 1 day 17 hours ago) and read 28134 times:



Quoting PHKLM (Reply 15):
AFAIK autoland is not equal to auto-thrust, the former was not applicable, whereas the latter partially caused this crash.

From what i understand, it is during the autoland that the retard mode comes into play, when it pulls the throttles back to idle when you are 24 feet above the runway. Thats why, despite the throttles being increased, the auto throttle pulled it back again.

I may be wrong.

Regards
Nitin



I want every single airport and airplane in India to be on A.net!
User currently offlineStevAAn From Netherlands, joined Mar 2007, 44 posts, RR: 0
Reply 18, posted (5 years 7 months 3 weeks 1 day 17 hours ago) and read 28061 times:



Quoting EMA747 (Reply 16):

Well other crew also thought it was not a problem? Or in other words, the problem occured 2 times before the crash, but it seems no action was taken for this to investigate..



747
User currently offlineStar_world From Ireland, joined Jun 2001, 1234 posts, RR: 0
Reply 19, posted (5 years 7 months 3 weeks 1 day 17 hours ago) and read 28059 times:



Quoting EMA747 (Reply 16):
I don't have much detailed knowledge of real world 737 flying but don't the both A/Ps need to be engaged to get the A/T to do something like an autoland and retard?

Autoland is completely different - what's being referred to here is the autothrottle system, which is activated independently of the autopilot. Even on a manual (non-autoland) landing the AT is normally used.

Quoting EMA747 (Reply 16):
Why did the crew think it was not a problem? That's a big difference in feet.

Most likely because they knew they weren't at -8ft, they would have had both barometric altimeters (the most visible on the display) still showing ~1950ft as before, plus one of the RadAlts showing the correct altitude. On that basis they continued the approach.


User currently offlineDRAIGONAIR From Netherlands, joined Oct 2000, 708 posts, RR: 5
Reply 20, posted (5 years 7 months 3 weeks 1 day 17 hours ago) and read 28066 times:

It says (from press) that in the op. manual is there is a difference in radio alt. then then the plane has to be flow manually. Also what comes to mind is how 3 pilots did not notice the speed droping to stall speed.


cheers
User currently offlinePW100 From Netherlands, joined Jan 2002, 2506 posts, RR: 12
Reply 21, posted (5 years 7 months 3 weeks 1 day 17 hours ago) and read 28062 times:



Quoting EMA747 (Reply 16):
Why did the crew think it was not a problem? That's a big difference in feet.

[speculate mode] Crew apparently did not realize that the engaged autothrottle system went into retard mode at 1950 ft. This should only happen above runway at 40-50 ft as part of the flare.[/speculate mode]

Investigation Board will look extensively at LH radio alt relation and logic with autothrottle. Also crew actions need to be further investigated as this does not explain why the crew allowed the aircraft to bleed off so much speed. They should still have had the possibilty to manually increase throttlesetting.

Regards,
PW100



Immigration officer: "What's the purpose of your visit to the USA?" Spotter: "Shooting airliners with my Canon!"
User currently offlineWoody71 From United States of America, joined Jun 2008, 85 posts, RR: 0
Reply 22, posted (5 years 7 months 3 weeks 1 day 17 hours ago) and read 27875 times:

Do you not get an error in the a/t when the two Rad Altimeters don't agree? Or does it take its reading from only the left-hand rad alt?

User currently offlineComorin From United States of America, joined May 2005, 4900 posts, RR: 16
Reply 23, posted (5 years 7 months 3 weeks 1 day 17 hours ago) and read 27668 times:

I always thought critical functions like Autoland were protected by multiply redundant instrumentation - you would need instruments to agree before input was accepted. I also read somewhere that if you had three inputs, the two correct readings would outvote the false reading. My question is, does the 737NG only accept a single instrument input for Autoland?

Also, I'll await the translated report but I believe some reference was made to vortices towards the end of the conference - was wake turbulence ruled out?


Thanks again, translators !


User currently offlineHiflyer From United States of America, joined Nov 2004, 2175 posts, RR: 3
Reply 24, posted (5 years 7 months 3 weeks 1 day 17 hours ago) and read 27611 times:

PW100-thanks for the translation of the conference...my Dutch, or lack of, hindered my viewing...grin.

Was the question raised that as they lost the LH radalt, which commanded the autothrottles, when did they breakout of the clouds...could see the ground...compared to when they pushed the throttle forward? It seems to be pretty much as the same time as wasn't the cloud base reported at 700 feet and the throttles went forward at 450 feet during a steep descent?

Now here is a questions that has been bothering me...the carrier flies both the Airbus and the Boeing...a lot of airbus from 310 to 319 to 320 to 330 to 340....and just the 734 and the 738. Would have the automation differences between the two types possibly have led a crewmember who had formerly been on the Bus to not be as concerned with the LH radio altimeter fail?? Would have airbus flight control 'law' come into play here?


25 Jpiddink : Sad news was added later after questions from turkish press: all cockpit crew were found dead at the moment the first emergency worker arrived. To ans
26 Joost : Yes. Or, more precisely, no evidence for wake turbulence was found during the investigation.
27 Post contains links PW100 : http://www.flightglobal.com/articles...ation-focuses-on-crew-actions.html Flight Global has some additional information, that was not read out during
28 EMA747 : I'm sorry if I'm not getting the full picture here but I am just try to get my head around what was going on.... At 1950ft the speed (if I remember co
29 Max777geek : Sorry guys, unregarding of A/T engaged or not, shouldn't the manual input override the A/T setting, if even, in whatever plane it's installed ? Id exp
30 Mcdu : The original 737's did not have A/T to touchdowm but I believe the NG 737's have the ability to have the A/T engaged (selected) until touchdown like
31 Robcol99 : The PIC of this flight has only flown 737 (734 and 738) in his civilian pilot career. Same goes for the other two as far as I know.
32 PW100 : Yes, apparently you can manually override. But when in retard mode, when the throttles are released, they will not stay in the last selected manual s
33 Derik737 : It appears from the information I have received it's only the left-hand radio altimeter. Here's the specification from the AMM for Flare Retard Mode:
34 EMA747 : Were both radio altimetres working correctly during the first part of the descent and approach? Was it a sudden fault with the LH one?
35 Lexer : So these six seconds were basically lost in powering up the engine as a result of the retard setting. The six seconds appeared to go unnoticed by the
36 Wolbo : That sounds counter intuitive and therefore potentially dangerous. If there is a manual override of an automatic system that must have been done by a
37 PW100 : The Safety Board reported that only the LH radio altimeter is feeding the autothrottle and/or autopilot. The RH radio altimeter is not connected to th
38 CityhopperNL : It seems that once again this was a crash that has been caused by multiple factors. I don't know if a radalt error is a reason to keep a plane on the
39 TK787 : This is the one I don't understand. Is the workload that much that none of them paid attention to air speed? Is there any kind of warning voice alarm
40 EMA747 : Am I the only one who thinks this programming in the A/T logic is not very good? As has now been proved a problem with the LH alt can bring a plane d
41 CityhopperNL : Well, I guess it is not counter intuitive at all, because the pilot makes the decision to engage the autopilot and autothrottle, and if the system is
42 Bahadir : you would think that the autopliot on the right side would gets its feed from the RA on the right side. Why would I want to rely on the LH RA if the
43 CosmicCruiser : Someone still has to fly the jet. You don't sit there wondering what's going on and let the jet smack the ground. I would think they would have had a
44 OV735 : A very tragic accident with tragic results. This exemplifies how important it is to ensure that pilot training covers the old-style monitoring of inst
45 Mcdu : The MCP is the Mode Control Panel, and MCP speed indicates that the airspeed window selection on the MCP is the guidance for the A/T. It will try to
46 EMA747 : If Boeing address this it will be one instance where lessons have been learned and hopefully stop this ever happening again. Sad to have the crash th
47 Nomadd22 : All you have to do to overide the A/T is manually advance the throttles. If you want them to maintain the manual setting you either hold them or turn
48 CityhopperNL : I'm now confused too, by your post and Mcdu's. PW100's first post shows that autopilot was engaged, and I don't see any indications that it was disen
49 EMA747 : Nomadd22 do you mean you have to hold them there if it is on retard mode?
50 OV735 : As I understood from PW100's post above, the crew probably acknowledged the difference, but didn't consider it a problem, since the right hand RA as
51 Osiris30 : Not necessarily. If you need to put power in temporarily on approach to catch back up to the GS, there is no reason to not want the throttles to auto
52 N14AZ : from the Dutch side from Flightgobal / Boeing. How does this fit together? Can someone explain? Maybe I missunderstand these phrases.
53 TK787 : I am not a pilot just trying to understand. Could someone please explain this? If F/O is flying the plane can he engage B as the master to control th
54 Severnaya : All three pilots were qualified for the a/c, but the F/O did not have that much experience in airline operations (he was a former air force pilot).
55 Osiris30 : Agreed 100%, but I find it sad it's "old-style" monitoring in some circles these days. All those little knobs and dials have important information on
56 Jpiddink : The report mentioned that the pilots noticed the differing radalts but did not consider it a serious problem. Only when the stall-alerts started, the
57 EMA747 : As far as I am aware yes but it will only take the radalt off the LH one regardless of which A/P is in command.
58 Osiris30 : Sorry to respond to your point twice (I'm not picking on you, honest ). However, I was just thinking about this and depending on the stage of flight
59 Comorin : Pilots - are there different CRM protocols when you have 3 people in the cockpit? Is it distracting to have an expert jumpseating behind you? Thanks
60 CityhopperNL : Yes, well I'm trying not to judge the pilots too hard as of yet cause we don't have all info, but your point is clear. I'm sure they didn't think abo
61 Starlionblue : Quoting NCB from previous thread: Hardware malfunction. Left radio altimeter failed on approach (indicating minus 8ft iso 1850ft) with auto-pilot on,
62 Nomadd22 : The A/T uses servos to physically move the throttles. It's easy to manually override the servo, but if the A/T will move them back to whatever positi
63 EMA747 : I assume that it's not normal for both radalts disagree. If so could it not be implemented that once the plane is on A/T and has intercepted the LOC
64 Rheinwaldner : IMO inexcusable that automation relies on one sensor when two are available. Sensors needs to be checked for plausibility before feeded forward into a
65 Sudden : Very sad and unfortunate all this! By all means! I do wonder how the aircraft was able to be on idle for 100 seconds!!?? without the crew noticing tha
66 Md80fanatic : A sensible conclusion from the investigators. If the crew didn't notice immediately the engines spinning down, there would not be enough time to spool
67 Mir : IIRC, the A/P always thinks it's doing an autoland. If the crew is not doing an autoland, they disengage it at the appropriate point, and then the AP
68 Gonzalo : Quick question, had the 737NG the function for turning off the A/T when you press the throttles eachother ( ---->
69 Mir : To be precise, a strike against pilots not monitoring the automation. -Mir
70 Post contains links PW100 : Here is the official Initial Press Statement of the Safety Board in English: Link Also, as said before, the Board has issued a Safety Warning to Boein
71 Post contains links Bahadir : here's the press release.. http://www.airporthaber.com/v3/extfiles/rapor.jpg
72 CrimsonNL : Also note that the safety board states that there was "almost certainly" no case of a controlled emergency landing in order to save extra lives. It wa
73 MD80fanatic : I really hate to burst anyone's bubble (actually I do), automation is best used in areas where humans have difficulty anyway. It leaves pilots free to
74 Theredbaron : Bet that Boeing s typing now a news directive that REQUIRES a working rad Alt as part of the 737 MEL requirements. Sad that this was cased by relying
75 757GB : Besides all the very informative technical discussion, it's just so sad that the aircraft went down due to a malfunctioning instrument and lack of awa
76 TristarSteve : What is an RA comparator? If RA fails you get a yellow box, but this one didn't fail, just gave the wrong height. This is not uncommon for RA. The si
77 MD80fanatic : I think we are a bit too arrogant with our technology.....and sad events like this don't seem to humble us at all.
78 NCB : A/P was on. If radar altitude readings don't agree right and left, a warning shows up in magenta: 'RA'. Basically, at that point, it's A/T off, A/P o
79 PW100 : Although very premature so I have to enter [Speculation Mode] * it appears that initial crew reaction to the speed loss and descend through the glide
80 Spitfire : To NCB : The Radio Altimeter -8ft indication took place while the A/C was at 1950 feet (close to the FAF which is at 6.2 ILS DME and 2000 feet). From
81 CityhopperNL : You make it look like these 6 seconds started at the point that they noticed the altimeter malfunction and that 6 seconds later the plane came down,
82 CityhopperNL : PW100 I agree with your analysis. And probably, failing to disengage AT or to go TOGA sealed their fate indeed. I would imagine that the stick shaker
83 DRAIGONAIR : The first thing you learn when you fly an airplane is your basic scan. The airspeed went 40kts below vref. They should have seen that the airspeed wa
84 TheSonntag : Don't you think it is actually rather ironic that this happened on the 738, which for example does not use FBW and is not as automated as the A320, f
85 Pylon101 : Well, we have got a pretty clear picture. A tragically simple clear explanation. I used to fly 737-800NG in Flight Simulator. And information given fu
86 Derik737 : Once again, this is the most important fact in my opinion. Plain and simple, the crew is responsible for flying the airplane. In this case, they forg
87 FFlyer : How does the above relate to this: The latter is from the Flight Global quote higher in this thread. 100 seconds...!
88 FlyLKU : I am curious how much time elapsed here. If there is anything more important than altitude and airspeed I don't know what it is. While preliminarily
89 TristarSteve : Are you sure about this? I have no B737NG manual, but the B777 does not have this feature which makes me suspicious.
90 AirbusA370 : I find it also very interesting, that the much critisised Airbus FBW philosiphy gives the pilots more authority over the thrust levers during flare.
91 JoeCanuck : Unfortunately, it seems like the pilots, (at least the FO), were unaware of the relationship between the LH radio altimeter and the auto throttle reta
92 Post contains links JoeCanuck : Boeing comments; http://www.flightglobal.com/articles...ots-to-altimeter-fault-boeing.html
93 Spitfire : When you take over : "I have control", you have already your left hand on the stick and your right one on the thrust levers, even if the copilot has
94 TrojanAE : Not to beat a dead horse, but as was stated previously, the crew had 100 seconds from the time the RA disagreement occured until they first took acti
95 EMA747 : Does anyone with experience of the 737NG know if this RA and A/T retard mode thing is ever mentioned in any training or manuals? Is it a case of it's
96 Spitfire : Not 6 seconds ...for 100 seconds, 1 minute 40 seconds....
97 Hiflyer : I understood that the throttles went to retard when the radalt went to -8 at 2000 feet on the final. Believe the 6 seconds were the throttles being p
98 NCB : You may be right, my understanding was that 6 seconds elapsed between engines reaching flight idle and the stick shaker. I find it unlikely since it
99 727forever : It would seem to me that the distractions were fatigue and inexperience. Was this not an all night flight? New guy in the right seat? An experienced
100 Osiris30 : Guys, I really think everyone is missing the key thing here. *Regardless* of what the A/T did, or what the pilots did or did not realise about the RA
101 Hiflyer : Over at another thread it was stated that the two FO's both joined Turkish in around 2007. Now..the PF was the newbie in type with a Training Captain
102 Haggis79 : read again... at1950ft they were high and fast and had descended through the glide path when the stick shaker finally went off.... i.e. they probably
103 Osiris30 : NCB: The error and subsequent thrust retardation happened approximately 100s before stick shaker. For 100 seconds *prior* to the stall warning the ai
104 DRAIGONAIR : The altitude didnt have anything to do with it and the time of the fail to stall wasnt a matter of seconds. They did notice the fail of the Right RA
105 Mcdu : Absolutely. Too many let the automation fly the airplane. The A/P should never be doing something your hands would not already be doing. That holds t
106 757GB : I really wonder what TALPA will say. I imagine silence initially, though they might go against Boeing. It's kind of hard to back out when they absolut
107 Greaser : I agree. I think this one will be pilot error. At the least, they should have gone around if they needed more time to fix any problem.
108 EMA747 : So what you are saying is that the A/T when into retard mode 100s before the stick shaker and the FO applying full power during which time it lost a
109 Post contains links NCB : I guess people are refering to this: "The throttles remained at idle for about 100s during which time the aircraft slowed to 40kt (75km/h) below refer
110 MD80fanatic : I think there is a problem with translation going on. 100 seconds the throttles were idle (meaning no one moved them for 100 seconds)...... OR 100 sec
111 EMA747 : Don't believe 99% of what the media says. BBC Radio this afternoon said "the faulty altimeter caused a loss of airspeed that made the plane crash" Wh
112 Osiris30 : Sequence as I understand it: RA breaks Throttles go to idle 100 seconds stick shaker FO applies power captain decides to take over 6 seconds of retar
113 CosmicCruiser : Having never flown a 737 I was wondering if it didn't have a comparator system like the altimeters. I tried to look in my manuals and there was no re
114 MD80fanatic : We should always keep our own abilities sharp...and asking questions is a perfect way to do it. If an official wishes to claim this plane stayed alof
115 Mir : He did, but he was talking about the barometric altimeter. A radar altimeter - the component that malfunctioned here - is something that should be in
116 MD80fanatic : Mir, This plane was one mile from touchdown.....meaning not more than 350-400 feet if they were on GS......but actually they were below at this point.
117 Mir : See, I'm not sure if you can have a vote-out-the-bad-one system with only two. It still strikes me as odd that a single failure could lead to this sc
118 Post contains links JoeCanuck : http://www.flightglobal.com/articles...-sudden-altimeter-step-change.html [Edited 2009-03-04 12:30:01]
119 EZEIZA : if it wasn't 100s, how much time would you think really went by? Because regardless of 100, or 90, or even 60s, it seems way too much time for three (
120 Nomadd22 : I'm trying to figure why the ra didn't indicate failure. -8 is likely a zero reading with an 8 foot offset to account for the difference between the t
121 PW100 : Well it all started at 1950 ft, when airspeed was still considerably over 160 kts, and well above the glideslope. So there was quite an excess of ene
122 Haggis79 : the plane crashed one mile from touchdown.... the RA failure occured at 1950 feet, way more out than just a mile from the runway. See Osiris' post ab
123 Derik737 : The fact of the matter is that the throttles were at idle for approximately 100 seconds according to the DFDR. As they may have been "hot and high",
124 Post contains links OwlEye : Reconstruction of the crash: http://www.rtl.nl/components/actueel...k10/wo_reconstructie.avi_plain.xml
125 MD80fanatic : Thanks Joe, I missed that. Even more so, from 1950 feet (6 miles out on GS) there was a RETARD command given by the AT, which means throttles tail off
126 Post contains links Hiflyer : http://www.ais-netherlands.nl/aim/09...tml/graphics/eAIP/AM-IAC-18R-3.pdf is the approach plate for the runway. Using the GoogleEarth OpenATC kmz file
127 CrimsonNL : He has a point here about the fact that theres no mention of the 100 sec in the official statement.. Could anyone please clarify this before everyone
128 Haggis79 : and it didn't... it went from above GS to below GS within those 100 seconds If they had noticed the problem before the stick shaker kicked in, they c
129 TristarSteve : Yes -8 is the minimum it can be with flat nose oleo and tyres. Normally on the ground it is -4 or -6. So the RA was transmitting a valid reading, jus
130 NCB : So you think that with flaps 30, gear down, idle, you can stay 100 seconds without hearing the stick shaker and lose only 40-60kts while losing 1850f
131 Post contains links GerbenYYZ : According to Wikipedia the elevation of Schiphol airport is -11 feet (-3m). The airport is below sea level. http://en.wikipedia.org/wiki/Amsterdam_Ai
132 PW100 : Well, I have re-read the intial report [Dutch version] and I am astonished to find out that it does NOT mention the 100 seconds. I am very certain th
133 MD80fanatic : How could you not notice though? There is a warning for below GS, at the very least. And before long, with no power you'd get a SINK RATE blaring non
134 JoeCanuck : The radio altimeter indicates altitude above ground. Terrain elevation is above sea level.
135 Post contains links JoeCanuck : I'll link to this again. Here's what Boeing says happens with a RA fault; http://www.flightglobal.com/articles...ots-to-altimeter-fault-boeing.html
136 Viscount724 : No, scheduled departure from Istanbul 7:55 AM local time, arrival AMS 10:40 AM. Block time 3:45. One hour time difference.[Edited 2009-03-04 13:12:59
137 GerbenYYZ : " target=_blank>http://www.flightglobal.com/articles....html The above link is where the 100 seconds come that we keep discussing... From the linked
138 PW100 : According to openATC this is the Altitude - Speed sequence: Time [UTC] - Alt [ft] - Ground Speed [kts] 09:21:23 - 7750 - 267 09:21:38 - 7425 - 258 09:
139 Post contains links Vikkyvik : Is this the official report: http://www.onderzoeksraad.nl/docs/ra...rten/Persverklaring_4_maart_GB.pdf If so, then the report states: "In practice, t
140 DRAIGONAIR : METAR EHAM 251025Z 22011KT 3500 -DZ BR OVC007 05/04 Q1027 TEMPO 2500= (1027-1013) x 30 = 420. 1625 plus 400? 2025ft close enough to 2000ft
141 NCB : Gliding distance has nothing to do with an airplane's weight. Different from gliding speed which increases with weight. ************ ****************
142 Comorin : Interesting to note that fail-safe engineering was not used in the design of of the A/T and LH RA linkage in this type. If the MD11's and 777's have t
143 DaBuzzard : Push throttles up, disconnect a/t, away you go........no "You are landing whether you want to or not".
144 Qualitydr : We have a complete CVR transcript somewhere? I fear I've missed a link in all these posts. I wonder what state/position the aircraft was in when the
145 MD80fanatic : I don't think APPR mode will automatically keep the airspeed just above absolute control loss, in the event of a total loss of thrust. APPR responds t
146 JoeCanuck : You scenario only makes sense if they did not know the RA controlled the auto throttle and did nothing once they noticed the RA was giving a faulty r
147 NCB : So basically about 15 seconds for the pilots to realise that something was wrong, if we may believe this data, which approximately coincides with my
148 Cmoltay : Boeing's press release mentions the 100 secs.
149 JoeCanuck : That's not necessarily true. The radio altimeter started reading incorrectly at 1950' and set the auto throttles to retard mode, whether or not they
150 MilesDependent : What was that crash where the captain and F/O had different airspeeds etc displaying on their controls? The autopilot was going off one system only. A
151 Post contains links Spitfire : Have a look on the timing here : http://www.openatc.com/THY1951/ At 09: 23:53 1625 ft (=2000 ft) speed 174 kts (it's a ground speed here !) track 203
152 Hiflyer : I have read elsewhere that 18R uses 2000 as a prelim approach to clear potential 18C traffic which is kept at 3000 until established. As THY came in
153 Doktor71 : Hello all, my first post here. I am no aviation professional but decided to join due to the high grade of professional postings here, especially at th
154 Post contains links Haggis79 : that sounds awfully like the Birgenair crash... http://en.wikipedia.org/wiki/Birgenair_Flight_301
155 Spitfire : They maybe flew manual ILS or visual approaches ....no A/T, no A/P...in that case no problem at all ![Edited 2009-03-04 14:04:16]
156 NCB : I guess that only few know that a faulty LH RA could affect A/T settings the way they did here. It's a programming blunder of Boeing to allow erroneo
157 Max777geek : That's what I tought, I knew the behaviour is like that, but, whenever I saw a pilot manually pushing the levers to have power, expecting they to com
158 MilesDependent : Yup, that's the one. Thanks.
159 Max777geek : From a computer logic perspective, what happened (if it will be extabilished to be happened as I did read until now) is just plain wrong. If you have
160 JoeCanuck : I would find it surprising that after the previous failures of the same radio altimeter that the issue wasn't brought up. I think I read that the sam
161 Spitfire : This afternoon I jumped in my (very) old B737 300-400- 500 operations manuals, and at least for those type of a/c, I didn't find any reference about
162 NCB : Now it all makes sense. In that case the 100 seconds of idle would have started before the RA exception occured. It would not make sense if it starte
163 EMA747 : Reading these few posts about the fact that maybe they were at idle thrust before the problem and that the 100s maybe doesn't mean that the pilots jus
164 Woody71 : Welcome Doktor71, Regarding your question, the transponder sends out the Baro Altitude to ATC as well as to the TCAS. So all air traffic will see you
165 Doktor71 : Thx, and what about speed?
166 ULMFlyer : I read in another forum that with the RA 1 indicating -8 ft, a number of these GPWS warnings would have been inhibited. Can't vouch for which ones ex
167 JoeCanuck : According to the report, this is the flight segment where the RA retarded the auto throttles; The altitude reading will come from the aircraft transp
168 Osiris30 : Before you go lecturing someone on reading well, please tell me where I can find the configuration of the aircraft at 1950 ft as flaps 30, gear down
169 Spitfire : Excuse me , but if i calculate correctly 09:25:38 minus 100 seconds = 09:23:58 ..... So between the points 09:23:53 and 09:24:08 .
170 Woody71 : The transponder sends all the info, speed, alititude, heading, to ATC but I can only assume that it gets its speed readings from the same place the F
171 Osiris30 : Give a better solution. Per Boeing's statement the crew would have been alerted to the retarded state of the throttles. What else would have them do?
172 Osiris30 : Guys, there was a warning, as well as several other indicators. The crew misunderstood/misinterpretted/underestimated them. They aircraft didn't simp
173 727forever : Hmm. With this experience we should have seen better performance. I would have to think that fatigue and lack of Boeing systems knowledge will come i
174 Mir : Not exactly. You could still engage TO/GA and have the throttles advance automatically. Quite plausible. There might have been a change on the FMA, b
175 727forever : Not quite. This would be acceptable as they still had 950' to get slowed. With flaps and gear and idle thrust not out of the question.
176 Spitfire : BTW, who said the a/c was in landing configuration when intercepting the G/S ???? They could have made a" low drag/ low noice approach", which means :
177 Doktor71 : I just reviewed Turkish Media quoting both TALPA and Turkish Pilots Association after the initial results of the Dutch Investigation were released: Tu
178 Mir : Well, we know the gear wasn't down when the RA made its error. So it's fair to assume that the flaps weren't in landing configuration either. -Mir
179 Spitfire : Flying time IST- AMS should have been something near 3 hours roughly...As they "landed" around 9:30 GMT (10:30 local time in AMS) the T/O from IST wa
180 LHRSpotter : Wasn't this the exact same scenario in the BA38 777 crash at LHR. The autothrottle only commanded thrust increase in the final moments of the descent
181 Boeing747_600 : So if my understanding is correct, both the (experienced instructor) Captain and F/O ignored the significant speed bleed for over a minute and a half
182 Osiris30 : Nope.. not at all. The BA 777 crash was a result of fuel flow starvation to the engines that made then unable to comply with increased thrust request
183 Doktor71 : Official figures from todays flight TK1951, also a B738, departed Istanbul 6:05 GMT, arrived 8:45 GMT Amsterdam, taken from official website of THY.
184 Spitfire : I have done that thousand of times during my career. Sometimes, when all went well (with the ATC): idle thrust at FL 370 or 390 and engine spooled up
185 FlyLKU : Agreed. The human pilot is always the PIC even when the autopilot is doing the actual flying.
186 Boeing747_600 : Yes, because it (the A/T) remained engaged and because the F/O released his grip on the thrust levers. Unlike the A/P which is disengaged with suffic
187 Osiris30 : There is a reason for that too. An accidentally disengaged A/T is far more dangerous than an accidentally disengaged AP in most phases of the flight,
188 Boeing747_600 : Perfectly OK, since you guys maintained airspeed. That's all that matters, even to ATC. The TK pilots sadly neither maintained airspseed, nor reacted
189 727forever : Not sure if your statement is accusatory or not, but it is the same profile that they were using yes. However, when your fuel temp is not allowed to
190 757GB : I'm not sure if it is the one you are referring to, but I do remember reading about Eastern Airlines flight 401 (the Ghost Flight), the L1011 that cr
191 CosmicCruiser : Very similar to the DL L1011 that crashed in DFW from the windshear. They pushed the throttles up but every time they got back to "bug" the A/T pulle
192 Bahadir : If they started the approach hot and fast, the idle throttle might become the norm after a while.. No. They started fresh in IST when the airplane ca
193 Mir : It's not that one. Eastern 401 was a result of an accidental AP disengage, followed by a slow descent into terrain while four people in the cockpit o
194 Boeing747_600 : I concur completely. The logic behind the A/T design is very sound. An A/T was never intended to be a substitute for situational awareness when it co
195 LHRSpotter : No, not accusatory at all, quite the opposite. I was agreeing about flying the approach without adding power being a normal practice. And contrary to
196 Ciaran : This reminds me of the Bergenair 757-200 flight 301 scanario when the autopilot took its primary info from a dodgy pitot tube on the LH, and Boeing wh
197 Osiris30 : Then I completely apologize for mis-interpretting what you were getting again. Mea Culpa.
198 XT6Wagon : Doesn't matter, radar altimiter tells you how high you are above whatever is below. So "0" is the same regardless if you are landing on the lowest sp
199 Post contains links Spkyflyer : Irish Times article: 'A faulty altimeter shut down the engine of a Turkish Airlines flight before it crashed last week near Amsterdam airport, killing
200 Osiris30 : Very bad reporting. The engines didn't shut down first of all. Second of all that aircraft hadn't (to my knowledge) had a previous issue with thrust
201 MD80fanatic : Or get rid of the problem of too much automation for good. This machine thought it was at ground level and spooled down, a human wouldn't do that. Pi
202 Haggis79 : right.... let's best get back to the technology used for the DC-8.... or why stop there - let's go back to the JU 52! I mean wasn't flying waaaayyy s
203 Osiris30 : They already can. You just don't hit the CMD button (or whatever it is labeled this week) ever. Problem solved. The 737 will do what you tell it, whe
204 MD80fanatic : Not all automation is bad, TCAS, Radar, etc. Automation should relieve a burden allowing pilots time to do other things. If the added time to do other
205 MD80fanatic : I don't know, but how hard it is to physically resist the throttle motors? I am getting this image that it takes considerable effort? I have no exper
206 Osiris30 : Many companies have a 'manual throttle by x feet unless fully auto-landing' policy. It's for a reason obviously. Having said that, autoland systems c
207 Traindoc : Certainly everyone is looking for quick answers to the TK crash. If there is a major safety issue, the sooner it is made aware and fixed the better fo
208 MD80fanatic : From what I have read here.... 1) Idle descent to 2000 ft. while slowing to set speed. 2) Before set speed is reached (and throttle up) RA fault cause
209 PlaneWasted : To those blaming too much automation: There will always be accidents related to too much automation, but as long as there is fewer accidents with auto
210 Osiris30 : The information available states the plane responded to all inputs by the pilots accordingly and appropriately and delivered more thrust when the thr
211 Sxmarbury33 : Would hitting TO/GA on the throttles override the Flare/Idle FMA and autothrottles? Is flare mode even armed for a single channel AP approach? If so,
212 PlanesNTrains : That's an interesting response, when you had already said: There are so many posts in these threads that it can be very difficult to follow. However,
213 727forever : Thanks. It is often hard to detect tone in written communication. Your observations are correct though. That's one. Now, tell me the accident to hour
214 Post contains links HB-IWC : Please continue the discussion in the following thread: TK B738 Crash At Amsterdam - Part 8 This thread is now archived.
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