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ManaAdaSystem
The 737 NG is a good aircraft, but it does have it's flaws. Warning systems are not up to modern standards. Helios and cabin altitude warning springs to mind. Being modified as we speak. |
Engines running or not?
While we would get a better answer probably this week, I would like to point to 3 "evidences":
-several eyewitness reported increasing sound of the engines short of the impact. One supposed eyewitness (on the ground) said: "There was no explosion but the noise of the impact, a big bang, the ground trembled and there was the sound of engines howling like they reversed power or were just overturning by lack of resistance.*" "*Jeroen Jonkers, an Amsterdam resident, is an eyewitness of the crash of a Turkish Airlines flight in Amsterdam. He contacted Hurriyet Daily News via its website and sent his story. This is his story in his own words." http://arama.hurriyet.com.tr/arsivnews.aspx?id=11090641 (I know, maybe not the best source, but I think a detached, running, engine would make a very particular noise and the description doesn't sound like a fake). -then this picture, from the highway, showing the first seconds after the impact, with dust "traces" from the engines. The engines nearly 80-100 m in front of the plane wing (aparently) http://media.nu.nl/m/m1bzv76a43o6.jpg There are a lot of pictures showing both an engine and the plane, but taken with telephoto lens (or similar zoom) that gives a wrong distance feeling ("the telephoto shot appears to compress the distance between objects due to the perspective from the more distant location." Wikipedia). -Both engines apparently travelled the same distance and one remained in the same "flight" direction. I tend to think it was due to gyroscopic effect. Well, that's all my speculation and I would wait the DFR and CVR readings. added "" |
Video
Big Blue Eyes,
I watched a great number of live feeds and loops on TV from the first shots shown by Sky and BBC 24. There were injured with broken limbs being carried out of the middle section of the aircraft long after this video was supposedly taken - yet they don't appear as trapped in their seats. No I don't believe that sightseers are allowed anywhere near the aircraft but personal belongings have to be removed and catalogued and debris trails are mapped - in fact many accident scenes have large numbers of people swarming over them (most not in uniform) once the recorders have been removed and photo evidence has been taken from key sites such as, in this case, the cockpit. That's why I asked when the clear up and mapping teams gained access - a point you missed in your hurry to pour scorn on my analysis. |
Nobody is bothering to investigate EMP disruption of digital aircraft systems |
I'm not aware of any documented cases to suggest that the use of mobiles on board have ever interfered with aircraft systems, no more than there is evidence to suggest that it's dangerous to use them while filling up your car at the petrol station. But it's better not to take that chance so they prohibit their use in these situations - fair enough. In the Ryanair case (using OnAir technology that has already been used elsewhere) the chance of such interference occuring is greatly reduced (if it exists at all) as the phones need only produce minimum power output to communicate with the on board transmitter, as opposed to maximum output to communicate with a ground station. While I would of course hope they investigate all possibilities in this crash, I personally don't feel they'll find anything untoward in this regard. What amazes me is the disagreement amongst bread and butter pilots as to all the various A/T modes, procedures, etc for this aircraft. Surely one guy's 738 rating is exactly the same as the next guy's (ie there's only one way to fly this aircraft properly), and everyone should be singing from the same hymn sheet (though this is where different company SOPs come in I suppose) |
Originally Posted by 892
What amazes me is the disagreement amongst bread and butter pilots
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In the Ryanair case (using OnAir technology that has already been used elsewhere) the chance of such interference occuring is greatly reduced (if it exists at all) as the phones need only produce minimum power output to communicate with the on board transmitter, as opposed to maximum output to communicate with a ground station. This is just one more reason to believe that interference from mobile phones has nothing to do with the accident in question, and is probably not much more likely than an alien laser attack. So while rumours are the gist of this forum, I would suggest to stick to slightly more realistic scenarios. |
My bets are with Belgique's analysis.
The explanation will revolve around what the AT was or was not doing... Why? Something to do with Occam's Razor? Precedents, reported and un-reported, exist for very similar aircraft behaviour. |
"The use of mobile phones on board aircraft by flight crew, cabin crew and passengers presents a source of uncontrolled electro-magnetic radiation with a risk of adverse interference effects to required aircraft systems including those used for communications and navigation." UK CAA. I think the CAA know what they are talking about! |
Close up pic of blades: http://www.dallasnews.com/sharedcont...VS2IVPRU.1.jpg
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One more engine close up: http://static.guim.co.uk/sys-images/...urkish-001.jpg
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Mobile Phones
Well, recently I was paxing to SYD aboard a [non British] B777 [configured for inflight mobile phone use] where everyone awake was happily using their cell/mobile phones.
Good point - But! That aircraft was configured to be mobile phone friendly. I think interference from mobile phones is a theory that should be looked at, as has previously been said. If it ‘s nothing at all to do with this then fine and dandy. But worth looking at and worth checking mob phone records from masts in that area. In fact - wouldn’t the ‘on’ mobile phone kick-in at just about the geographical point of the incident? I know nothing about mob phones, but worth investigation - even if it’s just for ‘elimination purposes’ as the police would say. |
The What - and now the "HOW" and "WHY"
"De Telegraaf" reports that the Boeing was descending much too fast. From the radar registration it appears that the aircraft descended at 1344 ft/min instead of the usual 700/800 ft/min. 45 Seconds before the crash the descent rate was 576 ft/min at a low 85 knots speed. Speed at time of crash was 83 knots. Speed in the last 2 minutes was 159, 148, 145, 129, 117, 85, 83 knots. . In an attempt to validate my interpretation of post 779's English, I've attempted to re-write it more clearly (see the coloured bits), as I'm a steam-driven multi-pilot. I'd like a high-tech man to validate If you are in FLCH descent and not following the FD, the throttles will stay in idle (HOLD) until down to the MCP ALT. Switching off the FD changes the A/T to speed mode and everything is fine. That's the reason why you have to switch off the FD during visual approaches. If the AFDS was in LVL CHG (FLCH for the 757 crowd) prior to FD disengagement and prior to ALT capture, the A/T would remain in ARM (i.e. ready but inert - not good). Subsequently pressing the SPEED button on the Mode Control Panel (MCP) would restore the A/T to MCP SPD mode (with FD's off, such as on a manually-flown visual approach). However if the AFDS was in V/S mode at time of FD disengagement, then the A/T would remain in MCP SPD and increase thrust as required to maintain whatever was set as the "MCP-selected" speed. Might a fair conclusion therefore be that: "the AFDS was in LVL CHG prior to FD disengagement and prior to ALT capture, so the A/T remained in ARM (i.e. ready but inert - not good)?" |
A Scenario for an insidious A/T knock-out?
Auto-throttle can conventionally and generically be knocked out (disconnected) in a number of ways:
. e.g. (and typically) . ATS OFF/ON button pushed, A/T DISC on left throttle pressed, AP disengaged, ALL INTERRUPT button on yoke pressed, and......... . Pilot manually pushes throttle lever and actual position and autothrottle position differ by >10 degrees for 3s. (a Turkish trainee's typical ab initio error?) . Is it within the realm of possibility that a trainee (that's not used to auto-throttle) should sight unseen (by the other pilots) make such a singular inadvertent input and then realising his mistake, thereafter cease making throttle inputs, thinking that the auto-throttle was still doing its thing? . Plausible on a 738? |
bobcat4
Helios Airways Flight 522 was a 737-300 which made its first flight in December 1997. Cabin altitude warning/configuration take-off warning is not similar on the NG (IIRC). |
UNCTUOUS (#823), you did not state what type you fly. Regarding the 737NG:
1) ATS OFF/ON button pushed, 2) A/T DISC on left throttle pressed, 3) AP disengaged, 4) ALL INTERRUPT button on yoke pressed, and......... 5) Pilot manually pushes throttle lever and actual position and autothrottle position differ by >10 degrees for 3s. 1) Yes, it's a switch on the MCP 2) Yes, actually on both thrust levers 3) Nope 4) Nope, yoke button disengages A/P only 5) Nope again (that answers, "Plausible on a 738?") Lotsa speculation going on here but I agree that this is a Rumours Net and I enjoy some of the reading. I've found some pearls like PJ2 and DC-ATE posts. I would tend to side with PJ2 but appreciate both's, generally respectful, way of posting. I also agree with whoever said that statistically, most of the speculative writing going on here will prove wrong at the end of the investigation process. May I recommend "Safety is no Accident" (Tench William H.) reading to those interested in the matter? Thanks also to the poster that mentioned the speed deselect method, I had never used it b4; I moslty fly fully manual (FD) below 1000 AGL. I'd like to ask the poster who said speed deselect was forbidden at one of his airlines why was so? Regarding automatic operation, may I also remind that A/T only (no A/P) operation is forbidden/not recommended (we don't don't do it, can't remember which is the right one) on the 737NG. That has been already said but a later poster did not notice it). And finally one request: please take time to read all posts (diagonally is ok;)) b4 posting. |
Electromagnetic radiation
Otto Nove Due wrote:
I'm not aware of any documented cases to suggest that the use of mobiles on board have ever interfered with aircraft systems, no more than there is evidence to suggest that it's dangerous to use them while filling up your car at the petrol station. Although a receiver will emit electromagnetic radiation from its local oscillator, it is a mind-boggling low power. Probably less than background radiation from ground stations or cosmic radiation (the latter was ironic). :) |
First of all, I am not a qualified pilot so will not be offering comment on anything I'm not qualified to do. Having read the full thread and having worked with emergency services for 14 years and qualified in matters of crash investigation can I say that the first priority will always be the preservation of life. Yes damage caused by rescuers will often make matters more complicated but no investigator would ever criticise anyone acting in good faith to rescue survivors. Investigators will aways, by careful examination of the damage and witness statements including those from rescuers be able to establish what is impact damage from that of rescue damage. Certainly this is the policy in the UK and I would imagine for the rest of Europe.
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Re the video: It's quite obviously a film taken well after the event probably with dubbed sound. There is a ruddy great hole in the cockpit roof - made by the long departed firemen.
The JAA accuracy standards for Mode S is +/- 125' but what is the actual accuracy of the tx units installed? To put any real credence on Google plot with interpolated data collected from a spotters SBS1 unit doesn't sit well with me. Kegworth scenario / engine failure / stretched glide / stall all seem like plausible options. |
Originally Posted by eltonioni
(Post 4756797)
Re the video: It's quite obviously a film taken well after the event probably with dubbed sound. There is a ruddy great hole in the cockpit roof - made by the long departed firemen.
It is possible that the audio was dubbed in after, and that this video was shot much later. But it looks authentic to me. At what part of the 1:03 long video did you see a "ruddy great hole in the cockpit roof "? All I saw was the small hole made by the reinforced door frame being pushed up by the impact. |
Eyewitnesses + Engine noise
I'm not a pilot, but I know that sound travels at 340m/s (sea level)..
This means that for someone 1000m from the crash the sound and what he/she sees have a time diffirence of ~3 seconds... With a vertical speed of 4000ft/min, 3 seconds is 200ft. Somenone reporting that he heard the engines 'reving up when the plane hit the ground', then in reality the engines reved up at 200ft. Have it in mind when you think about eyewitnesses reports, eye witnesses are not flight data recorders, and I doubt that the accident board will ask them to testify. Add to that that planes sound diffirently depending on the angle that you are(a bit extreme comparison, but have you seen an A380 slow flyby? You can barley hear it from some angles) |
Eltonioni
The mode S altitude reporting units normaly work to 25ft incriments. The +/_ 125 ft is the operational limitation.
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Not much to go on so far. As far as I can gather the a/c was at flight idle (or close to it) and losing airspeed until the crew advanced throttles and the ground got in the way of the recovery from one or more of below g/s, low speed and high rod.
How long does it take in the 737-800 to get climb thrust in landing configuration after putting the throttles forward from flight idle? |
Video seems genuine
Those claiming that the video is fake or made a day or two after the incident should note that in the video, only the left-hand front door is open (left, as seen from front of plane) whereas the later still photography published by the Dutch fire service of the rescue operations show that both front doors have been opened. This supports the fact that the video was indeed taken before the emergency services arrived. Plus, the fairly obvious fact that the video shows people wandering aimlessly all over the crash site - which would hardly be the case a few hours later...
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There are plenty of cases where people have made a "little movie", in circumstances where some might expect everybody to be either in shock, or legging it, or both. When the London Underground was bombed recently, several mobile phone movies were made.
It would seem completely possible that everybody sitting in a section of the airframe might have walked out - the movie indeed shows this. It also shows the overhead lockers still in place (though open) so that airframe section did not come down that hard. |
RatherBeFlying
From rusty memory (someone will correct me) I think the certification requirement is to get 95% of TOGA thrust within 5 seconds. We're not talking about climb thrust here.
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quote] From rusty memory (someone will correct me) I think the certification requirement is to get 95% of TOGA thrust within 5 seconds. We're not talking about climb thrust here. [/quote]
Building on the above. I think that what is important here is the rate of change of thrust vs time, vs the rate of change of pitch (due to thrust changes) vs rate of change of airspeed. In the long and short of it, in spte of the guesses, a little DFDR data could go a long way towards establishing if the aircraft had already reached a critical AoA before the thrust was changed or the thrust change preceeded it. Some of the posts while intelligent and well intentioned are leading too far ahead of any confirmed useful facts. |
An observation from the transponder data:
The aircraft descended out of cloud almost at the same instant that the groundspeed reached 120 kts, i.e. the indicated airspeed was then around 130 kts which I guess was fairly close to Vref. And it was practically on the glide slope. Scenario: A quick glance at the instruments indicated everything was OK, so attention shifted to the runway ahead. But, as the data suggests, in fact the airspeed was decaying at a rate that only ~10 seconds later took the aircraft below 110 kts indicated, which is, I guess, about the stick shaker activation speed. Is it plausible that the cloudbreak caused a diversion of attention at the critical time? Just asking. |
Hmmm
The crew would presumably have had to not react to the following 1) Glideslope aural alert if GS was captured of course 2) EGPWS Terrain Terrain Warning 3) Possibly a stall warning 4) Possibly a radar contoller warning re altitude dme So they ignored all of this or left it too late, and flew into the ground - all 6 eyes???? Come on, this would be very very unlikely. There must be more to this than meets the eye. I would not be too hard on the crew just yet.... |
video
There are plenty of cases where people have made a "little movie", in circumstances where some might expect everybody to be either in shock, or legging it, or both. When the London Underground was bombed recently, several mobile phone movies were made.
I'm convinced the video is genuine, and all the more sad for that. And above comment is of course, even more sadly, true. As I mentioned in a previous post, none - or very few - of us know how we might behave in this kind of emergency situation. I prefer to think my first inclination would be, wow, I'm still in one piece, let's see what help I can be to those less fortunate. But maybe the shock factor would make me whip out my phone. But I don't think so. |
The video is obviously genuine and taken soon after the accident. OK, so making a film on a mobile phone would not be the priority for most of us (I hope), but this guy just survived a plane crash and I'm sure had any residual sense shaken out of him. People act in different ways. Simple as that.
It must have been the most bewilderingly disorientating situation to be put through. I felt nauseous just watching it, let alone what it must be like to be there. The eerie calm captured on tape is surely what you would expect immediately after an accident and before the emergency services arrive. No need for conspiracy theories IMHO. |
Dusttraces engines
Thx for pointing out the pic of the engines blowout smoke.
They has to be still going (few secs) while seperated from the a/c. So my withness that engines were still running during impact and after is most likely. I was upm to 50 mtr from the a/c at the site. Engines were +/- 80-100 mtr in front of a/c almost parallel . The tailwing was +/- 100-125 mtr behind a/c. while tailsection was still attached (0r close to) at back of the a/c. The degree of damage to the fuselage was not in the extend to think 50tn heavy a/c was hitting the ground fast. Pulling the nose high up with (max) power seems to me a controled crash landing. http://photonews.hurriyet.com.tr/Liv...s/DSCN1122.JPG |
Autothrottle "clicks out"
Regarding some earlier post about the auto throttle i would just like to mention the fact that i have experieced on 737-800 aircrafts how the auto throttle "clicks out". The so called "auto throttle arm switch" leaves its armed postion and goes to off. It does this without any warning. If this would happen during an ILS app while reducing speed, it might well go unnoticed and lead to a stall.
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F/A's Action in this incident
I have seen some hint of people complaining of the lack of cc helping with the evacuation of the pax in this accident. Considering two would be in the very front between the cabin and flight deck they would have been very lucky to have survived seeing the state of others within that part of the a/c and were probably unconscious. As for the two at the rear, there whole world was ripped apart with the impacting of the rear fuse and they would not have been in a position to help either.
So come on people, think before you make these unfounded remarks. I am not going to speculate on this accident, I do hold some views from what visible evidence is available to us all, but as an ex ground engineer with over 45 years experience I leave this to experienced pilots and the investigators. Time will tell. |
"crashresident" ,
How long did you stay at the site? Can you confirm or disprove these statements: "According to the eye-witnesses and passengers, first aid came 40 minutes after landing," said Ziya Yilmaz, Turkish Air Line Pilots Associaton (TALPA) president tells ATI. "The first officer was screaming and waiting 40 minutes for rescue. We will inform IFALPA and ask why?" Akyuz continued: "When we first arrived at the scene we saw people lying on the ground injured. Some of them had broken legs... I entered the fuselage from one of the open doors and walked to the back part of the plane. There were couple of people there and we helped them to get out." He also commented: "It took around 20 minutes before the rescue teams got to the scene as a secondary road leads there." The Safety Board said it is unable, at present, to provide the time it took for the crash rescue team to arrive at the accident scene. Runway 18R is the furthest of the runways from the main part of Schiphol airport, and the wrecked hull was about 1km short of the runway threshold outside the airport boundary. |
Regarding some earlier post about the auto throttle i would just like to mention the fact that i have experieced on 737-800 aircrafts how the auto throttle "clicks out". The so called "auto throttle arm switch" leaves its armed postion and goes to off. It does this without any warning. If this would happen during an ILS app while reducing speed, it might well go unnoticed and lead to a stall If the localizer was captured above the path,the pilot(or trainee) may have not been able to program the automatics for a recapture.Perhaps then they took alll the automatics out.During the recapture,they get distracted(or rather fixated) and forget that thrust is manual. Automation.Great tool.But you never ask of George what you cant do yourself.Pilots should be trained to fly the plane manually with raw data first then introduce the AFDS incrementally.Basics first.Airmanship. |
The ground was presumeably still v. cold and wet. possibly not smoke from a (hot) engine but steam from the ground?
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Status of flight attendents
Reports I've read indicate a total of 4 FAs. One was killed, one lost a leg (likely the two sitting directly behind the cockpit). One commented that she was glad she carefully explained to the passengers how to operate the exists as they were the ones who opened the exit and then carried her out of the aircraft. That leaves either one or two FAs who could have assisted the passengers after the crash, depending on if the FA who lost her leg was the same one who commented about the passengers assisting her.
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Originally Posted by Lon More
(Post 4757381)
The ground was presumeably still v. cold and wet. possibly not smoke from a (hot) engine but steam from the ground?
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Crash-site
to LiS,
I arrived aprox 10min. (10.45)at the site. stayed there for 1 our 15 min. Help arrived when aproached a/c. At that time volunteers rescueteams were helping pax. It may take several minutes for medics to enter the a/c for safety reason. So help was there, was quick and efficient. |
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