Cypriot airliner crash - the accident and investigation
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For the sake of the engineers it is only fair to point out that the statement on page 22 of the English version of the report shows the statement that the valve WAS returned to AUTO.
It may be of significance that one of the actions in the Boeing QRH for depressurisation is to select Manual? The picture is by no means clear to me.
It may be of significance that one of the actions in the Boeing QRH for depressurisation is to select Manual? The picture is by no means clear to me.
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Why is the Take Off Warning sounding???
On the 737 the Take Off Configuration warning and Cabin Altitude warning both use the same aural alert. This has caused confusion for many crews over the years. The Take Off Config warning is usually checked during the preflight and the alert is very familiar. The same horn for Cabin Altitude is usually canceled very quickly after the loud bang in the Simulator.
The continual sounding of the horn can be debilitating. It has been known for a crew to be sitting there at FL 350 wondering what is going on when the Purser launches into the cockpit (prior to September 11) wanting to know why the aircraft is not descending, the passenger O2 had deployed.
Due to a mechanical failure the cabin alt had been gradualy climbing.
May be the Helios crew where in a similar quandary, with the aircraft climbing quickly their TUC may have expired before they realised the problem.
The continual sounding of the horn can be debilitating. It has been known for a crew to be sitting there at FL 350 wondering what is going on when the Purser launches into the cockpit (prior to September 11) wanting to know why the aircraft is not descending, the passenger O2 had deployed.
Due to a mechanical failure the cabin alt had been gradualy climbing.
May be the Helios crew where in a similar quandary, with the aircraft climbing quickly their TUC may have expired before they realised the problem.
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The Helios/ajet position, according to today's Cyprus Mail:
Ajet stands firm over accident position
By Elias Hazou
OFFICIALS from ajet, formerly known as Helios Airways, yesterday stuck to their guns over the cause of last summer’s crash, focusing on build deficiencies on Boeing planes.
The company says it has carried out extensive tests strongly showing that it is “near to impossible” for a Boeing 737 jet to take off with the decompression switch on manual, as a report into the accident by Greek investigators suggests.
The tests showed that venturing a takeoff on manual generates so much noise that it bursts passengers’ eardrums, not to mention the fact the hatch door would not shut in the first place.
But Air Accident Investigator Akrivos Tsolakis’ fact-finding report found that the airflow valve was set at a 14 degrees angle from the manual position, allowing for partial pressurisation. For this type of Boeing, it should have been on the auto switch before takeoff.
According to the official version, on the night before the accident ground crew had reset the switch to manual, but on the fateful flight the pilots apparently omitted to conduct the pre-flight checks.
The problem was compounded in the air, when the pilots misread an alarm for a takeoff configuration glitch, because the sound emitted for that is identical to the one for a decompression problem.
Mistaking the alarm for a false takeoff configuration warning - which could not be the case, as the plane was already airborne - the aviators were troubleshooting in the wrong direction, while all the time the plane steadily depressurised, leading to the onset of hypoxia.
Strangely enough, although in his probe Tsolakis mentioned this omission by the engineer, he made no recommendations about Helios, merely noting the airline’s operational deficiencies under the “latent” (not immediate) causes of the crash.
But Helios insists that two series of tests - one in May, the other in August - all but eliminate the possibility the decompression switch was on manual. Both these tests were carried out in England.
The results, they say, were not taken into account in the Tsolakis report.
The company is planning a third run of tests to be supervised by a former UK air accident investigator and aviation expert.
While agreeing that the primary cause of the accident was depressurisation, Helios disagrees with Tsolakis on how this came about.
They say the engineer had set the switch to auto, as required, but the electrical system did not respond due to bad wiring on the plane - i.e. a manufacturing fault.
Thus, the system “read” the switch as being on auto while in reality it was not.
By extension, according to Helios, that would explain why the pilots assumed the decompression configuration was fine. Thus the airline is also ruling out pilot error.
“Either way, whether the switch was on auto or manual, the point is that the accident is not a direct result of the actions/omissions of airline staff,” said Christos Neocleous, a spokesman and lawyer for Helios yesterday.
“I want to make this clear: we are not attacking the Tsolakis report. In fact, we believe it was very professional in all respects. But we do have reservations about these two points, which suggest a lack of a safety culture at the airline,” Neocleous told the Mail.
And even if the engineer on duty had left the decompression switch in the manual position, that person could not be blamed, because Boeing’s manual for 737s was vague on this matter.
Prior to the accident, instead of explicitly instructing ground technicians to reset the decompression switch to auto, the manual simply said that the switch should be set “to the previous position,” i.e. from manual to auto.
Boeing has since updated its manuals to correct this ambiguity.
Asked what the company would do with their findings, Neocleous offered:
“The accident report is final. It cannot be changed.”
But he hinted the airline might seek compensation from the manufacturers. He said wiring problems on 737s had been widely reported prior to the accident, so Boeing should have fixed the problem.
On the other hand, before the accident there had been recurrent problems with the air conditioning system aboard Helios planes, suggesting faulty electrics. Passengers had often complained of freezing, but apparently the airline took no steps to resolve this issue.
Boeing is also being sued in the United States by the relatives of the victims.
Copyright © Cyprus Mail 2006
Ajet stands firm over accident position
By Elias Hazou
OFFICIALS from ajet, formerly known as Helios Airways, yesterday stuck to their guns over the cause of last summer’s crash, focusing on build deficiencies on Boeing planes.
The company says it has carried out extensive tests strongly showing that it is “near to impossible” for a Boeing 737 jet to take off with the decompression switch on manual, as a report into the accident by Greek investigators suggests.
The tests showed that venturing a takeoff on manual generates so much noise that it bursts passengers’ eardrums, not to mention the fact the hatch door would not shut in the first place.
But Air Accident Investigator Akrivos Tsolakis’ fact-finding report found that the airflow valve was set at a 14 degrees angle from the manual position, allowing for partial pressurisation. For this type of Boeing, it should have been on the auto switch before takeoff.
According to the official version, on the night before the accident ground crew had reset the switch to manual, but on the fateful flight the pilots apparently omitted to conduct the pre-flight checks.
The problem was compounded in the air, when the pilots misread an alarm for a takeoff configuration glitch, because the sound emitted for that is identical to the one for a decompression problem.
Mistaking the alarm for a false takeoff configuration warning - which could not be the case, as the plane was already airborne - the aviators were troubleshooting in the wrong direction, while all the time the plane steadily depressurised, leading to the onset of hypoxia.
Strangely enough, although in his probe Tsolakis mentioned this omission by the engineer, he made no recommendations about Helios, merely noting the airline’s operational deficiencies under the “latent” (not immediate) causes of the crash.
But Helios insists that two series of tests - one in May, the other in August - all but eliminate the possibility the decompression switch was on manual. Both these tests were carried out in England.
The results, they say, were not taken into account in the Tsolakis report.
The company is planning a third run of tests to be supervised by a former UK air accident investigator and aviation expert.
While agreeing that the primary cause of the accident was depressurisation, Helios disagrees with Tsolakis on how this came about.
They say the engineer had set the switch to auto, as required, but the electrical system did not respond due to bad wiring on the plane - i.e. a manufacturing fault.
Thus, the system “read” the switch as being on auto while in reality it was not.
By extension, according to Helios, that would explain why the pilots assumed the decompression configuration was fine. Thus the airline is also ruling out pilot error.
“Either way, whether the switch was on auto or manual, the point is that the accident is not a direct result of the actions/omissions of airline staff,” said Christos Neocleous, a spokesman and lawyer for Helios yesterday.
“I want to make this clear: we are not attacking the Tsolakis report. In fact, we believe it was very professional in all respects. But we do have reservations about these two points, which suggest a lack of a safety culture at the airline,” Neocleous told the Mail.
And even if the engineer on duty had left the decompression switch in the manual position, that person could not be blamed, because Boeing’s manual for 737s was vague on this matter.
Prior to the accident, instead of explicitly instructing ground technicians to reset the decompression switch to auto, the manual simply said that the switch should be set “to the previous position,” i.e. from manual to auto.
Boeing has since updated its manuals to correct this ambiguity.
Asked what the company would do with their findings, Neocleous offered:
“The accident report is final. It cannot be changed.”
But he hinted the airline might seek compensation from the manufacturers. He said wiring problems on 737s had been widely reported prior to the accident, so Boeing should have fixed the problem.
On the other hand, before the accident there had been recurrent problems with the air conditioning system aboard Helios planes, suggesting faulty electrics. Passengers had often complained of freezing, but apparently the airline took no steps to resolve this issue.
Boeing is also being sued in the United States by the relatives of the victims.
Copyright © Cyprus Mail 2006
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According to the official version, on the night before the accident ground crew had reset the switch to manual, but on the fateful flight the pilots apparently omitted to conduct the pre-flight checks
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But Helios insists that two series of tests - one in May, the other in August - all but eliminate the possibility the decompression switch was on manual.
They say the engineer had set the switch to auto, as required, but the electrical system did not respond due to bad wiring on the plane - i.e. a manufacturing fault.
Thus, the system “read” the switch as being on auto while in reality it was not.
They say the engineer had set the switch to auto, as required, but the electrical system did not respond due to bad wiring on the plane - i.e. a manufacturing fault.
Thus, the system “read” the switch as being on auto while in reality it was not.
Is the consensus here that, as was suggested a long time ago, the official report is an attempt to fit what has been discovered into a chosen scenario, rather than the other way around, or has it contributed to understanding?
Cheers,
Rich.
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It would seem to me that, if Helios/ajet is claiming that Boeing manufactured a defective plane, and that the plane had serious electrical problems [by the way, if there had been an inkling of that, why would they continue to operate the plane?], wouldn't it be important to view the maintenance records from the DBA operation from the previous five years? I'm sure that the Boeing lawyers would want to see those, and I wonder if the Tsolakis investigation also looked at those. I think I'd want to, if I were the investigator.
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This situation would have been a non event to a competent crew.
There is something that nobody has mentioned as far as I am aware.In the aftermath of the crash the reports seemed to imply that the Captain's radio call to dispatch and/or the engineer was almost exclusively centered on the cooling problem.However,the report says that the skipper did report "takeoff config warning on" during his call.If he did actually use these words to a qualified engineer,then I would say that it would be encumbent upon the engineer to remind him that such a scenario is not possible and to get him to check the cabin altitude.If he reported it to dispatch only then its a different matter.
Another small niggling item;the Captain reported that his equip cooling lights were OFF.Thats a normal situation.Obviously not what the skipper meant to say but his English wasnt perfect.The engineer seems to have taken him literally and not taken into account his less-than-perfect English.Why would the Captain call him to report a normal situation?Facetious or genuine error you decide?
I think the report has exonerated the engineer and that is correct.this was a flight-crew error.I think the point is that you can exonerate somebody without being entirely happy with them either.
"The step is there in the 737-3/4/500 AMM, ref TASK 05-51-91-702-001 Cabin Pressure Leak Test.
Near the end is the following:
F. Put the Airplane Back to its Usual Condition"
CaptainSandL,
Apologies - I didnt know it was in the 737 Manual, but that is possibly the exception to the rule. This statement has possibly been amended into the 737 manual as a result of previous incidents?
As stated by Fargoo - Engineers may try and return the flight deck to its original condition but it is more often left in the state "at the end of work". I don't know of anyone that will try to reset switches at the end of work. However; What is the "Usual Condition"? That may vary from contract to contract.
Rigga
Near the end is the following:
F. Put the Airplane Back to its Usual Condition"
CaptainSandL,
Apologies - I didnt know it was in the 737 Manual, but that is possibly the exception to the rule. This statement has possibly been amended into the 737 manual as a result of previous incidents?
As stated by Fargoo - Engineers may try and return the flight deck to its original condition but it is more often left in the state "at the end of work". I don't know of anyone that will try to reset switches at the end of work. However; What is the "Usual Condition"? That may vary from contract to contract.
Rigga
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There is something that nobody has mentioned as far as I am aware.In the aftermath of the crash the reports seemed to imply that the Captain's radio call to dispatch and/or the engineer was almost exclusively centered on the cooling problem. However,the report says that the skipper did report "takeoff config warning on" during his call. If he did actually use these words to a qualified engineer, then I would say that it would be encumbent upon the engineer to remind him that such a scenario is not possible and to get him to check the cabin altitude. If he reported it to dispatch only then its a different matter.
Cheers,
Rich.
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As for the MM end statement, this is a Boeingism and loads of the function checks end in that statement.
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I can confirm that that both versions of the report in that part (paragraph 1.6.2.3.2) are an acurate (word-to-word) copy of one another.
If anything so far, by reading (large portions but not yet all of) both versions of the report I get the impression that the English version is actually the original one and that the report was subsequently translated into Greek rather than the other way around.
I could be wrong of course although I somehow doubt it.
TR
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It seems to me that the report is intimating that this was a bleeds off takeoff, why else post the Irish reports which were also bleeds off. There were other reports they could have included where a defective outflow valve was the culprit, but they didn't. After-crash photos of the control panels also seem to support that theory.
It seems quite plausible (though not proven) that the pilots were in the process of reconfiguring from bleeds off when the E&E recurring problem popped up, diverting the pilot's attention.
Some posters contend that a bleeds off was not done, as conditions did not warrant it. However, 115 pax going away on holiday will be carrying a lot of luggage, thereby adding a lot of weight. And, in mid-August on Cyprus, the temperatures were probably in the 30s (celsius), even in the morning.
It seems quite plausible (though not proven) that the pilots were in the process of reconfiguring from bleeds off when the E&E recurring problem popped up, diverting the pilot's attention.
Some posters contend that a bleeds off was not done, as conditions did not warrant it. However, 115 pax going away on holiday will be carrying a lot of luggage, thereby adding a lot of weight. And, in mid-August on Cyprus, the temperatures were probably in the 30s (celsius), even in the morning.
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As someone mentioned above, it must be tough being the guy at the beginning of the "trail of errors" so it's possible the engineer "honestly convinced himself" he had reset to AUTO. And being only human (and still alive) was not likely to admit he could be wrong.
Psychological factors and all that - similar to the pyschology of not spotting the pressurisation issue in three (?) checklists and a warning horn.
Whatever else happens as a result of this sad story, I don't think anyone will accuse the engineer of false evidence.
These comments made against the background that I am
- not a pilot
- not a psychologist
- a lawyer
Thanks to the mods of this board for the opportunity to comment.
Glad to be shot down for any errors of fact I may have made.
Neil
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Midland - I concur - it is a struggle to read it properly.
Still too many open holes for my liking - no pun intended.
'Thanks for the thanks' on behalf of Danny and the team - this is an important topic.
Still too many open holes for my liking - no pun intended.
'Thanks for the thanks' on behalf of Danny and the team - this is an important topic.
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BFC,
Very unlikely.First of all a bleeds off wouldnt have been necessary even in summer.Secondly,if crews forget to reconfigure after obstacles,they certainly clue into the problem when the horn goes off passing 10000'.They have the mindset.They've briefed a bleeds off,they've operated switches on the pneumatic panel just minutes ago and they've made a mental note to reconfigure after obstacles.The 522 crew didnt have this mindset..they werent expecting to have to reconfigure the pneumatic panel at all after takeoff.Because they went bleeds ON.
Forgetting the PACKS is totally different.In this case the crew would not be expecting to reconfigure after takeoff and would have to actually scan the panel to see why the plane was not pressurizing.The report spoke of "look but dont see" syndrome,especially with the distraction of a horn.Theres the Irish scenario.
Forgetting the switch in MAN is similar to the PACKS OFF problem.A crew would have to actually scan the panel to see why.Take a crew in the climb passing 12000 just like 522 ;When they look up at the panel following the cabin alt horn,their scan is probably going to be bleeds then packs.This is after levelling off and donning O2(if above 130).Now some crews arent going to make the connection to the mode selector at this moment.Except perhaps if it was at nighttime because the green MANUAL light is going to stand out like a sore thumb.Some crews will immediately pick up the MANUAL indication and reselect AUTO.They'll continue their flight just so long as masks havent dropped.If the masks drop they may still continue at 250.
Some crews wont pick it up at all;they look but just dont see.The report spoke of pilots rarely having to touch the pressurization mode selector in anycase.So this crew will return to base and when the engineer points out the problem they'll probably look a bit sheepish and notch up another one for the memory bank.
It doesnt matter whether you're the ace who continues at 250 and saves the company money or the sheepish one who puts the schedule back 3 hours.Both saw the problem,levelled off and saved lives.
522 didnt do this.WHY?CRM?Mindset?Cockpit argument?Distraction with E&E problem?PLAIN BAD LUCK?(After all what are the chances of that E&E master caution annuciation masking the O2 drop again?)It would be fascinating if only it werent so sad.
Very unlikely.First of all a bleeds off wouldnt have been necessary even in summer.Secondly,if crews forget to reconfigure after obstacles,they certainly clue into the problem when the horn goes off passing 10000'.They have the mindset.They've briefed a bleeds off,they've operated switches on the pneumatic panel just minutes ago and they've made a mental note to reconfigure after obstacles.The 522 crew didnt have this mindset..they werent expecting to have to reconfigure the pneumatic panel at all after takeoff.Because they went bleeds ON.
Forgetting the PACKS is totally different.In this case the crew would not be expecting to reconfigure after takeoff and would have to actually scan the panel to see why the plane was not pressurizing.The report spoke of "look but dont see" syndrome,especially with the distraction of a horn.Theres the Irish scenario.
Forgetting the switch in MAN is similar to the PACKS OFF problem.A crew would have to actually scan the panel to see why.Take a crew in the climb passing 12000 just like 522 ;When they look up at the panel following the cabin alt horn,their scan is probably going to be bleeds then packs.This is after levelling off and donning O2(if above 130).Now some crews arent going to make the connection to the mode selector at this moment.Except perhaps if it was at nighttime because the green MANUAL light is going to stand out like a sore thumb.Some crews will immediately pick up the MANUAL indication and reselect AUTO.They'll continue their flight just so long as masks havent dropped.If the masks drop they may still continue at 250.
Some crews wont pick it up at all;they look but just dont see.The report spoke of pilots rarely having to touch the pressurization mode selector in anycase.So this crew will return to base and when the engineer points out the problem they'll probably look a bit sheepish and notch up another one for the memory bank.
It doesnt matter whether you're the ace who continues at 250 and saves the company money or the sheepish one who puts the schedule back 3 hours.Both saw the problem,levelled off and saved lives.
522 didnt do this.WHY?CRM?Mindset?Cockpit argument?Distraction with E&E problem?PLAIN BAD LUCK?(After all what are the chances of that E&E master caution annuciation masking the O2 drop again?)It would be fascinating if only it werent so sad.
Last edited by Rananim; 23rd Oct 2006 at 10:08.
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Not being an expert myself.... can I ask if that's wise? I mean would O2 continue to be consumed if they continued with masks dropped or is it automatically switched off? What happens if they have another loss of CP an hour or two later?
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Use of Accident Final Reports
Right or wrong, there is little that can be done once a Final Report has been issued. Very quietly the Judicial Review has been removed from most legislation so someone wronged has little or no comeback.
What us aviation types should be jumping up and down about and decrying from the rooftops (or FL340!) is the fact that it has been announced that the Final Report into the Helios Accident will be used as the basis of the Kallis Inquiry in Cyprus to determine criminal or civil liability. I have been told that Judge Kallis has said that he will not consider anything that doesn't agree with the Reports Findings.
It is interesting that the JOINT RESOLUTION REGARDING CRIMINALIZATION OF AVIATION ACCIDENTS by FSF has just been circulated and Captain Tsolakis, who wrote the Report, is the Chairman the Flight Safety Foundation–Southeastern Europe.
This is the thin end of the wedge but I don't hear any indignant cries from either Captain Tsolakis or the FSF - double standards or what.
What us aviation types should be jumping up and down about and decrying from the rooftops (or FL340!) is the fact that it has been announced that the Final Report into the Helios Accident will be used as the basis of the Kallis Inquiry in Cyprus to determine criminal or civil liability. I have been told that Judge Kallis has said that he will not consider anything that doesn't agree with the Reports Findings.
It is interesting that the JOINT RESOLUTION REGARDING CRIMINALIZATION OF AVIATION ACCIDENTS by FSF has just been circulated and Captain Tsolakis, who wrote the Report, is the Chairman the Flight Safety Foundation–Southeastern Europe.
This is the thin end of the wedge but I don't hear any indignant cries from either Captain Tsolakis or the FSF - double standards or what.
Last edited by airsnoop; 20th Oct 2006 at 10:47. Reason: typo and amplification