Cypriot airliner crash - the accident and investigation

[flyboy2]

Cypriot airliner crash to be re-enacted
http://www.iol.co.za/index.php?set_i...6a6a20051217ah

December 16 2005 at 02:03PM

By Michele Kambas

Nicosia - Greek investigators will re-enact the flight of a doomed Cypriot airliner on December 19 in an effort to discover why the plane crashed north of Athens in August killing all 121 people on board.

The Boeing 737-300 operated by Helios Airways rammed into a hillside on August 14, the worst accident on record for either Greece or Cyprus and the worst in Europe this year.

Investigators are trying to work out what happened on board the plane - travelling from Larnaca in Cyprus to Prague - to render its two pilots unconscious, leaving a flight attendant with an emergency oxygen kit grappling with the controls
Costas Orphanos, head of the Cypriot crash investigation committee, said authorities had formed a picture of what had happened, but needed the re-enactment to verify the findings.

"What happened was unheard of, the way it happened was unheard of," Orphanos said when asked what made the disaster different from other air crashes.

He declined to be more specific pending release of the committee's findings at the end of February.

"It will be something which should concern the aviation industry as a whole, and it is our obligation to ensure that nothing like this happens again," he said.

"I haven't seen anything like this before, and I've been in the aviation industry for 40 years."

Seventeen people, pilots and engineers, will take part in Monday's flight using an Olympic Airways Boeing 737-300. Orphanos gave no further details.

The Helios jet crashed into the Greek mountains after flying on autopilot for over two-and-a-half hours. It is thought that the passengers, the majority of them Cypriots, were unconscious.

Two Greek fighter jets scrambled to intercept what was then regarded as a "renegade aircraft" and saw the co-pilot slumped in the cockpit and a steward wrestling with the controls. The pilot was nowhere to be seen.

Helios, a subsidiary of Britain's Libra Holidays Group, has defended its maintenance record but disclosed the aircraft had previously had decompression problems.

Air decompression reduces oxygen supplies and can lead to rapid loss of consciousness.

Relatives of the dead said they were still struggling to come to terms with their loss, a heavy blow to a small Mediterranean island with less than one million people.

"Some say time heals all wounds. In our case the anxiety and waiting to find out what happened just opens wounds further," said relatives' representative Nicholas Yiasoumis.

Relatives will not be present at the re-enactment.

[The Good Samaritan]

Seventeen people, pilots and engineers, will take part in Monday's flight using an Olympic Airways Boeing 737-300. .

Does Olympic have a compatible -300 like the one crashed????

[Oshkosh George]

According to this list,they have one,SX-BLC.

http://www.airfleets.net/flottecie/O...ctive-b737.htm

Any volunteers for pax on this re-enactment?

[Jet2]

Flight took place today as reported by the BBC

http://news.bbc.co.uk/1/hi/world/europe/4542226.stm

Greek investigators have taken part in a re-enactment aimed at determining what caused a Cypriot airliner to crash near Athens in August.

All 121 people on board died when the Helios Airways Boeing 737-300 lost cabin pressure and hit a hillside.

Greek investigation chief Akrivos Tsolakis said the re-enactment was unprecedented for Greece.

A Greek F-16 fighter jet also flew alongside the plane on Monday, as happened on the fatal day.

"We hope certain basic questions will be answered," said one of the investigators, Serapheim Kamoutsis.

Monday's reconstruction flight left Larnaca airport at 1107 - two hours after the original flight on 14 August - due to the position of the sun, the AFP news agency reported.

An Olympic Airways Boeing 737-300 was used, taking the same flight path as the Helios jet.

As a mark of respect, the re-enactment was given the symbolic flight number 121, in memory of the crash victims.

Coroners said those on board the Helios jet were alive - though possibly unconscious - when it crashed.

A pressure valve left in manual mode is thought to have contributed to the crash by failing to adjust the in-flight cabin pressure.

All but 11 of the victims were Cypriot.

The crash orphaned 47 Cypriots, 26 of them children.

A flight attendant is believed to have tried to take control of the airliner during its final moments.

The pilots of two Greek F-16s who shadowed the airliner just before the crash said they saw the co-pilot slumped over the controls and the captain was missing from the cockpit.

Flight 522 had been heading for Athens en route to Prague when it lost contact with air traffic controllers, sparking a security alert before it crashed.

[SaturnV]

From Reuters

Aviation experts said after re-enacting the doomed Boeing 737-300 flight from Larnaca in Cyprus to Prague, that the steward -- who had some flight training and used an emergency oxygen kit -- actually flew the plane for 10-12 minutes.

"We have indications that (he) controlled the plane. He took a portable oxygen device and opened the cockpit door using a code," Seraphim Kamoutsis, head of the Greek investigations team, told a news conference after the simulation.

[airside]

Yep,
photos of re-enact flight avaialble here :

www.11aviation.com

or here :

http://tinyurl.com/dusac

Not easy to see something like tha very often
Elliott

[PAXboy]

This may seem like a rude question but is honestly asked: What is gained by flying a machine round this route - as opposed to running it in the SIM?

From an outsider's point of view, if they can reconstruct the flight path, then they have already learnt what the machine was doing 'on the outside' but that can make zero change to what they know about the events on the inside of the machine.

This flight looks more like a publicity event for the investigator and a tribute flight as an expression of sympathy for the friends and relatives.

[Kyprianos Biris]

link to the other thread with a video of the low pass

http://www.pprune.org/forums/showthr...&pagenumber=86

[PAXboy]

This confirms that the event to be a 'memorial' flight for the bereaved families and should, really, have been advertised as such. The new data learned from this must be very small.

[DingerX]

While here and there some are getting sanctimonious about this "reenactment", unfortunately it serves a specific scientific purpose. The investigating board's job is to create a hypothesis concerning what happened, and then as accurately as possible test that hypothesis. That can mean recreating the conditions if possible.

Of course, there's no ruling out that some officials may want to milk this event for as much political gain as possible, and do their business with a certain pomposity and flair.

[big fraidy cat]

If you check on the old Cypriot thread [see Tech Log], you will see my post referring to the press conference, which was held after the re-enactment flight. I think that it proves that the re-enactment was worthwhile. I don’t want to post it here again, as it just takes up too much space.

Also on that thread, in my response to a query from The Hawk who asked ‘what new input’, it might be worth repeating those details here as well.

The new input is that they tested some of their hypotheses in real time, and found that they were implausible, and apparently this was not earlier ascertained in the simulator.

Most particularly among them is the fact that the cabin attendant, Andreas Prodromou, entered the cockpit using the door code (and not an axe!). Further, that he entered the cockpit way prior to any engine flameout; that he took manual control of the plane, and that they still don’t know how he disengaged the autopilot.

They also discovered that setting the pressurization switch to manual in reality really had little or no effect on the cabin pressure. In the final analysis at this point, there was no sudden death at 14000 feet.

[Techman]

Paxboy,

A simulator is nothing more than a box full of wires. Fidelity is not guaranteed.

[PAXboy]

Techman: Thanks for that. I usually preface my remarks to indiucate that I am not crew and that my PPRuNe name shows that too.

[Flight Detent]

big cat,

I'm curious to know the specifics of your statement -
Setting the pressurization switch to manual has little or no effect on cabin pressure.

Since in reality it makes a very large difference to the cabin pressure, I'm wondering just what was the position of the outflow valve at the point the switch was set to manual?
I'm totally avoiding the question of that big indicator light above the switch that shows MANUAL, when it's set.

On landing, the outflow valve autos to fully open slowly, so it's always fully open unless the switch is set to manual and the valve intentionally toggled towards closed.

I can't understand how, if the valve is fully open (and who knows if it was) it doesn't make any difference to the cabin pressure - of course it will!

Cheers, FD

[big fraidy cat]

Flight Detent

Here's a copy of today's article in The Athens News. I think that it addresses your question. Information on the postion of outflow valve has not yet been released.


Helios puzzle 'recreated'

Questions about the strangest crash in aviation history multiply as Greek investigators re-enact the doomed flight which killed 121 people

By Dimitris Yannopoulos

AN UNPRECEDENTED "re-enactment" of the doomed Helios Airways flight that crashed 50km outside Athens on August 14 "has cast some light on the dark spots in the four-month probe", the Greek investigators said after the flying drill on the evening of December 19.
But 'experiments' carried out during the mock flight also raised more questions that needed further analysis, veteran captain Akrivos Tsolakis, chairman of the Air Accident Investigation and Aviation Safety Board (AAIASB) told reporters. "Some of our assumptions and flight recorder data were confirmed, but others need revision and further scrutiny," Tsolakis said.
All 121 people on board were killed when the Boeing 737-300 slammed into a hillside.
The plane apparently had lost cabin pressure after takeoff, incapacitating the pilots, and eventually crashed into a Grammatiko hillside as it ran out of fuel after flying pilotless for nearly three hours. Investigators carried out the re-enactment of Helios Flight 522 from Larnaca, Cyprus, to Athens to analyse the causes of Greece's worst air disaster and probably the weirdest accident in aviation history.

Flight attendant's heroism

The most striking new finding of the flight's recreation was that the flight attendant, Andreas Prodromou, was in control of the Cypriot Helios Airways plane in its final path, 15-20 minutes before it crashed. A trained pilot who was working as a steward with Helios until he could find a co-pilot's job, Prodromou - donning a cabin crew oxygen mask - tried to save the doomed flight and wrestled with the controls after entering the cockpit by punching in the door code while the plane was still doing its holding rounds at 34,000 feet over the island of Kea.
Tsolakis had earlier hypothesised that Prodromou entered the cockpit after the plane's left engine burned out. AAIASB executive director Serafeim Kamoutsis said they now believe that the 25-year-old Prodromou entered the cockpit before the engine failure while the plane was still in a holding pattern and the pilots were unconscious or partially conscious. "He tried to fly the plane manually as best as he could when the autopilot disengaged," Kamoutsis said, adding that it was too early to say how the auto-pilot was disabled.

Why not climb down

Tsolakis said he believed the Cypriot airliner suffered a "partial, and not total loss of pressure" at an early stage in the flight. At its highest "cruising" altitude of 34,000 feet, the plane's cabin altitude – the pressure inside the fuselage - had reached 26,000 feet when, under normal pressurisation, it should remain at 8,000 feet throughout the flight. "This (loss of pressure) occurred during the ascent, in the first five minutes after takeoff from Larnaca..." Tsolakis said. The flight attendant, with other members of the cabin crew, remained conscious, however, because they used the plane's portable supply of oxygen, he added.
Asked by the Athens News why they didn't stop the climb below 10,000 feet when the pressurisation problem was obvious but not yet fatal for the crew or passengers, Tsolakis admitted that this remains a mystery. "We are still investigating why the pilots continued their ascent and did not respond properly," Tsolakis said.
Kamoutsis admitted that at a cabin-altitude ascent rate of 2,500 feet per minute most passengers' eardrums would feel like bursting within seconds from takeoff. Normal ascent rate of a fully pressurised cabin is 300-400 feet per minute - anything above that rate can be painful. "We know that this makes the theory of the confusion of the decompression alarm signals with configuration problems difficult to swallow," Kamoutsis told the Athens News, referring to the initial speculation that, at 12,000 feet, the pilots mistook the decompression alarm signal for a takeoff warning that only sounds on the ground. "But we have no other rational explanation for their failure to climb down before they passed out," he said.
Investigators suspected that a mode selector switch for controlling the plane's two pressure valves had been placed on the wrong setting, but, following the re-enactment flight, Tsolakis cautioned that this fact alone was not enough to explain the accident. "The switch is not the main issue," he said, acknowledging that the position of the switch on "manual" instead of "auto" could not by itself produce such loss of pressure. "We have to look into the factors behind the position of the switch to determine why it was found in that position and what happened to the pressure valve after takeoff."

[BOAC]

Back into the fray after a while:

If that journalist's article is a true representation of what Mr Tsolakis is saying/thinking then he and his team are some way off track! To allay my concerns I am hoping it is a translation problem as there are some significant questions arising from the article.

One of the big questions for me is why it took so long for the c/crew to enter the flight deck, and reading the newspaper reports, this seems to have been ignored so far?

[big fraidy cat]

BOAC

I was baffled too, since most of the international press carried the same news from the Tsolakis briefing about Prodromou entering the cockpit earlier with the code. So I contacted the editor of the Athens News; he advised that, due to space restrictions, the article, which went to press late Thursday, had to be limited to 750 words. He very kindly sent me the original draft, which included the comments on the Prodromou and cabin crew issue, as noted below. For the sake of brevity, I will just excerpt the Q & A.

According to the reporter’s original draft, which includes some marginal notes, the question you raise about the timing of the cabin crew’s entrance was asked more than once. The answer was: “This is still under investigation. We don’t know yet whether they could or did get into the cockpit earlier.”

Again, according to the draft, several reporters asked how the flight attendant and at least one other of the cabin crew had survived for 2.5 hours at an unpressurized cabin altitude of 26,000 feet. The answer was: “They used auxiliary O2 bottles.” Q: How long do these last? A: “Twenty-five minutes – they were using them interchangeably.”

Continuing, the next questions were: Why were traces of the co-pilot’s DNA (saliva) found on two different cockpit oxygen masks? Was there a lack of oxygen, or did the co-pilot need more until he could lower the plane? Did the captain leave his seat to find spare bottles in the passenger cabin? A: “This is still under investigation.”

Q: What about the medical report stating that both pilots had severe coronary blockage? The co-pilot’s wife strongly disputes this. A: “We haven’t studied the evidence of that in the coroner’s report. It is not yet confirmed.”

BOAC, there is much more in this text of the press conference; these are just a few of the topics covered. All in all, the re-enactment of the flight raised more questions than were answered.

Finally, I would like to wish you and all of our fellow pruneys a very Merry Christmas and all the best for the New Year to come!!

[SASless]

Cabin/cockpit altitiude does not change in the Sim....as it does in the actual aircraft.

If some of the volunteers were masked and some unmasked then the effects of the loss of pressure...and such could be measured...compared to theories...etc.

I can see some benefit to a re-enactment as it relates to the investigation. However it would appear the long list of questions that would remain far outweigh what benefit the reenactment would answer. It almost sounds like a few pages out of a Richard Wambaugh novel where the detectives tried to reenact their theory that would turn a murder into a suicide and thus solve the case quickly. Wambaugh described a situation where the cops fired a Colt .45 over a thousand times to get a single spent shell casing to land on top of a wardrobe in order to prove their convenient theory.

Is this what is going on here....pick an answer and find the evidence to support it?

[Helios Ray]

Insupportable Answers

SASless,

Pick an answer and find the evidence to support it?

Hmmm... I don't think so. Problem is they've picked the most implausible answer and can't find credible evidence to support it.

This is the real mystery of the Helios investigation IMHO.

What's the problem with saying the decompression happened at 34,000 feet and, for some reason (eg lack of O2, radio malfunction, APU failure etc), they didn't have time to react before the onset of hypoxia.

Makes more sense than having to say it all happened at 12,000ft but "the crew didn't realise it because they thought it was the T/O Config horn" and... 15 minutes later, they were still talking with Helios LAME, at 29,000ft.

Any thought on this puzzle, anybody?

[Deserter]

In defence of Captain Tsolakis

Helios Ray,

You are obviously no veteran of the 100-page Cypriot thread, but the point you're making is both original and serious.
Nevertheless, I don't see why you seem to imply that the available data are no less implausible than the 'answers' given to explain them.

You obviously take into account the new evidence which the investigation has unveiled relatively recently - when the previous thread had abruptly fallen silent

The new facts (confirmed during the re-enactment briefing) are

(1) Cabin Alt Horn sounded at 12,000ft, about 4 minutes from takeoff (09:11) - NOT at 15,000ft as previously assumed.

(2) At 29,000ft, about 15 minutes from takeoff (09:20), the crew was still in communication with the ground - ATC and Helios maintenance chief.

(3) The cabin altitude at the end of the plane's 2.28-hour flight at cruise alt FL340, was around 26,000 feet.

The above new data are broadly consistent with the timeline put forward by Captain Tsolakis in his first full interview with Flight International on Aug.24:

http://www.flightinternational.com/A...no+fuel++.html

In this interview the Greek Chief Investigator also reveals something extraordinary about the plane's airworthiness:
[quote]Tsolakis says he is worried at what he is finding in the engineering records of the aircraft, which had required air conditioning system rectification five times in less than two months, leading Helios engineers to question the aircraft's fitness to fly.[/qote] The importance of that observation will become apparent later.

This is then followed by the central tenet of the sudden death scenario:

It was only 4min 50s into the flight before the crew reported to ATC an air conditioning malfunction, Tsolakis reveals, but they kept climbing. Passing through 14,000ft, the cabin altitude warning alert activated and it was not cancelled.

Four months later, we know that the sequence of these early events was the reverse of what Tsolakis had implied: The cabin altitude sounded at 12,000ft, ie BEFORE the crew notified ATC of their airconditioning problem. And then, the cabin altitude horn WAS cancelled as they manually restored the OFV to the closed (or at least partially closed) position.

Here is what Tsolakis tells TA NEA daily in a full-page interview two months after his FI interview, on October 29:

When the plane took off from Larnaca airport, "the environmental control system packs and bleed switches were configured correctly. But the pressure mode selector switch was in MANUAL and pressurization of the aircraft was not automatically controlled, resulting in an increasing cabin altitude as the airplane climbed," Tsolakis tells the mass-circulation daily.
And then, here comes his salvo: "It appears that the captain and the first officer knew that [PMSS set in MANUAL]. As the plane was climbing at a rate of 4,000 feet per minute, the cabin altitude warning horn sounded in the flight deck and was cancelled by the crew, who believed that they had regained control of the pressurisation inside the aircraft, by manipulating the outflow valve manually. They then continued to climb."

In other words: No mixup of horns, no PMSS 'unwittingly' set in Manual, full open pressure valve shut manually by the crew, pressurization restored (temporarily), plane continues to climb while dealing with secondary problems (E&E bay cooling) with Helios engineers. This is all stated succinctly in another respectable aviation website:

http://www.b737.org.uk/accident_reports.htm

The aircraft departed Larnaca at [09.07 Greek time] for Athens. The crew reported to Cypriot ATC that they had a problem with the air conditioning system and wanted to remain at 16,000ft. At [09:22] the crew said that they had solved the problem and requested a climb to 34,000ft. Radio contact was lost with the aircraft at approximately [09:37], as it was entering Greek airspace, 30 minutes after its departure, although it did sqwark 7700.

Did they really hold their climb at 16,000 feet, when they started talking with Helios Maitrol? Was the 'problem' solved at 30,000 feet, when they requested a climb to 34,000 feet? Probably not.

Given Tsolakis' aforementioned evaluation of the plane's lackluster pressurization record and airworthiness, it is easy to understand how the �problem� re-emerged in full force after they decided to revert back to AUTO. From a (manually) closed position, the OFV gradually or swiftly opened again by one-third, and remained in the same position until it was found at the crash site, with the FDR registering cabin alt 26,000 feet at FL340.

It had happened before at the same cruise altitude (16 December 2004). It happened again on August 14. But this time - even though they were prepared for it - they couldn�t bring the plane down.

They just couldn't climb down an inch from 34,000 feet - not even glide down! For how long did they try to do so? How did Prodromou finally manage it by disengaging the autopilot?
Nobody will ever know for sure. But Tsolakis is right when he speaks to London's Guardian newspaper on December 15, shortly before his controversial re-enactment of the fateful flight:

It was a tragedy waiting to happen," said Mr Tsolakis. Ultimately, he said, every area of the aviation industry, from the manufacturers of the plane, to the airline, the mechanics, civil aviation ground staff, and pilots were to blame for the crash.