Helios Airways Flight 522
5B-DBY, the aircraft involved in the accident, at Prague Ruzyně International Airport in March 2005.
|Date||14 August 2005|
|Summary||Uncontrolled decompression due to pilot error, leading to incapacation and fuel exhaustion|
|Site||Grammatiko, Marathon, Greece|
|Aircraft type||Boeing 737-31S|
|Flight origin||Larnaca International Airport|
|Stopover||Athens International Airport|
|Destination||Prague Ruzyně Int'l Airport|
Helios Airways Flight 522 (HCY 522 or ZU522) was a Helios Airways Boeing 737–31S flight that crashed into a mountain on 14 August 2005 at 12:04 EEST, north of Marathon and Varnavas, Greece, whilst flying from Larnaca, Cyprus. A lack of oxygen incapacitated the crew, leading to the plane's eventual crash after running out of fuel. Rescue teams located wreckage near the community of Grammatiko, 40 km (25 mi) from Athens. All 121 on board were killed.
With 121 dead, this was the deadliest aviation disaster in Greek history, surpassing the crash of an Olympic Airlines DC-6 in which 90 passengers and crew lost their lives. It was the 69th crash of a Boeing 737 (the most numerous passenger jet aircraft in the world) since it was brought into service in 1968.
The aircraft involved in this incident was first flown on 29 December 1997 and had been operated by DBA until it was leased by Helios Airways on 16 April 2004 and nicknamed Olympia, with registration 5B-DBY. Aside from the downed aircraft, the Helios fleet consisted of two leased Boeing 737-800s and an Airbus A319-111 delivered on 14 May 2005. The aircraft had arrived in Larnaca from London Heathrow at 01:25 that morning.
The flight was scheduled to leave Larnaca, Cyprus, at 09:00 local time, to Prague via Athens. The scheduled arrival time in Athens was 10:45. Hans-Jürgen Merten, a 59-year-old German contract pilot hired by Helios for the holiday flights, was the captain. Pampos Charalambous, 51, a Cypriot who flew for Helios, served as the first officer. 32-year old Louisa Vouteri, a Greek national living in Cyprus, replaced a sick colleague as the chief purser.
Flight and crash 
|Date: 14 August 2005
All times EEST (UTC + 3h), PM in bold
|0907||Departs Larnaca International Airport|
|0912||Cabin Altitude Warning sounds at 12,040 feet (3,670 m)|
|0914||Pilots report air conditioning problem|
|0920||Last contact with crew;
Altitude is 28,900 feet (8,809 m)
|0923||Now at 34,000 feet (10,400 m);
Probably on autopilot
|0937||Enters Athens Flight Information Region|
|1012–1050||No response to radio calls from Athens ATC|
|1020||Athens ATC calls Larnaca ATC;
Gets report of air conditioning problem
|1024||Hellenic Air Force (HAF) alerted
to possible renegade aircraft
|1045||Scheduled arrival in Athens|
|1047||HAF reassured that the problem
seemed to have been solved
|1055||HAF ordered to intercept by Chief of
General Staff, Admiral Panagiotis Chinofotis
|1105||Two F-16 fighters depart Nea Anchialos|
|1124||Located by F-16s over Aegean island of Kea|
|1132||Fighters see co-pilot slumped over,
cabin oxygen deployed, no signs of terrorism
|1149||Fighters see an individual in the cockpit,
apparently trying to regain control of aircraft
|1150||Left (#1) engine stops operating,
presumably due to fuel starvation
|1154||CVR records two MAYDAY messages|
|1200||Right (#2) engine stops operating|
|1204||Aircraft crashes in mountains
near Grammatikos, Greece
When the aircraft arrived from London Heathrow earlier that morning, the previous flight crew had reported a frozen door seal and abnormal noises coming from the right aft service door, and requested a full inspection of the door. The inspection was carried out by a ground engineer who then performed a pressurization leak check. In order to carry out this check without requiring the aircraft's engines, the pressurisation system was set to "manual". However, the engineer failed to reset it to "auto" on completion of the test.
After the aircraft was returned into service, the flight crew overlooked the pressurisation system state on three separate occasions: during the pre-flight procedure, the after-start check, and the after take-off check. During none of these checks did the flight crew notice the incorrect setting. The aircraft took off at 9:07 with the pressurisation system still set to "manual", and the aft outflow valve partially open.
As the aircraft climbed, the pressure inside the cabin gradually decreased. As it passed through an altitude of 12,040 feet (3,670 m), the cabin altitude warning horn sounded. The warning should have prompted the crew to stop climbing, but it was misidentified by the crew as a take-off configuration warning, which signals that the aircraft is not ready for take-off, and can only sound on the ground.
In the next few minutes, several warning lights on the overhead panel in the cockpit illuminated. One or both of the equipment cooling warning lights came on to indicate low airflow through the cooling fans (a result of the decreased air density), accompanied by the master caution light. The passenger oxygen light illuminated when, at an altitude of approximately 18,000 feet (5,500 m), the oxygen masks in the passenger cabin automatically deployed.
Shortly after the cabin altitude warning sounded, the captain radioed the Helios operations centre and reported "the take-off configuration warning on" and "cooling equipment normal and alternate off line". He then spoke to the ground engineer and repeatedly stated that the "cooling ventilation fan lights were off". The engineer (the one who had conducted the pressurization leak check) asked "Can you confirm that the pressurization panel is set to AUTO?" The captain, however, disregarded the question and instead asked in reply, "Where are my equipment cooling circuit breakers?". This was the last communication with the aircraft.
The aircraft continued to climb until it leveled off at FL340, approximately 34,000 feet (10,000 m). Between 09:30 and 09:40, Nicosia ATC repeatedly attempted to contact the aircraft, without success. At 09:37, the aircraft passed from Cyprus Flight Information Region (FIR) into Athens FIR, without making contact with Athens ATC. Nineteen attempts to contact the aircraft between 10:12 and 10:50 also met with no response, and at 10:40 the aircraft entered the holding pattern for Athens Airport, at the KEA VHF omnidirectional range, still at FL340. It remained in the holding pattern, under control of the auto-pilot, for the next seventy minutes.
Two F-16 fighter aircraft from the Hellenic Air Force 111th Combat Wing were scrambled from Nea Anchialos Air Base to establish visual contact. They intercepted the passenger jet at 11:24 and observed that the first officer was slumped motionless at the controls and the captain's seat was empty. They also reported that oxygen masks were dangling in the passenger cabin.
At 11:49, flight attendant Andreas Prodromou entered the cockpit and sat down in the captain's seat. Prodromou held a UK Commercial Pilot License, but was not qualified to fly the Boeing 737. Crash investigators concluded that Prodromou's experience was insufficient for him to gain control of the aircraft under the circumstances.
In any case, he did not have time to save the stricken aircraft. Almost as soon as he entered the cockpit, the left engine flamed out due to fuel exhaustion, the plane left the holding pattern and started to descend. Ten minutes after the loss of power from the left engine, the right engine also flamed out, and just before 12:04 the aircraft crashed into hills near Grammatiko. There were no survivors.
The aircraft was carrying 115 passengers and a crew of 6. The passengers included 67 due to disembark at Athens, with the remainder continuing to Prague. The bodies of 118 people were recovered. The passenger list included 93 adults and 22 people under the age of 18. The passengers comprised 103 Cypriot nationals and 12 Greek nationals.
Suspicions that the aircraft had been hijacked were ruled out by Greece's foreign ministry. Initial claims that the aircraft was shot down by the fighter jets have been refuted by eyewitnesses and the government.
The flight data recorder and cockpit voice recorder were sent to Paris for analysis. Authorities served a search warrant on Helios Airways' headquarters in Larnaca, Cyprus, and seized "documents or any other evidence which might be useful in the investigation of the possibility of criminal offences."
Many of the bodies recovered were burned beyond visual identification by the post-impact fire. However, it was determined that a body found in the cockpit area was that of a male flight attendant and DNA testing revealed that the blood on the aircraft controls was that of flight attendant Andreas Prodromou, a pilot-in-training with approximately 260–270 hours of training completed. Autopsies on the crash victims showed that all were alive at the time of impact, but it could not be determined whether they were conscious as well. Prodromou was not originally scheduled to be on the flight; he joined the crew so he could spend time with his girlfriend, a fellow Helios flight attendant.
The emergency oxygen supply in the passenger cabin of this model of Boeing 737 is provided by chemical generators that provide enough oxygen, through breathing masks, to sustain consciousness for about 12 minutes, normally sufficient for an emergency descent to 10,000 feet (3,000 m), where atmospheric pressure is sufficient to sustain life without supplemental oxygen. Cabin crew have access to portable oxygen sets with considerably longer duration. Emergency oxygen for the flight crew comes from a dedicated tank.
The Hellenic Air Accident Investigation and Aviation Safety Board (AAIASB) determined that the direct causal chain of events that led to the accident was
- non-recognition by the pilots that the pressurisation system was set to "manual",
- non-identification by the crew of the true nature of the problem,
- incapacitation of the crew due to hypoxia,
- eventual fuel starvation,
- impact with the ground.
Previous pressurization problems 
On 16 December 2004, during an earlier flight from Warsaw, the accident aircraft experienced a rapid loss of cabin pressure, and the crew made a successful emergency descent. The cabin crew reported to the captain that there had been a bang from the aft service door, and that there was a hand-sized hole in the door's seal. The Air Accident and Incident Investigation Board (AAIIB) of Cyprus could not conclusively determine the causes of the incident, but indicated two possibilities: an electrical malfunction causing the opening of the outflow valve, or the inadvertent opening of the aft service door.
The mother of the first officer killed in the crash of Flight 522 claimed that her son had repeatedly complained to Helios about the aircraft getting cold. Passengers also reported problems with air conditioning on Helios flights. During the two months before the crash, the aircraft's Environmental Control System required repair five times.
News media widely reported that shortly before the crash a passenger sent a text message indicating that one of the flight crew had become blue in the face, or roughly translated as "The pilot is dead. Farewell, my cousin, here we're frozen." Police later arrested Nektarios-Sotirios Voutas, who admitted that he had made up the story and given several interviews in order to get attention. Voutas was tried by a court of first instance on 17 August 2005 and received a suspended 6-month imprisonment sentence under a 42-month probation term.
Another hoax involved photographs allegedly showing the aircraft being chased by Greek fighter jets. The photos were actually of a Helios 737–800 (rather than the crashed 737-300) with the registration altered and the fighter jets added.
Subsequent developments 
- The company announced successful safety checks on their Boeing fleet 29 August 2005 and put them back into service.
- The company renamed itself from "Helios Airways (www.flyhelios.com)" to "αjet (www.ajet.com)".
- The Government of the Republic of Cyprus detained Ajet’s aircraft and froze the company’s bank accounts. Ajet no longer operates flights as of 11 June 2006.
- In March 2011, the Federal Aviation Administration in the United States released an airworthiness directive requiring all Boeing 737 aircraft from −100 to −500 models to be fitted with two additional cockpit warning lights. These would indicate problems with take-off configuration or pressurization. Aircraft on the United States civil register are required to have the additional lights by 14 March 2014.
Lawsuits and criminal proceedings 
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Families of the dead filed a lawsuit against Boeing on 24 July 2007. Their lawyer, Constantinos Droungas, said "Boeing put the same alarm in place for two different types of dysfunction. One was a minor fault, but the other – the loss of oxygen in the cockpit – is extremely important". He also said that similar problems had been encountered before on Boeings in Ireland and Norway. The families are claiming 76 million euros in compensation from Boeing.
On 23 December 2008, Helios Airways and four of its officials were charged in Cyprus with 119 counts of manslaughter and of causing death by recklessness/negligence. The four officials were former chief pilot Ianko Stoimenov, chairman of the board Andreas Drakos, chief executive officer Demetris Pantazis, and operations manager Giorgos Kikidis. The trial began in November 2009, the state prosecutors finished presenting their case in June 2011. The case was dismissed, and the defendants acquitted, on 21 December 2011. The panel of judges hearing the case ruled that there was no "causal association between the defendants and the negligence they were charged with for the fatal accident". An appeal was filed by the Cypriot Attorney-general, and in December 2012 the Supreme Court set aside the acquittal and ordered a new trial. Two months later, the retrial was dropped under double jeopardy rules, as the charges had already been heard in Athens.
In December 2011, shortly after the end of the case in Cyprus, a trial began in a Greek magistrates court in which chief executive officer Demetris Pantazis, flight operations manager Giorgos Kikkides, former chief pilot Ianko Stoimenov and chief engineer Alan Irwin were charged with manslaughter. All except Irwin had been previously charged and acquitted by the Cypriot authorities. In April 2012 all were found guilty and sentenced to 10 years imprisonment and remained free on bail pending an appeal.
Relatives of the dead filed a class action suit against the Cypriot Government – specifically the Department of Civil Aviation – for negligence that led to the air disaster. They claim that the DCA was turning a blind eye to airlines’ loose enforcement of regulations, and that in general the department cut corners when it came to flight safety.
The Canadian television series Mayday, which examines aerial incidents, their causes and results, created a documentary episode, titled Ghost Plane, about the disaster. Discovery Channel UK also produced a 45-minute documentary about the accident, titled Aircrash Unsolved: The Mystery of Flight 522.
See also 
Other accidents caused by decompression resulting in pilot incapacitation due to hypoxia:
- 737 Production list
- AAIASB final report, section 1.1, page 3 (PDF page 15 of 198).
- AAIASB final report, section 1.1, page 4 (PDF page 16 of 198)
- "Ghost Plane." Mayday
- "Two trying to save jet ID'd ." News24. Archived 17 June 2009 at the Wayback Machine
- AAIASB final report, section 126.96.36.199.2, pages 21–2 (PDF pages 33–34 of 198)
- AAIASB final report, section 3.2.3, page 159 (PDF page 171 of 198)
- AAIASB final report, section 3.2.1, page 159 (PDF page 171 of 198)
- AAIASB final report, section 1.16.2, page 66 (PDF page 78 of 198)
- AAIASB final report, section 2.2.4, page 121 (PDF page 133 of 198)
- AAIASB final report, section 2.2.4, page 122 (PDF page 134 of 198)
- AAIASB final report, section 1.1, page 5 (PDF page 17 of 198)
- AAIASB final report, section 2.2.5, page 125 (PDF page 137 of 198)
- AAIASB final report, section 1.1, pages 5–6 (PDF pages 17–18 of 198)
- AAIASB final report, section 1.1, page 6 (PDF page 18 of 198)
- "Helios Crash: Background information". Famagusta Gazette. Retrieved 22 July 2012.
- Don Phillips (16 August 2005). "Crash inquiry focuses on oxygen mask use". New York Times. Retrieved 24 June 2007. "The F-16 pilots reported seeing the co-pilot slumped in his seat and the captain's seat empty."
- AAIASB final report, section 2.2.7, page 127 (PDF page 139 of 198)
- AAIASB final report, section 188.8.131.52, page 15 (PDF page 27 of 198)
- AAIASB final report, section 1.1, page 7 (PDF page 19 of 198)
- Greek "Αεροπορική τραγωδία" Flash.GR Archived 15 April 2009 at the Wayback Machine
- Greek Ο κατάλογος των θυμάτων ERT[dead link]
- AAIASB final report, section 1.13.1 "Medical Information", page 57.
- AAIASB final report, section 184.108.40.206, page 102 (PDF page 113 of 198)
- news in.gr – Βεβαρημένο το παρελθόν του αεροσκάφους που συνετρίβη, σύμφωνα με μάρτυρες
- " Helios 737 crashed with no fuel and student pilot at the controls" Radar Vector, 21 August 2005
- Phillips, Don (16 August 2005). "Crash inquiry focuses on oxygen mask use". International Herald Tribune. Retrieved 24 June 2007.
- "Pilot 'alive when plane crashed'", CNN, 2005-08-17 Archived 18 January 2008 at the Wayback Machine
- "Hoax crash SMS: Man freed". News 24. 17 August 2005. Archived from the original on 30 September 2007. Retrieved 24 June 2007.
- "Fake Helios pictures identified", Flight International, 17 August 2005
- Hradecky, Simon. "FAA requires separate configuration and cabin altitude warning lights on Boeing 737s". Aviation Herald. Retrieved 8 February 2011.
- "Cyprus air crash victims' families make 76 mln eur legal claim against Boeing". Forbes (AFX News). 25 July 2007. Retrieved 26 July 2007.[dead link]
- Elias Hazou (2009). "Five face manslaughter charges over Helios crash". Cyprus Mail.[dead link]Archived 15 April 2009 at the Wayback Machine
- Stefanos Evripidou (17 June 2011). "State wraps up Helios case". Cyprus Mail. Retrieved 29 June 2011.
- "Five charged for Helios jet crash". BBC News. 23 December 2008. Retrieved 4 May 2010.
- "Cyprus files charges over airline disaster". Reuters. 23 December 2008.
- Elias Hazou (23 December 2011). "AG to appeal Helios ruling". Cyprus Mail. Retrieved 23 December 2011.[dead link]
- "Helios verdict due on Friday". Cyprus Mail. 18 April 2012. Retrieved 22 April 2012.[dead link]
- "Cyprus: Charges dropped for air crash defendants". KSL.com. 13 February 2013. Retrieved 23 May 2013. "Attorney General Petros Clerides told The Associated Press that he dropped the charges because European Union laws stipulate that defendants tried and convicted in one EU country can't be tried for the same crime in another EU country."
- "Helios verdict due on Friday". Cyprus Mail. 18 April 2012. Retrieved 22 April 2012.[dead link]
- George Psyllides (21 April 2012). "Ten years for former Helios bosses". Cyprus Mail. Retrieved 22 April 2012.[dead link]
- Air Accident Investigation and Aviation Safety Board
Further reading 
- Kaminski-Morrow, David. "Failure to recognise non-pressurisation led to August 2005 Helios 737 crash." Flight International. 10 October 2006.
- Learmount, David. "Investigation dispels myths around Helios Airways crash." Flight International. 17 October 2006.
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