Leasons learnt from Helios disaster
The European Aviation Safety Authority, EASA, issued a safety information bulletin at the end of last year that incorporated recommendations from the Greek Air Accident Investigation and Aviation Safety Board. The recommendations were provided by the Greek Authorities in an accident report into the 2005 Helios Airways crash.
The accident occured in August, when the Boeing 737-300 crashed after exhausting its fuel supply with everyone on board unconscious due to hypoxia. All 121 passengers and crew were killed with no injuries on the ground as the jet came down on sparsely populated land near the approach to Athens airport.
The investigation discovered that following maintenance a switch on the presurisation panel (see image below) had been inadvertantly left in the 'Manual' position. The pilots subsequently missed two oppurtunities in the check lists prior to take off to check that the switch was in 'Auto'. As a result the aircraft did not pressurise on departure and the crew misidentified the pressurisation warnings.
The main outcome of the investigation has been the EASA bulletin relating to cabin crew members duties should the oxygen masks deploy on departure or during a climb. In the future if the arcraft does not immediatly stop climbing or begin a descent the flight attendant nearest the cockpit is to knock on the door informing the pilots and ensuring they have donned their oxygen masks.
There are also further recommendations being studied which include mandatory hypoxia training for all crew in simulation devices, the installation of damage protected imaging devices in the cockpit to keep a record of all switch movements and the possibility of including cabin altitude as a parameter on Flight Data Recorders, FDRs.
