HELLENIC REPUBLIC MINISTRY OF TRANSPORT & COMMUNICATIONS AIR ACCIDENT INVESTIGATION & AVIATION SAFETY BOARD (AAIASB) AIRCRAFT ACCIDENT REPORT HELIOS AIRWAYS FLIGHT HCY522 BOEING 737-31S AT GRAMMATIKO, HELLAS ON 14 AUGUST 2005 11 / 2006 ACCIDENT INVESTIGATION REPORT 11 / 2006 Accident of the a/c 5B-DBY of Helios Airways, Flight HCY522 on August 14, 2005, in the area of Grammatiko, Attikis, 33 km Northwest Of Athens International Airport The accident investigation was carried out by the Accident Investigation and Aviation Safety Board in accordance with: x ǹȃȃǼȋ 13 x Hellenic Republic Law 2912/2001 x E.U. Directive 94/56 The sole objective of the investigation is the prevention of similar accidents in the future. The Accident Investigation and Aviation Safety Board Chairman Captain Akrivos D. Tsolakis Members A. Katsifas G. Kassavetis Supreme Court Judge ret. Captain Ȁ. Alexopoulos G. Georgas Mechanical & Electrical Engineer Hellenic Air Force Brigadier ret. (Meteorologist) Secretary J. Papadopoulos ii TABLE OF CONTENTS TABLE OF CONTENTS ................................................................................................ iii ABBREVIATIONS........................................................................................................ viii DECLARATION............................................................................................................. xii SYNOPSIS......................................................................................................................... 1 1. FACTUAL INFORMATION................................................................................. 3 1.1 History of Flight ........................................................................................ 3 1.2 Injuries to Persons .................................................................................... 9 1.3 Damage to Aircraft ................................................................................... 9 1.4 Other Damage ........................................................................................... 9 1.5 Personnel Information.............................................................................. 9 1.5.1 Captain ........................................................................................................ 9 1.5.2 First Officer............................................................................................... 11 1.5.3 Cabin Attendants....................................................................................... 13 1.5.3.1 Chief Cabin Attendant .......................................................................... 13 1.5.3.2 Cabin Attendant number two................................................................ 14 1.5.3.3 Cabin Attendant number three.............................................................. 14 1.5.3.4 Cabin Attendant number four ............................................................... 15 1.5.4 Ground Engineers ..................................................................................... 15 1.5.4.1 Ground Engineer number one............................................................... 15 1.5.4.2 Ground Engineer number two............................................................... 16 1.5.4.3 Ground Engineer number three............................................................. 16 1.5.5 Air Traffic Controllers .............................................................................. 16 1.5.5.1 Nicosia ACC ......................................................................................... 16 1.5.5.2 Athinai ACC......................................................................................... 16 1.6 Aircraft Information............................................................................... 17 1.6.1 General...................................................................................................... 17 1.6.2 Maintenance History.................................................................................. 18 1.6.2.1 Maintenance Program ........................................................................... 18 1.6.2.2 Scheduled Maintenance ........................................................................ 19 1.6.2.3 Unscheduled Maintenance.................................................................... 20 1.6.2.3.1 Decompression Occurrence on 16 December 2004.......................... 20 1.6.2.3.2 Aft Service Door Occurrence on 13 August 2005............................ 21 1.6.3 Systems Descriptions................................................................................ 23 1.6.3.1 Bleed Air System .................................................................................. 23 1.6.3.2 Air Conditioning ................................................................................... 23 1.6.3.3 Pressurization System ........................................................................... 23 1.6.3.3.1 Outflow Valves ................................................................................. 27 1.6.3.3.2 Pressurization Outflow...................................................................... 27 1.6.3.3.3 Flow Control Valve........................................................................... 28 1.6.3.3.4 Outflow Valves (two units)............................................................... 28 1.6.3.4 Equipment Cooling System .................................................................. 29 1.6.3.5 Oxygen Systems.................................................................................... 31 1.6.3.5.1 Cockpit Oxygen System ................................................................... 32 iii 1.6.3.5.2 Passenger Cabin Oxygen Systems.................................................... 32 1.6.3.5.2.1 Passenger Oxygen............................................................................. 32 1.6.3.5.2.2 Passenger Portable Oxygen............................................................... 33 1.6.4 Cabin and Flight Deck Doors ................................................................... 34 1.6.4.1 Cabin Doors.......................................................................................... 34 1.6.4.2 Flight Deck Door .................................................................................. 36 1.7 Meteorological Information ................................................................... 36 1.8 Aids to Navigation................................................................................... 36 1.9 Communications ..................................................................................... 37 1.9.1 Radio Communication Failure.................................................................. 37 1.9.2 Handover from Nicosia ACC to Athinai ACC ......................................... 38 1.10 Airport Information................................................................................ 38 1.10.1 Larnaca Airport......................................................................................... 38 1.10.2 Athens International Airport “El. Venizelos”........................................... 39 1.11 Flight Recorders...................................................................................... 39 1.11.1 Cockpit Voice Recorder (CVR)................................................................ 39 1.11.2 Flight Data Recorder (FDR) ..................................................................... 40 1.12 Wreckage and Impact Information....................................................... 41 1.12.1 Wreckage Distribution.............................................................................. 41 1.12.2 Aircraft System Components.................................................................... 47 1.12.2.1 Overhead Cockpit P5 Panel .............................................................. 48 1.12.2.2 P5 Air Conditioning Panel................................................................ 50 1.12.2.3 P5 Cabin Pressurization Panel .......................................................... 50 1.12.2.4 Cabin Pressure Controllers ............................................................... 51 1.12.2.5 Forward Outflow Valve .................................................................... 51 1.12.2.6 Aft Outflow Valve ............................................................................ 52 1.12.2.7 Pneumatic System Components........................................................ 54 1.12.2.8 Flight Deck Oxygen Cylinder........................................................... 54 1.12.2.9 Flight Crew Oxygen Masks .............................................................. 54 1.12.2.10 Portable Oxygen Bottles ................................................................... 55 1.12.3 Engines...................................................................................................... 56 1.12.4 Landing Gear............................................................................................ 56 1.12.5 Doors......................................................................................................... 56 1.13 Medical and Pathological Information ................................................. 57 1.13.1 Medical Information ................................................................................. 57 1.13.2 Physiological and Psychological Effects of Low Cabin Pressure ............ 58 1.13.3 Hypoxia....................................................................................................