Issued November 2016 REPORT SL 2016/11 REPORT ON SERIOUS AVIATION INCIDENT AT SVOLVÆR AIRPORT HELLE ON 2 DECEMBER 2010 INVOLVING BOMBARDIER DHC-8-103, LN-WIU, OPERATED BY WIDERØE'S FLYVESELSKAP AS The Accident Investigation Board has compiled this report for the sole purpose of improving flight safety. The object of any investigation is to identify faults or discrepancies which may endanger flight safety, whether or not these are causal factors in the accident, and to make safety recommendations. It is not the Board's task to apportion blame or liability. Use of this report for any other purpose than for flight safety shall be avoided. Accident Investigation Board Norway • P.O. Box 213, N-2001 Lillestrøm, Norway • Phone: + 47 63 89 63 00 • Fax: + 47 63 89 63 01 www.aibn.no • [email protected] This report has been translated into English and published by the AIBN to facilitate access by international readers. As accurate as the translation might be, the original Norwegian text takes precedence as the report of reference. Photos: AIBN and Trond Isaksen/OSL Accident Investigation Board Norway Page 2 TABLE OF CONTENTS NOTIFICATION ................................................................................................................................. 3 SUMMARY ......................................................................................................................................... 3 1. FACTUAL INFORMATION .............................................................................................. 5 1.1 History of the flight .............................................................................................................. 5 1.2 Injuries to persons .............................................................................................................. 14 1.3 Damage to aircraft .............................................................................................................. 14 1.4 Other damage ..................................................................................................................... 14 1.5 Personnel information ........................................................................................................ 14 1.6 Aircraft information ........................................................................................................... 15 1.7 Meteorological information ............................................................................................... 19 1.8 Aids to navigation .............................................................................................................. 22 1.9 Communications ................................................................................................................ 22 1.10 Aerodrome information ..................................................................................................... 23 1.11 Flight recorders .................................................................................................................. 27 1.12 Wreckage and impact information ..................................................................................... 34 1.13 Medical and pathological information ............................................................................... 34 1.14 Fire ..................................................................................................................................... 34 1.15 Survival aspects ................................................................................................................. 35 1.16 Tests and research .............................................................................................................. 35 1.17 Organizational and management information .................................................................... 41 1.18 Additional information ....................................................................................................... 44 1.19 Useful or effective investigation techniques ...................................................................... 48 2. ANALYSIS ........................................................................................................................ 48 2.1 Introduction ........................................................................................................................ 48 2.2 Diverging explanations ...................................................................................................... 49 2.3 Likely scenario ................................................................................................................... 51 2.4 Wind shear as triggering factor .......................................................................................... 51 2.5 Critical phase of the sequence of events ............................................................................ 52 2.6 Sensory illusion .................................................................................................................. 55 2.7 Take-over of flight controls ............................................................................................... 56 2.8 The importance of the commander being tired .................................................................. 57 2.9 Assessment of flight operations conditions ....................................................................... 58 2.10 Vulnerability when circling in darkness ............................................................................ 60 2.11 Assessment of measures and safety margins ..................................................................... 61 2.12 Why did it turn out well? ................................................................................................... 61 3. CONCLUSION .................................................................................................................. 62 3.1 Findings .............................................................................................................................. 63 4. SAFETY RECOMMENDATIONS ................................................................................... 66 APPENDICES ................................................................................................................................... 67 Accident Investigation Board Norway Page 3 SERIOUS INCIDENT REPORT Type of aircraft: Bombardier Inc. DHC-8-103 Nationality and registration: Norwegian, LN-WIU Owner: Widerøe’s Flyveselskap AS, Bodø Operator: Same as owner Persons on board: 38 (commander, first officer, cabin crew and 35 passengers) Injuries: None Material damage: None Accident site: Approx. 1.5 km north-northeast of the threshold of runway 19 at Svolvær Airport Helle (ENSH) (approx. 68°15'24"N 14°41'11"E) Accident time: Thursday 2 December 2010 at 18:18 hours. All times given in this report are local time (UTC + 1 hour), if not otherwise stated. NOTIFICATION The Accident Investigation Board Norway (AIBN) was only made aware of the incident in December 2012, two years after it had taken place. AIBN assessed the existing information, and collected further information. After an evaluation, AIBN concluded in June 2013 that the occurrence was to be considered an aviation incident. An investigation was not opened. In February 2015, the incident was subject to significant attention, and AIBN found that the incident could contain a greater learning potential than first assumed. The decision not to investigate was changed. AIBN initiated an investigation in mid-March 2015. Following initial investigations, the Accident Investigation Board reclassified the case as a serious aviation incident. In accordance with ICAO Annex 13, Aircraft Accident and Incident Investigation, AIBN notified the investigation authority in the manufacturing country Canada (Transportation Safety Board, TSB) of the incident and announced that an investigation had been opened. TSB appointed an accredited representative who assisted with the investigation, supported by advisors from Bombardier. SUMMARY Widerøe's flight WIF814 was en route from Bodø to Svolvær with three crew members and 35 passengers on board. It was dark, with cumulonimbus clouds, rain and hail showers in the area. There were gale force winds with strong gusts at Svolvær Airport. The commander (the captain), who was Pilot Flying, was about to perform a visual circling over the sea in order to land towards the south. Just before turning into the final approach, the airplane began to buffet and lose altitude, and there was a significant loss of airspeed. Despite full power being applied, the airplane continued to lose both airspeed and altitude. The stall warning (stick shaker) activated. The nose of the aircraft was lowered and stalling was prevented, or a stall recovery performed, but the altitude above the terrain became very low (25 m) before the aircraft began to climb, and the situation was resolved. The first officer further increased engine power, to the maximum available, and at some point took over the flight controls on his own initiative. After the incident, which transpired over the course of approx. 10 seconds, the crew interrupted the approach Accident Investigation Board Norway Page 4 and continued to Leknes where they landed normally. The Accident Investigation Board Norway (AIBN) concludes that the airplane was exposed to severe wind shear from a cumulonimbus cloud. There was no aircraft damage and no physical injuries. The crew perceived the incident differently. The commander has described that he had brought