Early Descent Error in 1988 Wider?e Flight In May 1988, Wider?e flight WF 710, a de Havilland Canada DHC-7, encountered a catastrophic crash near Br?nn?ysund, Norway, resulting in the loss of all 36 occupants. The aircraft, operated by Wider?es Flyveselskap and registered as LN-WFN, had accumulated significant airframe hours and cycles since its first flight in 1980. The flight, on a domestic route from Namsos to Br?nn?ysund, was executing a VOR/DME approach to Br?nn?ysund Airport. Crucially, the aircraft commenced its final descent approximately 4 nautical miles earlier than planned, leading it to fly below the safe terrain clearance altitude, ultimately colliding with the Torghatten hillside. An aspect of this accident that got particular attention back in the time when this accident happened was the presence of two mobile phones onboard, a detail not included in the original 1989 investigation report. In 2013, this information led the Norwegian Accident Investigation Board (SHT) to conduct a supplementary investigation, assessing whether electromagnetic interference from these devices could have influenced the aircraft's instruments or systems. The supplementary investigation, while comprehensive, found no evidence of such interference. The focus was on the potential impact of mobile phone emissions on the aircraft's VOR/DME navigation systems, the autopilot, and the altimeter systems. Expert analysis from Honeywell Aerospace and the UK Air Accidents Investigation Branch (AAIB) suggested that the aircraft's analog-based avionics were unlikely to be disrupted by electromagnetic interference from mobile phones. Ultimately, the SHT concluded that the descent started prematurely due to reasons that could not be definitively ascertained. The supplementary report reaffirmed the initial finding that the aircraft descended below the safe terrain clearance altitude without clear causation, ruling out mobile phone interference. This case underscores the complexities in determining the precise causes of aviation accidents. Subscribe to our Aviation Safety Newsletter NOW and get the hot stuff free and without delay:?https://lnkd.in/eGZqhPHR! My accident reviews are short summaries of publicly available accident reviews and reports and do not constitute any interpretation nor express my opinion or the opinion of any organization.
