ASN Aircraft accident de Havilland Canada DHC-6 Twin Otter 200 N563MA Mt Iliamna, AK
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Status:Accident investigation report completed and information captured
Date:Tuesday 6 September 1977
Time:14:52 ADT
Type:Silhouette image of generic DHC6 model; specific model in this crash may look slightly different
de Havilland Canada DHC-6 Twin Otter 200
Operator:Alaska Aeronautical Industries
Registration: N563MA
MSN: 196
First flight: 1969
Total airframe hrs:15369
Engines: 2 Pratt & Whitney Canada PT6A-20
Crew:Fatalities: 2 / Occupants: 2
Passengers:Fatalities: 11 / Occupants: 11
Total:Fatalities: 13 / Occupants: 13
Aircraft damage: Damaged beyond repair
Location:Mt Iliamna, AK (   United States of America)
Phase: En route (ENR)
Nature:Domestic Scheduled Passenger
Departure airport:Iliamna Airport, AK (ILI/PAIL), United States of America
Destination airport:Anchorage International Airport, AK (ANC/PANC), United States of America
Flightnumber: 302
The Twin Otter struck the southwest side of Mount Iliamna, approx. 7000 feet MSL in IMC conditions.

Probable Cause:

PROBABLE CAUSE: "The failure of the flight crew to use proper navigational procedures for the route to be flown, especially their failure to use the available back-up means of navigation to verify the position and the progress of the flight."

Accident investigation:

Investigating agency: NTSB
Status: Investigation completed
Duration: 240 days (8 months)
Accident number: NTSB/AAR-78-05
Download report: Final report

Controlled Flight Into Terrain (CFIT) - Mountain

» NTSB-AAR-78-5

Follow-up / safety actions

NTSB issued 5 Safety Recommendations

Show all...


photo of DHC-6-Twin-Otter-200-N563MA

This map shows the airport of departure and the intended destination of the flight. The line between the airports does not display the exact flight path.
Distance from Iliamna Airport, AK to Anchorage International Airport, AK as the crow flies is 310 km (194 miles).
Accident location: Approximate; accuracy within a few kilometers.

This information is not presented as the Flight Safety Foundation or the Aviation Safety Network’s opinion as to the cause of the accident. It is preliminary and is based on the facts as they are known at this time.
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DHC-6 Twin Otter

  • 930+ built
  • 44th loss
  • 30th fatal accident
  • 2nd worst accident (at the time)
  • 47th worst accident (currently)
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