Mishap Case Study
Photo: PH-BFC, from Creative Commons.
- Date: 15 December 1989
- Time: 11:48
- Type: Boeing 747-406
- Operator: KLM Royal Dutch Airlines
- Registration: PH-BFC
- Fatalities: 0 of 14 crew, 0 of 231 passengers
- Aircraft Fate: Repaired
- Phase: En route
- Airport: (Departure) Amsterdam-Schiphol International Airport (AMS/EHAM), Netherlands
- Airport: (Destination) Anchorage International Airport, AK (ANC/PANC), United States of America
At FL250 the aircraft flew into a normal looking cloud, which turned out to be a volcanic ash cloud (the result of an eruption of Mount Redoubt). Power was added to climb out of the cloud. About 10-15 seconds later all 4 engines failed and the standby electrical system failed. The crew were able to restart the engines after numerous attempts. The no. 1 and 2 engines were relit while descending through FL130 and the remaining 2 engines were relit at FL110. The aircraft landed safely at Anchorage, substantially damaged by the in-flight blasting by volcanic ash. The windshields were damaged, as were internal aircraft systems, avionics and electronics.
Inadvertent encounter with volcanic ash cloud, which resulted in damage from foreign material (foreign object) and subsequent compressor stalling of all engines. A factor related to the accident was: the lack of available information about the ash cloud to all personnel involved.
NTSB Record of Incident, ANC90FA020, KLM Royal Dutch Airlines, December 15, 1989 in Anchorage, AK