Partial power loss involving a Fokker B.V. F27 MK 50, VH-FNC, Wagga, New South Wales, on 17 November 1993

The left engine suffered a 5 second power interruption while the aircraft was cruising in moderately heavy rain. Following the power interruption the engine continued to operate normally. This was one of a series of similar events that led to the manufacturer undertaking instrumented and filmed flight tests. These disclosed that ice was building on the engine inlet and when released was being ingested into the engine.

Further testing found that the inlet heating cycle was being interrupted by electro-magnetic interference in the de-icing controller. This allowed ice to build up. Two modifications were introduced. SB F50-71-037 rerouted the bonding cable for the oil cooling flap actuator to reduce EMF transmission and SB F50-71-041 enlarged the lower cowl bypass duct to allow any displaced ice to eject overboard rather than through the engine. The operator has embodied both modifications and to date has not had a recurrence of power interruptions.