Incident Diamond DA40 Diamond Star F-GUVQ, Sunday 26 June 2011

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Date:	Sunday 26 June 2011
Time:
Type:	Diamond DA40 Diamond Star
Owner/operator:	Diamant Air
Registration:	F-GUVQ
MSN:	D4.131
Year of manufacture:	2005
Fatalities:	Fatalities: 0 / Occupants:
Other fatalities:	0
Aircraft damage:	Minor
Category:	Incident
Location:	Montélimar Ancone Airport - France
Phase:	En route
Nature:	Unknown
Departure airport:	Clermont-Ferrand Auvergne Airport (CFE/LFLC)
Destination airport:	Cannes-Mandelieu Airport (CEQ/LFMD)
Investigating agency:	BEA
Confidence Rating:	Accident investigation report completed and information captured

Narrative:
The pilot was navigating between the airfields of Clermont-Ferrand Aulnat and Cannes Mandelieu. After approximately 1 hour of flight, while cruising at FL95, over the Montélimar aerodrome, the pilot noticed that the "ECU(2) A fail" and "ECU B fail" lights came on, followed by a decrease in engine power of about 5%. He carried out a forced landing on the Montélimar airfield.

Conclusion

The incident was due to the deterioration of a wire of the Vrail plug, probably during its replacement in March 2009. The successive interventions, during which the Prail valve was connected and disconnected several times, probably led to the final breakage of the wire.

This disconnection led to the complete opening of the Prail valve. The resulting fuel pressure in the intake manifold then dropped, resulting in a significant loss of engine power and the inability to maintain level flight.

Accident investigation: