ASN logo
ASN Wikibase Occurrence # 193925
Last updated: 11 September 2020
This information is added by users of ASN. Neither ASN nor the Flight Safety Foundation are responsible for the completeness or correctness of this information. If you feel this information is incomplete or incorrect, you can submit corrected information.

Type:Silhouette image of generic MCR4 model; specific model in this crash may look slightly different
Dyn'Aéro MCR-4S
Registration: LN-DLH
C/n / msn: 145-1438
Fatalities:Fatalities: 0 / Occupants: 3
Other fatalities:0
Aircraft damage: Substantial
Location:Storliedalen, Oppdal -   Norway
Phase: En route
Departure airport:Ålesund-Vigra Airport (AES/ENAL)
Destination airport:Røros Airport (RRS/ENRO)
Investigating agency: AIBN
On 26 February 2017 LN-DLH was on the way from Ålesund Airport (ENAL) to Røros Airport (ENRO) at a height of approx. 9000 ft. A few minutes after passing Molde, a bang was heard and vibration occurred in the engine. The commander decided to perform an emergency landing on the frozen lake Ångardsvatnet. Due to a a snow layer on the ice, the aircraft groundlooped and settled with the nose into the snow. There was extensive damage to the aircraft. Neither the pilot nor the two passengers were physically injured.
The examination of the engine revealed that one of the engine's pistons had failed. The piston slanted in the cylinder and hit the cylinder head with subsequent rupture of the connecting rod. The piston skirt had broken off on one side. Similar incipient fractures were found in the other three pistons. The engine did not have Rotax original pistons, and they did not have full circumference piston skirts as the original pistons had.

A metallurgical examination of the pistons showed that they had a coarse granular structure. Such a structure weakens the properties of the material, and the crack formation in the pistons was of an intergranular nature. Damages were found in the piston tops indicating that detonation had occurred. EDS analysis showed that there were ferrous fragments embedded in the piston crowns, and the damages were atypical as symptoms of detonation. The cause of these damages has not been found.

The investigation revealed a number of violations of Norwegian regulations regarding the production of the engine parts and the modification of the engine.



Accident investigation:
Investigating agency: AIBN
Status: Investigation completed
Download report: Final report

Revision history:

02-Mar-2017 08:46 iverdaa Added
02-Mar-2017 21:07 Geno Updated [Cn, Source]
04-Jun-2017 15:34 LN-DLH Updated [Source, Embed code]
24-Jan-2019 16:20 Anon. Updated [Departure airport, Destination airport, Embed code]
11-Sep-2020 17:43 harro Updated [Departure airport, Narrative, Accident report, ]
11-Sep-2020 18:27 harro Updated [Damage]

Corrections or additions? ... Edit this accident description