Robin DR400-120 Forced Landing in Fontaine-le-Comte (F-BUPO)

Accident Overview and Flight Details On August 30, 2014, at approximately 13:20 local time, a Robin DR400-120 with registration F-BUPO, operated by a general aviation club, suffered a forced landing in a rural area near Fontaine-le-Comte (86). The aircraft was on a local flight involving a pilot and a passenger. The pilot had recently obtained a private pilot license on July 27, 2014, and had 56 total flight hours. The passenger, with 197 hours, assumed control during the emergency. The aircraft was heavily damaged during the landing rollout after crossing a ditch and contacting vegetation. ## Investigation Findings The BEA investigation determined that the loss of engine power was caused by contamination of the engine lubricating oil. Examination of the Lycoming O-235-K2B engine revealed solidified deposits throughout the lubrication system, with the oil pickup strainer completely clogged. These deposits caused severe friction between moving parts, potentially leading to component seizure. ## Contamination Source Analysis Laboratory analysis identified isocyanates in the deposits, compounds typically found in polyurethane hardeners, paints, and adhesives, but not in lubricating oils. The maintenance workshop responsible for the aircraft's service indicated that their fabric coating products did not contain isocyanates, but their polyurethane paint hardener did. The workshop manager stated that lubricating oil was not stored with paint products and that the different product packaging made accidental mixing unlikely. The aircraft's last 100-hour inspection was performed on August 13, 2014, with 18 flight hours accumulated since. The last painting operation on the aircraft was in February 2012. ## Conclusion The investigation concluded that the power loss resulted from oil contamination causing increased friction in the engine. However, the source of the contamination could not be determined, nor could it be established whether the contamination was recent or if the polymerization process was rapid or slow, or whether engine heating influenced the process.