Textron Aviation TTX Inc. T240 N420WT accident near Ravendale, California

Probable cause

The inadequate maintenance and inspection of the engine induction system, which resulted in the separation of the right induction tube from the turbocharger compressor outlet and the subsequent loss of engine power during departure.

NTSB analysis

The instructor pilot reported that during takeoff about 100 ft above ground level (agl) and near the end of the runway, the engine sustained a sudden loss of engine power. The pilot lowered the nose and extended the flaps for the off-airport forced landing. The airplane impacted the snow-covered terrain.

Postaccident examination of the airplane indicated that the right induction tube connecting the turbocharger compressor outlet to the intercooler inlet had separated from the turbocharger compressor outlet flange. Two inches of the induction tube was installed into the 3-inch-long rubber coupling, leaving only 1 inch remaining to be installed on the turbocharger compressor outlet flange. It is likely that when the engine was at high RPM during the takeoff climb, the improperly installed lower rubber coupling separated from the turbocharger compressor outlet flange, resulting in the loss of engine power.

The engine was installed on an engine test stand and it ran successfully at various RPM settings. The engine test run revealed no evidence of mechanical malfunctions or failures that would have precluded normal operation. Maintenance records indicated that the last 100-hour inspection was performed two days before the accident. During this inspection the induction tubes would have been removed and inspected.

Text from the NTSB. Open the NTSB docket for WPR22LA090 for the full record.