Cessna 172 N1443E accident near Swea City, Iowa

Probable cause

The pilot's failure to replace the oil filler cap during his preflight inspection, which resulted in oil starvation and a subsequent total loss of engine power.

NTSB analysis

The pilot conducted a preflight inspection of the airplane in preparation for a night cross-country flight, during which he added a half quart of oil to the engine. During the flight, the pilot noticed that the oil pressure gauge was near zero. The pilot diverted back to his departure airport; the engine started to shake, then lost all power, and he subsequently conducted a forced landing to a road. Examination of the airplane noted substantial damage to the fuselage and engine oil on the side of the cowling; the engine oil filler cap/dipstick was located 2 to 3 ft in front of the airplane. Borescope examination of the engine revealed scoring on the Nos. 2 and 4 cylinders, consistent with inadequate lubrication.

In a follow-up interview with the pilot, he stated that he typically placed the oil filler cap/dipstick in the wing's tie-down loop when checking the engine oil level or adding oil. It is likely that the pilot forgot to replace the dipstick during his preflight inspection, which resulted in the loss of engine oil in flight and a subsequent total loss of engine power due to oil starvation.

Text from the NTSB. Open the NTSB docket for CEN20LA014 for the full record.