Piper PA28 N1830T accident near Homestead, Florida

Probable cause

A total loss of engine power due to the in-flight separation of the No. 3 cylinder because of the fatigue cracking of its respective mounting studs and through bolts, which resulted from inadequate maintenance by unknown personnel.

NTSB analysis

The student pilot reported that the airplane was in cruise flight at 5,500 ft mean sea level when the engine began to vibrate. Shortly after, the engine "began coming apart" with pieces striking the underside of the cowling, indicative of a catastrophic failure. The student pilot performed a forced landing to a swampy area. The airplane came to rest in shallow water and sustained substantial fuselage damage.

Examination of the engine revealed that the No. 3 cylinder had separated from the crankcase. During subsequent examination, both through bolts and three of the four remaining cylinder studs were also found fractured, and the fracture surfaces were consistent with fatigue cracking, likely due to insufficient application of torque on the through bolts during installation or the loss of torque in the through bolts. Additionally, unapproved room temperature vulcanization-type material found on the crankcase halves could have contributed to a loss of torque on the through bolts, but a definitive determination could not be made. The engine was overhauled about 28 years before the accident, and it had been operated for about 1,050 total hours since the overhaul. The airplane's most recent annual inspection was performed about 8 months before the accident, and it had been operated about 230 hours since the inspection. Available maintenance records did not reveal any in-service cylinder replacements or reinstallations.

Text from the NTSB. Open the NTSB docket for ERA14LA042 for the full record.