Beech A36TC N60RW accident near Tupelo, Mississippi

Probable cause

A preexisting stress rupture that initiated at a spot weld in the turbocharger v-band exhaust clamp, which resulted in the failure of the clamp and separation of the exhaust tailpipe, an in-flight fire, and subsequent impact with terrain.

NTSB analysis

The airline transport pilot was taking off in the turbocharged reciprocating engine-equipped airplane for a personal flight. One witness reported seeing something fall from the airplane as it departed. Shortly after departure, the pilot notified air traffic control of smoke in the cockpit. The airplane then made a left, westbound turn back toward the airport, about 500ft above the ground and then it turned back toward the approach end of the departure runway while descending. Two witnesses also reported seeing fire and smoke coming from the bottom, left side of the airplane before it impacted terrain.

After the accident, airport personnel found the exhaust tailpipe and fractured v-band coupling on the runway. A support clamp, which was intended to support the exhaust tailpipe, was not found. Examination of the v-band coupling revealed stress rupture features at the edge of a spot weld that attached the outer band to the retainer, which led to the v-band fracturing, the exhaust tailpipe separating from the airplane, and an in-flight fire. Review of the maintenance records did not reveal when the v-band coupling was installed or last inspected.

There is a longstanding history of accidents and incidents resulting from v-band coupling failures on both fixed-wing aircraft and rotorcraft. Although before the accident the Federal Aviation Administration (FAA) had issued six v-band-specific airworthiness directives (AD) and other guidance materials and recommendations related to v-band failures, none of them were specific to the accident airplane make and model. Subsequent to the accident, the FAA published a notice of proposed rulemaking to obtain public feedback regarding a proposed AD that would require a repetitive annual inspection of, and would impose a 500-hour life limit on, the exhaust tailpipe v-band coupling on the accident aircraft make and model.

Text from the NTSB. Open the NTSB docket for ERA16FA185 for the full record.