Introduction
On June 16, 2022, at approximately 1400 central daylight time, a Cessna T206H, registration N52854, sustained substantial damage in an accident near Austin, Texas. The pilot was seriously injured. The flight was conducted as a public use operation.
Accident Narrative
The pilot reported that the accident flight was the first flight following a 100-hour maintenance inspection. Departing from Austin-Bergstrom International Airport (AUS), the pilot shortly after takeoff informed air traffic control of smoke in the cockpit and requested a return to AUS. The smoke intensified, obscuring the instrument panel. When the pilot attempted to increase engine power, he found that the engine had stopped producing power. After opening the side windows, he observed a body of water below and ditched the airplane into Lady Bird Lake, near Austin.
Postaccident Examination
Postaccident examination revealed that the V-band exhaust coupling securing the turbocharger exhaust had fractured. The General Aviation Joint Steering Committee had issued a best practices guide that recommended life limits for various clamp styles, including a 500-hour life limit on spot welded V-band couplings, the type that failed in this accident. The Federal Aviation Administration had also issued Special Airworthiness Information Bulletin (SAIB) CE-18-07 on December 14, 2017, which described accidents resulting from V-band clamp failures and recommended detailed inspections at 100-hour intervals.
Maintenance History
According to maintenance records, the airplane’s most recent annual inspection was completed on December 13, 2021, and included an exhaust system inspection. A 100-hour inspection was completed on June 15, 2022, also noting an exhaust system inspection. Neither entry specifically documented inspection of the V-band exhaust couplings, and investigators could not determine whether a specific inspection of the V-band clamp had been performed. The total time in service of the failed clamp was not determined.