CEN17LA255

During the initial climb after takeoff for a non-scheduled cargo flight, the engine experienced a partial loss of power and the commercial pilot reversed course to return to the airport. Unable to reach the runway, the pilot landed the airplane in a field, during which it sustained substantial damage. An examination of the engine revealed no anomalies that would have precluded normal operation. Thermal damage was noted on the lower left side of the engine near the turbocharger. Examination of the turbocharger and housing revealed thermal damage and erosion within the turbocharger housing. Further, the turbocharger had been reconfigured with a different compressor housing and the addition of wear washers. The erosion of the turbocharger housing and induction wye was likely caused by excessive internal turbine temperatures. This erosion would have reduced performance, but likely would not have resulted in the airplane's ability to climb or maintain flight. The reconfiguration of the turbocharger with the wear washers likely would result in the abnormal wear of the bearings and subsequent instability and rub, but would not have precluded normal operation.

On July 3, 2017, about 2006 mountain daylight time, a single engine Beech A36 airplane, N24LF, lost engine power during the initial climb after takeoff from El Paso International Airport (ELP), El Paso, Texas. The commercial pilot and passenger were not injured. The airplane sustained substantial damage. The airplane was registered to and operated by GTA Air, Inc., under the provisions of 14 Code of Federal Regulations Part 135. Visual meteorological conditions prevailed and a Federal Aviation Administration (FAA) visual flight rules flight plan had been filed for the flight. The non-scheduled domestic cargo flight departed ELP and was en route to Dallas Love Field Airport (DAL), Dallas, Texas.According to the pilot, he climbed to an altitude of 4,800 ft and the engine lost power. The pilot reversed course towards ELP and intended to land on runway 26R. The glide of the airplane did not reach the runway and the wings and fuselage were substantially damaged during the forced landing to a field. The airplane was equipped with a Continental IO-520-BB87B engine. The engine had been modified with the addition of a Tornado Alley Turbo Whirlwind system under a supplemental type certificate. Examination of the airframe and engine revealed thermal damage concentrated on the lower left side of the engine. The induction tube, forward of the turbocharger compressor, was melted and the remains were found in the cowling below. The induction wye exhibited a hole emanating outward from the turbine wheel. The engine, magnetos, and related systems were otherwise unremarkable. The turbocharger on the accident airplane was not part of the original modification. Examination and disassembly of the Hartzell Engine Technologies turbocharger (SN HSGL00002) revealed that the turbocharger had been reconfigured with a different compressor housing and the addition of wear washers. The turbocharger had originally been sold to the operator on a factory remanufactured engine from Continental Motors in 2015 (TSIO-520-EB5B – SN 1031058). According to the operator, they did not repair or modify the turbocharger, they only loosened and tightened the V-band clamp and loosened and tightened the hot side bolts. Investigators were unable to determine who modified the turbocharger prior to its installation on the accident airplane. Evidence of high temperatures and thermal distress were noted on the turbine housing exhaust flange, the thrust collar, thrust spacer, and back plate. The turbine and compressor wheels exhibited evidence of rub within their housings. The turbine wheel hub exhibited evidence of hard rub with the center housing seal bore area. The turbine housing exhibited red coloring on the internal surfaces, bubbling of the exhaust flange, and spiraling tongue erosion, which according to Hartzell are consistent with high turbine inlet temperatures.