Incident Overview
The pilot of a cargo aircraft on an on-demand air taxi flight departed Louisville, Kentucky, reportedly with a known oil leak in the right engine. The flight was on its second leg. Approximately 14 minutes after entering Mansfield approach control airspace, the pilot requested and received an altitude change from 5,000 to 3,000 feet, citing significant ice accumulation. After transitioning to Cleveland approach airspace, the pilot reported the right engine had failed and requested to return to Mansfield. The pilot was informed of Mansfield weather conditions, then indicated a desire to proceed to Cleveland before reporting an inability to maintain altitude and reiterating a request to go to Mansfield.
Approach and Loss of Radar Contact
Mansfield approach provided vectors for an Airport Surveillance Radar (ASR) approach to Runway 23. When the aircraft was approximately 1.5 miles from the threshold, the pilot reported lowering the landing gear. Shortly thereafter, the aircraft disappeared from the radar scope.
Investigation Findings
Examination revealed improper weld repairs to the right engine case. The number six cylinder had separated from the case due to fatigue cracking in the through bolts and studs. The official probable cause findings identified the following:
- Occurrence #1 (loss of engine power - total): Mechanical failure/malfunction during cruise. The right engine experienced a total failure; the crankcase was cracked; improper major repair by maintenance personnel; fatigue of engine assembly components; separation of a cylinder; the pilot continued operation with known deficiencies; and company-induced pressure.
- Occurrence #2 (in-flight collision with object): During the approach phase from the final approach fix to the threshold. The object was trees; weather conditions included icing and below approach/landing minimums; lighting was dark night; and the pilot delayed in-flight planning/decision.
- Occurrence #3 (in-flight collision with terrain/water): During an uncontrolled descent.
No information was provided regarding injuries, fatalities, or aircraft registration.