Accident Summary
The pilot of a Hughes 269B helicopter aborted a landing after encountering dust and reduced visibility at the intended landing site. During the climbout, at a speed of approximately 50-60 mph and an altitude of roughly 140 feet above ground level, the engine rapidly lost power. The pilot executed an autorotation landing from an airspeed and altitude condition slightly outside the limitations of the height-velocity diagram, resulting in a hard landing.
Examination Findings
Post-crash examination revealed that the #1 cylinder fuel injector line had separated approximately one inch outboard of the injector unit. Metallurgical analysis determined that the separation was due to fatigue. The engine log indicated that this was the second occurrence of a #1 cylinder fuel injector line separation in recent history.
Further examination uncovered that three of the hold-down bolts for the #3 cylinder had also separated. Metallurgical analysis again identified fatigue as the cause of these separations. The flange of the #3 cylinder was observed to be painted with a primer paint measuring between 0.0014 and 0.0028 inches in thickness. According to Textron Lycoming Service Bulletin 271A, the primer paint thickness on the flange should not exceed 0.0005 inches.
Additionally, both cylinder hold-down plates showed signs of fretting and rubbing damage. The engine underwent a major overhaul on July 8, 1994, during which the engine was painted, assembled, and delivered to Cascade Airframe Repair. The #3 cylinder was subsequently removed and honed on an unspecified date. The precise date when the #3 cylinder flange was painted could not be determined.