Engine Power Loss During Initial Climb Due to Muffler Baffle Blockage and Non-Compliance with Airworthiness Directive (N5087W)

Incident Summary

During the initial takeoff climb, the engine experienced a partial loss of power. The pilot reported that the pre-flight inspection and before-takeoff run-up revealed no discrepancies. As the airplane departed from runway 17, the pilot noticed that the airplane was climbing slower than usual. At an altitude of 150 feet above ground level, crossing the departure end of the runway, the engine speed dropped noticeably. Engine power continued to decay until it reached idle, airspeed decreased, and the airplane began to descend.

Investigation Findings

A post-accident examination of the engine identified that the internal muffler baffle was not secured to its attaching point and was blocking the engine exhaust pipe/manifold. Review of maintenance logbooks and other evidence indicated that Airworthiness Directive (AD) 70-16-05 had not been complied with. This directive mandates a visual inspection of both the exterior and interior of the muffler.