FTW99LA036

The engine lost partial power during the initial takeoff climb. The pilot stated that the pre-flight inspection and before takeoff run-up revealed no discrepancies. As the airplane departed runway 17, the pilot realized that the airplane was 'climbing slower than usual.' The airplane was crossing the departure end of the runway, at 150 feet agl, when 'the engine speed dropped noticeably.' The engine power continued to decay until it was at idle, the airspeed continued to drop, and consequently, the airplane began to descend. The post accident engine examination revealed that the internal muffler baffle was not secured to its attaching point and was blocking the engine exhaust pipe/manifold. A review of maintenance logbooks and evidence collected during the investigation indicates that airworthiness directive 70-16-05, which mandates a visual inspection of the exterior and interior of the muffler, was not complied with.

On November 25, 1998, at 0900 central standard time, a Piper PA-28-160 airplane, N5087W, sustained minor damage during a forced landing following a loss of engine power after takeoff from the Majors Airport, near Greenville, Texas. The instrument rated private pilot and his passenger sustained serious injuries. Visual meteorological conditions prevailed and an IFR flight plan was filed for the Title 14 CFR Part 91 personal flight. The flight was originating at the time of the accident.

The 900 hour pilot reported in the Pilot/Operator Aircraft Accident Report (NTSB Form 6120.1/2) that the airplane had been repositioned from the Addison Airport prior to the accident flight. He had planned to fly the airplane from Greenville to Little Rock, Arkansas. The pre-flight inspection did not reveal any discrepancies and the before takeoff run-up was normal.

The pilot, who was the owner and operator of the airplane, stated that he initiated the takeoff from runway 17. The engine power "came up smoothly, the engine gauges were nominal, and the plane's acceleration to lift off was normal." The airplane traveled approximately 6,000 feet down the 8,030 foot runway, when the pilot realized that the airplane was "climbing slower than usual." The airplane was crossing the departure end of the runway, at 150 AGL, when "the engine speed dropped noticeably." The engine power decayed until it was at idle, the airspeed continued to drop, and the airplane began to descend. The pilot stated that "there was no particular roughness, or unusual noise; the power was simply dropping, as if someone were pulling the power back."

The pilot further stated that the airplane touched down one mile south of the departure end of the runway in a nose low attitude and the nose landing gear assembly separated from the airplane. Subsequently, the airplane slid into a pond, where it came to a stop 30 feet from the shore. No additional damage was incurred by the airplane.

The wreckage of the airplane was examined at Air Salvage of Dallas, Lancaster, Texas, on December 8, 1998. An FAA inspector reported that the examination revealed that the internal muffler baffle was not secured to its attaching point and was blocking the engine exhaust pipe/manifold. The FAA inspector stated that "the bolts attaching these connectors appeared corroded and deteriorated to such a condition to indicate that they had not been removed at the last annual inspection," which occurred in June 1998. The FAA inspector added that the last annual inspection was written up, but not signed in the aircraft's logbooks.

Airworthiness directive AD 70-16-05 requires an inspection every 50 hours to check the muffler "for signs of cracks, burn-throughs, weld separations, failed internal baffles, and general condition." Additionally, the inspection of the muffler assembly should be accomplished by performing the following; "remove the muffler assembly by disconnecting air ducts, stacks, shrouds, as necessary to permit a thorough visual inspection of the exterior and interior surfaces."