NTSB Factual Report

On April 14, 2010, about 1236 eastern daylight time, an experimental amateur-built T-51 Mustang, N551RD, registered to and operated by a private individual, sustained substantial damage during a forced landing after a loss of engine power in the vicinity of Lakeland, Florida. The private pilot and one passenger were not injured. Visual meteorological conditions prevailed and no flight plan was filed for personal flight operating under the provisions of 14 Code of Federal Regulations Part 91. The flight originated at 1231 from the Lakeland Linder Regional Airport (LAL), Lakeland, Florida, and was enroute to the South Lakeland Airport (X49), Lakeland, Florida.

The pilot reported that after a preflight inspection and normal takeoff, he flew the airplane in the local traffic pattern for one circuit and then proceeded on a short flight toward his destination. While climbing through about 1,000 feet mean sea level with the flaps and landing gear retracted, the engine suddenly lost power. The pilot attempted to restore engine power by turning on the No. 2 master switch and also the No. 1 auxiliary fuel pump but he was not successful. He maneuvered the airplane toward a field for a forced landing and touched down on a dirt path with the gear and flaps retracted. The airplane came to rest upright about 155 feet from its initial touchdown point.

Examination of the engine compartment by NTSB, FAA, and airplane designer representatives' in-situ at the accident site and after recovery revealed that the right exhaust manifold was secured to an aluminum exhaust manifold adapter by two bolts on the upper part of the adaptor. The two bolts on the lower part of the adaptor were not in position but were later found when the airplane was moved. There was no evidence that the two upper bolts had been safety wired. After removal of the right exhaust manifold, all four threaded holes of the aluminum manifold adapter were found stripped and heat damaged. The adapter also exhibited some erosion consistent with heat damage on the bottom center of the adaptor.

The insulation of the crankshaft synchronizer and timing electrical wires located in the engine compartment beneath the right exhaust manifold were found heat damaged with chafed insulation and exposed conductors on two of the wires. The chafing through the insulation of the wires was in a straight line, nearly perpendicular to the wire length and was consistent with contact by the right lower longeron. The crankshaft synchronizer and timing electrical wires were not heat protected or fire-shielded.

Operational testing of the synchronizer and timing sensors system using the airplane’s battery power and the heat damaged synchronizer and timing wires was satisfactory.. The engine was then rotated through several rotations using the starter and the ignition system appeared to be operational. With battery power applied, the chafed electrical wires with the exposed conductors were then placed against the right lower longeron and the ignition system became inoperative.

Examination of the left exhaust manifold adapter which was manufactured from a similar material as the right side revealed that one of the upper bolts was found finger loose, and the bottom center portion also exhibited heat related erosion but to a lesser extent than the right side.

NTSB Probable Cause

The builder’s use of inadequate material for the exhaust manifold adapters resulting in heat damage and chafing of the crankshaft synchronizer and timing wires that rendered an inoperative ignition system and loss of engine power.