Accident Overview
On April 24, 2008, at 1810 eastern daylight time, a Cessna 182, registration N5358B, piloted by an airline transport pilot, sustained substantial damage on impact with terrain during landing on runway 18 (4,000 feet by 75 feet, asphalt) at Romeo State Airport (D98), Romeo, Michigan. The aircraft had previously attempted to land on runway 36 (2,600 feet, grass) at Kunstman Private Airport (PVT), Ray, Michigan, during which a portion of the left main landing gear separated. The pilot aborted that landing and returned to D98. Visual meteorological conditions prevailed. The 14 CFR Part 91 personal flight was not operating on a flight plan. The pilot was uninjured.
Sequence of Events
The pilot reported that he approached PVT from the southwest and flew a non-standard approach to runway 36 to avoid a farm to the south. The planned touchdown point was about one-quarter down the runway to avoid a rise. The approach airspeed was about 65 miles per hour in a slight right slip. The wind was from the east with gusts. About 3 feet above the ground, the airplane lost lift and touched down in a slight right crab, left wing and tail low, and not too hard. The pilot heard a pop like a tire blow and aborted the landing. Airborne, he saw a hole in the left flap and a portion of the left landing gear missing. He also noted damage to the leading edge of the horizontal stabilizer and a portion of the elevator missing.
Examination of the PVT runway revealed a ground scar about 15 feet to the left of the prepared grass surface, consistent with the initial touchdown. Two scars from the left main and nose gear were about 18 feet long, where they separated from the airplane. The left main and nose landing gear were broken off 90 degrees to the right of the landing direction. A portion of the left main landing gear strut remained attached, with a corresponding scar approximately 45 feet long. No indications of right main gear touchdown were found.
Maintenance History
The airplane underwent a "Hi time Inspection" on August 28, 2006, at total aircraft time of 5,639.3 hours. During this inspection, the mechanic removed and sent the main landing gear struts for nondestructive testing, but the struts were lost in shipping. A second set was ordered and installed, but later found to be incorrect. A third set was ordered from North Sound Aviation, Sedro Woolley, Washington, and installed.
FAA Form 337, Major Repair And Alteration, dated March 6, 2006, documented repair of the struts. The form was signed by a U.S. certificated mechanic who owned North Sound Aviation, which is not a certificated repair station. The form identified left and right main landing gear struts by serial numbers 3P13 and 3P82, respectively. Item 8 described stripping paint, checking contour and strength, magnafluxing with no defects noted, and cleaning and priming. The approved data for the repair was not cited on the form.
An FAA Blue Ribbon report showed that this Form 337 was not present in FAA aircraft records. Advisory Circular 43.9-1E states that the person performing a major repair should prepare Form 337 in duplicate and forward a copy to the local FAA district office within 48 hours. The AC also requires identifying and describing the approved data used.
Metallurgical Examination
The left main landing gear strut was examined by the National Transportation Safety Board Materials Laboratory. The strut was transversely fractured about 15 inches from the lower end. Most of the fracture showed overstress features emanating from near the forward edge. The mating face was severely damaged. The exterior surface had intact white paint, with paint applied to irregular or pitted surfaces in many locations.
No old oxidation was present on the fracture. There were four fracture zones. Zone 1, near the forward edge, contained intergranular features mixed with overstress. Zone 2 had overstress and intergranular features with a thin band of fatigue cracking around most of its perimeter. Zone 3 was overstress with propagation away from fatigue cracking. Zone 4 was final overstress. A metallographic section through zone 1 showed altered microstructural layer indicative of excessive thermal input such as welding, extending 0.08 inch below the surface. Microhardness in this layer averaged HRC 51, while core hardness was HRC 43.