History of Flight
On March 2, 2010, at 1345 central standard time, a Beech 65-A90 (King Air), registration N129LA, experienced a collapse of the left main landing gear during the landing rollout on runway 09 at DeKalb Taylor Municipal Airport (DKB), DeKalb, Illinois. The flight was a 14 CFR Part 91 maintenance test flight and had originated from DKB at 1330. Visual meteorological conditions prevailed. The pilot and a pilot/mechanic-rated passenger were uninjured.
The pilot reported that the flight was conducted to check engine performance and throttle settings. After remaining in the traffic pattern, the pilot decided to return for adjustments. During landing on runway 09, the touchdown was normal, but approximately three-quarters through the rollout, the left main landing gear wheel began to vibrate. Suspecting a flat tire, the pilot applied reverse thrust and braking. As the airplane slowed, the left main landing gear collapsed, and the airplane skidded to a stop, striking the propeller. The pilot stated that a crosswind landing and an unbalanced fuel load resulted in a heavier left wing, contributing to the gear collapse. The pilot also reported that the landing was performed with the flaps fully retracted.
Personnel Information
The pilot held a commercial pilot certificate with airplane single-engine land, airplane multi-engine land, instrument airplane, and rotorcraft-helicopter ratings. He reported a total flight time of 8,100 hours, with 1,200 hours in the accident airplane make and model. He was the president of Win Win Aviation Inc. The passenger, who held an airline transport pilot certificate and a mechanic certificate with airframe and power plant ratings and inspection authorization, was invited to ride along and did not perform any pilot duties.
Aircraft Information
The accident aircraft was a 1966 Beech 65-A90 (King Air), serial number LJ-129. It was purchased by Win Win Aviation, Inc. on August 21, 2009, and sold to Eagle Air Transport, Inc. on February 18, 2010, with the sale recorded on April 20 and April 30, 2010. A logbook entry dated February 26, 2010, indicated that a 6-year landing gear inspection had been completed, including magnetic particle inspection of the left and right main landing gears, which were found acceptable. A subsequent entry dated March 1, 2010, documented the installation of Pratt & Whitney PT6A-28 engines and that the airplane was ground run, rigged, and found airworthy. The airplane's maximum gross weight was 9,650 lbs; its weight at the time of the accident was 7,451 lbs.
Meteorological Information
The DKB Automated Observing System recorded winds at 1323: 360 degrees at 8 knots; at 1343: 020 degrees at 7 knots; at 1400: 020 degrees at 6 knots; and at 1423: 340 degrees at 8 knots.
Wreckage and Impact Information
The airplane came to rest off the left side of runway 09, near the intersection with the parallel taxiway to runway 2/20. A skid mark from the left main landing gear tire began between the centerline and the right side of runway 09. The airplane sustained damage to the left main wheel well, the left wing, and the left propeller. The left main landing gear shock absorber assembly cylinder was separated from its piston at the brazed joint adjacent to the upper torque knee collar. The brazed joint had paint on its mating surface.
Tests and Research
According to the FAA, the airplane’s left main landing gear strut was serviced four times before the accident. After each servicing, the strut lost pressure overnight while in the retracted position. It was then inflated to a 6-inch extension, approximately twice the recommended extension. After the last inflation, the strut held pressure. In preparation for the maintenance test flight, the left wing was fueled while the right wing remained nearly empty to compress the left wing strut.
Examination of the left main landing gear strut was performed at Hawker Beechcraft Corporation under FAA supervision. The examination revealed that the separation signatures exhibited torsional overload. The brazed joint showed acceptable braze coverage and no anomalous voids, but also evidence of corrosion. The left main landing gear shock absorber assembly was part number 50-810002, which is not approved for installation on Beech 90 series (King Air) airplanes but is approved for Beech 65 series (Queen Air) airplanes. The part was designed with dampening rates for Queen Air landing loads. Upon arrival, FAA inspectors were informed by the pilot that the left main landing gear was a Queen Air part.