Incident Overview
On October 19, 2012, at approximately 1412 eastern daylight time, a Cessna 560XL (registration N576QS) received minor damage during gear retraction after takeoff from Nantucket Memorial Airport (ACK) in Massachusetts. The aircraft was operated by NetJets Aviation, Inc. under 14 CFR Part 135 as an air taxi flight. Visual meteorological conditions prevailed, and an instrument flight rules flight plan was filed. The flight was destined for Lexington, Kentucky (LEX).
The flight crew consisted of an airline transport pilot and a co-pilot, along with one passenger; none were injured. According to the crew, at 400 feet above ground level after takeoff, the flaps were retracted. Shortly thereafter, tower personnel informed them that fuel was pouring from the left wing. The crew also observed hydraulic and stabilizer annunciator lights and a gear unlocked indication. A slight rumble was felt in the airframe. The left wing fuel indicator decreased by approximately 500 pounds, and the crew noted a heaviness in the right wing. The flight remained in the traffic pattern and returned to ACK for an uneventful landing with a fuel imbalance of about 1,000 pounds.
Findings
An inspector from the Federal Aviation Administration examined the airplane at the accident site. The left main gear aft trunnion pivot pin was not in place, causing the aft portion of the left main gear trunnion to separate from the aft trunnion fitting. The end of the aft trunnion punctured the interior of the gear well, resulting in minor damage to surrounding structure. The pivot pin was later found loose and undamaged in the flap track area of the left wing. The retaining bolt intended to restrain the pivot pin was in place and secured with a nut and cotter pin.
Maintenance Background
A review of maintenance records revealed that the left main gear trunnion had been removed and replaced with a new unit on September 1, 2012, by a maintenance vendor. According to the Cessna 560XL Maintenance Manual, during installation of the aft main landing gear trunnion, the trunnion pivot pin must be slid forward, aligning a hole in the trunnion with a hole in the pivot pin. The pivot pin is then secured with the retaining bolt, washers, nut, and cotter pin.