History of Flight
On July 28, 2012, at 0832 Pacific daylight time, a Piaggio P180, registration N146SL, arrived at Henderson Executive Airport, Henderson, Nevada. Post-flight inspection revealed the left elevator was missing from the tail. The flight, operated by Avantair under Part 135, had departed San Diego, California, about 0735 with two crew and two passengers. Visual meteorological conditions prevailed, and an IFR flight plan was filed. The crew reported a non-eventful departure and flight, but noted that more back pressure on the controls was required for a normal landing.
According to Avantair's trip sheet, the crew's planned schedule was to depart Camarillo, California, at 0552, arrive San Diego at 0642, then depart San Diego at 0730 and arrive Henderson at 0822. The crew arrived at Camarillo at 0500, preflighted the aircraft, and departed at 0615. The aircraft arrived San Diego at 0715. The captain went to the FBO to sign for services and performed a walk-around on one side. The first officer met passengers and loaded baggage; he did not perform the required walk-around. The aircraft departed San Diego at 0735 and arrived Henderson at 0832.
On July 31, 2012, at 1720, personnel at Camarillo Airport found a flight control surface in the grass off runway 8 near taxiway C. It was identified as a Piaggio P180 elevator. An FAA inspector collected it and delivered it to the NTSB on August 1.
Personnel Information
The captain, age 31, held an Airline Transport Pilot certificate with multiengine land and instrument ratings, and a first-class medical certificate issued April 16, 2012, with no limitations. He reported 5,037 total flight hours.
The first officer, age 34, held an Airline Transport Pilot certificate with similar ratings, and a first-class medical certificate issued April 11, 2012, with no limitations. He reported 5,624 total flight hours.
Aircraft Information
The 10-seat twin-turboprop business aircraft, serial number 1091, was manufactured in 2004. It was powered by two Pratt & Whitney PT6A-66 850-hp engines and two Hartzell HC-E5N-3A controllable pitch propellers. The aircraft was in a continuous airworthiness program. Total airframe time at landing was 8,351.9 hours. The most recent maintenance was a 150-hour “A” inspection on July 2, 2012, at TAT 8,269.4 hours, which includes visual inspection and functional check of the elevator. The most recent maintenance was on July 27, 2012, at TAT 8,350.3 hours, to repair the right main landing gear door rod assembly and navigation lights.
On June 4, 2012, at TAT 8,191.5 hours, Avantair complied with AD 2010-23-01 requiring removal and inspection of elevator hinges. The elevators were reinstalled. Examination of the left horizontal stabilizer hinge fittings revealed no damage or witness marks. The two sets of bolts, nuts, and straight bushings attaching the left elevator were not located.
The A&P mechanic who removed the right elevator reported that the self-locking nuts were loose and could be removed by hand. He photographed the loose nuts.
Additional Information
On August 7, 2012, Avantair initiated a fleet-wide inspection of all Piaggio P180 aircraft to inspect and replace elevator mounting hardware. The Executive Vice President confirmed on December 6, 2012, that all elevator self-locking nuts had been replaced with new hardware.
Flight Recorders
The aircraft was equipped with an L-3/Fairchild FA2100-1010 CVR recording 30 minutes. The CVR was sent to the NTSB Audio Laboratory. The recording was of excellent quality. Conversation between 0815 and 0825 pertained to operations. At 0825, ATC cleared the aircraft for a visual approach to runway 17R. At 0829, gear was lowered. One minute later, a rattling sound began and continued to touchdown. At 0831:24, an automated voice announced “five hundred above, sink rate, sink rate.” The captain replied “correcting.” After landing, the crew discussed unusual control feel. The captain made a cell phone call describing lack of normal elevator control during rotation and landing, and that the aircraft did not rotate until 120 kts despite yoke full back at 106 kts. He noted that the first officer had felt strange controls on departure from Camarillo.
Tests and Research
The left elevator command lever with fractured torque tube and right elevator attachment hardware were examined by the NTSB Materials Laboratory. The left attachment fitting was fractured through a flange, with deformation consistent with overstress from downward bending. The right elevator attachment hardware was tested for running torque. For one bolt/nut combination, on-running torque was 1.2 in-lbs and off-running torque was 1.5 in-lbs. For the second, on was 8.5 in-lbs and off was 9.0 in-lbs. According to the P180 maintenance manual, self-locking nuts should be discarded when running torque falls below 3.5 in-lbs for ¼-28 nuts. Exemplar hardware showed on-running torque between 6.1 and 7.0 in-lbs and off-running between 6.8 and 8.8 in-lbs.