Aviation Accident Summaries

Aviation Accident Summary WPR11LA143

Nephi, UT, USA

Aircraft #1

N891X

MOONEY M20F

Analysis

Before the accident flight, the pilot diverted to an alternate airport due to inclement weather. While landing, the pilot felt a shimmy in the landing gear but reported that the landing was otherwise normal. The pilot did not inspect the landing gear. On the accident flight, the pilot flew to his intended airport and decided to conduct a soft-field landing; he lowered the nose landing gear after the main landing gear touched down. Upon contact with the runway, the nose landing gear began to shimmy. The airplane veered to the left of the runway and the pilot attempted to return it to runway centerline. The nose landing gear then collapsed, and the airplane continued off the runway and into a snow bank, where the nose gear was sheared off. The pilot reported that when he purchased the airplane the year before, he had felt a similar shimmy in the landing gear. He further stated that 2 weeks before the accident, the airplane had gone through an annual inspection during which the landing gear actuator had been sent out for overhaul. The pilot had flown the airplane about 10 hours since the inspection. The cause of the nose gear failure was not determined because postaccident examination could not determine if the damage occurred before the impact with the snow bank or during the accident sequence.

Factual Information

HISTORY OF FLIGHTOn February 23, 2011, about 0900 mountain standard time, a Mooney M20F, N891X, departed the runway after the nose landing gear collapsed during the landing roll out at Nephi Municipal Airport (U14), Nephi, Utah. The owner/pilot operated the airplane under the provisions of 14 Code of Federal Regulations Part 91 as a personal flight. The pilot, the sole occupant, was not injured. The airplane sustained substantial damage to the fuselage after it impacted a snow bank and the main landing gear was sheared off. Visual meteorological conditions prevailed for the cross-country flight that departed Mesquite Airport (67L), Mesquite, Nevada, at 0645 Pacific standard time; no flight plan had been filed. The flight was en route to Nephi. According to the pilot, an annual inspection had been completed about 2 weeks prior to the accident; since that time he had flown the airplane about 10 hours. During the inspection, work had been done on the landing gear. On the Friday before the accident (February 18) he had flown from General William J. Fox Airfield (WJF), Lancaster, California, with the intent on landing at Nephi; however, due to weather he diverted to Mesquite. The pilot reported that he felt a significant shimmy upon landing at Mesquite. He also reported that he had purchased the airplane a year ago, and initially had landing gear problems. On the day of the accident he drove from Nephi to Mesquite to pick up his airplane and fly it to Nephi. The flight to Nephi was uneventful. Upon arrival to Nephi, the pilot configured the airplane for a soft field landing. The airplane touched on the main landing gear and as the nose gear contacted the ground, he felt a "bad shimmy," which pulled the airplane off to the left of the runway. He attempted to correct back to the runway, but the nose landing gear collapsed. The airplane continued off the runway into a snow bank where the main landing gear was sheared off. The pilot provided a verbal statement, but did not return the National Transportation Safety Board (NTSB) form 6120.1; Pilot/Operator Aircraft Accident/Incident Report. PERSONNEL INFORMATIONThe pilot, age 52, held a private pilot certificate with a rating for airplane single-engine land. He was issued a third-class medical on November 5, 2009, with the limitation that he must have available glasses for near vision. No personal flight record was made available by the pilot to the NTSB investigator-in-charge (IIC). The IIC obtained the aeronautical experience listed in this report from a review of the Federal Aviation Administration (FAA) airmen medical records on file in the Airman and Medical Records Center located in Oklahoma City, Oklahoma. On the pilot's most recent application for a medical certificate dated, November 5, 2009, the pilot reported a total time of 167 hours, with 11 hours logged in the past 6 months. AIRCRAFT INFORMATIONThe four-seat, low-wing, retractable-gear airplane, N891X, serial number 670257, was manufactured in 1967. It was powered by a Lycoming IO-360-A1A 200-hp engine and equipped with a Hartzell model HC-CZYK-1BF constant speed propeller. Review of copies of maintenance logbook records showed an annual inspection was completed February 4, 2011, at a recorded tachometer reading of 1,521.37 hours, and an airframe total time of 4,726.37 hours. Contained in the logbook entry was that the landing gear actuator had been removed and sent out for an overhaul. The actuator was reinstalled and the landing gear was rigged. According to an entry in the engine logbook, dated January 13, 2010, it showed that an audit had been completed for the airplane, engine, and propeller. At that time, the mechanic ascertained that the airplane total time was 5,629.99 hours, the engine accrued 770.0 hours-time since new, and the time on the propeller was 51.47 hours. The airplane was inspected by an airplane repair station on behalf of the insurance company. The repair facility reported that the damage was such that they were not able to determine if the damage had occurred pre impact or had happened during the accident sequence. METEOROLOGICAL INFORMATIONThe closest weather reporting station was Provo Municipal Airport (PVU), Provo, Utah, 30 miles north from the accident site. The recorded weather at 0850 indicated winds were variable at 4 knots; visibility 15 miles; scattered clouds at 9,000 feet; temperature was -01 degrees Celsius and dew point was – 06 degrees Celsius; altimeter setting 29.99 inches of Mercury. AIRPORT INFORMATIONThe four-seat, low-wing, retractable-gear airplane, N891X, serial number 670257, was manufactured in 1967. It was powered by a Lycoming IO-360-A1A 200-hp engine and equipped with a Hartzell model HC-CZYK-1BF constant speed propeller. Review of copies of maintenance logbook records showed an annual inspection was completed February 4, 2011, at a recorded tachometer reading of 1,521.37 hours, and an airframe total time of 4,726.37 hours. Contained in the logbook entry was that the landing gear actuator had been removed and sent out for an overhaul. The actuator was reinstalled and the landing gear was rigged. According to an entry in the engine logbook, dated January 13, 2010, it showed that an audit had been completed for the airplane, engine, and propeller. At that time, the mechanic ascertained that the airplane total time was 5,629.99 hours, the engine accrued 770.0 hours-time since new, and the time on the propeller was 51.47 hours. The airplane was inspected by an airplane repair station on behalf of the insurance company. The repair facility reported that the damage was such that they were not able to determine if the damage had occurred pre impact or had happened during the accident sequence.

Probable Cause and Findings

The failure of the nose gear during landing for reasons that could not be determined due to postaccident damage.

 

Source: NTSB Aviation Accident Database

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