# NTSB SEA95LA153: Piper PA-20, N6953K, Ogden, UT, July 18, 1995 - Type: NTSB accident investigation - Classification: Accident · No injuries · Limited investigation · Final report - Date: July 17, 1995, 19:35 local (Jul 18, 1995, 01:35 UTC) - Place: Ogden, UT - Coordinates: 41.239067, -112.1296 (estimated) - Nearby events: https://openairdocs.org/map.md?lat=41.2391&lon=-112.1296&mi=10 - Phase of flight: [Landing](https://openairdocs.org/ntsb-phases/550) (OpenAirDocs' grouping) - Highest injury: No injuries - Injuries: 2 uninjured - Status: Completed, report December 4, 1995 - Report: Approved by Office Director - NTSB case key (mKey): 42195 - NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=SEA95LA153 - NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/42195/pdf - Page: https://openairdocs.org/ntsb/SEA95LA153 ## Probable cause THE PILOT-IN-COMMAND'S FAILURE TO MAINTAIN DIRECTIONAL CONTROL. HTE LOOSE TAILWHEEL ASSEMBLY BOLT WAS A FACTOR. ## Sequence of events In NTSB's coding before 2008 (https://www.ntsb.gov/GILS/Documents/codman.pdf). - On ground/water encounter with terrain/water, landing - roll - landing gear,tailwheel assembly - loose part/bolt/nut/clamp/etc (contributing factor) - directional control - not maintained, pilot in command(cfi) (cause) ## Analysis THE FLIGHT INSTRUCTOR STATED THAT HE HEARD A STRANGE NOISE AND FELT A VIBRATION DURING THE LANDING ROLL. HE THOUGHT THAT IT MIGHT BE A FLAT MAIN LANDING GEAR TIRE AS HE WAS HAVING TO INPUT MORE LEFT RUDDER CONTROL TO MAINTAIN RUNWAY CENTERLINE. AS THE AIRPLANE SLOWED, THE CFI WAS UNABLE TO MAINTAIN DIRECTIONAL CONTROL AS THE NOSE VEERED TO THE RIGHT AND THE AIRPLANE GROUND LOOPED. DURING THE POST CRASH INSPECTION, THE TAILWHEEL PIVOT BOLT WAS FOUND TO BE LOOSE. REVIEW OF THE AIRCRAFT LOGBOOKS INDICATE THAT IT HAD BEEN 19 MONTHS SINCE THE LAST ANNUAL INSPECTION. ## Factual narrative On July 17, 1995, at 1935 mountain daylight time, a Piper PA-20, N6953K, ground looped after landing at the Ogden Airport, Ogden, Utah. Visual meteorological conditions prevailed at the time and no flight plan was filed for the local instructional flight. The airplane was substantially damaged and the flight instructor and student pilot were not injured. During a telephone interview and subsequent written statement, the flight instructor stated that this was his first flight with this student pilot who was preparing to take the private pilot check ride. The student pilot was at the controls for takeoff and the flight stayed in the pattern to practice touch-and-go landings. During the first approach, the flight instructor stated that he took control of the airplane on final approach to demonstrate a procedure to the student. After a three point touchdown, the flight instructor noticed a strange noise and felt a vibration that he couldn't pin down. The flight instructor thought that it may be a flat main landing gear as he was having to input more left rudder control to maintain runway centerline. As the airplane slowed to 10 to 15 knots, the flight instructor stated that he was unable to maintain directional control as the nose of the airplane veered to the right and the airplane ground looped. A Federal Aviation Administration Inspector from the Salt Lake City, Utah, Flight Standards District Office, inspected the airplane and found that the tailwheel pivot bolt was loose, which resulted in the tailwheel shimmy during the landing roll. The airframe and engine logbooks indicate that the last annual inspection was performed on 12/16/93. The logbooks list several major repairs and alterations since 12/7/93. ## Aircraft - Registration: [N6953K](https://openairdocs.org/aircraft/N6953K), registered now, S/N 20-46 (OpenAirDocs) - Reported make and model: PIPER PA-20 - Registry model: [Piper PA-20](https://openairdocs.org/model/piper-pa-20) (registry code 7102002) (OpenAirDocs) - Category: Airplane - Serial number: 20-043 - Engines: LYCOMING O-320-A2B 150 horsepower reciprocating - Damage: Substantial damage - Flight: Instructional, Part 91 - Registered owner: Hyman E. Harrelson - Airworthiness certificate: Standard, Normal - Last inspection: Annual, December 16, 1993 - Airport: OGD, Ogden-Hinkley, runway 34, 5,352 × 150 ft, asphalt ## Flight crew As NTSB recorded them. NTSB leaves out names. - Pilot; age 59; flight instructor, commercial; airplane ratings: multi-engine land, single-engine land, single-engine sea; instrument ratings: airplane; medical: class 2, valid medical--w/ waivers/lim; seat: right; flight hours: 4,775 total, 15 in this make and model, 4,624 as pilot in command, 63 in the last 90 days, 20 in the last 30 days ## Weather - Conditions: Visual (VMC), Day - Wind: calm - Visibility: 30 statute miles - Lowest ceiling: 18,000 ft broken - Temperature: 86 °F, dew point 48 °F - Altimeter: 29.00 inHg - Observed at: OGD ## FAA reports on this event (1) The FAA's own accident and incident reports, matched to the aircraft by N-number and date (OpenAirDocs). - [Accident 19950717024669A](https://openairdocs.org/incident/19950717024669A), Jul 17, 1995: Piper PA20, Ogden, UT, Substantial damage. Ground looped on landing. CFI at controls. Found loose tailwheel pivot bolt. Caused shimmy and loss of control. From the NTSB's public API. Aircraft are matched to registry aircraft by N-number and event date, checked against the reported serial number, make and model; the registry's history has gaps, so older matches can be wrong. Compare the reported make and model. --- OpenAirDocs.org is an independent research project of [Contrail Labs](https://contraillabs.com/). It is not affiliated with the FAA or the NTSB. Source documents are U.S. government works in the public domain.