# NTSB CEN21LA009: Mooney M20F, N7798M, Denver, CO, October 2, 2020 - Type: NTSB accident investigation - Classification: Accident · No injuries · Class 4 · Limited · Final report - Date: October 2, 2020, 10:35 local (16:35 UTC) - Place: Denver, CO - Coordinates: 39.58, -104.85 (estimated) - Nearby events: https://openairdocs.org/map.md?lat=39.5800&lon=-104.8500&mi=10 - Phase of flight: [Landing](https://openairdocs.org/ntsb-phases/550) (OpenAirDocs' grouping) - Defining event: [Landing: Landing gear collapse](https://openairdocs.org/ntsb-events/094) - Highest injury: No injuries - Injuries: 2 uninjured - Status: Completed - Report: Approved by Office Director - Investigation class: Class 4 - Basic report with no Prelim publish - NTSB office: Central Region - NTSB case key (mKey): 102105 - NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=CEN21LA009 - NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/102105/pdf - Page: https://openairdocs.org/ntsb/CEN21LA009 ## Probable cause Failure of the landing gear motor that prevented the gear from extending fully to the down and locked position, which resulted in a gear collapse on landing and a subsequent loss of directional control. ## Findings NTSB's coded findings; those marked are part of the probable cause. - [Landing gear system: gear extension and retract sys](https://openairdocs.org/ntsb-findings/01023230): Aircraft › Aircraft systems · Failure (probable cause); cases with it: [Mooney M20F, 3 cases](https://openairdocs.org/ntsb-findings/01023230/cases.md?model=5870214), [All aircraft, 416 cases](https://openairdocs.org/ntsb-findings/01023230/cases.md) ## Sequence of events The events NTSB coded, in order, by phase of flight. The defining event best describes what happened. - [Landing: Landing gear collapse](https://openairdocs.org/ntsb-events/094) (defining event); cases with it: [Mooney M20F, 3 cases](https://openairdocs.org/ntsb-events/094/sequence.md?model=5870214), [All aircraft, 1,787 cases](https://openairdocs.org/ntsb-events/094/sequence.md) ## Analysis The pilot reported that during takeoff the cabin door opened and during the climb and on raising the landing gear, he failed to receive the gear “UP” light. The passenger attempted to close the door while the pilot recycled the landing gear. The pilot reported that gear had likely not retracted based on the airplane’s failure to climb and gain airspeed as it would have, had the gear retracted. The pilot decided to return to the airport and contacted the air traffic control tower to visually assess the gear position. While maneuvering for the air traffic control tower to verify the gear, the pilot continued to cycle the gear up and down receiving no indications of a change in the gear position. The pilot reported the floorboard landing gear position indicator showed “GEAR DOWN” giving him the indication that the landing gear was down. The air traffic controller advised the pilot the gear appeared to be in the down position and cleared the airplane to land. The airplane touched down near the 1,000-foot marker on the runway on the two main wheels. A “split second” later, the right main and nose landing gear collapsed, and the airplane slid off the right side of the runway impacting a runway light with the right wing. The airplane’s right wing sustained substantial damage. A postaccident examination of the landing gear showed the landing gear motor would engage for about 5 seconds and then stop leaving the landing gear in an intermediate position. A subsequent bench test of the landing gear motor resulted in the motor failing to engage or move, indicative of it being inoperative. ## Aircraft - Registration: [N7798M](https://openairdocs.org/aircraft/N7798M), registered now, S/N 22-0040, built 1974 (OpenAirDocs) - Reported make and model: MOONEY M20F (NO SERIES) - Registry model: [Mooney M20F](https://openairdocs.org/model/mooney-m20f) (registry code 5870214) (OpenAirDocs) - Registry engine: [Lycoming I0360 series](https://openairdocs.org/engine/lycoming-i0360-series) (registry code 41515, reciprocating) (OpenAirDocs) - Category: Airplane - Serial number: 22-0040 - Year built: 1974 - Airframe hours: 3286.85 - Engines: Lycoming IO-360-A1A 200 horsepower reciprocating - Damage: Substantial damage - Flight: Personal, Part 91 - Airworthiness certificate: Standard, Normal - Last inspection: Annual, June 19, 2020, 118.13 hours before - Destination: Same as departure - Airport: APA, Centennial, runway 17, 10,001 × 100 ft, asphalt - Equipment: Onboard weather, Stall warning system, ADS-B, Auto-pilot, Data recorder, Electronic flight bag or handheld device ## Flight crew As NTSB recorded them. NTSB leaves out names. - Pilot; age 39; injuries: none; commercial; airplane ratings: single-engine land; instrument ratings: airplane; medical: class 2, without waivers/limitations; last flight review June 24, 2020; seat: left; restraint: 3-point; flight hours: 467 total, 114 in this make and model, 405 as pilot in command, 101 in the last 90 days, 27 in the last 30 days ## Weather - Conditions: Visual (VMC), Day - Wind: variable at 6 knots - Visibility: 10 statute miles - Temperature: 66 °F, dew point 25 °F - Altimeter: 30.24 inHg - Observed at: KAPA ## 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 20201002022289A](https://openairdocs.org/incident/20201002022289A), Oct 2, 2020: Mooney M20F, Centennial, CO, Minor damage. On 02/10/2020 at approximately 1015 hrs (MDT), N7798M, sn 22-0040, Mooney M20F, during takeoff at Centennial airport, (kapa) Centennial, CO. The sole door on… 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.