ERA21LA170 · Mooney M20C
Mooney M20C · Accident: fuel related during takeoff
From an unrecorded airport to Tangier Island Airport (TGI)
Event
- NTSB case
- ERA21LA170
- Event typeAccident: someone killed or seriously injured, or the aircraft substantially damaged (NTSB definition). Incident: an occurrence that affected or could have affected safety, short of that. Glossary
- Accident
- InvestigationHow far the investigation had got when the record was published: preliminary, ongoing, final or completed. Unknown where the source does not say. Glossary
- Completed
- Event fatalities
- Unknown
- Ground fatalities
- Unknown
- OperationWhat kind of flying it was, grouped by the rules it flew under: airline (US Part 121), air taxi and commuter (Part 135), general aviation (Part 91 and similar), military or government. Glossary
- General aviation
- WeatherVisual meteorological conditions (VMC): good enough to fly by looking outside. Instrument conditions (IMC): cloud or low visibility, flying by instruments. Glossary
- Visual Meteorological Cond
Mooney M20C
- Aircraft type
- Mooney M20
- Category
- Airplane
- RegistrationThe aircraft's tail number, such as N12345 or G-ABCD. Registrations are reissued, so the same one years apart can be a different aircraft. Glossary
- N2953L
- Operator
- Unknown
- Onboard fatalities
- Unknown
- Route
- From not recordedTo Tangier Island Airport (TGI), Tangier Island, VA
- Aircraft age
- About 54 years (built 1967)
- Flight rulesThe regulations the flight operated under: in the US, Part 91 (general aviation), Part 121 (airlines), Part 135 (air taxi and commuter) and others; for flights abroad, the NTSB's coarser commercial or non-commercial code. Glossary
- Part 91: General Aviation
- Phase of flightThe stage of the flight when things started to go wrong: standing, taxi, takeoff, initial climb, en route, maneuvering, approach or landing. Glossary
- Takeoff
- Defining eventThe single coded event the NTSB judges best describes what happened (records from 2008 on). Older records name the first occurrence in the sequence instead. Glossary
- Fuel related
- DamageDestroyed: beyond practical repair. Substantial: damage that affects the structure, performance or handling and normally needs major repair. Minor: less than that. Glossary
- Substantial
Cause areas
- Aircraft › Aircraft handling/service
- Aircraft › Aircraft oper/perf/capability
- Personnel issues › Action/decision
- Personnel issues › Task performance
Approximate · Coordinates as recorded by the NTSB; no uncertainty radius is established.
NTSB narrative
The pilot planned for a recreational trip of 2 hours or less. During his preflight inspection, he found, “a bunch of water” in the left fuel tank, which he said he continued to sample until it was free of water. He then dried his collection tube and sampled the tank twice more reporting the sample was clear with no water. Before departure, with the fuel selector positioned to the left fuel tank, he performed an engine run-up with no engine or engine systems discrepancies reported. During takeoff he rotated at 83 mph and when over the runway the engine began to “cough/sputter.” He continued straight ahead, but review of airport surveillance video revealed that the airplane likely stalled and landed hard resulting in substantial damage to the left wing.
A postaccident examination of the airplane found that there was water in the flexible fuel hose from the firewall fitting to the engine-driven fuel pump inlet, and about 5 ounces of fluid drained from the carburetor bowl contained equal parts of fuel and water. On-wing pressure testing of the fuel caps revealed extensive leakage from both and a subsequent examination revealed evidence of unapproved or missing parts from both caps. The correct parts were then installed on both caps and they passed testing to 25 psi, but leakage was noted during on-wing pressure testing. Additional testing identified leakage between the adapter and the doubler of each assembly at low pressures, which increased in intensity as the pressure increased.
Prior to the accident flight, the co-owners of the airplane replaced the seals on both fuel caps which did not eliminate the water intrusion. In addition, they purchased wing covers in an attempt to further reduce the potential for water intrusion; however, they were not installed on the airplane when the pilot arrived at the airport for the accident flight. They did not alert their mechanic of the issue.
Although the pilot reportedly sampled the left fuel tank until water was no longer present, he likely did not drain out all the water from the tank nor did he drain the selector valve sump as part of his inspection. The results of the extensive postaccident testing revealed that even if the fuel caps were repaired properly, additional issues were present with each fuel tank filler cap assembly that were not addressed by the owners. Had the owners consulted with their maintenance provider about the water intrusion, it is likely that the root cause of the water intrusion could have been identified.
Probable cause
Improper maintenance of the airplane by its owners and their failure to have qualified maintenance personnel determine the root cause of water infiltration into the fuel system. Also causal was the pilot’s inadequate preflight inspection, which failed to remove all of the water contamination from the fuel system prior to the flight and resulted in the partial loss of engine power during the takeoff. Contributing was the pilot’s exceedance of the critical angle of attack, which resulted in an aerodynamic stall and subsequent hard landing.
Verbatim NTSB analysis and probable cause from the NTSB dataset
Sources
NTSB record ERA21LA170
- Event ID
- 20210404102860
- Case number
- ERA21LA170
- Dataset
- full-current
- Source SHA-256
- 5cf380f0061817c0331a6b2d8cc7e0ee3a79bea469a1001dc5c10e56f35f5ab3
Source notes (5)
- Unreviewed is an editorial label, not an investigation status. API-sourced is not report-checked or human-reviewed. Explicit event totals are used without summing aircraft injury tables; onboard allocation is withheld. Unknown values remain unknown. The operation category is mapped from the NTSB-reported FAR part and has not been reviewed.
- Filled from the NTSB case API where the bulk record had no value: investigation status, cause areas. Values present in the bulk record are kept.
- The date is the local date, which is the same as the UTC date the NTSB stores.
- API snapshot SHA-256: 2aa2947a0709cd5508fc9a42875cdc0d2f9bf6af1e0d66f6bf04c72204ffa5e4; retrieved 2026-09-16T13:55:13.490Z.
- Corrected after a review of the NTSB narrative, which states these values explicitly: destination. TGI is Tangier Island Airport in Virginia, as another record in the same release labels it; the state is recorded as MD.