ERA15LA123 · American AA-1
American AA-1 · Accident: loss of engine power (partial) during takeoff
From Fort Meade Executive Airport (FME) to Fort Meade Executive Airport (FME)
Event
- NTSB case
- ERA15LA123
- 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
- API-reported fatalities
- 0 · all aircraft and ground
- 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
American AA-1
- Aircraft type
- American AA-1
- 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
- N6116L
- Operator
- Cline Thomas Lytton
- Onboard fatalities
- Unknown
- Route
- From Fort Meade Executive Airport (FME), Fort Meade, MDTo Fort Meade Executive Airport (FME), Fort Meade, MD
- Aircraft age
- About 45 years (built 1970)
- 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
- Loss of engine power (partial)
- 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 power plant
- Personnel issues › Action/decision
Approximate · Coordinates as recorded by the NTSB; no uncertainty radius is established.
NTSB narrative
The commercial pilot reported that, during the 4 months before the accident, the airplane had experienced ongoing engine issues, including engine roughness. Maintenance personnel were informed about the engine roughness, and a mechanic attributed the problem to the ignition system and subsequently replaced components of the system.
The pilot reported that the purpose of the flight was to verify that the previous repairs made to eliminate the engine roughness had resolved the problem. The pilot performed a thorough preflight inspection and a full-power engine run-up and noted no discrepancies. During the initial climb, when the airplane was about 250 ft above ground level, the engine rpm decreased from 2,500 to 1,500 and then increased to 1,900. The pilot's attempts to restore engine power were unsuccessful. The airplane impacted treetops and then came to rest on the ground inverted.
Postaccident examination of the engine revealed that all of the dry valve tappet clearances were less than prescribed by indications on the engine data plate. The reported loss of engine power and engine roughness was consistent with the valve clearances being incorrectly adjusted.
The engine operator's manual and a nonmandatory service instruction (SI) referenced in the manual specify that the tappet clearances should be checked every 100 hours of operation. A review of the maintenance logbooks revealed that the last check of the tappet clearances was performed in accordance with the SI about 224 hours, or about 7 years 7 months, before the accident by the same mechanic who had been troubleshooting the recent engine issues. If the mechanic had checked the dry tappet clearances while troubleshooting the ongoing engine issues, it is likely that he would have detected the incorrect dry tappet clearances and properly resolved the ongoing engine issues.
Probable cause
The mechanic’s failure to detect the incorrect dry valve tappet clearances while troubleshooting ongoing engine issues, which resulted in partial loss of engine power during takeoff. Contributing to the partial loss of engine power was the mechanic's failure to inspect the dry tappet clearances in accordance with the engine operator's manual and a referenced service instruction.
Verbatim NTSB analysis and probable cause from the NTSB dataset
Sources
NTSB record ERA15LA123
- Event ID
- 20150209X81643
- Case number
- ERA15LA123
- Dataset
- full-current
- Source SHA-256
- 5cf380f0061817c0331a6b2d8cc7e0ee3a79bea469a1001dc5c10e56f35f5ab3
Source notes (4)
- 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. 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: f991fcf4d02a5e5daffa05b1e0e90ceef9588030080780b2f7f2410c088a505a; retrieved 2026-09-16T02:04:41.275Z.