FTW98LA154 · Grumman American AA-1B
Grumman American AA-1B · Accident: loss of engine power during an emergency descent
From 309 · Afton, OK to Tulsa Riverside Airport (RVS)
Event
- NTSB case
- FTW98LA154
- 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
- 0
- 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
Grumman American AA-1B
- Aircraft type
- Grumman 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
- N9940L
- Operator
- Unknown
- Onboard fatalities
- Unknown
- Route
- From 309 · Afton, OKTo Tulsa Riverside Airport (RVS), Tulsa, OK
- Aircraft age
- Not recorded
- 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
- Emergency descent
- First occurrenceThe 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
- 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
- Reason for occurrence undetermined
Approximate · Estimated position: the centre of Tulsa, OK, the place the record names. Not the accident site.
NTSB narrative
The airplane experienced a complete loss of engine power, followed by a forced landing, near Tulsa, Oklahoma. The airplane was receiving flight following from Tulsa approach control and descending from 4,500 feet to 3,000 feet, when the 'power suddenly reduced, surged and reduced.' The pilot stated that the carburetor temperature gauge indicated 47 degrees Fahrenheit. The pilot switched the fuel tank selector switch from the left to the right tank, but there was no change in engine performance. The pilot was unable to maintain altitude and was assigned vectors to a nearby airstrip. The airplane was 100 yards from the runway when the engine lost complete power. The airplane contacted muddy terrain short of the intended field and slid 50 feet, coming to rest inverted on a fence. The pilot reported that fuel was dripping on him as he exited the airplane. The airplane and engine were examined at the site by an FAA inspector and subsequently at the ILIFF Aircraft Repair and Service Co., Inc., Tulsa, Oklahoma, on March 24, 1998. No mechanical anomalies were found that could have contributed to the loss of power.
Probable cause
The complete loss of engine power for an undetermined reason. A factor was the lack of suitable terrain for the forced landing.
Verbatim NTSB analysis and probable cause from the NTSB dataset
Sources
NTSB record FTW98LA154
- Event ID
- 20001211X09675
- Case number
- FTW98LA154
- Dataset
- historical-pre2008
- Source SHA-256
- 89e2df6d848e7ab3b42e7d7c7a03ff403303057a26ca04c95b3ea67201c3ce74
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: 7039817e9f3386b33d1452a9918936acb60e444d6d9c7df7b83369401db7a1d2; retrieved 2026-09-21T20:53:06.024Z.