FTW89DPJ08 · Grumman G-164
Grumman G-164 · Accident: airframe, component or system failure while maneuvering
From Hooker, OK (no airport) to an unrecorded destination
Event
- NTSB case
- FTW89DPJ08
- 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 G-164
- Aircraft type
- Grumman G-164
- 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
- N788Y
- Operator
- Gray, Ronald W. · private individual
- Onboard fatalities
- Unknown
- Route
- From Hooker, OK (no airport)To not recorded
- 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 137: Agricultural
- 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
- Maneuvering · turn to reverse direction
- 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
- Airframe, component or system failure
- 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
- Engine assembly, mount › Failure, total
- Engine assembly, mount › Fatigue
Approximate · Coordinates as recorded by the NTSB; no uncertainty radius is established.
NTSB narrative
DURING PULLUP FOR A TURNAROUND MANEUVER, THE ENG FELL FROM THE AG AIRPLANE. CONTROL WAS LOST & THE AIRPLANE HIT FLAT IN A FIELD. A POST-ACDNT INVESTIGATION REVEALED THE UPPER RIGHT ENG MOUNT (FIREWALL ATTACH BOLT) HAD FAILED FROM FATIGUE. THE LOWER RIGHT BOLT HAD ALSO FAILED PRIOR TO ENG SEPARATION, BUT ITS FACTURE SURFACE WAS TOO BADLY DAMAGED TO VERIFY THE REASON OF FAILURE. THE UPPER LEFT & LOWER LEFT ATTACH BOLTS WERE FOUND NECKED DOWN AT THEIR RESPECTIVE FRACTURES FROM OVERLOAD FAILURE.
Probable cause
FAILURE OF THE UPPER RIGHT ENGINE MOUNT (FIREWALL ATTACH BOLT) DUE TO FATIGUE, AND FAILURE OF THE LOWER RIGHT MOUNTING BOLT FOR AN UNKNOWN REASON, WHICH ALLOWED OVERLOAD FAILURE OF THE TWO REMAINING MOUNTING BOLTS AND SEPARATION OF THE ENGINE.
Verbatim NTSB analysis and probable cause from the NTSB dataset
Sources
NTSB record FTW89DPJ08
- Event ID
- 20001213X28820
- Case number
- FTW89DPJ08
- 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: local date, investigation status. Values present in the bulk record are kept.
- The date is the local date; the NTSB stores the UTC date 1989-07-08.
- API snapshot SHA-256: 2ea26800059d5df30f2f16de73fa3c02ddca622fd352818bdda25051f94a4da7; retrieved 2026-09-21T15:53:08.524Z.