Grumman G164 accident near Opelousas, Louisiana, August 29, 2018
On August 29, 2018 at about 4:30 pm local time, a 1968 Grumman G164, registered N956X, was substantially damaged in an accident during maneuvering near Opelousas, Louisiana. It was a personal flight under general aviation rules (Part 91). No one was hurt; 1 person was on board or involved. The weather was visual conditions (good weather).
The NTSB's probable cause their words, unchanged
The loss of two securing bolts that allowed the left magneto to move around, which disrupted the spark timing and resulted in the engine losing total power.
Source: NTSB aviation accident database, copy made October 5, 2026. Docket and reports at the NTSB.
What the record shows
- Date
- August 29, 2018 · about 4:30 pm local time
- Place
- Opelousas, Louisiana · map
- Type
- Accident
- Injuries
- No one was hurt; 1 person was on board or involved.
- Weather
- visual conditions (good weather)
- Aircraft
- Grumman G164 A, built 1968 · all G164s on the register
- Registration
- N956X · no longer on the register · serial 507
- Damage
- Substantial damage
- Flight
- Personal flight · general aviation rules (Part 91)
The NTSB's narrative final · quoted from the NTSB record
The private pilot was practicing crop-dusting maneuvers when the engine lost total power; he performed a forced landing in an open, muddy field. The airplane nosed over and sustained substantial damage. Postaccident examination of the engine revealed that two of three bolts that secured the left magneto had come loose and were missing. The safety wire was broken, and the Sims coupling was heavily damaged. The magneto could easily be moved around, which disrupted the spark timing and resulted in a total loss of power.
The complete narrative as the NTSB published it. The NTSB's docket holds the report as a PDF and any photographs, statements and other documents from the investigation.
The factual record from the NTSB's investigation tables, in plain English
What happened, in order
- Loss of engine power (total) during maneuvering defining event
- Off-field or emergency landing during emergency descent
- Nose over/nose down during landing
The NTSB's findings
- cause Aircraft › Aircraft power plant › Ignition system › Magneto/distributor › Inoperative
- Environmental issues › Physical environment › Terrain › Wet/muddy terrain › Contributed to outcome
Pilot
- Certificate: private
- Ratings: single-engine land
- Flight time: 208 hours in all; 15 in this make and model; 55 in the last 90 days; 35 in the last 30 days; 208 as pilot in command
- Last flight review: April 14, 2017
- Medical certificate: Class 3 (without waivers/limitations)
- Seat: sngl
- Injury: no injuries
The aircraft
- Airframe total time: 12,058 hours
- Last inspection: annual inspection, August 8, 2018
- Maximum gross weight: 4,497 lb
- Seats: 1
- Landing gear: fixed
- Engine: Pratt & Whitney R985-14B (piston); 0 hours total
The flight
- Departed from: 6LA5 Church Point LA at 4:00 pm
- Destination: 6LA5 Church Point LA
- Flight plan: none
Weather at the time
- Light: daylight
- Wind: from 240° at 5 knots
- Visibility: 10 statute miles
- Sky: scat at 2,800 ft
- Temperature: 86°F (30°C), dew point 70°F (21°C)
- Altimeter: 30.10 inHg
- Observation at 4:35 pm from KOPL, 10 miles away
Injuries
| Fatal | Serious | Minor | None | |
|---|---|---|---|---|
| Flight crew | 1 |
Documents from the investigation the NTSB's docket: the evidence folder behind the report
3 documents, released by the NTSB on October 3, 2018. View them here, or download them; the NTSB redacts some personal details before release, and this site shows the NTSB's own titles rather than its file names.
| # | Document | What it is | |
|---|---|---|---|
| 1 | Pilot/operator Aircraft Accident Report, NTSB Form 6120.1 | PDF, 7 pages | View Download |
| 2 | E-mail from FAA Inspector | PDF, 1 page | View Download |
| 3 | Report Photos | PDF, 3 pages | View Download |
The same docket at the NTSB · documents without a copy here are fetched from the NTSB when you open them.
Everything on this page comes from the NTSB's public records. The narrative, probable cause and findings are the NTSB's own words; the coded tables behind the report are written out in plain English, with pilots' ages, home towns and medical details left out. The documents and photographs are the NTSB's docket, shown as the NTSB released them. This site's own text never names anyone involved. A preliminary report can change; the final report usually follows one to two years later, and the page is refreshed when it does.