Aerofab LA-4 accident near Big Prairie, Michigan, July 8, 2023
On July 8, 2023 at about 1:10 pm local time, a 1966 Aerofab LA-4, registered N993PT, was substantially damaged in an accident during landing near Big Prairie, Michigan. It was an instructional flight under general aviation rules (Part 91). No one was hurt; 2 people were on board or involved. The weather was visual conditions (good weather).
The NTSB's probable cause their words, unchanged
The airplane’s collision with a submerged log during a water landing.
Source: NTSB aviation accident database, copy made October 5, 2026. Docket and reports at the NTSB.
What the record shows
- Date
- July 8, 2023 · about 1:10 pm local time
- Place
- Big Prairie, Michigan · map
- Type
- Accident
- Injuries
- No one was hurt; 2 people were on board or involved.
- Weather
- visual conditions (good weather)
- Aircraft
- Aerofab LA-4 180, built 1966
- Registration
- N993PT · no longer on the register · serial 341
- Damage
- Substantial damage
- Flight
- Instructional flight · general aviation rules (Part 91)
The NTSB's narrative final · quoted from the NTSB record
The flight instructor and pilot receiving instruction were completing water landings in the amphibious airplane. They had already completed several landings on the same pond without incident. During the accident landing, upon touchdown the airplane impacted a submerged log, which punctured a large hole in the hull. The pilots egressed without further incident and the airplane sank. The pilot reported no preimpact mechanical malfunctions or failures with the airplane that would have precluded normal operation.
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
- Collision during takeoff/land during landing defining event
The NTSB's findings
- Environmental issues › Physical environment › Object/animal/substance › Hidden/submerged object › Effect on equipment
- Environmental issues › Physical environment › Object/animal/substance › Hidden/submerged object › Awareness of condition
Pilot
- Certificate: private
- Ratings: single-engine land; single-engine sea
- Flight time: 1,372 hours in all; 121 in this make and model; 57 in the last 90 days; 24 in the last 30 days; 1,266 as pilot in command
- Last flight review: February 1, 2023
- Medical certificate: BasicMed (without waivers/limitations)
- Seat: left
- Injury: no injuries
Flight instructor
- Certificate: airline transport pilot, flight instructor
- Ratings: multi-engine land; single-engine land; single-engine sea; instructor: airplane multi-engine; instructor: airplane single-engine; instructor: instrument airplane; instrument: airplane
- Medical certificate: Class 1 (with waivers/limitations)
- Seat: rgt
- Injury: no injuries
The aircraft
- Airframe total time: 2,533 hours
- Last inspection: annual inspection, October 19, 2022
- Maximum gross weight: 2,400 lb
- Seats: 4
- Landing gear: retractable
- Engine: Lycoming O-360-A1A (piston); 2,533 hours total
The flight
- Departed from: 3GM Grand Haven MI at 11:10 am
- Flight plan: none
- A second pilot was aboard
Weather at the time
- Light: daylight
- Wind: from 180° at 4 knots
- Visibility: 10 statute miles
- Sky: broken clouds at 4,100 ft
- Temperature: 63°F (17°C), dew point 57°F (14°C)
- Altimeter: 29.89 inHg
- Observation at 8:55 am from KRQB, 13 miles away
Weather report (METAR): KRQB 081255Z AUTO 18004KT 10SM BKN041 OVC049 17/14 A2989 RMK AO2 T01660137
Injuries
| Fatal | Serious | Minor | None | |
|---|---|---|---|---|
| Flight crew | 2 |
Documents from the investigation the NTSB's docket: the evidence folder behind the report
2 documents, released by the NTSB on September 28, 2023. 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, 11 pages | View Download |
| 2 | 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.