Cessna 172G accident near Mckinney, Texas, August 5, 1989
On August 5, 1989 at about 3:30 am local time, a Cessna 172G, registered N4377L, was substantially damaged in an accident near Mckinney, Texas (Municipal airport). It was a personal flight under general aviation rules (Part 91). No one was hurt; 4 people were on board or involved. The weather was visual conditions (good weather).
The NTSB's probable cause their words, unchanged
TOTAL FAILURE OF THE ENGINE ASSEMBLY/ROCKER ARM/TAPPET SHAFT.
Source: NTSB aviation accident database, copy made October 5, 2026. Docket and reports at the NTSB.
What the record shows
- Date
- August 5, 1989 · about 3:30 am local time
- Place
- Mckinney, Texas · Municipal · map
- Type
- Accident
- Injuries
- No one was hurt; 4 people were on board or involved.
- Weather
- visual conditions (good weather)
- Aircraft
- Cessna 172G · all 172Gs on the register
- Registration
- N4377L · no longer on the register · serial 17254455
- Damage
- Substantial damage
- Flight
- Personal flight · general aviation rules (Part 91)
The NTSB's narrative final · quoted from the NTSB record
DURING A NIGHT CROSS-COUNTRY FLIGHT, THE ENGINE LOST POWER AND DURING THE FORCED LANDING, THE AIRPLANE IMPACTED TREES AND THEN THE TERRAIN. DURING A PARTIAL TEARDOWN OF THE ENGINE, IT WAS FOUND THAT THE NUMBER 3 CYLINDER EXHAUST VALVE ROCKER ARM SHAFT HAD BROKEN. THERE WAS ALSO A LARGE GAP BETWEEN THE ROCKER ARM AND THE EXHAUST VALVE STEM.
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
Pilot
- Certificate: private
- Ratings: single-engine land
- Flight time: 600 hours in all; 550 in this make and model; 50 in the last 90 days; 28 in the last 30 days; 510 as pilot in command
- Medical certificate: Class 3 (valid medical--no waivers/lim.)
- Seat: left
The aircraft
- Airframe total time: 3,573 hours
- Last inspection: annual inspection, December 30, 1988; 137 hours since
- Maximum gross weight: 2,300 lb
- Seats: 4
- Landing gear: fixed
- Engine: Continental O-300-D (piston); 0 hours total
The flight
- Departed from: MLC Mcalester OK at 2:00 am
- Destination: HQZ Mesquite TX
- Flight plan: none
- Runway 0
- A second pilot was aboard
Weather at the time
- Light: night, dark
- Wind: from 160° at 12 knots
- Visibility: 12 statute miles
- Sky: clear
- Temperature: 84°F (29°C), dew point 72°F (22°C)
- Altimeter: 29.00 inHg
Injuries
| Fatal | Serious | Minor | None | |
|---|---|---|---|---|
| Crew | 1 | |||
| Passengers | 3 |
Documents from the investigation the NTSB's docket: the evidence folder behind the report
The docket, the folder of records gathered during an investigation (maintenance records, photographs, witness statements, examinations), has not been read from the NTSB for this case yet; the list appears here once it has. Open the docket at the NTSB.
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.