Cessna 177RG accident near Folsom, California, July 13, 1996
On July 13, 1996 at about 6:52 pm local time, a Cessna 177RG, registered N52185, was substantially damaged in an accident near Folsom, California. It was a personal 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
An oil starvation failure of the engine due to a mechanic's failure to put the proper gasket stack on when the propeller governor was replaced. The mechanic's omission was due to the airframe manufacturer's failure to ensure that the service and parts manuals for the aircraft contained the most recent information concerning the unique gasket requirement for this airplane.
Source: NTSB aviation accident database, copy made October 5, 2026. Docket and reports at the NTSB.
What the record shows
- Date
- July 13, 1996 · about 6:52 pm local time
- Place
- Folsom, California · map
- Type
- Accident
- Injuries
- No one was hurt; 2 people were on board or involved.
- Weather
- visual conditions (good weather)
- Aircraft
- Cessna 177RG · all 177RGs on the register
- Registration
- N52185 · no longer on the register · serial 177RG1187
- Damage
- Substantial damage
- Flight
- Personal flight · general aviation rules (Part 91)
The NTSB's narrative final · quoted from the NTSB record
The aircraft was in cruise flight when the pilot noticed the oil pressure rapidly decrease, followed shortly thereafter by engine roughness. With a loud knock, the engine lost power and oil began to spray on the windshield. The aircraft collided with ground obstructions during a forced landing attempt on a road. Disassembly of the engine revealed only trace amounts of oil in the case, with a typical oil starvation heat distress failure of the numbers 3 and 4 connecting rods. During removal of the propeller governor only a MS9144-01 screen gasket was installed between the governor and the mounting pad. An oil path was observed running between the gasket and the pad from the high pressure oil port to the outside edge of the pad. Review of Lycoming publications (published in 1987) revealed that this particular engine requires a unique gasket and plate stack to prevent oil leakage between the governor and it's mounting pad. The maintenance records disclosed that 1.4 hours prior to the accident, the propeller governor was removed for repair then reinstalled on the engine. Both the mechanic who performed the work and the IA who inspected the job stated that the current Cessna 177 maintenance and parts manuals were used for procedural guidance. Both said they were unaware of a special gasket stack requirement for this particular engine, and they would not routinely refer to engine manuals for a governor installation since the governor is an airframe component. The Cessna service manual only speaks to the installation of the MS screen gasket, and uses the term 'gasket' in the singular form. The special Lycoming gasket and plate are not mentioned in either Cessna manual. Cessna Aircraft stated that they were aware of the Lycoming requirement for a special gasket stack for the Cessna 177RG aircraft application and are in the process of revising the Service and Parts manuals accordingly.
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; instrument: airplane
- Flight time: 400 hours in all; 50 in this make and model
- Medical certificate: Class 2 (valid medical--no waivers/lim.)
- Seat: left
The aircraft
- Airframe total time: 3,869 hours
- Last inspection: 100-hour inspection, June 28, 1996; 28 hours since
- Maximum gross weight: 2,800 lb
- Seats: 4
- Landing gear: retractable
- Engine: Lycoming IO-360-A1B6D (piston); 0 hours total
The flight
- Departed from: HWD Hayward CA at 6:09 pm
- Destination: Q61 Georgetown CA
- Flight plan: none
- Runway 0
- A second pilot was aboard
Weather at the time
- Light: daylight
- Visibility: 20 statute miles
- Sky: scat at 1,000 ft
- Temperature: 88°F (31°C), dew point 57°F (14°C)
- Altimeter: 29.00 inHg
Injuries
| Fatal | Serious | Minor | None | |
|---|---|---|---|---|
| Crew | 1 | |||
| Passengers | 1 |
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.