Piper PA-23-160 accident near Concord, California, September 2, 1992
On September 2, 1992 at about 9:41 pm local time, a Piper PA-23-160, registered N4305Y, was destroyed in an accident near Concord, California (Buchanan Field). It was an instructional flight under general aviation rules (Part 91). 2 people were killed. The weather was visual conditions (good weather).
The NTSB's probable cause their words, unchanged
The following Probable Cause was modified on April18, 2007, as a result of new information provided to the NTSB. THE IMPROPER INSTALLATION OF THE 1.75 INCH OD PLUG IN THE CRANKSHAFT BY UNKNOWN MAINTENANCE PERSONNEL WHICH RESULTED IN AN INADVERTENT FEATHERING OF THE LEFT ENGINE PROPELLER.
Source: NTSB aviation accident database, copy made October 5, 2026. Docket and reports at the NTSB.
What the record shows
- Date
- September 2, 1992 · about 9:41 pm local time
- Place
- Concord, California · Buchanan Field · map
- Type
- Accident
- Injuries
- 2 people were killed.
- Weather
- visual conditions (good weather)
- Aircraft
- Piper PA-23-160 · all PA-23-160s on the register
- Registration
- N4305Y · no longer on the register · serial 2028
- Damage
- Destroyed
- Flight
- Instructional flight · general aviation rules (Part 91)
The NTSB's narrative final · quoted from the NTSB record
The following Brief was modified on April18, 2007, as a result of new information provided to the NTSB. THE AIRCRAFT COLLIDED WITH A BRIDGE WHILE TRYING TO RETURN TO THE AIRPORT AFTER REPORTING AN EMERGENCY DURING THE PREVIOUS TOUCH AND GO LANDING. WITNESSES INDICATED BOTH ENGINES SOUNDED LIKE THEY WERE RUNNING AND BOTH PROPELLERS WERE TURNING. THE LEFT ENGINE PROPELLER WAS FOUND FEATHERED AFTER THE ACCIDENT. INVESTIGATION REVEALED A 1.75 INCH OD PLUG INSTALLED IN THE CRANKSHAFT TO SEPARATE OIL PRESSURE FROM THE PROPELLER GOVERNOR AND THE ENGINE CRANKCASE WAS BLOWN AFT DAMAGING THE NUMBER ONE ROD CONNECTING JOURNAL OIL TRANSFER TUBE. EXAMINATION OF THE PLUG DISCLOSED THAT IT WAS INSTALLED BACKWARDS.
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: flight instructor, commercial pilot, private
- Ratings: multi-engine land; single-engine land; instructor: airplane multi-engine; instructor: airplane single-engine; instrument: airplane; rotorcraft: glider
- Flight time: 800 hours in all; 170 in this make and model; 650 as pilot in command
- Medical certificate: Class 2 (invalid medical for flight)
- Seat: rgt
The aircraft
- Last inspection: annual inspection, January 23, 1992
- Maximum gross weight: 3,800 lb
- Seats: 5
- Landing gear: retractable
- Engine: Lycoming O-320-B3B (piston); 0 hours total
- Fire on the ground
The flight
- Departed from: HWD Hayward CA at 9:05 pm
- Flight plan: none
- Runway 19, 4,400 ft by 150 ft
- A second pilot was aboard
Weather at the time
- Light: daylight
- Wind: from 300° at 13 knots
- Visibility: 40 statute miles
- Sky: scat at 20,000 ft
- Temperature: 79°F (26°C), dew point 52°F (11°C)
- Altimeter: 30.00 inHg
- Observation at 9:41 pm from CCR, 1 miles away
Injuries
| Fatal | Serious | Minor | None | |
|---|---|---|---|---|
| Crew | 2 |
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.