| Crash location | Unknown |
| Nearest city | Concord, CA
37.977978°N, 122.031073°W |
| Tail number | N4305Y |
|---|---|
| Accident date | 02 Sep 1992 |
| Aircraft type | Piper PA-23-160 |
| Additional details: | None |
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.