Casualties unknown

Night Visual Approach Ends in River Impact; Left Engine Found Not Operating (N966MA)

Napa, CA, US

On March 12, 2004, a Mitsubishi MU-2B-40 (registration N966MA) was involved in an aviation accident near Napa, CA. Investigators recorded the probable cause as: The pilot's failure to maintain control of the airplane following a shutdown of the left engine during a night visual approach. A factor contributing to the accident was the dark night. This summary draws on records from the U.S. National Transportation Safety Board (NTSB) historical archive.

Sourcesthe U.S. National Transportation Safety Board (NTSB) historical archivePrimary reportUpdated 2026-06-10Data APIEditorial standards

While on a night visual approach, the airplane entered a descending turn and struck a river. Investigation revealed the left engine was not rotating and its propeller was feathered at impact, while the right engine was operating.

Accident Sequence

According to radar data and air traffic control communications, the airplane was southeast of the airport and maintaining a westerly heading south of the airport. At 2030, the pilot reported leaving 6,000 feet and stated that he had the airport in sight. The controller cleared the airplane for the approach. The pilot then requested to cancel his IFR clearance and switch to the traffic advisory frequency, which was approved. No further radio transmissions were recorded from the flight.

At approximately 2035, radar data showed the airplane cross a river and begin a sharp left turn away from the airport. After completing about 90 degrees of turn, the airplane abruptly disappeared from radar contact. The last radar target was on the west side of the river near the location where the wreckage was later found.

The impact occurred in a river, and the airplane had been executing a descending turn during the visual approach at night. The wreckage was highly fragmented and was recovered from the river several weeks after submersion.

Investigation Findings

Teardown and examination of the engines revealed that the left engine was not rotating or operating at the time of impact, and its propeller was in the feathered position. The type and degree of damage to the right engine was indicative of engine rotation and operation at the time of impact.

Investigators found no pre-existing condition on either engine or on the airframe systems that would have interfered with normal operation or explained the apparent shutdown of the left engine.

Investigation report by the U.S. National Transportation Safety Board (NTSB) historical archive. Original record: https://carol.ntsb.gov/event/20040319X00344. This page is a structured re-presentation; facts and quotes are in the National Transportation Safety Board (NTSB), United States.