Mooney M20M N741SB accident near Pomona, California

Probable cause

The pilot’s failure to maintain sufficient altitude to clear obstructions while maneuvering on the base leg of the traffic pattern for landing.

NTSB analysis

After the pilot reported to the airport air traffic controller that the airplane was inbound, he was cleared to land. The controller informed the pilot of departing traffic from the runway, but the pilot did not respond. Another controller noted that the airplane was low and on the base leg of the traffic pattern at that time. The controller who was in contact with the pilot noted that the airplane was low and that it then turned "wing up" and crashed. The airplane collided with a 75-foot-tall stanchion, which was in a fairground about 3/4 mile southeast of the airport. The pilot made no mayday calls during the approach or accident sequence. Witnesses observed the airplane at a lower-than-normal altitude for landing. The traffic pattern altitude for the airport is 2,013 feet. At the time of the accident, an overcast layer was reported at 2,000 feet. It is likely that the pilot was maintaining a lower altitude to remain below the overcast layer in visual conditions and failed to maintain sufficient altitude to clear the obstruction while on the base leg of the traffic pattern. A postaccident examination of the airframe and engine revealed no mechanical anomalies that would have precluded normal operation.

The pilot did not possess a medical certificate because he had not responded to a request by the Federal Aviation Administration for additional details regarding his diabetes diagnosis. However, review of the pilot's autopsy and toxicology testing revealed no evidence of sudden incapacitation. Although postaccident testing revealed the presence of diphenhydramine, it could not be determined if it was impairing at the time of the accident.

Text from the NTSB. Open the NTSB docket for WPR12FA044 for the full record.