Accident Sequence
The airplane experienced a loss of power in one engine during a missed approach and subsequently collided with obstructions. After the collision, the airplane came to rest upright approximately 500 feet from the approach end of the runway and was destroyed in a post-impact ground fire.
The pilot informed a responding sheriff's deputy and a Federal Aviation Administration (FAA) inspector that he conducted an Instrument Landing System (ILS) approach for landing and initiated a missed approach. When he added power, the left engine sputtered, and the airplane veered left. He activated the fuel boost pump, but the airplane contacted obstructions and crashed.
The responding sheriff's deputy also observed the accident. He heard an airplane engine making unusual sounds. The engine "seemed to get quiet and then revved higher as if to climb." He looked toward the sound and saw a series of blue flashes followed by an orange fireball. The deputy reported that there was dense fog in the area at the time.
Weather Conditions
At the time of the accident, the airport weather conditions were reported as 100 feet overcast and 1/4-mile visibility in fog. The landing minimums for the ILS approach are 200 feet and 1/2-mile.
Aircraft Configuration and Performance
According to the operator's records, when the airplane departed from Ukiah, its gross takeoff weight was approximately 5,909 pounds. The pilot operating handbook (POH) for the airplane lists the following items in the single-engine go-around checklist: 1. Throttle full forward 2. Wing flaps up 3. When positive climb rate achieved, gear up 4. Ensure the inoperative engine is feathered
For a gross weight of 5,900 pounds and the existing atmospheric conditions, the single-engine climb performance chart indicates an expected positive rate of climb of 500 feet per minute if the airplane was correctly configured. The chart also lists the following subtractions from that performance for the listed conditions:
- -400 fpm for windmilling inoperative engine
- -350 feet for landing gear down
- -200 fpm for flaps extended to 15 degrees
Examination of the wreckage revealed that neither engine's propeller was feathered, the landing gear was down, and the flaps were extended to 10 degrees. Without the correct configuration for a single-engine missed approach, the net climb performance would be negative 400 feet per minute.
Mechanical Findings
No discrepancies were noted during the airframe examination. The engine examination revealed no mechanical anomalies with either engine that would have precluded normal operation.
Regulatory Context
14 CFR 135.224 states that a pilot cannot initiate an approach if the weather conditions are below landing minimums when the approach is started outside the final approach fix. The pilot can continue the landing if already established on the approach and the airport goes below landing minimums. According to the operator's FAA-approved operating specifications, the operator had not been approved for lower than standard landing minimums.
Probable Cause
Loss of engine power in the left engine for undetermined reasons. Also causal was the pilot's failure to correctly configure the airplane for a single-engine missed approach, which resulted in a negative climb performance. A factor was the pilot's decision to initiate the approach when the weather conditions were below the published approach minimums.