San Luis Obispo Airport
Aircraft Accident/Incident Report

San Luis Obispo, California 93401
Monday, June 24, 2013 12:55 PDT

The pilot/owner had recently purchased the multiengine, high-performance, complex airplane. He had obtained his private pilot certificate 15 years before the accident and had limited flight experience, having amassed a total of about 118 hours of flight time. He had obtained his multiengine rating 5 weeks before the accident, and his total flight experience in multiengine airplanes was about 40 hours. Of that time, 18 hours were logged in the accident airplane of which 3 hours were while acting as pilot-in-command. On previous flights, the airplane's rear engine had been "stuttering" as the throttle was advanced. The pilot was able to forestall the problem by advancing the throttle slowly; however, the symptoms had been getting worse. A maintenance facility at the departure airport attempted to troubleshoot the engine problem but was not able to resolve the issue. Thus, the pilot intended to reposition the airplane to another airport where a different maintenance facility had agreed to continue the diagnosis. He planned to fly the airplane in the traffic pattern, perform a touch-and-go landing, and proceed to the other maintenance facility if the airplane performed correctly. He had also made plans to depart that night on an important and time-sensitive business trip to Europe from an airport close to the second maintenance facility. The departure for the initial flight appeared uneventful; however, during the approach for the touch-and-go landing, the pilot seemed distracted, missing multiple landing clearances issued by an air traffic controller. The airplane landed and used the full runway length for the ground roll, while making "popping" sounds similar to an engine backfiring, indicative of at least a partial loss of engine power. Having reached the end of the runway, the airplane lifted off and climbed to about 150 feet above ground level, and a short time later the pilot issued a mayday transmission. The airplane maintained the runway heading and the same altitude for about a mile and then began a descending right turn, striking a set of power distribution lines and a building. The length of the runway and its overrun area would have provided ample stopping distance for the airplane after the landing. Further, the area between the runway and accident site was comprised of level fields which would have been adequate for an emergency landing. The majority of the airplane's structure was consumed by postimpact fire. The front engine's propeller displayed considerable rotational damage, consistent with it producing power at the time of the accident. The rear propeller exhibited less significant rotational damage signatures, consistent with it operating at a reduced power level. The rear engine sustained thermal damage, which precluded a determination of the reason for the loss of power. Postaccident examination of the front engine revealed that the right magneto was set to an incorrect timing position. The left magneto had broken free during the impact sequence, so its timing position could not be ascertained. If the left magneto had been set to the correct timing position, the incorrect timing of the right magneto would have resulted in a minimal loss of engine power. Additionally, although no damage was noted to the right magneto, it is possible that it became misaligned during the impact sequence. Lastly, because the engine was producing power at the time of impact, it is unlikely that both magnetos were misaligned. Performance charts indicated that at the airplane's takeoff weight, a total loss of engine power from the rear engine should have allowed for an adequate takeoff profile, assuming the emergency procedures detailed in the Pilot's Operating Handbook for the airplane had been followed. However, examination revealed that the procedures had not been followed because at the time of impact, the flaps were not completely retracted, and the rear engine's propeller was not feathered. Although the pilot had the minimum experience required to fly the multiengine airplane, he had only acted as pilot-in-command of this airplane for 3 hours; and when he was faced with an emergency, he likely did not have the proficiency and confidence to readily deal with it. The pilot was likely distracted during the landing (as supported by the missed radio calls), failed to abort the landing and continued with his original plan to takeoff despite the loss of engine power, and was unable to appropriately configure the airplane for flight with only one engine operable after the takeoff.

Loss of engine power from the rear engine for reasons that could not be determined because of the postimpact thermal damage to the engine. Contributing to the accident were the pilot's decision to continue flight with a known deficiency, his failure to abort the takeoff during the ground roll, his failure to follow the correct emergency procedures following the loss of power, and his lack of experience in multiengine airplanes and the specific airplane make and model.