Background
Earlier on the day of the accident, the airplane was flown to the departure airport for a multiengine check ride. The occupants included the examinee, a certified flight instructor (CFI), and a private pilot who held a multiengine rating. That flight proceeded without any noted discrepancies.
Pre-Takeoff Engine Issues
During the engine run-up for the check ride, both the designated pilot examiner (DPE) and the examinee observed that the left engine was not producing sufficient power. They cycled the engine through higher and lower mixture settings before a normal run-up could be conducted. After completing a simulated engine failure, the check ride continued with a normal takeoff.
On the previous landing attempt after takeoff, the DPE noticed a loss of climb performance and that the left engine's manifold pressure indicated 21.5–22.0 inches of mercury. They considered an off-airport landing but managed to return to the airport. During the downwind leg, the right engine's oil temperature neared the upper limit and oil pressure decreased. On final approach, the right engine's oil pressure dropped further, approaching the lower redline. After landing, both oil pressure and temperature returned to normal.
Another run-up was performed, but the left engine did not develop power equal to the right. The check ride was discontinued. The DPE discussed the situation with the CFI, who contacted the flight school's mechanic. Both the CFI and mechanic agreed that the check ride should not continue but deemed it safe to ferry the airplane back to its home base.
Takeoff and Flight
Before the accident flight, the DPE observed the occupants boarding: the CFI took the back seat, the examinee occupied the right front seat, and the private pilot sat in the left front seat. During the takeoff roll, the airplane yawed left three times, returning to the centerline each time. The airplane lifted off after a prolonged ground roll and climbed very slowly.
Witnesses reported that the engine sounds were normal during takeoff. A few minutes later, a loud shriek was heard on the UNICOM frequency, and shortly thereafter, local law enforcement notified of an airplane down.
Accident and Post-Accident Examination
The airplane crashed into desert terrain near a rural residential area, about 3 miles from the airport. A post-impact ground fire thermally destroyed the aircraft and severely damaged engine accessories and controls.
Examination of the airframe revealed no discrepancies. Mechanical and valve train continuity were established for both engines. A compression check on the left engine showed low pressure on cylinders 2 and 4; both were staked, with no change in the number 2 cylinder and improved compression in number 4. Neither cylinder showed internal discrepancies upon removal. Due to thermal damage, no meaningful tests could be performed on fuel or ignition components.
Ground scars and impact damage indicated that the airplane struck the ground in a steep left bank and tumbled. The investigation noted that this could be consistent with a loss of power on the left engine and a failure to maintain airspeed above the single-engine minimum control speed. Anatomical evidence on the occupants was inconclusive as to who was manipulating the flight controls at impact.