Approach and Initial Maneuvers
At an altitude of 9,500 feet MSL and 35 DME, the copilot (second in command) began a hooded (simulated instrument) ILS approach to Runway 3. The wind included a tailwind component of 14 to 22 knots. The copilot planned to limit the descent rate to 500 feet per minute to avoid engine supercooling. As the aircraft approached the outer marker, the pilot in command (PIC) reported that the aircraft was off course and approximately 1,500 feet high. The PIC took control, maneuvered the aircraft back onto the course and glideslope, then returned control to the copilot to continue the approach.
High Descent Rate and Speed Increase
During the PIC's maneuvering, a descent rate of 2,500 feet per minute occurred and the airspeed increased by 31 knots. As the approach continued, the PIC extended the landing gear and flaps. When the aircraft slowed and began settling, the copilot advanced the throttles, but the engines did not respond. The PIC again took control, and both pilots manipulated the engine controls, but power was not restored. Their recollections of the events differed, and neither pilot could recall the engine instrument indications.
Ground Impact and Landing Gear Failure
The aircraft contacted the ground short of the runway, causing the landing gear to collapse. The aircraft slid through a fence. Post-accident examination found the mixture controls were positioned approximately 4 to 5 clicks aft of the full forward position, and the throttles were found at about three-quarters forward. Approximately 80 gallons of fuel remained in the wing tanks.
Investigation Findings
The investigation revealed a series of maintenance write-ups noting that the engines had run rich and rough, but no pre-accident part failure or malfunction was found. The engines were operationally checked and found to be functioning properly. A rear-seat passenger thought the PIC had pulled the propeller controls down and then back forward. A ground witness reported hearing a sound as if the propellers were reversed and revved up.
Probable Cause
No probable cause was stated in the investigation source.