History of Flight
On January 31, 2016, at 1459 Pacific standard time, a Piper PA46-310P, registration N777PG, executed a forced landing at Burns Municipal Airport, Burns, Oregon, following a total loss of engine power during cruise. The aircraft was operated by the private pilot as a 14 Code of Federal Regulations Part 91 personal flight. The pilot, the sole occupant, was not injured, and the airplane sustained substantial damage during the landing roll.
The cross-country flight departed Boeing Field/King County International Airport, Seattle, Washington, at 1318, with a planned destination of Scottsdale Airport, Scottsdale, Arizona. Visual meteorological conditions prevailed, and an instrument flight rules flight plan had been filed.
The pilot reported that about 90 minutes after departure while cruising at 19,000 ft, the engine "tone" decreased, accompanied by a drop in manifold pressure from 29 to 15 inches of mercury. He kept the throttle in the cruise power position and elected to divert to Burns after reporting an engine emergency to air traffic control. The engine did not regain power during descent, and the pilot did not perform any troubleshooting procedures. Arriving over the airfield with altitude remaining, he began a circling descent. During the landing approach, he moved the gear selection lever to DOWN, but did not hear or feel any indication of gear deployment, nor see three green lights confirming the gear was down and locked. He did not have time to perform the emergency extension procedure due to low altitude and decided to land gear-up on the snow adjacent to runway 30.
Just prior to touchdown, about 5 ft above ground level, the landing gear began to extend, and two green lights indicated the main landing gear had locked, but no green light for the nose gear. The airplane touched down, and the nose dug into the snow, resulting in an abrupt stop with substantial damage to the forward fuselage and both wings.
Aircraft Information
The low-wing, high-performance, pressurized airplane was manufactured in 1987. It was equipped with a twin-turbocharged six-cylinder Continental TSIO-550-C14B engine, manufactured in November 2011. The engine had accrued 431.8 flight hours at the time of the last annual inspection, completed 18 days and 9.7 flight hours before the accident.
The aircraft featured hydraulically operated, retractable, tricycle landing gear, with hydraulic pressure from an electrically driven hydraulic pump. Gear operation was controlled by a two-position selector switch. Three green lights, individually activated as each gear mechanically locks into the down position, are located above the selector.
The landing gear is held in the up position by trapped hydraulic pressure via a check valve in the pump assembly. The emergency gear extension system is activated by manually pulling a control on the instrument panel, which releases pressure on the up side and bypasses fluid to the down side. The landing gear is held in the down position by spring-loaded mechanical locking mechanisms.
The Pilot's Operating Handbook includes three initial steps for engine power loss in flight: switch fuel tanks, set auxiliary fuel pump to LOW, and set induction air to ALTERNATE. If power not restored, set auxiliary fuel pump to HIGH, mixture FULL RICH, and throttle to approximately 75% power.
Engine and Systems Examination
The airplane was equipped with a JPI EDM-700 Engine Monitor. Data extracted showed consistent exhaust gas and cylinder head temperatures until 1448, when an abrupt drop in EGT for all six cylinders to 150°F occurred, along with a similar TIT drop. CHT gradually fell to 80°F five minutes later. At 1459, EGT momentarily increased for 30 seconds then dropped; data ended at 1501. Battery voltage remained at 28 volts.
After the accident, control continuity was established for throttle, mixture, and propeller controls. The fuel mixture control was in the full-forward (RICH) position, propeller in full-forward (INCR), throttle in full-aft (CLSD). Auxiliary fuel pump switch was OFF, fuel selector valve in LEFT position, both magnetos ON, all circuit breakers appeared closed.
Significant quantities of fuel were recovered from both wings. Left and right collector/sump tanks each contained about 25 fluid ounces of blue fuel and about 1 tablespoon of clear fluid confirmed as water with water-detecting paste. The fuel filter bowl contained about 5 fluid ounces of blue fuel; the filter element was clear with no water. Fuel line fittings were secure with no leaks; all fuel and vent lines were clear and free of blockage.
The engine was removed and tested at Continental Motors. It started and ran smoothly from idle to 2,600 rpm and manifold pressures up to 35.59 inHg. No anomalies were found that would have precluded normal operation.
Landing gear examination revealed the nose gear remained stowed; both main gear struts were extended and locked but bent aft and separated from trunnion assemblies. The hydraulic system was intact with no leaks; the pump engaged and operated when power was applied. No anomalies were noted that would have prevented normal gear operation.
During the last annual inspection, the landing gear emergency down spring, up-pressure switch, and sequence valve were replaced. The mechanic noted the spring is typically replaced annually; the sequencing valve was replaced due to a leak at its actuating shaft, and the pressure switch was operating intermittently, requiring a tap to allow gear retraction during inspection.
The pilot reported a prior incident 6–7 years earlier when a turbocharger crossover pipe detachment caused a manifold pressure drop; that experience prompted him to descend rapidly rather than troubleshoot during the accident flight. He also reported two previous instances of landing gear failure to extend after high-altitude flight (FL22) in cold temperatures, which resolved as he got closer to the ground. He discussed this with mechanics, who suggested a thorough inspection if it persisted, but since it did not recur, no inspection was performed.