Accident Sequence
On June 10, 2010, about 1627 Pacific daylight time, a Piper PA-46-310P airplane, registration N121HJ, was substantially damaged during a forced landing near the Ontario International Airport (ONT), Ontario, California. The airplane was owned and operated by the pilot. The instructional flight was conducted under 14 CFR Part 91. The private pilot sustained minor injuries and the certificated flight instructor (CFI) was seriously injured. Visual meteorological conditions prevailed, and no flight plan was filed for the cross-country flight. The flight originated from Santa Monica Airport about 1550, with an intended destination of Lake Havasu, Arizona.
According to the pilot's written statement, a thorough preflight inspection revealed no mechanical issues. After departure, they flew northeast towards the Van Nuys VOR, then turned east to avoid Class Bravo airspace. During climb, the climb rate was greater than 500 feet per minute, intending to level off at 17,500 feet mean sea level. While passing through 16,000 feet, the pilot noticed manifold pressure had dropped to about 26 inches. Advancing the throttle increased pressure only one or two inches. About a minute later, a loud bang was heard from the engine area, followed by a loss of engine power.
After establishing best glide airspeed, the pilot and instructor began troubleshooting. Engaging the engine fuel boost pump seemed to worsen the situation; they switched to low boost. The pilot contacted Southern California Approach Control, declared the emergency, and elected to divert to ONT. During descent, they believed they were getting partial power. The propeller was windmilling, and no smoke or oil was visible. Near ONT, they attempted to fit into the traffic pattern while above or in an overcast layer, avoiding traffic below. They broke out of the overcast about 4 miles from Runway 26L. During approach, they were advised that Runway 26L was out of service and to land on Runway 26R. About 1 mile from the approach end of Runway 26R, the pilot thought the airplane was high and extended the landing gear and selected 10 degrees of flaps. Airspeed dropped and altitude decreased drastically. They advanced the throttle but the engine produced no power. They avoided landing on the runway due to a crossing semi truck and turned north. The airplane struck a fence about one-half mile from the approach end of Runway 26R and landed hard in an open field.
The flight instructor reported that during initial climb, power was reduced to 30 inches of manifold pressure at 1,000 feet agl. He observed the manifold pressure drop to 26 inches, and after the pilot increased throttle to 28 inches, a loud pop occurred and thrust fell off. When the auxiliary fuel boost pump was applied, the engine seemed to choke before selecting low boost. The engine appeared to produce partial power, and the mixture and propeller levers were full forward at the time of power loss. During descent, the engine responded but became rough when throttle was advanced more than half way.
Aircraft Information
The low-wing, retractable-gear airplane, serial number 46-8508105, was manufactured in 1985. It was powered by a Continental Motors TSIO-550-C1 engine (serial number 814565-R) rated at 310 horsepower, and equipped with a Hartzell PHC-G3YF-1E variable-pitch propeller. Maintenance logbook records showed an annual inspection completed on September 23, 2009, at a tachometer reading of 4,803 hours. The most recent engine logbook entry was on June 4, 2010, at a HOBBS time of 2,025.3 hours. That entry noted removal and inspection of the oil filter (no metal found), engine compression check (with low compression on cylinders #4 and #5), and replacement of cylinders #4 and #5 with overhauled exchange units. A run-up showed no leaks.
Examination
Examination by an FAA inspector revealed structural damage to the fuselage and wings, and separation of the left and right main landing gear. The airplane was recovered for further examination.
On July 20, 2010, the recovered engine and airframe were examined at Aircraft Recovery Services in Pearblossom, California, by representatives from Piper Aircraft, Teledyne Continental Motors, and the FAA under the supervision of the Safety Board investigator-in-charge. Continuity was found from the left and right fuel inlets through the fuel selector to the engine firewall outlet. The HOBBS hour meter read 2,028.4 hours.
Engine examination showed all accessories attached; three of four engine mounts were separated. Top spark plugs and rocker box covers were removed. The crankshaft was rotated by hand; rotational continuity was established throughout and valve train movement was normal. Thumb compression was obtained on all six cylinders. Left and right magneto impulse couplings actuated, and spark was observed on all ignition harness leads. The top spark plugs exhibited moderate to severe wear and were black in the electrode area.
The right hand 1-3-5 cylinder side induction elbow was observed displaced from the throttle and metering assembly. The clamp was secure to the induction hose, but the portion of the clamp that should have been installed beyond the retention bead on the throttle and control assembly was observed on the inboard side of the bead on the induction elbow. No surrounding impact damage was noted. Left and right turbochargers were intact and undamaged; turbine wheels rotated freely. The waste gate was intact and in the open position.
The engine was removed and shipped to Teledyne Continental Motors for further examination on November 30 and December 1, 2010. The engine mount legs, turbocharger hoses, and reservoirs were replaced to facilitate a test run. Induction tubes and ignition leads were repaired, and the right hand induction elbow was reinstalled and securely attached. The engine was run for about 15 minutes at various power settings with no anomalies, demonstrating the ability to produce rated horsepower. A magneto check was successful. The engine was shut down, and the right hand induction elbow was manually disconnected from the throttle and metering assembly where the elbow couples via hose and clamp. The engine was started a second time and ran through various power settings but did not produce rated horsepower during this phase.
Additional Information
Teledyne Continental Motors Service Bulletin SB08-13, issued September 30, 2008, provides instructions for induction system hose and clamp installation. It emphasizes proper positioning of the hose over the connection joint, centering clamps between tubing beads and hose ends, and torquing clamps to 25-35 inch-pounds. The bulletin states that failure to properly install induction system clamps and hoses may lead to failure of the hose to seal, loss of manifold pressure, and loss of engine power.