Accident Details
Probable Cause and Findings
An observed loss of engine power due to the bound/jammed turbocharger wastegate during takeoff, the pilot not maintaining airplane control, and the stall he inadvertently encountered. A factor was the maintenance personnel not replacing the turbocharger wastegate bypass valve assembly during the last annual inspection 8.7 hours of operation prior to the accident. An additional factor was the manufacturer's insufficiently defined inspection conditions for the bypass valve's proper operation.
Aircraft Information
Registered Owner (Historical)
Analysis
HISTORY OF FLIGHT
On July 4, 2005, about 1758 central daylight time, a Piper PA-46-310P, N4386G, piloted by a private pilot, was destroyed on impact with terrain during a forced landing following an observed in-flight loss of engine power after takeoff from runway 34 at the Grand Rapids/Itasca County Airport-Gordon Newstrom Field (GPZ), near Grand Rapids, Minnesota. The personal flight was operating under 14 Code of Federal Regulations Part 91. No flight plan was on file. The pilot sustained fatal injuries. The flight was originating at the time of the accident and its destination was unknown.
A witness located at GPZ observed the takeoff and stated that the airplane took off from the end of runway 34. About halfway down the runway the airplane emitted a sound like a rapid misfire, a pop, and then no more audible engine sounds. The airplane was about 300 - 400 feet above ground level at that point. He said that the airplane turned right then turned left to a bank where the wing was straight down. The airplane's wings then leveled, the airplane descended, and it impacted terrain. He stated that the time from the sounds to the impact was about two to three seconds.
PERSONNEL INFORMATION
The pilot held a private pilot certificate with airplane single-engine land and instrument airplane ratings. Federal Aviation Administration (FAA) records show that the pilot's last medical examination was completed on June 22, 2005, when he was issued a third-class medical certificate with the limitation that he shall possess glasses that correct for near vision. On the application for that medical certificate, the pilot reported that he had accumulated 2,200 hours of total flight time. He reported that he had accumulated 50 hours of flight time in the six months prior to that medical certificate application.
The pilot obtained flight instruction for the PA-46-310P from Simcom. Their training records showed that the pilot's last endorsement for a flight review was on July 1, 2004.
AIRCRAFT INFORMATION
N4386G, a 1985 Piper PA-46-310P, Malibu, serial number 46-8508037, was an all-metal airplane with semimonocoque fuselage and empennage construction. The airplane was powered by a six-cylinder, horizontally opposed, turbocharged, air cooled, fuel injected, Teledyne Continental Motors (TCM) TSIO-520-BE(1), serial number 528503, engine. The airplane's propeller was a two-bladed Hartzell BHC-C2YF-1BF model. The airplane was equipped with a pressurized cabin, wing flaps, spoilers, a constant speed propeller, and retractable tricycle landing gear. The airplane had a maximum seating capacity of six occupants, to include two cockpit positions and four cabin positions. The airplane has a certified maximum takeoff weight of 4,100 lbs.
The pilot's operating handbook and FAA approved airplane flight manual (POH), in part, stated:
Turbocharging is accomplished by two Garrett - A.I.D.
turbocompressors, one located on each side of the engine.
Turbochargers extract energy from engine cylinder exhaust
gases and use this energy to compress engine induction air.
This allows the engine to maintain rated power at altitude.
When engine induction air is compressed by the turbocharger,
the air temperature is increased. The elevated air temperature
is reduced by air aftercoolers located on each side of the engine.
This aids in engine cooling and improves engine power and
efficiency.
Each turbocharger extracts exhaust energy from its respective
bank of cylinders to pressurize the induction air. Air flows
through the induction inlet louvers into the induction air box,
where it is filtered and divided for distribution to the left and
right turbo compressors. At the compressor, air pressure and
temperature are increased. Pressure increases air density
making a greater mass of air available to the engine cylinders
on each intake stroke. Air then flows through an aftercooler
where air temperature is reduced, further increasing the density
of air available to each cylinder. Downstream the aftercoolers,
air flow joins at the "Y" junction of intake tubes on the top
front of the engine, then passes the throttle butterfly valve and
is divided to individual intake pipes flowing to each cylinder.
Metered fuel is injected into the cylinder head, upstream of the
intake valve. After the fuel burns in the cylinder, exhaust gases
flow into the exhaust manifold and then to turbocharger turbines
where exhaust energy is extracted to drive the compressor.
Turbo compressed air is throttled across the throttle butterfly
valve as set by the throttle lever. A sloped control system
monitors pressure differential and uses engine oil pressure to
automatically position the waste gate valve. The waste gate
bleeds excess exhaust gas from the exhaust manifold crossover
pipe and out the left exhaust stack, bypassing the turbocharger.
Thus the controller automatically maintains manifold pressure.
The engine is well protected against overboost damage from
excessive manifold pressure. The waste gate controller senses
manifold pressure and will continually adjust turbocharger
output, maintaining the manifold pressure set by the throttle. The
controller automatically protects the engine from overboost
damage by limiting manifold pressure to 38 in. Hg. In the event
of a controller malfunction, there is a pressure relief valve on
the induction manifold which will relieve manifold pressure at
42 in. Hg.
Manifold pressure limits can be exceeded with full throttle
operation during certain off standard ambient conditions and low
engine oil temperature. During such conditions limit manifold
pressure to 38 in. Hg maximum.
Aircraft logbooks show that the last annual inspection was performed on May 6, 2005. The aircraft had accumulated a total time of 1,847.7 hours at the time of that annual inspection.
The airplane's POH, in part, stated:
ENGINE POWER LOSS DURING TAKEOFF
If sufficient runway remains for a normal landing, leave gear down and
land straight ahead.
If area ahead is rough, or if it is necessary to clear obstructions:
Landing gear selector .............................. UP
METEOROLOGICAL INFORMATION
At 1755, the recorded GPZ weather was: Wind 290 degrees at 11 knots gusting to 17 knots; visibility 10 statute miles; sky condition few 8,000 feet; temperature 21 degrees C; dew point 12 degrees C; altimeter 29.94 inches of mercury.
AIRPORT INFORMATION
The North Central US Region Airport/Facility Directory (A/FD) indicated that the airport elevation at GPZ was 1,355 feet above mean sea level (MSL). GPZ was an uncontrolled airport with two runways, 10/28 and 16/34. The A/FD stated that runway 16/34 was 5,755 feet long and 100 feet wide. That runway's surface was composed of asphalt.
WRECKAGE AND IMPACT INFORMATION
The airplane fuselage came to rest upright northwest of the departure end of runway 34 at latitude 47 degrees 13.018 minutes North and longitude 93 degrees 30.918 minutes West. A ground scar, about 150 feet long with a 287 degrees magnetic heading, was observed. A radio antenna was found at the start of the scar. The airplane's propeller was detached from the engine propeller flange and was found about 135 feet from the start of the ground scar. The right wing was detached from the fuselage and was found near the end of the ground scar about 150 feet from the start of the scar. The airplane fuselage was about 168 feet from the start of the scar and the fuselage was orientated approximately on a 354-degree magnetic heading.
An on-scene examination was conducted. The propeller blades were marked A and B. The propeller blade marked with a "B" exhibited an s-shaped bend. Both propeller blades exhibited chordwise abrasion. The inboard section of the detached right wing exhibited rearward crushing. The wing's landing gear was extended and locked in the extended position. The right wing's fuel tank contained a blue liquid consistent with aviation gasoline. The right wing's fuel pump operated and pumped a liquid when the airplane's battery power was applied to it. The right wing's aileron control cables were separated from the aileron bell crank. The separation was consistent with overload.
The empennage exhibited a downward bend aft of the fuselage. Flight control cable continuity was traced to all flight control surfaces. Engine control continuity was established. The left wing's fuel tank contained a blue liquid consistent with aviation gasoline. The left wing's fuel pump operated and pumped a liquid when the airplane's battery power was applied. Fluid was found in the gascolator and it was drained into a glass container. That fluid was blue in color and did not contain any visible contamination. The fuel line from the gascolator to the engine driven fuel pump was torn at the gascolator's b-nut. The fuel line to the engine driven fuel pump was removed and a liquid was observed exiting that line when air pressure was applied to the torn line at the gascolator b-nut. The engine driven fuel pump was removed from the engine. A liquid was observed exiting the engine driven fuel pump when the pump was rotated by hand. The shear shaft was intact. The top sparkplugs were removed. The plugs exhibited a brown color. Engine continuity was established and each cylinder produced a thumb compression. The magnetos produced sparks. The Hobbs meter read 1856.4 hours. No pre-impact anomalies were detected with the airframe.
MEDICAL AND PATHOLOGICAL INFORMATION
The Itasca County Medical Examiner performed an autopsy on the pilot on July 5, 2005.
The FAA Civil Aeromedical Institute prepared a Final Forensic Toxicology Accident Report. The toxicology results for the pilot were negative for all tests performed.
TESTS AND RESEARCH
The collected fuel sample from the gascolator was taken to the 148th Fighter Wing, nea...
Data Source
Data provided by the National Transportation Safety Board (NTSB). For more information on this event, visit the NTSB Records Search website. NTSB# CHI05FA162