NTSB: MU-2 Dropped 12,000 Feet In A Single Minute Before Crash

For Brian Templeton of Waterford (MI), the end of the world came in the form of a flat spin from which he simply could not recover.

That's what witnesses to the March 25th accident told the NTSB about the crash of a Royal Air Freight Mitsubishi MU-2B near Pittsfield (MA). And radar data seems to confirm that, in the span of less than a minute, Templeton's aircraft plummeted more than 12,000 feet.

"Preliminary raw radar data indicated the airplane was level at 17,000 feet, flying in a northeast direction. At 0531, the airplane initiated a climb, and gained approximately 300 feet of altitude in about 1 minute. Over the following 50 seconds, the airplane descended from about 17,300 feet until the last radar contact at 05:33:17, at an altitude of about 5,700 feet," says the report, which was issued on Saturday.

The preliminary investigation turned up at least four witnesses to the accident. One said she looked up when she heard a sound like "'a metal I-beam going through a grinder,'" according to the narrative report. "This sound continued for about 5-7 seconds, stopped briefly, and started again. As the sound continued, she observed the airplane spinning in a nose-high, tail low attitude, almost as if it were 'hovering.' She stated that the airplane began to "veer to the right," as the metallic noise stopped again. She then heard a "whining" sound coming from the airplane, as it continued to spin. She lost sight of the airplane behind trees, and then heard the impact."

A second witness was standing at his apartment window when he saw the falling Mitsubishi. "He stated that he could hear the airplane before he could see it, due to an overcast cloud layer, at an altitude of about 1,500 feet. The witness described the sound as a loud 'howling' sound, similar to a pair of motorcycles. The sound was synchronized and continuous, with no interruption. When the witness observed the airplane 'break out of the clouds,' it was spinning in a counter-clockwise direction, with about a 10-degree nose-down attitude. As the witness observed the airplane spin, he also heard the sound of the engines get louder and quieter with each rotation. The witness reported that the airplane continued to spin until it impacted the ground."

That version was corroborated by the two other witnesses to the Pittsfield disaster, according to the report: "A third witness observed the airplane pass over his house in a south to north direction, in a 'flat spin.' According to the witness, as the airplane continued to travel to the north, he heard the sound of the engines 'throttling up, then throttling down, as if the pilot were trying to recover.'

"A fourth witness reported hearing a loud noise overhead, and looked up to see the airplane in a "flat spin." The witness reported that the engines were "very loud," and the airplane continued to spin until it impacted the ground," investigators stated in their report.

Sifting Through The Debris

Once investigators reached the scene, this is their account of what they found:

"The wreckage was examined at the accident site on March 25, 2004, and all major components of the airplane were accounted for at the scene. The airplane impacted a marshy field, upright, in a flat attitude, on a heading of 150 degrees. The fuselage section of the airplane was compressed to a height of about 4 feet, and indications of forward velocity on the wings or fuselage section were not observed.

Both wings remained attached to the fuselage with the right wing tilted slightly aft. Both fuel tip tanks were ruptured; however, a substantial amount of fuel was observed on the ground, in the area of both tip tanks. The outboard and inboard fuel tanks on each wing remained intact, and approximately 60 gallons of jet fuel were drained from the tanks. Both engines remained attached to their respective wings, and two out of three propeller blades on each engine were visible. All four of the visible blades displayed chordwise scratching and S-bending. One propeller blade on each engine was buried in the ground.

Flight control continuity was confirmed from the severely compressed floorboard area, to all flight control surfaces. The flap selector in the cockpit indicated that the flaps were set to 5 degrees; however, a measurement of the flap actuator revealed the flaps were in the retracted position. The elevator trim indicator in the cockpit displayed a trim setting of 5 degrees nose down, and a measurement of the elevator trim actuator indicated a setting of 18 degrees nose up. The rudder trim indicator in the cockpit displayed a setting of 2 degrees nose left, and a measurement of the rudder trim actuator indicated a setting of 13 degrees nose right.

The empennage section was partially separated at the vertical stabilizer attachment point. The empennage skin displayed a tear, which encircled the empennage, and the vertical stabilizer was angled about 45-degrees to the right.

"Examination of the cockpit revealed the right power lever was in the 'flight idle' detent and the left power lever was approximately half an inch forward of the 'flight idle' detent. Both right and left condition levers were positioned half-way between the 'takeoff' and 'taxi' detents. The left torque gauge indicated 112 percent torque, and the right torque gauge indicated 100 percent torque. Additionally, the cabin pressurization was set to 15,500 feet.

"Examination of the cockpit overhead switch panel indicated the right pitot/static heat was 'on' and the stall heat was 'on.' The remainder of the overhead switches, which included: propeller de-ice, engine intake heat, windshield anti-ice, and wing de-ice were all in the 'off' position.

"As the airplane was recovered from the accident site, the underside of the fuselage was examined, and the landing gear was observed in the retracted position. Additionally, one propeller blade on each engine, which had been buried in the ground, was visible. These propeller blades contained slight chordwise scratching.

"Examination of both engines revealed their compressor blades were bent opposite the direction of rotation, and the third stage turbine blades displayed evidence of metal splatter."

FMI: www.ntsb.gov