SEA97FA120
SEA97FA120

HISTORY OF FLIGHT

On May 24, 1997, about 1220 Pacific daylight time, a Piper PA-32-301T, N83211, operated by the pilot as a 14 CFR Part 91 personal flight, experienced an inflight break-up near Bend, Oregon. Instrument meteorological conditions prevailed at the time and an instrument flight rules flight plan was filed. The airplane was destroyed and both instrument rated private pilots were fatally injured. The flight had departed from Concord, California, earlier in the day and was en route to Redmond, Oregon.

Witnesses on a nearby golf course reported that the airplane's engine was heard clearly but that they could not see the airplane. The witnesses reported that they were actually looking at "a pretty nasty looking cloud" at the time. The witnesses reported that thunder was heard but they did not see any lightning. Shortly after this, a sound described as a "sonic boom" but not as loud was heard. After this sound, the airplane noise was no longer heard.

PERSONNEL INFORMATION

At the time of the accident the pilot held a private pilot certificate for single-engine land aircraft and an instrument rating. The pilot's flight logbook and records found among personal effects at the accident site indicated that the pilot had accumulated a total flight time of approximately 660 hours in all make and model aircraft. Approximately 220 hours had been accumulated in the accident aircraft.

The pilot-rated passenger held a private pilot certificate for single-engine land aircraft and an instrument rating. At the time of the accident, this pilot had accumulated a total flight time of approximately 892 hours, with about 220 hours in the accident aircraft.

METEOROLOGICAL INFORMATION

At 1216, the Redmond Airport was reporting 5,000 feet scattered, with 10 miles visibility. The wind was from 300 degrees at 10 knots, gusting to 15 knots. The temperature was 52 degrees. Rain was reported in the area.

Widely scattered thunderstorms and rain were reported in the Willamette Valley. An Airmet for the state of Oregon reported light to occasional moderate rime and mixed icing in the precipitation from the freezing level up to 12,000 feet. The freezing level was reported at around 7,000 feet. Another Airmet reported moderate turbulence for the state of Oregon.

COMMUNICATIONS

At 1106, the pilot made contact with Seattle Center and reported in at 12,000 feet.

At 1133, the controller gave the pilot the current Klamath Falls, Oregon, altimeter setting.

At 1135, the pilot notified the controller that they were climbing to 13,000 feet to get above the clouds. The controller responded that he noticed the climb and instructed the flight to maintain 13,000 feet.

At 1140, the pilot requested to deviate about five miles to maneuver around clouds. The controller approved the deviation to either side of the flight course, and to rejoin the airway when able.

At 1154, the pilot requested to descend to 12,000 feet. The controller approved the flight to descend and maintain 12,000 feet.

At 1202, the pilot informed the controller that they were at 12,300 feet and descending to 12,000 feet.

At 1206, the controller asked the pilot for her altitude. The pilot responded that they were at 12,800 feet and getting an updraft in the clouds. The pilot informed the controller that they were going to stay on top of the clouds for a few more minutes. The controller inquired as to how the pilot would classify the updraft, as the radar was showing the flight at about 13,200 feet. The pilot responded that it was better now and requested to descend to 10,000 feet. The controller stated that 12,000 feet was the lowest that he was able to give them at the time. The pilot responded that since they could not descend, then they wished to remain at 13,000 feet. The controller instructed the pilot to descend to 12,000 feet at pilot's discretion. The controller then inquired again as to the classification of the updraft. The pilot responded that it was a 500 feet per minute updraft.

At 1214, the pilot informed the controller that they were diverting "a little bit" for clouds and asked if they could descend to 10,000 feet. The controller responded that the flight could not descend to 10,000 feet due to terrain, and asked the pilot which way they were diverting. The pilot responded "to the right." The controller stated that deviation to the right was approved and to descend to 10,000 feet.

At 1215, the controller asked the pilot what the flight conditions were. The pilot responded that there was slight icing in the clouds and freezing rain.

At 1218, the controller inquired about the type of approach the pilot wanted for landing. The pilot responded that she wanted to descend now because she was picking up ice. The controller instructed the pilot to turn right to a heading of 40 degrees and descend and maintain 8,000 feet. The pilot responded to the instructions.

There were no further communications received by the flight after 1219.

WRECKAGE AND IMPACT INFORMATION

The wreckage was scattered over an area of 1,400 feet by 800 feet. The terrain was heavily wooded and low bush covered the ground. The ground was level, wet and rocky. The elevation at the accident site was approximately 4,400 feet.

The point of origin for wreckage measurements was taken from the location of the fuselage. The debris field was located due west of the fuselage. The fuselage was positioned with the nose of the airplane pointing to 320 degrees. The fuselage was laying on its left side and appeared to have collided with the terrain in a nearly level attitude. The structure was flattened. Fire consumed the fuselage and destroyed the cockpit and cabin area. Approximately 35 inches of the rudder remained attached to the empennage at the lower hinge. The engine remained attached at the firewall and was laying with the left side partially buried in the soil. The engine sustained severe heat distress which destroyed the accessory section. The propeller hub remained attached to the crankshaft. All three propeller blades displayed slight bending deformation. The inboard 109 inches of the right wing remained partially attached to the fuselage. The right flap was positioned in place with the right wing and sustained fire damage to the inboard section.

The entire left wing separated from the fuselage at the wing root. The left wing was found approximately 800 feet northwest of the fuselage. Both the aileron and the flap remained attached at their respective hinges. The left main landing gear remained attached. The control cables had been pulled to separation and partially cut through the lower skin of the wing. Minor leading edge tip damage was noted to the wing. The fuel tank remained intact.

The outboard section of the right wing was located approximately 500 feet to the northwest of the fuselage and about 300 feet southeast of the left wing. The aileron had separated from the hinges and was found in two pieces about 400 feet due south of the wing and about 300 feet due west of the fuselage.

The entire vertical stabilizer had separated from the fuselage at the base and was found approximately 800 feet west of the fuselage. The leading edge plastic covering was missing. The vertical stabilizer was bent slightly to the left.

The right side stabilator separated near the root and was found about 1,300 feet due west from the fuselage and about 500 feet southwest from the vertical stabilizer. The trim tab separated at the hinges and was located in the debris field about 400 feet southeast of the horizontal section. The stabilator was creased and bent from the inboard leading edge aft and outboard.

The left side stabilator separated near the root and was found about 1,100 feet northwest of the fuselage and about 400 feet to the north of the right side stabilator. The trim tab had separated from the hinges and was found among the debris field. The left stabilator was creased and bent similar to the right side stabilator.

Several items of baggage, paper, golf bags and clubs, along with, miscellaneous pieces of aircraft skin, plastic, and plexiglass were also found among the debris field.

MEDICAL AND PATHOLOGICAL INFORMATION

Dr. Joseph A Chorny, Physician/Pathologist from Central Oregon Pathology Consultants, Bend, Oregon, reported that the cause of death to the pilot was from multiple blunt force injuries.

Toxicological samples were taken and sent to the Civil Aeromedical Institute, Oklahoma City, Oklahoma, for analysis. The results of the analysis was reported as negative.

TEST AND RESEARCH

Sections from the wing structure, the aft portion of the empennage, and sections from the left and right stabilators were sent to the National Transportation Safety Board Materials Laboratory for examination. The sections were: the inboard portion of the left wing main spar and a short portion of the spar carry through; the mating portions of the right wing main spar from about 109 inches from the wing root; the outboard portion of the right wing aft spar; the outboard portion of the right wing front spar; The aft portion of the empennage; the inboard end of the left stabilator and trim (two pieces), and the inboard end of the right stabilator (two pieces).

The metallurgist reported that all of the fractures of the wing spar components were typical of overstress separations. The left wing main spar carry-through upper cap was typical of a tensile overstress separation. The lower cap was typical of a twisting (leading edge down) and downward bending overstress separation. The fracture features were indicative of a fracture under wing down-loading condition, with initial fracture in the upper spar cap.

The right wing main-spar lower cap pieces were buckled in compression adjacent to the separation. The upper cap pieces were bent downward over a length of about 12 inches inboard of the separation. The upper spar cap pieces on the outboard side were bent upward directly adjacent to the separation. The metallurgist reported that the right wing main-spar separation was indicative of down loading of the wing resulting in the initial compression buckling of the lower spar cap, followed by downward bending of the upper spar cap prior to the final separation of the upper spar cap in an up bending direction.

The metallurgist reported that the fractured components in the empennage were typical of overstress separations. The fractures and damage to both the left and right side stabilator was symmetrical and indicated nearly identical wrinkles that intersected the leading edge. Both sides of the stabilator front main spar fractured about one foot outboard of the empennage. The upper cap of the main spar was bent and twisted adjacent to the separation. The metallurgist reported that the fractures were consistent with a leading edge down twisting deformation. The lower cap of the main spar contained compression buckling and bending deformation. The rear spar also contained substantial bending and twisting deformation indicative of separation under a leading edge down twisting deformation.

ADDITIONAL INFORMATION

The wreckage was recovered from the accident site by Specialty Aircraft Services and taken to Redmond, Oregon. The wreckage was released to the owner's representative on September 17, 1997.

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