Aviation Accident Summaries

Aviation Accident Summary SEA94FA018

NORTH BEND, OR, USA

Aircraft #1

N79405

CESSNA 172K

Analysis

THE AIRCRAFT WAS OBSERVED BY WITNESSES TO DIVE STEEPLY TOWARD THE GROUND FROM PATTERN ALTITUDE UNTIL IT DISAPPEARED FROM VIEW. THE PATHOLOGIST REPORTED THAT THE CAUSE OF DEATH WAS MULTIPLE TRAUMATIC INJURIES AND ATHERIOSCLEROTIC HEART DISEASE.

Factual Information

HISTORY OF FLIGHT On October 22, 1993, at approximately 1501 Pacific daylight time, a Cessna 172K, N79405, was destroyed when it collided with terrain about two miles north of North Bend, Oregon, while conducting touch and go landings at the North Bend Airport. The private pilot was fatally injured. Visual meteorological conditions prevailed at the time of the accident. No flight plan was filed for the personal flight, conducted under 14CFR91. There was no fire. A witness, who worked at the airport as a weather observer, stated that he had been in radio contact with this aircraft and others in the vicinity, prior to the crash. He stated that he had observed the aircraft departing runway 31 at North Bend approximately 1446, and it remained in the pattern, completing two touch and go landings. During each landing, the pilot called in his traffic position. The last radio call that the witness heard was a call on final approach on his second touch and go. He then observed the aircraft departing straight out from runway 31. A few moments later, the witness communicated with a Beech King Air, and gave an airport advisory, then began to look for N79405 so he could advise the other aircraft of its position. He then spotted N79405 just to the northwest of the airfield, about 1.5 miles off the extended centerline of runway 31. He estimated its altitude as between 800 and 1000 feet. He stated that, at the time he spotted the aircraft, it was in a near vertical dive of approximately 75 to 80 degrees. He stated that he immediately attempted to contact the pilot by radio, asking if he was all right. He stated that there was no response. The witness then advised an inbound US Coast Guard helicopter of the apparent crash. The Coast Guard helicopter diverted and spotted the crash site within about a minute. The helicopter dropped off two rescue personnel, then returned for fuel. The witness stated that he kept his eyes on the Cessna until it disappeared behind a dune. At no moment during that time did he see any attempt to pull out of the dive nor see a change in the course of the aircraft. The assistant airport manager stated that he had observed the last departure of N79405, and noted that about three fourths of the way down the runway, it still had 20 degrees of flaps extended. He noted that the pilot retracted the flaps, the aircraft settled a bit, then continued to climb out. An additional witness observed the steep descent, and stated that the aircraft seemed to level out prior to her losing sight of it. PERSONNEL INFORMATION The pilot's biannual flight review was recorded in the back of his log book. The log entry did not reflect the make or model of aircraft used. WRECKAGE AND IMPACT INFORMATION The aircraft impacted in trees and dense brush between sand dunes. All distances and directions are approximate, due to environmental constraints at the scene of the accident. The fuselage, right wing, cabin area, and horizontal control surfaces were approximately 60 feet northeast of the trees which had sustained the initial impact. The left wing was about 30 feet to the north or northwest of the main wreckage. The engine, propeller, vertical fin, and smaller pieces, such as the alternator armature, and portions of the seats, were dispersed north through northeast of the trees which sustained the initial impact, for approximately 150 feet. The vertical fin was separated from the aircraft, and showed evidence of leading edge damage. The engine accessories, including the magnetos, carburetor, muffler, and alternator, were separated from the aircraft. The magnetos were not found in the dense brush at the site. The horizontal stabilizer and elevators remained intact, with the right elevator horn folded downward about 90 degrees. The stabilizer had several wrinkles. The rudder and rear spar of the vertical fin remained attached to the rudder cables. Continuity of the rudder and elevator control cables was established to the cabin area. The fuselage, cabin area, and tail cone were crushed, folded, wrinkled, sheared, and otherwise distorted to the point of being unrecognizable. The leading edge of the right wing, outboard of the fuel tank to the tip, was crushed and torn free. Aileron cable continuity was established for the right wing to the cabin. The left wing, which was separated, had sustained leading edge impact damage. The airspeed indicator face was found by a family survivor, who had visited the scene, and it was forwarded for inspection. MEDICAL AND PATHOLOGICAL INFORMATION The pilot's torso was recovered several days after the accident. The medical examiner acquired some fluids for toxicological testing. Autopsy results stated that the cause of death was multiple traumatic injuries and atherosclerotic heart disease. The pathologist noted that there was marked prior myocardial infarction, including myocardial sclerosis, severe, septum and left posterior myocardial wall, at least 7 cm in linear dimension, and coronary atherosclerotic disease as follows: 1) severe, right, with 50-60% narrowing, 2) severe, left circumflex with focal occlusion, and 3) left anterior descending artery (not identified). TESTS AND RESEARCH The engine and carburetor were inspected after the wreckage was removed by the salvage company. The top piston ring of the number 3 cylinder was found to be broken, with evidence of carbon buildup on the ring. No evidence of scoring was found in the cylinder. No other mechanical discrepancies were noted. ADDITIONAL INFORMATION The wreckage was moved to Specialty Aircraft Co. in Redmond, Oregon. The wreckage was released to Phoenix Aviation Management, on November 9, 1993.

Probable Cause and Findings

LOSS OF CONTROL WHILE IN FLIGHT DUE TO PILOT INCAPACITATION FROM ATHEROSCLEROTIC HEART DISEASE.

 

Source: NTSB Aviation Accident Database

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