Aviation Accident Summaries

Aviation Accident Summary SEA98FA001

LEADORE, ID, USA

Aircraft #1

N2938B

Piper PA-28-181

Analysis

An aircraft was seen flying to the east under a 300-500 foot overcast about 25 miles west of the accident site. At that time, the ambient light conditions had just turned from dusk to dark, and witnesses sensed that the pilot was following the road that ran near the center of the valley through which the aircraft was flying. The aircraft was next seen about 20 miles east of the first sighting, flying low over the road, and entering the west side of Gilmore Summit. When the pilot did not arrive at his destination, a search was begun. The aircraft was located in the hills near the summit. Local officials reported that during the evening, the weather had been getting worse, the clouds had been lowering, and snow started falling in the summit, soon after the time of the accident.

Factual Information

HISTORY OF FLIGHT On October 10, 1997, approximately 1930 mountain daylight time, a Piper PA-28-181, N2938B, impacted the terrain about 20 miles east of Leadore, Idaho. The private pilot and his passenger received fatal injuries and the aircraft, which was owned and operated by Western Aviation, Inc., of Blackfoot, Idaho, was destroyed. The 14 CFR personal pleasure flight, which departed McCall, Idaho about one hour and 10 minutes prior to the accident, and was en route to Blackfoot, Idaho, was reportedly operating in instrument meteorological conditions at the time of the accident. No flight plan had been filed, and the ELT, which was activated by the impact, was the primary means by which the wreckage was located. According to witnesses, the pilot and his passenger had been working in Pasco, Washington, on the day of the accident. Individuals at the work site said that the pilot seemed to be in a hurry as he left for the airport in order to fly to his home in Blackfoot, Idaho. According to FAA records, he did not file a flightplan, receive an FAA-provided pre-flight weather briefing, or contact any FAA facilities en route. The aircraft's route after departing Pasco could not be determined, but it is known that the pilot made an en route stop in McCall, Idaho. The pilot reportedly landed in McCall shortly before 1800 mountain daylight time, and the aircraft took on 20 gallons of 100 Low-Lead aviation fuel. Prior to departing McCall, the pilot called his wife at 1806. According to family members, during that call he said that he planned to continue on to Blackfoot, but that the weather was starting to get bad, and that might slow his progress. The pilot departed McCall about 1820, and no one reported seeing the aircraft again until it was observed just west of Leadore, Idaho, by two individuals who were driving west on State Route 28. According to the witnesses near Leadore, they first spotted the aircraft when they were just a couple of miles west of Leadore. They said that they were heading west toward Salmon when they saw the aircraft's lights coming toward them. The aircraft was flying under an overcast, which they estimated was between 300 and 500 feet above the ground, and appeared to them to be following the road. They said they were real surprised to see the aircraft because the clouds were so low, and because it was just changing from dusk to dark. They said that it was not snowing in the valley at that time, but it looked like it might be snowing on the hills around the valley. As the aircraft got closer, they first thought the pilot may be trying to land at the airstrip at Leadore, but as it continued toward them at a low altitude at what appeared to them to be a very slow speed, they became convinced that he was trying to land on the road. They therefore pulled off to the side of the road in order to give the pilot a clear landing area, but the aircraft overflew their location and continued on to the east. The next, and last, reported sighting of the aircraft took place at about 1930, when it was witnessed about three miles west of Gilmore Summit (about 20 miles east of Leadore) by two individuals who had just come over the summit driving west on Route 28. The individual who reported seeing the aircraft at that location said that when it was first spotted, it was quite a ways out, and although she could see its flashing lights, she was not sure at first what it was. Then as it got closer, the witness and the other individual with her could see that it was an aircraft that was "... just following the highway." The witness said that the aircraft "...wasn't very far off the ground," and that it passed by the side of their vehicle going in the opposite direction. She further stated that, "I could look out my window and just raise my eyes and see the windows of the side windows of the airplane. So it wasn't very far off the ground." She also said that it had already turned dark when they first spotted the aircraft, and that when it flew by them it appeared to be going "...real straight and level, just real steady." She said that "...the plane didn't seem to be in any distress or having any problems." When the pilot did not arrive home as expected, a missing aircraft notice (ALNOT) was issued, and the wreckage was ultimately located about one mile southwest of where State Route 28 passes over Gilmore Summit, at coordinates North 44 25.10 West 113 15.10. METEOROLOGICAL INFORMATION At 1854, the weather observation taken at Salmon, Idaho, which is located about 50 nautical miles northwest of the accident site, reported clear skies, 10 statute miles visibility, with winds from 180 degrees at 5 knots. The 1847 weather observation for Idaho Falls, located about 75 miles southeast of Gilmore Summit, showed winds variable at 5 knots, 25 miles visibility, light rain, few clouds at 2,800 feet, 4,800 foot broken, 7,500 overcast, temperature 14 degrees Celsius, dew point 06 degrees, with an altimeter setting of 29.67. A special observation taken at Idaho Falls at 1852 showed that the winds were coming from 220 degrees and had increased to 10 knots, gusting to 20. It also reported a visibility of 25 miles, few clouds at 2,200 feet, 4,800 broken, 7,500 overcast, temperature 15 degrees, dew point 2 degrees, altimeter 29.65. The remarks section of the report indicated that there had been a wind shift associated with a frontal passage at 52 minutes after the hour. The next regularly scheduled weather observation taken at Idaho Falls (at 1947) showed winds from 020 degrees at 5 knots, 10 miles visibility, 7,500 scattered, 10,000 overcast, temperature 12 degrees, dew point 04, and an altimeter setting of 29.64 degrees. There are no other observation stations on a line between Salmon and Idaho Falls, but local officials reported that the weather in the valley between Leadore and Gilmore Summit had been getting worse all afternoon. They also said that, although it was not snowing at the summit at the time of the accident, the ceiling had been getting lower all evening, and that soon after the time at which the aircraft was seen near the summit, it started snowing throughout the valley. WRECKAGE AND IMPACT INFORMATION The wreckage site was located at 8,000 feet above sea level (MSL) in the densely forested hills about one mile southwest of Gilmore Summit. The initial point of impact was about 160 feet up a conifer tree that was estimated to be 200 feet high. From that point, the wreckage track ran on an uphill slope on a heading of 220 degrees. About 15 feet past the initial impact point, the aircraft collided with another tree, which was uprooted and sheared off about 25 feet above the ground. About 30 feet below the top of this tree was a straight-edged slice, which cut nearly half way through the approximately 18 inch diameter of the tree (see photo). Most of the left wing was located about ten feet past the base of this tree, and most of the right wing was located about 40 feet beyond the right wing. The fuselage and engine were located about 65 feet past the left wing, and the propeller was found about 15 feet to the left of the fuselage. The empennage had separated from the fuselage, and was found in four sections along the impact track. The left wing fuel tank had taken a direct tree impact, had split open, and there had been a small fire near the left wing root. Both wings had round impact indentations in their leading edge. The left wing had two such indentations. One, which was almost directly in front of the center of the fuel tank, was approximately 10 inches in diameter, and had crushed the leading edge nearly straight back about 24 inches. The second round indentation, which also pushed the leading edge straight back, was about eight inches in diameter, and was eight inches deep into the wing. The right wing had a round indentation just inboard of the fuel tank, which was about 10 inches both in diameter and depth. It also had a more angular indentation about 18 inches outboard of the fuel tank cap, which was about 20 inches in depth. The sides of all of these indentations were aligned almost directly 90 degrees to the lateral axis of the aircraft. The right wing flap had separated from the wing, but the right aileron, as well as both the left flap and left aileron were still attached to the wing aft spar. The fuselage, which was torn open at the top just behind the back seat, was in one piece, but the engine, firewall, and instrument panel had been pushed back into the cabin area. The crankshaft flange had sheared from the crankshaft, and the propeller was still bolted to the flange. One propeller blade, which was bent back about 45 degrees along its outer one-half, showed longitudinal twisting, and had chord-wise scratching from the tip to the mid-point. The other blade, which was bent forward about 10 degrees along its outer one-third, showed no other significant impact damage. During the investigation, the engine was subjected to a teardown inspection. During that inspection it was determined that both magnetos were able to produce a spark, and mechanical continuity was established from the crankshaft, through the camshaft, to the valve train. Compression was present in all cylinders, and the oil screen was free of any particles. The air filter element was unobstructed, and the fuel pump produced a suction on the intake side when operated by hand. The carburetor drain plug had been pulled out by the impact, and the carburetor throat was fractured at its mounting flange. All fuel had drained from the carburetor bowl. ADDITIONAL DATA AND INFORMATION The FAA Toxicology and Accident Research Laboratory completed a forensic toxicology examination of the pilot, and no Carboxyhemoglobin or Cyanide were detected in the blood, and no Ethanol or drugs were found in the urine. An autopsy was completed on the pilot, and the cause of death was listed as accidental due to multiple injuries secondary to deceleration. The aircraft wreckage was released to Idaho Intermountain Claims, Inc., at Salmon, Idaho, on November 5, 1997.

Probable Cause and Findings

the pilot's inadvertent entry into instrument meteorological conditions, and his failure to maintain clearance from wooded terrain in the area where he was maneuvering. Factors relating to the accident include: darkness, low ceiling, and high/mountainous terrain.

 

Source: NTSB Aviation Accident Database

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