Aviation Accident Summaries

Aviation Accident Summary SEA97FA041

CAMBRIDGE, ID, USA

Aircraft #1

N6425W

Cessna P210N

Analysis

Weather information obtained by the pilot prior to departure indicated low ceilings and visibility with mountain obscurement due to clouds, precipitation and fog. Occasional moderate turbulence with moderate rime or mixed icing was also forecast. Another pilot flying in the area at the time of the accident reported observing 'very black clouds' that had a 'roll to them and moving fast.' That pilot also reported that the clouds looked 'very violent,' and stated that before he turned around to find another route, he was experiencing light to moderate turbulence, but was not picking up any ice below the cloud base. Radar data indicates that after departure the flight headed in a westerly direction. The radar indicates that the airplane made a left turn approximately 180 degrees and was experiencing rapid increasing and decreasing altitude changes before the airplane descended rapidly and dropped from radar coverage. The wreckage was located in mountainous terrain. Evidence indicates that the airplane collided with the terrain in a steep nose down attitude.

Factual Information

HISTORY OF FLIGHT On January 2, 1997, about 1434 mountain standard time, a Cessna P210N, N6425W, registered to and operated by the pilot as a 14 CFR Part 91 personal flight, collided with mountainous terrain located ten miles north of Cambridge, Idaho. Visual and instrument meteorological conditions prevailed at the time and no flight plan was filed. The airplane was destroyed and the private pilot and her four passengers were fatally injured. The flight originated from McCall, Idaho, about 23 minutes prior to the accident. The flight was destined for Boise, Idaho. The Federal Aviation Administration reported that the pilot had filed an instrument flight rules flight plan, but did not open the flight plan after the airplane took off from McCall. At 1800 the same day, a search was initiated after concerned family members reported the airplane overdue. The wreckage was located on January 3 at 1800. No ELT signal was heard. Family members reported that the purpose of the flight was to help some friends by flying them out of McCall to Boise, since all of the roads were closed. The husband of one of the passengers reported that he was present at the airplane when the pilot was performing the preflight check and loading the baggage. The husband reported that the pilot was aware of the icing conditions at 8,000 feet and that the surrounding mountains were obscured by clouds. The husband reported that the pilot noted that the cloud conditions to the west were broken, and stated that she would fly to the west and then down a valley to the south into Boise, instead of going directly south out of McCall to Boise. A commercial pilot who was flying a Cessna 210 in the Council, Idaho, area about 1400, reported that he had departed from Boise and decided to fly to the west, instead of direct from Boise to McCall. The pilot stated that there was heavy air traffic along the direct route between McCall and Boise. Due to adverse weather, all of the roads leading into and out of McCall had been closed. The pilot stated that he decided to fly to the west, toward Council, in an attempt to bypass the heavy air traffic. He reported that he was flying at the bases of the clouds at about 6,500 feet and was maneuvering around the clouds and the terrain. He stated that just south of Council, the weather was pretty good so he flew toward Council Mountain, through Long Valley and into the Cotton Wood Drain. When the flight was about two to three miles south of Council, the pilot stated that he observed "very black clouds" that had a "roll to them and moving fast." He described the clouds as looking "very violent." He observed the cold front moving from the southwest to the northeast and was approaching the ridges into the McCall area. He decided to turn around and find another route into McCall. He stated that he was experiencing light to moderate turbulence and was not picking up any ice below the cloud layers, and there was no freezing rain. PERSONNEL INFORMATION At the time of the accident, the pilot held a private pilot certificate with an instrument rating for single-engine land aircraft. The pilot's flight logbook indicates that she had accumulated a total flight time of 1,310 hours, with 1,121 hours in the Cessna 210. A review of departure points and destination airports indicates that the pilot, on several occasions, made flights between Boise and McCall. The pilot held a third class medical certificate dated May 21, 1996. Federal Aviation Administration medical records indicate a limitation for the pilot to have available glasses for near vision. METEOROLOGICAL INFORMATION At 1328, the pilot made contact with the Boise Flight Service Station and requested an "instrument flight rules" weather briefing from McCall to Boise, with a departure time at about 1400. The specialist reported the weather advisories along the route of flight with low ceilings, visibility and mountain obscuration due to clouds, precipitation and fog. There was occasional moderate turbulence up through 18,000 feet, with occasional moderate rime or mixed icing from the freezing level at 8,000 to 9,000 feet through 24,000 feet. The specialist reported that a low pressure system aloft jet stream was moving in from the west and was moving across southern Idaho at the time. There was some clearing west of McCall, toward Council and Baker, and west of Boise. McCall was not reporting the weather. The pilot informed the specialist that the visibility was about two miles and the ceiling was about 500 feet, with light rain showers. The specialist checked the radar for the intensity of cloud build-up and reported that the radar was not showing the information, but reported the build-ups as "fairly spotty" north of Boise and moving to the east by northeast. The current weather for Boise at 1332, was reported as a few clouds at 6,000 feet. The ceiling was at 8,500 feet broken and the visibility was 10 miles. The temperature was 50 degrees, and the dewpoint was 41 degrees. The wind was from 110 degrees at 14 knots. The specialist reported that the McCall weather was not available. The NOTAM for the area identified the tacan azimuth at Donnelly was out of service. The specialist reported the weather at Baker which was showing showers in the vicinity, with scattered clouds at 2,000 feet, and broken at 8,000 feet and 6,000 feet. The specialist concluded the briefing by reporting the weather to the west at Squaw Butte, which was reported as obscured, with lower broken layers to the east toward Horseshoe Bend. The pilot then gave the specialist the information for an instrument flight rules flight plan and reported a departure time for 1400. The route of flight was reported as direct from McCall to Boise, with a cruising altitude at 12,000 feet. The time en route was estimated to be 35 minutes with three hours of fuel on board. The briefing was concluded at 1337. WRECKAGE AND IMPACT INFORMATION At the time of the accident, the aircraft collided with mountainous terrain that was covered with eight to ten feet of snow. The elevation at the accident sight is approximately 7,100 feet. Due to adverse weather shortly after the accident that buried the wreckage under several feet of snow, the on-site investigation was conducted after the snow melt. During the on-site investigation, the wreckage was located in an open meadow on a three to five degree up slope. Tall trees were nearby. The wreckage was contained within a fifty-foot radius. At the time of the accident, in order to remove the victims, rescue personnel moved sections of the wings and cut the fuselage. A reconstruction of the wreckage was performed at the accident site. The right wing was found in one piece and separated from the fuselage with a section of the carry through spar. The entire length of the leading edge was crushed rearward. The flap remained attached at the hinges. The aileron separated at the hinges but was located within the radius of wreckage. The left wing was separated from the fuselage and was in several pieces. The wing spar was pulled from the wing. The entire length of the leading edge was crushed rearward. The wing flap remained attached to a section of the wing at the outboard hinge. The inboard hinge was pulled away. The aileron separated at the hinges and was bent. The forward section of the fuselage was positioned with the nose down 90 degrees. The engine was positioned with the front left side partially buried in the soil. The fuselage structure was accordioned forward onto the engine. The top of the cabin had been removed by search and rescue personnel. The instrument panel was fully exposed. The aft section of the fuselage and empennage was bent up and forward. The right side horizontal stabilizer inboard section remained attached at the root. The outboard section separated approximately 40 inches from the root. The stabilizer tip was found nearby. The elevator separated at the hinges and was bent 90 degrees. The leading edge of the stabilizer was crushed rearward. The left side horizontal stabilizer separated at the root. The leading edge was severely crushed rearward. The elevator was torn in two pieces. The inboard section of the elevator remained attached at the middle hinge. The outboard section separated at the hinge. The lower section of the vertical stabilizer remained attached at the root. The upper section had separated. The leading edge of the vertical stabilizer displayed a circular indentation. The rudder separated at the hinges and was deformed at the top. All three propeller blades separated from the engine. The spinner broke away from the engine just aft of the flange. One propeller blade remained attached to the spinner. The blade remained straight with a chunk of the metal ripped from the tip. This propeller blade was found near the rear of the main wreckage. The second propeller blade separated from the hub and was located approximately 120 feet uphill from the main wreckage. The blade exhibited a slight aft bending. Trailing edge nicks were found near the blade tip. The third propeller blade separated from the hub and was found partially buried in the soil under the cockpit area. This blade was bent aft approximately 80 degrees about 20 inches inboard from the tip. The blade exhibited deep chordwise scoring on the back side with some leading edge nicks. Examination of the engine revealed that the firewall was crushed forward around the accessory section. All three of the left side cylinders were damaged. Most of the top of the number 6 cylinder was broken off. The right side cylinders remained intact. The right magneto was broken from the mount and the ignition leads were damaged. The injectors and injector lines were broken. The vacuum pump was broken from the mount. The rotor was broken into several pieces, however, the vanes were intact. The oil sump was severely crushed. The alternator was crushed. The spark plugs displayed normal operating signatures. The right magneto was damaged and would not produce a spark. The left magneto did produce a spark with hand rotation. MEDICAL AND PATHOLOGICAL INFORMATION Frank A. Roberts, M.D., St. Alphonsus Regional Medical Center, reported that the pilots cause of death was due to multiple traumatic injuries. Toxicological samples were sent to the Federal Aviation Administration Civil Aeromedical Institute for analysis. The results of the analysis were reported as negative. TESTS AND RESEARCH Radar data provided by the Federal Aviation Administration indicates that the aircraft was identified south of the McCall airport at 7,800 feet at 1415. The radar data indicates that the airplane was flying on a northwesterly heading and climbing before turning westerly for about five minutes. At 1420, the airplane begins to turn to the south and maintains an altitude of approximately 10,500 feet. At 1426, the aircraft begins to increase altitude and turn to a westerly heading. At 1428, the aircraft continues to climb and turn to a northwesterly direction. At 1430, the aircraft attains an altitude of 12,200 feet on a westerly heading. One minute later the airplane descends 100 feet to 12,100 feet. Approximately one minute later, the airplane descends 1,300 feet to 10,800 feet. At 1432, the aircraft begins a turn to the left on a southerly heading and the airplane increases altitude by 400 feet in 19 seconds, then decreases altitude 600 feet in 19 seconds. At 1433, the aircraft is at 10,800 feet and continuing the left turn to the east. The aircraft continues to descend 2,400 feet in 29 seconds before radar contact is lost at 8,400 feet. The accident site was located near the last radar target, at an elevation of 7,100 feet. ADDITIONAL INFORMATION The on-site investigation and wreckage recovery was conducted on July 17, 1997. The wreckage was transported to Specialty Aircraft, Redmond, Oregon. The wreckage was released to the owner's representative on September 18, 1997.

Probable Cause and Findings

the pilot's failure to maintain control of the aircraft. Flight into adverse weather and turbulence were factors.

 

Source: NTSB Aviation Accident Database

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