Aviation Accident Summaries

Aviation Accident Summary ANC95FA056

WASILLA, AK, USA

Aircraft #1

N9GZ

CESSNA 150

Analysis

THE STUDENT WAS ON THE SECOND LEG OF A SOLO CROSS COUNTRY FLIGHT. THE FLIGHT PLANNED COURSE WOULD HAVE TAKEN THE FLIGHT THROUGH AN AREA OF WIDE VALLEYS. HOWEVER, THE WRECKAGE WAS FOUND 17 MILES EAST OF THE FLIGHT PLANNED COURSE AT THE 3000' LEVEL OF A MOUNTAIN. THE WEATHER IN THE VICINITY OF THE FLIGHT PLANNED COURSE DURING THE TIME OF THE FLIGHT WAS HIGH OVERCAST. IN THE VICINITY OF WHERE THE WRECKAGE WAS LOCATED, THE MOUNTAIN TOPS AND UPPER RIDGES SURROUNDING THE VALLEYS WERE OBSCURED BY CLOUDS.

Factual Information

HISTORY OF FLIGHT On May 21, 1995, about 1230 Alaska daylight time, a wheel equipped Cessna 150 airplane, N9GZ, registered to Alaska Aircraft Sales of Anchorage, Alaska, and operated by Alaska Air Academy for the purpose of flight instruction, crashed into a mountain located 17 miles northeast of the Big Lake VOR (very high frequency omnidirectional range) on the 036 degree radial. The student solo flight, operating under 14 CFR Part 91, departed Lake Hood Airstrip, Anchorage, at 0800 on a cross country flight to Homer, Alaska. The pilot returned to Lake Hood, refueled the airplane, and obtained a weather briefing. He departed Lake Hood at 1205 for the second leg of his cross country flight. The destination was Talkeetna, Alaska. A visual flight rules flight plan was filed but not activated. Visual meteorological conditions prevailed throughout the area. The student pilot was fatally injured and the airplane was destroyed by impact forces. According to the owner of Alaska Air Academy, the student pilot had been to Talkeetna at least twice and was familiar with the route. The accident site was approximately 15 miles east of the flight planned course. WITNESSES There are no known witnesses to the accident. INJURIES TO PERSONS The student pilot, the sole occupant, received fatal injuries. DAMAGE TO AIRCRAFT The propeller, spinner, and starter ring gear separated from the engine. The engine was pushed upward from its normal location in relation to the cabin top to a 45 degree angle. The nose gear remained attached to the engine mount structure. The main cabin remained intact but was distorted. The ceiling of the cabin was crushed downward and compromised the cabin by 2 to 4 inches. The pilot side of the instrument panel was bent and pushed rearward into the cabin. The rudder pedals and adjacent floorboards were pushed up and rearward. The main landing gear remained attached to the fuselage in their proximate correct position. The empennage was bent toward the left side of the airplane midway between the main cabin and the horizontal stabilizer. The metal in the vicinity of the bend was torn. The horizontal stabilizer and elevators were unremarkable except for small dents. The rudder top was bent and the vertical fin was unremarkable. The right wing remained attached to the cabin roof and the right wing strut remained attached to both the upper and lower attach points. The inboard section of the right wing leading edge was not bent or dented. Outboard of the upper wing strut attach point, the wing was bent slightly rearward and the leading edge was bent and dented for the remaining span. The last 2 feet of the right wingtip was crushed rearward and upward. The right aileron was bent in the middle but remained attached to its hinges. The right flap was not damaged and remained in the retracted position. The left wing remained attached to the cabin roof but was bent rearward at the attach points. The left wing strut remained attached to both the upper and lower attach points. The leading edge of the entire left wing span was bent and crushed and the outboard portion of the leading edge from the landing light location was separated from the wing. The left wing tip was bent upward and the last 18 inches separated from the wing. The outboard 1/3 of the aileron was bent upward and folded over on to itself. The right flap, although not bent, was displaced from its retracted position to approximately 30 degrees extended. PERSONNEL INFORMATION The 48 year old student pilot was endorsed for solo flight in the Cessna 150 airplane on April 1, 1995. His student pilot certificate also showed endorsements for solo cross country flights dated April 29, 1995 and May 21, 1995. The student pilot's records showed he had a total of 31.7 hours of total flight experience, all in the Cessna 150 airplane, and had flown 2.5 hours in the last 24 hours. The records also show that the student pilot did not have any actual instrument flight experience and had received .5 hours of simulated instrument flight time. AIRCRAFT INFORMATION N9GZ was a Cessna 150 airplane and was equipped with a O- 320-E2D engine rated by the manufacturer at 150 horsepower. The engine had a total time of 1833.56 hours and had operated 28.76 hours since its last inspection. METEOROLOGICAL INFORMATION There are no weather reporting facilities near the accident site. The nearest weather reporting facility is Palmer, Alaska, located 13 miles east of the accident site. There is an AWOS (automated weather observation station) located at Wasilla Airport, Wasilla, Alaska, which is 12 miles south of the accident site. That facility reported the following weather. Measured ceiling 4,200 overcast, visibility 10 miles, temperature 49 degrees fahrenheit, dew point 39 degrees fahrenheit, wind calm, altimeter setting 30.00 inches of mercury. Weather briefing information, which was given to the pilot during his weather/preflight briefing, was requested from the FAA. Accoridng to the FAA Air Traffic Evaluation Division, the tape equipment which records the preflight briefings was inoperative and did not record the information. As a result, the weather information that the pilot received during the preflight briefing could not be included in the Air Traffic Accident Package. According to the National Weather Service (NWS), the area forecast for the Cook Inlet and Susitna Valley was forecast to be 3,000 feet scattered locally broken at Talkeetna and north; 5,000 feet broken, 8,000 feet broken, 11,000 broken, and 12,000 broken elsewhere, with clouds layered to 21,000 feet. The area forecast indicated that the area south of Big River Lakes (located 167 nautical miles from the accident site on a magnetic bearing of 210 degrees) and along the Alaska Mountain Range was forecast to have occasional ceilings below 1,000 feet with a visibility below 3 miles with light rain and fog. This weather was forecast to spread northward by 1800 to Skwentna (located 54 nautical miles from the accident site on a magnetic bearing of 260 degrees). The forecast showed no significant turbulence. The forecast showed areas of scattered moderate rime ice in clouds and in precipitation from 4,000 to 15,000 feet in the Big river Lakes area and along the Alaska Range. This icing was forecast to spread north to Skwentna by 1600 to 1800. Otherwise, the freezing level was 4,000 feet sloping upward to 6,000 feet in the Northern Cook Inlet area and then dropping to 2,000 feet in the vicinity of McKinley Park (located 49 nautical miles from Talkeetna on a magnetic bearing of 305 degrees). The NTSB IIC's (National Transportation Safety Board Investigator in Charge) visual observation of the ridge line, where the airplane crashed, showed that the ridge line was obscured by clouds. The observation was made on May 21, 1995, approximately 1500. The center of the Matanuska/Susitna Valley had high ceilings estimated at 5,000 feet and the visibility was 30 miles. A piece of note paper retrieved from the cockpit of the airplane showed information relating to the Susitna Valley. That information showed "some IFR - fog, turb, ice, gusting to 30." AIDS TO NAVIGATION The route of flight, according to the flight plan, showed that the student pilot intended to departed "Z41" Lake Hood Airstrip, fly to Talkeetna, and return to the Lake Hood Airstrip. According to the Manager of Alaska Air Academy, the student pilot intended to fly from the Lake Hood Airstrip, to Big Lake, and then up the valley to Talkeetna. He stated the student pilot had been to Talkeetna three previous times. Lake Hood Airstrip is co-located with Anchorage International Airport and is serviced by the Anchorage VOR (114.3 Mhz) located 8 miles southwest of Lake Hood on Fire Island. The intended route of flight would have taken the flight away from the Anchorage VOR and toward the Big Lake VORTAC (very high frequency omnidirectional range with tactical air navigation, 112.5 Mhz) located 23.5 miles northwest of Lake Hood. The next navigational aid along the intended route of flight would have been the Talkeetna VOR (116.2 Mhz), located 1.7 miles south of the Talkeetna Airport and 34 miles Northwest of the Big Lake VOR. All three of the navigational beacons are connected with a VOR airway, V456 between Anchorage and Big Lake and V491 between Big Lake and Talkeetna. The minimum en route altitude (MEA), for flights operating on instrument flight rules, between the Anchorage VOR and the Big Lake VOR on airway V456 is 2000 feet and the MEA between the big Lake VOR and the Talkeetna VOR on airway V491 is 3000 feet. The Radial for airway V491 from Big Lake VOR to Talkeetna VOR is 330 degrees. The VOR course indicator, omni bearing selector in the airplane was set to 330 degrees and the frequency set in the VOR navigation radio was 116.2, the correct frequency for the Talkeetna VOR. COMMUNICATIONS The last known communications with the airplane occurred during the airplane's departure from the Lake Hood Airport and airspace segment. The flight plan was never activated by the pilot. WRECKAGE AND IMPACT INFORMATION The airplane wreckage was located at the 3000 foot level of a mountain side at geographic coordinates 61 degrees, 42.5 minutes north, and 149 degrees, 25 minutes west, resting inverted with the nose pointing uphill on a heading of 260 degrees magnetic. The mountain side was located in a narrow steep ravine that aligned with 001 degrees magnetic. The valley floor rose at an approximate angle of 17.5 degrees and the sides sloped at an approximate angle of 36.5 degrees. The ground scars located on the mountain side were 25 feet above the main wreckage. The red navigation lens material was found in the main ground scar and was closest to the entrance of the ravine. The propeller and attached spinner which had separated from the engine, were located 27 feet away from the red navigation lens material along the same ground scar. The propeller and spinner were imbedded in the terrain. The green navigation lens material was located 18 feet beyond the propeller and spinner. These points were clearly connected with a straight ground scar beginning in the vicinity of the red lens material and ending in the vicinity of the green lens material. The direction of this straight line ground scar was 358 degrees. This ground scar was comprised of impacted dirt and overturned rocks. The airplane wreckage was examined and flight control continuity was established between the cockpit controls and the flight control surfaces. MEDICAL AND PATHOLOGICAL INFORMATION The autopsy was conducted by Doctor Michael T. Propst, Alaska State Medical Examiner, 5500 East Tudor Road, Anchorage, Alaska, 99507, on May 22, 1995, A toxicological examination by Dr. Propst showed that no drugs or alcohol were detected. There was a 0.3 percent saturation of carbon monoxide in the blood. According to the Pathologist, a 0.3 percent saturation would not have any effect on the pilot. TEST AND RESEARCH A Garmin 50 Global Positioning System (GPS) was found near the wreckage. The external antenna was not found but the suction cup used to mount the antenna was located close to the unit. The GPS unit was powered up and the waypoints were checked. Five waypoints were located in memory. None of the waypoints coincided with the location of the accident site, Talkeetna, or the flight planned route. The magnetic course from the accident site to Talkeetna was 326 degrees. According to the Chief Flight Instructor, he examined the completed flight plan and weather information presented to him by the student pilot. He stated that he felt there was nothing significant in the forecast to preclude the student pilot from completing the flight.

Probable Cause and Findings

THE STUDENT PILOT'S INADVERTENT VFR FLIGHT INTO INSTRUMENT METEOROLOGICAL CONDITIONS (IMC) AND FAILURE TO MAINTAIN CLEARANCE (OR ALTITUDE) FROM THE MOUNTAINOUS TERRAIN.

 

Source: NTSB Aviation Accident Database

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