Aviation Accident Summaries

Aviation Accident Summary SEA04LA095

Borah Peak, ID, USA

Aircraft #1

N117BS

WSK PZL Mielec PZL M-18B

Analysis

The pilot was on the first leg of a visual flight rules (VFR) cross-country flight that originated approximately one hour and 15 minutes prior to the accident. After failing to arrive at the scheduled destination, the FAA issued an Alert Notice (ALNOT) and a search for the missing airplane was initiated. Eight days after the search was initiated, the missing airplane was located in mountainous terrain near the summit of Borah Peak at an elevation of approximately 11,210 feet above mean sea level. Widespread areas of instrument meteorological conditions (IMC) were reported along the pilot's route of flight. Weather forecasts for the time and area of the accident included icing conditions and mountain obscuration.

Factual Information

HISTORY OF FLIGHT On May 22, 2004, about 1416 mountain daylight time, a restricted category WSK-PZL Mielec, M-18B (Dromader), N117BS, was destroyed when it collided with mountainous terrain near Borah Peak, Idaho. The airplane is owned by A-S Ranch, Inc, of Fort Benton, Montana, and was being operated as a visual flight rules (VFR) cross-country flight under the provisions of Title 14, CFR 91, when the accident occurred. The airline transport pilot-in-command was fatally injured in the accident. No flight plan was filed for the flight that originated from Dillon, Montana, approximately one hour and 15 minutes prior to the accident. The pilot's planned destination was Boise, Idaho. On the evening of May 22, the owner of the airplane contacted the Federal Aviation Administration (FAA) after the airplane failed to arrive at the scheduled destination. Subsequent to the report, the Boise, Idaho, Flight Service Station (FSS) issued an ALNOT (alert notice) for the missing airplane, and a search was initiated. On May 30, 2004, the wreckage was located on the eastern slope of Borah Peak at 44 degrees 07 minutes' north latitude and 113 degrees 46 minutes' west longitude. The wreckage came to rest on extremely steep, snow-covered terrain at approximately 11,210 feet above mean sea level (MSL). The summit of Borah Peak is 12,662 feet above MSL. According to the operator, the pilot was repositioning the airplane to Boise, Idaho, for inspection by the Office of Aircraft Services (OAS). At the conclusion of the Inspection, the airplane would have been repositioned to Wells, Nevada, to support firefighting efforts. METEOROLOGICAL INFORMATION The closest official weather reporting facility was located approximately 43 miles south-southwest of the accident site at Friedman Memorial Airport (KSUN), Hailey, Idaho, at an elevation of 5,319 feet msl. The following conditions were reported surrounding the time of the accident: KSUN weather at 1350, wind from 260 degrees at 06 knots, visibility 30 statute miles with showers in the vicinity, scattered clouds at 3,000 feet agl, ceiling broken at 4,500 feet, temperature 14 degrees Celsius (C), dew point -1 degrees C, altimeter 29.79 inches of Mercury (Hg). KSUN weather at 1445, wind from 260 degrees at 10 knots, visibility 30 statute miles with showers in the vicinity, scattered clouds at 3,000 feet, ceiling broken at 4,500 feet, temperature 15 degrees C, dew point -3 degrees C, altimeter 29.77 inches of Hg. The next closest weather observation site was located approximately 58 miles north at Lemhi County Airport (KSMN), Salmon, Idaho, at an elevation of 4,043 feet. The following conditions were reported at the approximate time of the accident: KSMN weather at 1335, automated system, wind from 200 degrees at 12 knots gusting to 15 knots, visibility 10 miles, a few clouds at 100 feet, scattered clouds at 4,600 feet, ceiling broken at 6,500 feet, temperature 11 degrees C, dew point 1 degree C, altimeter 29.71 inches of Hg. Remarks: automated system without a precipitation discriminator, hourly precipitation 0.08 inches. KSMN weather at 1415, automated system, wind from 170 degrees at 8 knots gusting to 17 knots, visibility 10 miles, a few clouds at 3,900 feet, scattered clouds at 4,700 feet, temperature 12 degrees C, dew point 7 degrees C, altimeter 29.72 inches of Hg. The conditions at the planned destination of Boise (KBOI), Idaho, located 109 miles southwest of the accident site at an elevation of 2,871 feet msl was as follows: KBOI weather at 1353, wind from 270 degrees at 9 knots, visibility 10 miles, sky clear below 12,000 feet, temperature 18 degrees C, dew point 1 degree C, altimeter 29.76 inches of Hg. The following In-Flight Weather Advisories were valid at the time of the accident: The National Weather Service issued AIRMET Sierra for mountain obscuration and AIRMET Zulu for icing conditions between the freezing level and 18,000 feet over the route of flight and the accident site. MEDICAL AND PATHOLOGICAL INFORMATION Western Pathology Associates, LLC, conducted an autopsy on June 3. According to the autopsy report, the pilot's cause of death was attributed to blunt force injuries to the head and trunk. The FAA Civil Aeromedical Institute (CAMI), Oklahoma City, Oklahoma, performed toxicological testing of specimens of the pilot. According to the postmortem toxicology report, results were negative for carbon monoxide, cyanide, and ethanol, however the specimens tested positive for the following substances; Diazepam, Nordiazepam, Oxazepam, Temazepam, Ephedrine, Pseudoephedrine, Triprolidine. Refer to the attached toxicology report for specific values and test parameters.

Probable Cause and Findings

The pilot's inadequate planning/decision, VFR into IMC, and his failure to maintain terrain clearance. Factors include mountainous terrain and instrument meteorological condition.

 

Source: NTSB Aviation Accident Database

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