Aviation Accident Summaries

Aviation Accident Summary WPR11FA005

Panguitch, UT, USA

Aircraft #1

N8437A

CESSNA 172

Analysis

The employer of the pilot and passenger reported to local authorities that they had not returned from a presumed elk-spotting flight for an upcoming hunting trip. The wreckage was subsequently located in a remote canyon area in rising mountainous terrain at an elevation of 9,600 feet. There were no witnesses to the accident; however, pilots flying in the area that afternoon noted that it was too windy to fly below the ridgeline and tree movement was visible; the sky was clear. The calculated density altitude for the area was 11,178 feet. Based on the final location and heading of the airplane, it is likely that the pilot may have attempted to maneuver at a low altitude in the canyon and was unable to maintain clearance from terrain in the windy conditions and high density altitude. Postaccident examination of the airframe and engine revealed no mechanical anomalies that would have precluded normal operation.

Factual Information

HISTORY OF FLIGHT On October 8, 2010, about 1610 mountain daylight time, a Cessna 172, N8437A, impacted mountainous terrain in the Dixie National Forest, about 15 miles northeast of Panguitch, Utah. The pilot/owner operated the airplane under the provisions of 14 Code of Federal Regulations (CFR) Part 91 as a personal flight. The commercial pilot and one passenger were fatally injured; the airplane sustained substantial damage. The personal cross-country flight departed Page, Arizona, at an undetermined time. Visual meteorological conditions prevailed, and no flight plan had been filed. The flight was destined to return to Page. According to a responding deputy from the Garfield County Sheriff's Department, they had been notified by the employer of the pilot and passenger on the morning of October 9, when they had not returned from their flight on October 8. Initial information was that the purpose of the flight was to spot elk in the Panguitch area for an upcoming hunting trip that the passenger had scheduled. The airplane had been refueled at Bryce Canyon Airport at 1510 with 10 gallons of fuel. The accident site was located early in the morning on October 9, 2010, about 15 miles northwest of the Bryce Canyon airport, at latitude 38-degrees 00.37 minutes north, and longitude 112-degrees 11.89 minutes west. The deputy reported that a smell of fuel was present on-scene. The right wing was raised with a small puddle of fuel formed at the end of the left wing fuel tank. He estimated that the airplane came through the trees at a 45-degree angle. The deputy further reported an 8-degree terrain slope at the accident site. There were no witnesses to the accident. However, pilots flying in the accident area about 1300 noted the conditions as too windy to be flying below the ridgeline; "you could see the trees moving." One pilot also reported that it was "severe clear, no clouds, and very windy." PERSONNEL INFORMATION The pilot, age 41, held a commercial pilot certificate with ratings for airplane single-engine land and single-engine sea, issued on September 20, 2008. On December 01, 2008, she reported her flight experience included 260 hours total time and 42 hours in the previous 6 months. The pilot held a second-class medical certificate; it had the limitation that she must wear corrective lenses. No personal logbooks were located for the pilot. AIRCRAFT INFORMATION The airplane was a 1957 four-seat, high-wing, fixed-gear Cessna 172 airplane, serial number 36134. It was powered by a TCM O-300-D-3, serial number 24878-D-1-D 145-horsepower engine. Aircraft logbooks were not available for review to the investigative team; the Hobbs hour-meter observed at the accident site indicated 2,733 hours. METEOROLOGICAL INFORMATION An Aviation Routine Weather Report (METAR) for the Bryce Canyon Airport (BCE), Bryce Canyon, Utah, at 1553: was wind from 260 degrees at 10 knots; clear skies; visibility 10 miles; temperature was 55 degrees Fahrenheit; dew point was 30 degrees Fahrenheit; altimeter setting was 30.31 inches of mercury. BCE was about 15 nautical miles from the accident site on a southwesterly heading. Relevant meteorological data was used to calculate the density altitude; 11,178 feet. WRECKAGE AND IMPACT INFORMATION Garfield County Sheriff's Department was notified of the Search and Rescue efforts at 0636 on October 9, 2010. The accident site was located at 0832 by Classic Lifeguard Aeromedical Services; they were aided to the accident site by the emergency locator transmitter (ELT). According to the deputy, the left yoke was broken, and the right yoke had to be cut to facilitate removal of the right seat passenger. Two inspectors from the Federal Aviation Administration (FAA) and a representative from Cessna Aircraft Company accompanied the National Transportation Safety Board (NTSB) investigator-in-charge (IIC) to the accident site on October 14, 2010. The accident site was located in the South Fork of Deep Creek in the Mount Dutton range on a heading of 180 degrees, and an elevation of 9,600 feet. The airplane came to rest in a copse of trees, and remained intact in a nose down attitude. The airplane remained upright on an 8 percent grade with the right wing in a raised position. The airplane was located toward the base of one of the mountains, facing perpendicular to the relative terrain. The empennage section was crushed and folded to the left. Both wings showed uniform crush damage the length of the wing from the leading to trailing edge. The horizontal stabilizer also had uniform crush damage from the leading to trailing edge. There was no damage to the rudder. All three landing gear remained attached to the fuselage with the nose landing gear folded aft under the cabin section. The engine and propeller also remained attached to the airframe. The engine was pushed back into the cockpit. On scene, one propeller blade appeared relatively undamaged; the other propeller blade was bent aft about 12 inches from the hub with ground impact damage. An Aspen tree about 6 inches in diameter, in the flight path of the accident airplane, was observed cut and in the main wreckage. The cut was angular and measured about 14 inches in length. Recovery personnel found ½ gallon of fuel in the right fuel tank and 1 gallon of fuel in the left fuel tank. To facilitate recovery efforts, the engine and both wings were disconnected by recovery personnel. MEDICAL AND PATHOLOGICAL INFORMATION An autopsy was performed on the pilot on October 10, 2010, by the State of Utah, Department of Health, Office of the Medical Examiner, Salt Lake City, Utah. The FAA's Civil Aerospace Medical Institute performed forensic toxicology on specimens from the pilot with no results for carbon monoxide, cyanide, volatiles, and tested drugs. TEST AND RESEARCH The airframe and engine were examined on October 12, 2010, at Air Transport, Phoenix, Arizona, under the auspices of the NTSB IIC. Representatives from Cessna Aircraft Company and Continental Motors, Inc., (CMI) were present. There were no mechanical problems that were noted with the airframe. With the exception of the unbraided carburetor fuel inlet line, there were no mechanical anomalies identified in the engine that would have precluded normal operation. Flight control continuity was established to all control surfaces during the airframe examination. Visual examination of the engine revealed a hole in the oil sump case, with no other large holes observed. The engine was freely rotated by hand with no binding. The magnetos remained attached to the engine and the ignition leads had impact damage. During manual rotation of the crankshaft spark was visible at a couple of ignition lead ends from each magneto. The lower spark plugs were removed from the cylinders. The spark plug electrodes had normal signatures when compared to a Champion AV-27 chart. The number 2, 4, and 6 lower spark plugs were saturated with an oil residue. The remaining spark plug electrodes had gray deposits. The fuel inlet line had frayed braided material and was retained by the NTSB for further inspection. Subsequent testing by the NTSB's material laboratory revealed no leaks in the fuel inlet line. Detailed reports for the airframe and engine examination, as well as, the examination of the fuel inlet line are attached to the public docket for this report.

Probable Cause and Findings

The pilot's decision to conduct a low-level flight into a canyon in windy conditions at a high density altitude, which resulted in a collision with trees and terrain.

 

Source: NTSB Aviation Accident Database

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