Aviation Accident Summaries

Aviation Accident Summary SEA93FA214

ELLENSBURG, WA, USA

Aircraft #1

N172LS

CESSNA 172N

Analysis

WHILE ATTEMPTING TO SCOUT HUNTING AREAS AT A LOCATION WHERE THE PILOT PLANNED TO HUNT ELK DURING THE UPCOMING WEEK, THE AIRCRAFT WAS BEING MANEUVERED AT LOW-LEVEL IN-AND-AROUND A CANYON ON THE WESTERN EDGE OF AN ELK PRESERVE. WHILE THE PILOT AND HIS TWO PASSENGERS WERE MAKING OBSERVATIONS OF THE TERRAIN THEY HOPED TO HUNT, THE PILOT'S ATTENTION WAS DIVERTED FROM THE TASK OF FLYING THE AIRCRAFT. HE ALLOWED HIS AIRSPEED TO DETERIORATE TO A POINT WHERE THE AIRCRAFT STALLED, AND THE PILOT WAS UNABLE TO RECOVER BEFORE THE AIRCRAFT SPUN INTO THE TERRAIN.

Factual Information

HISTORY OF FLIGHT On September 30, 1993, approximately 1800 Pacific daylight time (PDT), a Cessna 172N, N172LS, registered to the Whidbey Island Navy Flying Club, impacted the terrain while maneuvering in Coleman Canyon, approximately 15 miles north of Ellensburg, Washington. The private pilot and his two passengers received fatal injuries, and the aircraft was destroyed. The personal pleasure flight, which was being conducted under 14 CFR 91, had departed Bowers Field, Ellensburg, Washington about 1745. The pilot, who had filed a VFR flight plan to Whidbey Island Naval Air Station, was in visual meteorological conditions at the time of the accident. On the first leg of this flight, the pilot had departed Whidbey Island Naval Air Station at about 1430 PDT and, according to the time/date block of a video tape found in the wreckage, arrived in Ellensburg at 1625. While at Ellensburg, the aircraft was fueled with 12.5 gallons of aviation fuel at about 1650. Then at 1655, the pilot called Seattle Flight Service, received an abbreviated weather briefing, and advised them that he planned to depart Ellensburg at 1800. The pilot departed Ellensburg at 1745 and opened his VFR flight plan with Seattle Flight Service at 1747. The video tape that was found in the wreckage showed that during both the flight to Ellensburg and the return flight to Whidbey Island, the pilot spent time maneuvering the aircraft at low level in and around Coleman Canyon. During these portions of the video, the cockpit conversation centered on elk and deer hunting in the area. About one minute prior to the end of the tape, which occurred at 1754, the aircraft was flying almost directly over the location where it ultimately impacted. According to evidence observed on the recovered video tape, at that time the aircraft was at an altitude that put it level with the top of a ridge located about one-half mile northeast of the accident site. This ridge was approximately 500 feet higher than the point of impact. The video tape did not appear to record any portion of the crash sequence. According to the Kittitas County Sheriff, the aircraft impacted the terrain at the west edge of an elk preserve in an area where the elk season would be opening four days after the crash. He also said that all three occupants possessed elk hunting licenses for the upcoming season. In addition, a representative of the NAS Whidbey Island Flying Safety Office said that prior to the flight, the pilot had indicated a portion of the flight would include observation of possible hunting locations in the Ellensburg area. Officials at Whidbey Island Naval Air Station also said that the pilot had said that he hoped to hunt the area soon after the season opened. WRECKAGE AND IMPACT INFORMATION The aircraft impacted the terrain at 5,280 feet above sea level (ASL) at geographic coordinates 120 degrees, 22 minutes, 16 seconds west and 47 degrees, 12 minutes, 31 seconds north. The impact site was located on gently sloping grassy terrain, which was sparsely populated by small groupings of coniferous trees. The entire airframe was intact, and the fuselage was laying on a magnetic heading of 190 degrees. There were no other ground impact marks other than those at the point which the aircraft was located. The engine was embedded in the soft soil at about a 35 to 45 degree nose down attitude and about 25 degrees left side down, and the aft portion of the fuselage was pointing upward at this same angle. Both wings showed direct rearward crushing along their entire length, and the outboard four feet of the left wing was crushed backwards at about a 45 degree angle to the spar. Both wings were still attached to the fuselage by their lift struts, and the fuselage skin from the engine compartment to about two feet aft of the cabin was crushed and buckled. According to the Sheriff's Department the occupants and their equipment had been thrown forward into the instrument panel. The outboard one-half of both propeller blades showed a considerable amount of leading edge damage and chord-wise scarring, and both blades showed longitudinal twisting. The bolts that hold the propeller to the crankshaft were bent in a direction opposite the rotation of the engine, and the spacer between the propeller and the crankshaft had fractured. Functional continuity was established for all flight control surfaces, and mechanical continuity was established between the crankshaft, pistons, camshaft, accessory gearing, pushrods, rockers and valves. Fuel was present in the carburetor, and there was no evidence of oil contamination or starvation. No unusual build-ups or contamination was found on the spark plugs. No pre- impact engine anomalies or malfunctions were detected. ADDITIONAL DATA AND INFORMATION An autopsy report issued by Western Laboratories, Inc., of Yakima, Washington stated that "No evidence of pre-mortem disease or injury sufficient to explain loss of aircraft control..." was found. According to the FAA Forensic Toxicology Report, no Carboxyhemoglobin, Cyanide, Ethanol, or drugs were found in the blood or vitreous fluids of the pilot. On October 2, 1993, the aircraft was released at the scene to U.S.A.I.G. Claims Service, a representative of the owner.

Probable Cause and Findings

THE PILOT'S FAILURE TO MAINTAIN AN AIRSPEED ABOVE STALLING SPEED (VS), AND HIS INADEQUATE REMEDIAL ACTION. FACTORS INCLUDE THE PILOT'S DIVERTED ATTENTION, AND AN INADVERTENT STALL/SPIN.

 

Source: NTSB Aviation Accident Database

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