Aviation Accident Summaries

Aviation Accident Summary SEA96FA137

PRAY, MT, USA

Aircraft #1

N7529J

Piper PA-28R-180

Analysis

The pilot initiated a landing on a 6,000 by 30 foot paved airstrip. Both edges of the airstrip dropped off into drainage ditches immediately beyond the edges of the pavement. There was a crosswind from the right, which was variable and gusty. The density altitude was over 7,300 feet. Witnesses stated the aircraft touched down two to three times during the landing, and the pilot appeared to have difficulty maintaining a straight path on the pavement. A photo showed the aircraft's right main gear at the edge of the pavement as it approached the end of the landing area. The witnesses said that close to the end of the landing area, the aircraft became airborne again, climbed about 20 to 75 feet above ground level, and started a left turn. The aircraft's left wing then dropped, and the aircraft crashed. The airstrip had a 60 to 80 foot high ridge along its west edge for its entire length, and there was a 361 foot hill about 1/3 mile beyond the end of the airstrip with higher mountainous terrain beyond the hill. Flap system components were found in the up position at the accident site; the aircraft's flaps-up/gear-up stall speed was 71 MPH at 20 degrees bank and 79 MPH at 40 degrees bank. No preimpact mechanical failure or malfunction of the aircraft or engine was found. About 18 miles north at Livingston, MT, the 1249 mdt wind was from 220 degrees at 18 gusting 27 knots.

Factual Information

HISTORY OF FLIGHT On June 27, 1996, approximately 1233 mountain daylight time, a Piper PA-28R-180, N7529J, was destroyed in a collision with terrain following a loss of control during an aborted landing at the Chico Hot Springs Lodge airstrip near Pray, Montana. The private pilot and one passenger were fatally injured. Another passenger was seriously injured. The 14 CFR 91 flight originated at Salt Lake City International Airport, Salt Lake City, Utah. Visual meteorological conditions existed and no flight plan had been filed. The surviving passenger submitted a written statement through her attorney, in which she characterized the flight from Salt Lake as "very smooth and uneventful" before the accident. However, she stated that she had no recollection of the accident sequence beyond the point at which the airplane cleared a car which was blocking the approach end of the airstrip to vehicle traffic. She did recall the pilot referring to an airport directory before landing at the lodge, but did not recall him "asking anyone at Chico about the winds, which he usually did in the past trips there," or being given wind information by the lodge airstrip operators over the UNICOM frequency on which the lodge airstrip operates. Witnesses to the accident reported that the airplane touched down two to three times during its landing attempt. One witness reported that during one touchdown, he observed the airplane drift to the west edge of the pavement and then become airborne again. The witnesses stated that as the airplane approached the end of the landing surface, it became airborne and climbed to an altitude between 20 and 75 feet above ground level. It then began to turn left. The witnesses stated that the left bank then abruptly increased to an approximate 90-degree left wing down attitude. The airplane's nose then dropped and it impacted in a field east of the road. The airplane cartwheeled and came to rest inverted. Some witnesses reported that just before the crash, they heard the airplane's engine "gunning." One witness was taking pictures of the aircraft as it landed, from a vantage point south of the south end of the strip. This witness shot a series of four pictures (attached) of the accident aircraft during the accident sequence. The first two pictures showed the aircraft during its attempted landing. In the first picture, the aircraft was distant, just above the ground, and the south end windsock was fully extended with a 60-degree right crosswind. The second photo showed the aircraft's right main gear at the west edge of the pavement; the south end windsock was almost fully extended and showed almost a direct right crosswind. The third photo captured the instant of ground impact. It showed the aircraft striking the ground at approximately 30 degrees nose down and 90 degrees left wing down. The south end windsock in this photo was extended about half-way and showed about a 45-degree right crosswind. The final photo showed the aircraft lying inverted with its left wing broken off and a fire burning in the engine compartment. The accident occurred during the hours of daylight at approximately 45 degrees 20.4 minutes North and 110 degrees 41.7 minutes West. PERSONNEL INFORMATION The pilot had logged over half of his total time in the accident aircraft, including 25 hours in the accident aircraft in the previous 90 days. A test report for an FAA Commercial Pilot computerized knowledge examination dated March 31, 1996, was found in the pilot's personal effects in the aircraft wreckage. The pilot had scored 93 percent on the exam, with the following subject area codes listed as missed: I27 (Air Masses and Fronts), I44 (Surface Analysis Chart), H66 (Principles of Flight and Performance Characteristics), I08 (Using the Navigation Instruments), H02 (Airplanes and Engines), and H04 (Airplane Performance). Documents were also found in the pilot's personal effects indicating completion of Phase II of the FAA Pilot Proficiency Award (Wings) Program on May 29, 1995; and attendance at four FAA Wings Program safety seminars since 1992, most recently on June 24, 1995 for Phase III of the program. The surviving passenger, in her written statement, stated: "[The pilot] was, to the best of my knowledge, a well trained and competent pilot. I had no hesitation flying with him. I had total trust in [the pilot], having flown with him in difficult circumstances before, which he handled well....I had flown...to Chico Hot Springs with him on four prior occasions. Each time we flew to Chico, we would land on the same strip where the accident happened several times, so I had flown with [him] to landings on this strip about 20 times total." The pilot's logbook contained one entry documenting a previous trip to Chico Hot Springs, in June-July 1990. The pilot logged five flights and six landings at the airstrip for that trip. AIRCRAFT INFORMATION According to the Piper Cherokee Arrow Owner's Handbook, the aircraft has a main gear wheel tread (the distance between the main gear wheels) of 10 feet 6 inches. At 2,500 pounds gross weight, zero bank angle, and power off, its flaps-down/gear-down stall speed is 63 MPH, and its flaps-up/gear-up stall speed is 69 MPH. These speeds increase to 65 and 71 MPH, respectively, at 20 degrees bank; and to 72 and 79 MPH, respectively, at 40 degrees bank. According to the aircraft owner's handbook, at 7,000 feet density altitude, on a paved level dry runway, and at a gross weight of 2,500 pounds, the aircraft's landing ground roll distance is 990 feet with 40 degrees of flaps. The chart does not give landing distance data for density altitudes over 7,000 feet. The aircraft's rate of climb at 7,500 feet density altitude is given as approximately 470 feet per minute, at 2,500 pounds gross weight with gear and flaps retracted. METEOROLOGICAL INFORMATION The surviving passenger stated that the pilot told her he obtained a weather briefing before departure. She stated that she did not know "if he obtained it in person at the weather office...or by phone to a flight service station", although she said he "told us it was clear to Chico...." Winds at Livingston, Montana, 18 nautical miles north-northeast of the accident site, were reported at 220 degrees magnetic at 18 knots, gusting to 27 knots, at 1249. Witnesses to the accident also reported that strong and gusty right quartering headwinds existed at the accident site at speeds estimated up to 40 knots. In a post-accident interview with investigators, the lodge manager responsible for airstrip operations stated that such conditions existed in the area "about 50 percent of the time." Based on the temperature and altimeter setting reported in the 1249 Livingston observation, and Livingston's field elevation of 4,656 feet, Livingston density altitude was 7,356 feet. The Chico Hot Springs Lodge airstrip elevation is 5,280 feet. AERODROME AND GROUND FACILITIES The Chico Hot Springs Lodge airstrip consists of a 6,000-foot-long by 30-foot-wide section of paved public road north of the lodge complex. Investigators at the accident site measured the landing direction at 151 degrees magnetic. Before an aircraft lands at the airstrip, the road is blocked to vehicle traffic by positioning vehicles at each end of the landing area. The landing surface has a 60-to-80-foot-high ridge adjacent and parallel to the west edge of the road along its entire length. A hill rising to 5,641 feet above sea level (361 feet above the airstrip elevation) is located 1/3 statute mile beyond the south end of the landing area, with mountainous terrain rising immediately beyond the hill. Both sides of the airstrip have an abrupt drop-off of 1 to 2 feet into drainage ditches immediately beyond the pavement edges. The airstrip has a windsock at each end of the landing area. Both windsocks appeared to be functional and in good condition during the on-scene investigation. The lodge operates a UNICOM radio in a room adjacent to its reception desk and publishes procedures for airstrip arrivals. This procedure consists of contacting the lodge on the UNICOM radio before landing and waiting until lodge personnel advise the pilot on the radio that the strip has been blocked to vehicle traffic before landing. During the on-scene investigation, investigators did not observe any wind-indicating instruments near the UNICOM radio. The lodge manager responsible for airstrip operations stated that the UNICOM radio operators were reception desk personnel and were not trained in aircraft operations or aircraft radio phraseology, other than the lodge procedure for blocking the airstrip to vehicle traffic. The lodge manager also stated to investigators that the UNICOM operators did not routinely pass wind information to pilots arriving at the airstrip. The airstrip is listed in the Montana state airport directory, which is published by the Aeronautics Division of the Montana State Department of Transportation. The 1996 edition of the directory, which was the current edition at the time of the accident, showed the airstrip in a graphical depiction as being oriented northeast/southwest, rather than its actual direction of 151/331 degrees magnetic, although it identified the runway in the airstrip textual description as "32/14." The directory also gave the width of the airstrip as 35 feet rather than the actual value of 30 feet, and did not mention the presence of the high terrain either adjacent to the west edge of the airstrip or off the south end of the strip. There were no warnings in the 1996 state airport directory of potentially hazardous crosswind conditions at the airstrip. The directory also indicated "2% GRADE SOUTH TO NORTH" but did not specify whether the grade was uphill or downhill. WRECKAGE The aircraft wreckage was examined at the accident site on June 28, 1996. The examination of the wreckage revealed no evidence of pre-impact malfunction in either the airframe or engine. The aircraft was located in a field approximately 350 feet east of the south end of the airstrip. The aircraft was inverted and had come to rest on a magnetic heading of 165 degrees. Its left wing was separated and located approximately 25 feet west of the rest of the aircraft; investigators were informed that the left wing had been moved off the aircraft after the accident to allow rescue and recovery of the victims. A series of ground scars began about 150 feet west of the fuselage, with the largest scar being about 100 feet west of the fuselage. Pieces from the aircraft including windshield glass, automatic direction finder sensing antenna, landing light glass, and occupants' personal effects were located along either side of the line of ground scarring to the aircraft. The ground scar farthest from the aircraft contained red glass fragments. The engine remained attached to the aircraft but was missing its cowling; the cowling sections were located in a debris field just west of the fuselage. The engine was fire-damaged in the aft accessory and firewall area. Both propeller blades were bent and twisted (one blade was bent forward and the other displayed S-bending) and displayed chordwise scratching. The flap handle, flap control mechanism, and right flap were in the "up" position. The left wing flap was broken into a tucked position under the left wing lower surface. All three landing gear were down. Fuel was found in both tanks as well as in the engine-driven fuel pump. FIRE Witnesses reported that a fire had ignited in the engine compartment after ground impact. The fire was immediately extinguished by ground personnel using handheld fire extinguishers. MEDICAL AND PATHOLOGICAL INFORMATION An autopsy on the pilot was performed by Dr. D.C. Lehfeldt, M.D., on June 28, 1996. Toxicology testing was performed on the pilot by the FAA Civil Aeromedical Institute (CAMI), Oklahoma City, Oklahoma. The CAMI toxicology tests detected the presence of acetaminophen (trade name Tylenol), pseudophedrine (trade name Sudafed), and phenylpropanolamine (a decongestant) in the pilot. SURVIVAL ASPECTS The crash was witnessed. Personnel on the ground nearby immediately responded to the scene and called for aid. Emergency medical aid responded from Livingston; records of the response to the scene indicated that no breathing or pulse was noted in either front seat occupant on primary examination at 1309. The rear seat passenger survived, but sustained serious injuries. ADDITIONAL INFORMATION The aircraft wreckage was released to Mr. Charles E. Carstensen of the Carstensen Company, Montrose, Colorado, on February 13, 1997. Mr. Carstensen is the insurance adjuster representing the aircraft owner.

Probable Cause and Findings

the pilot's delay in initiating a go-around, and his failure to obtain and/or maintain sufficient airspeed to avoid higher terrain during the go-around, which resulted in a stall and collision with terrain. Factors relating to the accident were: the narrow landing area, variable/gusty crosswind conditions, the resultant lack of directional control during the landing, high density altitude, and mountainous/hilly terrain beyond the end of the airstrip.

 

Source: NTSB Aviation Accident Database

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