Aviation Accident Summaries

Aviation Accident Summary DEN03FA028

Steamboat Spgs, CO, USA

Aircraft #1

N7989C

Piper PA-32-300

Analysis

The pilot departed with three passengers and three dogs, but only two seats. The airplane had been reconfigured (STC SA00352DE) for parachute jumping operations. The STC included the stipulation that the airplane could be used only for parachutist launching operations. Also, Title 14 CFR Part 91.107, (a)(3), states that each occupant of a civil aircraft must be provided with an approved seat [the fatally injured passenger was not] with seat belt, for movement on the surface, takeoff, and landing operations. The pilot proceeded to fly up a heavily forested mountain valley with a 14 to 18 knot tail wind (increasing ground speed while reducing climb performance). The airplane's center of gravity was calculated to be 2.33 inches aft of allowable limitations. Due to insufficient altitude, the airplane impacted tree covered terrain with approximately 4 feet of snow at 9,527 feet (10,200 feet density altitude). One occupant was trapped under aircraft debris for 4 to 5 hours; she died shortly after reaching the hospital. An examination of the airplane revealed no anomalies.

Factual Information

HISTORY OF FLIGHT On December 29, 2002, at approximately 1300 mountain standard time, a Piper PA-32-300, N7989C, was destroyed when it impacted terrain while maneuvering near Steamboat Springs, Colorado. The commercial pilot and one passenger were seriously injured, another passenger received minor injuries; however, one passenger was fatally injured. The airplane was being operated under Title 14 CFR Part 91. Visual meteorological conditions prevailed for the personal, cross-country flight that originated from Bob Adams Field (SBS) Steamboat Springs, Colorado, approximately 20 minutes before the accident. No flight plan had been filed, but the pilot said he was en route to Canon City, Colorado. The pilot said he had flown his three passengers and three dogs from Canon City, to Steamboat Springs, for Christmas celebrations. He said that on Thursday, December 26, he departed Steamboat Springs, on a solo flight back to Canon City, to fly parachutists up for jumps. He said that he flew the same departure path up Harrison Creek to cross Rabbit Ears Pass (elevation 10,007 feet). This flight was uneventful. On Saturday, he returned to Steamboat Springs to fly his passengers and dogs back to Canon City on the following day. The pilot said he departed Steamboat Springs, at approximately 1230, on runway 32. He said that he headed south towards Rabbit Ears Pass, and was climbing to approximately 10,700 feet. He said that while flying up Harrison Creek, he encountered a "wind sheer or downdrafts," and the airplane would not clear the mountainous terrain. The pilot said he "decided to put the aircraft down in terrain with trees." At 1304, a "9-1-1" call was made to the Routt County Sheriff’s dispatch office by one of the passengers, reporting that the airplane had gone down. Search and rescue efforts were initiated, and the airplane was located at 1612 by two helicopters. Rescue workers arrived at the scene at 1700, and the pilot and three passengers were transported out by snowmobiles. The three dogs were rescued on the following day, December 30th, 2002. A pilot at Steamboat Springs airport observed an airplane, matching the description of the accident airplane, depart at approximately 1245. He stated it looked "slow with a low angle of attack. It appeared to be laboring, and turned west and downwind with very shallow turns." He said "It just didn't look right. It appeared to be having difficulty climbing." Another witness, located in the valley approximately 2 miles west of the Harrison Creek mouth, said she heard a "loud airplane, which sounded like an 18 wheel truck using its Jake brake" flying low towards Harrison Creek. She said that it was between 1230 and 1300. The fatally injured passenger had been trapped under debris of the airplane until the rescue team could cut her out. She died shortly after reaching the hospital in Steamboat Springs. PERSONNEL INFORMATION The pilot holds a commercial pilot certificate with airplane single and multiengine land, and instrument ratings. He also holds a basic ground instructor certificate, a mechanic's certificate with airframe and power plant ratings, and a senior parachute rigger's (back pack) certificate. He had accumulated 3,500 total hours of flight experience; 600 hours in make and model. The pilot also stated he had 6 hours of flight time in the airplane within the preceding 24 hours. The pilot received a second-class FAA medical certificate on October 10, 2001. The certificate required that the holder wear lenses for distant vision and possess glasses for near vision. AIRCRAFT INFORMATION The airplane (S/N 32-7640051) was a single engine, propeller-driven, fixed landing gear, two seat airplane (normally a 6-place airplane, but 4 seats had been removed to allow parachute operations). It was manufactured by Piper Aircraft Company in 1975. It was powered by a Lycoming IO-540, six cylinder, reciprocating, horizontally opposed, direct drive, air cooled, fuel injected engine, which had a maximum takeoff rating of 300 horsepower at sea level. The last annual inspection was performed on April 10, 2002. At the time of the accident, the aircraft maintenance records and tachometer indicated that the airframe had accumulated approximately 8,597 hours. The airplane's current registration, in the pilot's name, was dated February 25, 1997. On July 17, 1998, a Supplemental Type Certificate was issued for the "installation of a bolt-on departure bar assembly, handrail assembly and step assembly. This installation was approved for use in parachute jumping operations only." The most recent weight and balance measurement for the airplane was performed on January 19, 1999. "The airplane was in parachute jumper airlift configuration. Alteration was in accord with STC SA00352DE." The parachute jumper configuration involved removing the rear passenger seats and cargo door. In place of these seats was a piece of plywood with holes cutout for the seatbelts (this is where the fatally injured passenger was sitting). The airplane's manufacturer representative said that the service ceiling of this aircraft was 16,250 feet. METEOROLOGICAL INFORMATION At 1255, weather conditions at Hayden, Colorado (elevation 6,602 feet), 280 degrees 23 nautical miles (nm) from the accident site, were as follows: wind 270 degrees at 7 knots; visibility 10 statue miles (or greater); sky condition, clear; temperature 36 degrees Fahrenheit; dew point 18 degrees Fahrenheit; altimeter setting 29.69 inches. According to search and rescue pilots flying Enstrom 280C piston powered helicopters in the area of the accident, there were "no unusual sinks or down drafts," and no turbulence was reported. A landowner, standing in front of her barn (approximately 6 nm west of the accident site at the mouth of Harrison Creek), said there was a "bit of a breeze directly out of the west." She estimated the wind to be approximately 14 to 18 knots. The density altitude at the accident site (elevation 9,527 feet) was estimated to be 10,200 feet. WRECKAGE AND IMPACT INFORMATION The airplane was found in a heavily forested, steep mountainous valley (elevation 9,527 feet; N40 degrees, 20.08 minutes; W106 degrees, 41.33 minutes). The conifer trees were up to approximately 18 inches in diameter and up to approximately 75 feet in height. An approximate 150 foot long debris path (tree branches and aircraft parts) was oriented approximately 140 degrees (the Harrison Creek had a 085-265 degree orientation). The summit of Rabbit Ears Pass was 4 nm from the accident site, on a 010 degrees heading. To the north (340 degrees; 1 nm) of the accident site was Walton Peak, elevation 10,599 feet. The fuselage was found nearly upright (approximately 35 degrees right rotation), with both wings, and most of its horizontal stabilizer and elevator separated. All of the airplane's major components were accounted for at the accident site. All the flight control surfaces were identified; flight control cable continuity was not possible due to impact damage. The left wing was found inverted in trees, approximately 25 feet above the ground. The wing spar's longitudinal axis was nearly level, and the leading edge was sloping approximately 35 degrees down. At approximately the midsection of the wing, a tree (approximately 12 inches in diameter) was imbedded in the wing. This impact arc extended from the leading edge aft to the main spar area. The main fuel tank was fractured, and the main landing gear was partially separated. The inverted left wing was found on the right side of the airplane's impact energy path. The right wing was separated from the fuselage and broken into several pieces. The section forward of its main wing spar was separated. The fuel tank was fractured. The empennage displayed substantial impact damage, and only the vertical stabilizer and its rudder remained attached. The fuselage was minimally deformed, but the occupiable space for the two front seat occupants was reduced considerably. The remaining seats had been removed during the STC conversion, and only sheets of plywood could be seen in the aft section of the fuselage. Due to the deep snow and seasonal weather, the airplane wreckage was not recovered until June 10th, 2003. The engine and airframe were inspected on August 19th, 2003. Crankshaft, camshaft, and valve train continuity was verified. During the initial inspection, thumb compression was verified on all but number two cylinder. Its valve cover and rocker arms were removed, then thumb compression was obtained. One propeller blade was bent aft with some twisting, and the other blade displayed minimal back bending with significant twisting. Both blades exhibited chordwise striations and green transfer material. The yellow propeller spinner exhibited minimal damage. No preimpact engine or airframe anomalies, which might have affected the airplane's performance, were identified. MEDICAL AND PATHOLOGICAL INFORMATION Toxicology tests were not performed on the pilot due to his immediate medication and hospitalization. TESTS AND RESEARCH According to one of the passengers, there were only two seats in the airplane. He and the fatally injured passenger were sitting on a "pad of some kind." The passenger reported he had a seat belt around him. According to Title 14 CFR Part 91.107, (a)(3), "Each person on board a U.S.-registered civil aircraft must occupy an approved seat or berth with a safety belt and, if installed, shoulder harness, properly secured about him or her during movement on the surface, takeoff, and landing." A weight and balance calculation for the flight was performed using the airplane's last weight and balance data (January 19, 1999), and the occupants and the cargo weight which was acquired from interviewing the survivors. The airplane was certified for a maximum gross weight of 3,400 pounds, and center of gravity limits of 76 to 96.33 inches aft of datum. The airplane's gross weight (with occupants and cargo) at the time of the accident was estimated to be 3,280 pounds. The center of gravity limits at this weight were 88.30 to 96.33 inches. The calculated center of gravity of the airplane at the time of the accident was 98.66 inches, or 2.33 inches aft of the aft most limit. According to Title 14 CFR Part 91.9, (a) .....no person may operate a civil aircraft without complying with the operating limitations specified in the approved Airplane or Rotorcraft Flight Manual, markings, and placards....." A 3-D topographical study of Harrison Creek, by the Investigator-In-Charge, revealed a perpendicular ridge, orientated approximately 175 degrees jutting into Harrison Creek. The valley makes a semicircular diversion to the south, right at the impact area. The airplane was found on this southerly protruding ridge. The Investigator-In-Charge determined that the 14 to 18 knot wind that was reported by the witness at the mouth of Harrison Creek, would have been blowing right up the creek. This would have made any airplane's ground speed just that much faster, and their rate of climb per mile would be correspondingly less. ADDITIONAL DATA The airplane, including all components and logbooks, was released to a representative of the owner's insurance company on January 18, 2003.

Probable Cause and Findings

the pilot's inadequate in-flight planning/decision making resulting in insufficient altitude to fly over the mountain, and the subsequent inadvertent stall/mush into tree covered mountainous terrain. Contributing factors were the tail wind and high density altitude weather conditions, the airplane's aft center of gravity condition exceeding limitations, and the improper use of the airplane by the pilot [STC limitation to haul parachutist only; two passengers flying without seats].

 

Source: NTSB Aviation Accident Database

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