Aviation Accident Summaries

Aviation Accident Summary SEA07FA119

Marion, MT, USA

Aircraft #1

N8771T

Cessna 182C

Analysis

After preflighting the airplane, adding fuel and checking the oil, the pilot radioed that he was taxiing to runway 32. Witnesses subsequently observed the airplane takeoff on runway 32, make a 180-degree turn toward the south, and then fly downwind and parallel to the runway at an altitude of between 300 and 500 feet above ground level. At approximately the end of the runway the airplane was observed making a left turn onto base leg for runway 32, followed by a steep turn to final before nosing into the ground and bursting into flames. The initial onsite examination of the airplane revealed that the engine's oil cap was not attached to the oil filler tube. A further examination revealed damage to the oil filler tube and no damage to the oil filler cap, which would indicate that the cap was not in place at the time of impact. A section of the right aileron and pieces of the airplane's windshield were examined for oil residue; no oil residue was detected on those parts. Weight and balance information for the flight indicated that the airplane was approximately 165 pounds over its maximum gross takeoff weight at the time of the accident. As a result of the engine's oil filler cap not being secured to the oil filler tube, it is reasonable to expect that an amount of oil would have escaped the engine and blown back over the pilot's windscreen, thereby obstructing his vision. The obstructed windscreen, coupled with the airplane's gross takeoff weight being exceeded, would most probably explain the pilot's loss of control while attempting to return to the runway. No pre-impact anomalies were noted with either the airframe or the engine.

Factual Information

HISTORY OF FLIGHT On May 12, 2007, about 1015 mountain daylight time, a Cessna 182C, N8771T, was substantially damaged when it collided with terrain while maneuvering for a precautionary landing at the Carson Field Airstrip (MT53), Marion, Montana. The certificated commercial pilot and four (skydiver) passengers were killed. Visual meteorological conditions prevailed at the time of the accident for the local skydiving flight, which was operated in accordance with 14 CFR Part 91. A flight plan was not filed. The flight departed MT53 about 5 minutes prior to the accident. Prior to departing on the first flight of the day a witness observed the pilot perform his preflight, which included checking the oil and fuel level. The witness then observed the pilot taxi the airplane to the fueling pit, add 25 gallons of fuel, then watched him sump both of the airplane's fuel tanks. The witness stated that after he heard the airplane take off, "I heard the plane turn around, which was not normal. I looked outside and saw the airplane flying to the south. I went back to the portable radio to talk to the pilot when another witness informed me that the airplane had crashed." The witness also revealed, relative to the pilot checking the oil, "I witnessed the pilot pull out and check the dipstick, but did not witness him removing the oil filler cap nor add any oil to the airplane." (The airplane's engine had separate orifices for adding oil and checking the oil level.) A second witness, who was sitting in the living room of a home located near the runway, reported hearing the pilot transmit over a radio, "taxiing 32 for takeoff." The witness stated that she then saw the airplane take off heading north, and a minute or so later she heard the sound of an airplane descending. The witness reported, "I looked up to see him approaching [runway 32] on his base leg, too low to make a safe turn to final. He was approaching perpendicular to the runway, just south of it, at what appeared to be about 50 to 100 feet above ground level (agl). I continued to watch him as the aircraft rocked slightly, then appeared to take a sharp left turn causing the nose to dive downward, left wing slightly dipped, and plummet to the ground." The witness stated that she did not hear any irregular airplane engine noise. Two additional witnesses reported seeing the airplane take off to the north, followed by it turning left to the south. One of the witnesses reported that the airplane was between 300 and 500 feet agl, and as it approached the [south] end of the runway, "It banked steeply left and went in." PERSONNEL INFORMATION A review of Federal Aviation Administration (FAA) records revealed that the pilot, age 28, was an instrument rated commercial pilot in airplane single-engine land aircraft. The pilot possessed a second-class medical certificate, dated October 26, 2006, with a limitation that required him to wear corrective lenses while performing the duties of a pilot. According to information provided by the operator of the skydiving company, the pilot had accumulated a total of 508.5 total flight hours; 46 hours in make and model; 27 hours in the preceding 90 days; 11 hours in the last 30 days, and no flight time in the preceding 24 hours. The pilot's most recent flight review was completed on August 5, 2006. The operator further reported that the pilot began flying for him on May 4, 2007. AIRCRAFT INFORMATION The owner of the skydiving company purchased the airplane on April 11, 1985. The airplane had accumulated a total of 7,478.5 hours at the time of the accident, with its last annual inspection completed on September 12, 2006, at a total airplane time of 7,379.2 hours. The airplane was equipped with a Teledyne Continental Motors O-470-L engine. The engine had received a major overhaul on January 26, 2001, at a tachometer (tach) time of 5,931.8 hours, and a top overhaul on July 16, 2006, at a tach time of 7,266.9 hours. The following modifications had been completed on the airplane to facilitate its role as a skydiving/jump airplane: the right control yoke and shaft were removed; all seats, except seat 1, were removed and special seatbelt brackets were installed; the right door was changed to open upward and a jump step was added to the right main gear leg. An FAA Form 337 Major Repair and Alteration, dated May 8, 2005, indicates Supplemental Type Certificates (STCs) SA694GL and SA693GL were installed on the airplane. These STCs allow for the use of automotive gasoline. METEOROLOGICAL INFORMATION At 0955, the weather reporting facility located at the Glacier Park International Airport (GPI), Kalispell, Montana, which is 31 nautical miles northeast of the accident site, reported wind 030 degrees at 7 knots, visibility 10 statute miles, sky clear, temperature 16 degrees C, dew point 5 degrees C, and an altimeter setting of 29.91 inches of Mercury. WRECKAGE AND IMPACT INFORMATION The airplane came to rest in a dry, level field at an elevation of 3,472 feet mean sea level (msl), at a measured distance of 345 feet south of the approach end of runway 32. An examination of the wreckage revealed that the empennage was intact from the baggage compartment's aft bulkhead to the end of the tailcone. The cabin and cockpit areas had both been consumed by post-impact fire from the firewall aft to the tail section. The outboard half of the left wing was found compressed and lying in front of the left horizontal stabilizer. The right wing was observed lying flat on the ground and was partially consumed by post-impact fire. Flight control continuity was confirmed for the primary flight controls. Flap control cable continuity was established, with the manual flap control handle observed separated from its mounting points; the position of the flaps could not be determined. The jackscrew measurement indicated that the horizontal stabilizer trim was set to the takeoff position. The fuel selector valve was found in the BOTH position, with the remainder of the fuel system consumed in the post-impact fire. The airplane's single seat was not located in the wreckage. One latched lap belt was found in the wreckage. No other lap belts were located. An onsite examination of the engine revealed that it had remained attached to portions of the firewall. Further examination revealed that the oil filler cap was detached from the oil filler tube and observed hanging by its chain between cylinders #4 and #6. The oil filler tube was partially separated from the engine's crankcase and exhibited impact damage to its top. The oil filler cap was undamaged with its securing tangs intact. MEDICAL AND PATHOLOGICAL INFORMATION An autopsy of the pilot was conducted at the Montana Division of Forensic Science, Missoula, Montana, on May 14, 2007. The cause of death was attributed to " blunt force injuries." FAA toxicological test results were negative for carbon monoxide, cyanide, and ethanol. TESTS AND RESEARCH After being removed from the accident site to a secured hangar, a detailed examination of the airframe and engine was conducted. The examination revealed that no anomalies existed with either the airframe or the engine, which would have precluded normal operation. The airplane's oil filler tube, oil cap, a section of the right aileron and four pieces of the windshield were sent to the NTSB Materials Laboratory in Washington, D.C. for examination. The oil filler tube and oil cap would be examined for proper operation and damage assessment, while the aileron and windshield pieces would be examined for possible oil residue. An NTSB Materials Research Engineer reported that the oil filler tube was bent at an angle of 10 to 15 degrees and that there was an indentation of approximately 0.5 inches long near its mouth on the tension side of the bend. The mouth was deformed inward at the position of the indentation, and the minimum width of the opening was measured to be approximately 1.95 inches. The oil filler cap was undamaged, except for the rubber gasket, which exhibited some deformation, bubbles and pockmarks on the surface consistent with high temperatures. The outer diameter of the internal flange with the locking tangs was measured to be 1.20 inches. It was not possible to insert the flange of the cap into the deformed mouth of the oil filler tube. A visual and tactile examination of the aileron and pieces of the windshield found no evidence of oil residue. ADDITIONAL INFORMATION WEIGHT AND BALANCE A weight and balance calculation indicated that the airplane was approximately 165 pounds over its maximum gross weight, and the center of gravity was at or near the aft limit at the time of the accident.

Probable Cause and Findings

The pilot’s failure to maintain aircraft control while maneuvering to reverse direction. Factors included the airplane exceeding its maximum gross takeoff weight, the improper preflight by the pilot by not securing an oil cap, the low altitude, and an obstructed windshield.

 

Source: NTSB Aviation Accident Database

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