Aviation Accident Summaries

Aviation Accident Summary ANC06FA080

Cooper Landing, AK, USA

Aircraft #1

N7658H

Piper PA-12

Analysis

The private certificated pilot departed with a passenger in a float-equipped airplane for the purpose of dropping food packages to a group of hikers at a remote cabin. After arrival in the area, the pilot performed two low-level passes. On the third pass, the passenger, in the rear seat of the airplane, began dropping packages. The airplane then made a turn, and flew between the cabin and the side of a mountain slope, located north of the cabin, on what appeared to the be the fourth pass. As the airplane came by the cabin, witnesses saw the left wing and nose come up. The airplane then turned 180 degrees to the right, and descended to the ground in a nose-down attitude. The airplane collided with the ground in a near-vertical attitude. Members of the group cared for the pilot and passenger, and one member departed the cabin on-foot to notify law enforcement personnel. Rescue personnel responded and transported the passenger to a hospital. Examination of the airplane did not disclose any preimpact mechanical malfunction.

Factual Information

HISTORY OF FLIGHT On June 27, 2006, about 1730 Alaska daylight time, a float-equipped Piper PA-12 airplane, N7658H, sustained substantial damage when it collided with the ground following a loss of control while maneuvering over a remote cabin, about 8 miles north of Cooper Landing, Alaska. The airplane was being operated as a visual flight rules (VFR) cross-country personal flight under Title 14, CFR Part 91, when the accident occurred. The airplane was operated by the pilot. The private certificated pilot received fatal injuries, and the sole passenger received serious injuries. Visual meteorological conditions prevailed, and a VFR flight plan was filed from Anchorage, Alaska, to the area of the cabin, with a return to Anchorage. The flight originated about 1700 from the Lake Hood Seaplane Base, Anchorage. Alaska State Trooper personnel reported that about 15 members of an Anchorage area church were on an annual camping/hiking trip along the Resurrection Trail in the Kenai Mountains. The group had arrived at a public-use cabin at the trail junction of the Resurrection and Devil's Pass trails. The annual trip included an aerial delivery of food, and the accident pilot was engaged in dropping food packages to the group at the cabin. The passenger, seated in the rear seat of the airplane, was engaged in the actual dispersal of the packages. Witnesses indicated that when the airplane arrived in the area, the pilot performed a low-level pass, in a down-valley direction, about 75 yards from the cabin. No food drops were performed at that time. A second, up-valley pass was performed, but no food drops were conducted. On the pilot's third, down-valley pass, multiple food packages were dropped close to the cabin. The airplane then made a turn and proceeded up-valley, between the cabin and the side of a mountain slope, located north of the cabin, on what appeared to the be the fourth pass. As the airplane came by the cabin area, witnesses saw the left wing and nose come up. The airplane then turned 180 degrees to the right and descended to the ground in a nose-down attitude. The airplane collided with the ground in a near-vertical attitude. Members of the group organized emergency care for the pilot and passenger. An adult member of the group departed the cabin on-foot, and eventually notified Alaska State Trooper personnel of the accident about 1949. Rescue personnel responded to the scene, and transported the passenger to a hospital in Anchorage. PERSONNEL INFORMATION The pilot held a private pilot certificate with airplane single-engine land, and airplane single-engine sea ratings. His most recent second-class medical certificate was issued December 19, 2003, and contained no limitations. According to the pilot's logbook, his total aeronautical experience consisted of about 135 hours, of which 62 hours were accrued in the accident airplane make and model. In the preceding 90 and 30 days prior to the accident, the logbook lists a total of zero, and 2 hours respectively. AIRCRAFT INFORMATION The airplane had accumulated a total time in service of 4,268 hours. Examination of the maintenance records revealed that the most recent annual inspection of the airframe and engine was accomplished on July 15, 2005, 41.5 hours before the accident. The engine had accrued a total time in service of 4,344 hours. The maintenance records note that a major overhaul was accomplished on August 12, 1994, 753 hours before the accident. METEOROLOGICAL INFORMATION The closest official weather observation station is Seward, Alaska, which is located 35 nautical miles southeast of the accident site. At 1653, an Aviation Routine Weather Report (METAR) at Seward was reporting, in part: Wind, 310 degrees (true) at 12 knots, gust to 19 knots; visibility, 10 statute miles; clouds and sky condition, clear; temperature, 70 degrees F; dew point, 43 degrees F; altimeter, 29.99 inHg. Witnesses at the accident site reported light wind conditions. COMMUNICATIONS After the airplane departed Lake Hood Seaplane Base, no further communications were received from the pilot. WRECKAGE AND IMPACT INFORMATION The National Transportation Safety Board investigator-in-charge (IIC) and a FAA inspector examined the airplane wreckage at the accident site on June 28, 2006. The accident was located about 800 feet north of a remote cabin, situated in a broad, east/west oriented mountain pass, about 2,350 feet mean sea level (msl). Rising, tundra-covered terrain, was located north of the cabin. Open and lower terrain was located south of the cabin. [All heading/bearings noted in this report are oriented using magnetic north.] All of the airplane's major components were found at the main wreckage area. The airplane collided with soft terrain in a near-vertical, nose-down attitude, and remained in that position throughout the investigation. The upper surface of the fuselage was oriented on about a 205 degree heading, and was canted to the right about 20 degrees. The right wing exhibited extensive spanwise leading edge aft crushing, and extensive aft chordwise wrinkling and folding. The aileron and flap remained attached to the wing, and the flap was retracted. The entire right wing was broken at the inboard wing attach points, and had spanwise downward displacement of the aft edge of the wing assembly. The left wing had spanwise leading edge aft crushing from the inboard end to about midspan, and had aft folding and crushing on about a 45 degree angle from midspan to the wingtip. The left aileron remained attached and had a upward bend at the outboard end. The left flap was extended about 30 degrees. Both lift struts remained attached to their respective wing and fuselage attach points. The left float remained attached to the fuselage at its rear attach point, and was in a near vertical attitude. The front section of the float was extensively crushed aft and bent upward. The right float was broken from its fuselage attach points, and was lying on the ground adjacent to the rear of the fuselage and left float, almost parallel to the wings, with the nose pointed toward the right wingtip. The front section of the right float was extensively crushed aft and bent upward. The empennage was undamaged. The elevator trim position appeared mid-range. Several food boxes were located around the wreckage. The fuel selectors for the left and right wing fuel tanks were in the "on" position. The rear seat throttle position was about mid-range. Blue-colored liquid having the smell and appearance of fuel was found in the left fuel tank. The right wing fuel tank did not contain fuel, but the fuel tank and/or fuel lines were damaged. The flight control surfaces remained connected to their respective attach points, and flight control system cable continuity was established to the cabin/cockpit area. The engine was partially buried in soft ground on about a 45 degree nose-down attitude, almost to the firewall. A mixture of fuel, water, and mud was at the engine impact site. One propeller blade was visible in the mud, and appeared to have a slight aft bend. The airplane was recovered by the owner, and on July 5, 2006, an external engine examination was conducted by the NTSB IIC in Anchorage. The examination revealed that the propeller was broken from the engine crankshaft flange, and the attachment bolts were sheared. One propeller blade was straight, and had leading edge gouging near the tip, torsional twisting, and chordwise scratching at the inboard end of the blade. The second blade was bent aft about 30 degrees about mid-span, and had leading edge gouging near the inboard end. The propeller spinner had aft rotational crushing and folding against the propeller hub. The engine sustained impact damage to the front portion of the engine. The crankshaft could be rotated by hand. Gear and valve train continuity, and compression in each cylinder was noted when the crankshaft was rotated. The exhaust tubes had expensive crushing and folding that produced sharp creases that were not cracked or broken along the creases. The throttle cable was attached to the carburetor linkage, and was in the full open position. The mixture cable was broken, and the mixture control was free to move. The carburetor's intake was packed with mud. The carburetor heat control cable was attached. The left magneto case was broken. The right magneto case was intact, and both magnetos produced impulse coupling activation upon hand rotation. The massive center electrode sparks plugs from the top of each cylinder were removed, and each had a gray appearance. They were wet with water, oil, and fuel. MEDICAL AND PATHOLOGICAL INFORMATION A postmortem examination of the pilot was conducted under the authority of the Alaska State Medical Examiner, 4500 South Boniface Parkway, Anchorage, Alaska, on June 28, 2006. The cause of death for the pilot was attributed to multiple traumatic injuries. A toxicological examination was conducted by the FAA's Civil Aeromedical Institute (CAMI) on July, 20, 2006, and was negative for any alcohol or drugs. ADDITIONAL INFORMATION The Safety Board did not take custody of the wreckage. No parts or components were retained by the Safety Board.

Probable Cause and Findings

The pilot's failure to maintain adequate airspeed while performing a low level pass, which resulted in an uncontrolled descent and collision with terrain. A factor contributing to the accident was an inadvertent stall.

 

Source: NTSB Aviation Accident Database

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