NTSB Factual Report

HISTORY OF FLIGHT

On August 29, 1999, at an estimated time of 1340 Alaska daylight time, a float equipped Cessna 170B airplane, N3402D, was destroyed by impact and postimpact fire after colliding with mountainous terrain, about 4.3 miles north-northeast of Cooper Landing, Alaska. The airplane was being operated as a visual flight rules (VFR) cross-country personal flight when the accident occurred. The airplane was operated by the pilot. The private certificated pilot, and the sole passenger, received fatal injuries. Visual meteorological conditions prevailed in the area. The flight originated at the Summit Lake Seaplane Base, located 7 miles northwest of Moose Pass, Alaska, about 1320.

After departure from Summit Lake, a family member reported the pilot intended to fly over glaciers near Seward, Alaska, and then return for landing at Campbell Lake, a private lake in Anchorage, Alaska. The airplane did not arrive, and was reported overdue on August 30, 1999, at 1011.

Search personnel located the wreckage at 3,100 feet msl on August 31, 1999, at 1522. Except for the floats, empennage, and a portion of one wing, the airplane was consumed by fire.

The accident occurred during the hours of daylight at longitude 60 degrees, 32.586 minutes north, and longitude 149 degrees, 43.760 minutes west.

PERSONNEL INFORMATION

The pilot held a private pilot certificate with airplane single-engine land, and single-engine sea ratings. The most recent third-class medical certificate was issued to the pilot on March 10, 1999, and contained no limitations.

No personal flight records were located for the pilot, and the aeronautical experience listed on page 3 of this report was obtained from a review of the airmen Federal Aviation Administration (FAA) records on file in the Airman and Medical Records Center located in Oklahoma City. On the pilot's application for medical certificate, dated March 10, 1999, the pilot indicated that his total aeronautical experience consisted of about 600 hours, of which 30 were accrued in the previous 6 months.

AIRCRAFT INFORMATION

The airplane and engine had an annual inspection on May 24, 1999. At that time, the airplane had accumulated a total time in service of 4,148.3 hours. The engine had accrued a total time in service of 2,257.7 hours since being installed new on February 3, 1975.

METEOROLOGICAL INFORMATION

The closest official weather observation station is Seward, Alaska, which is located 26 nautical miles southeast of the accident site. On August 29, 1999, at 1353, an automated weather observation system was reporting, in part: Wind, 150 degrees (true) at 10 knots; visibility, 10 statute miles; clear; temperature, 61 degrees F; dew point, 52 degrees F; altimeter, 29.71 inHg.

At 1335, an automated weather observation system at Soldotna, Alaska, located 38 nautical miles southwest of the accident site, was reporting in part: Wind, 280 degrees (true) at 7 knots; visibility, 10 statute miles; clear; temperature, 62 degrees F; dew point, 41 degrees F; altimeter, 29.71 inHg.

COMMUNICATIONS

No communications were received from the pilot.

WRECKAGE AND IMPACT INFORMATION

The National Transportation Safety Board investigator-in-charge (IIC) examined the airplane wreckage at the accident site on September 1, 1999. The terrain consisted of a small mountain valley oriented about east/west. The east end of the valley has rising terrain of about 15 degrees toward a "U" shaped canyon. The west end of the valley slopes downhill toward open areas of tundra and rock scree.

All of the airplane's major components were located at the main wreckage area. The airplane wreckage and the floats were found in a near vertical, nose down attitude, in a field of rocks located along the northern side of the valley. The airplane's upper surface, along the longitudinal axis, was oriented on a 105 degree heading. The outboard half of the left wing had spanwise leading edge aft crushing with more crushing evident along the lower portion of the leading edge. The wing was curled slightly upward and aft at the outboard end, and was lying on about 10 degree upsloping terrain to the left (north) of the wreckage point of rest. The left wing tip cap was separated from the wing and was resting just outboard of the end of the wing. It had scuffing and tearing of the fiberglass structure, but was not burned.

Small portions of paint chips, and windshield fragments were found on the ground, forward of the wreckage point of rest. A blackened/sooted area of rocks was noted on the ground, forward of the main cabin point of rest. The blackened area was a cone shaped pattern with the widest portion next to the main cabin area, narrowing to a point about 10 feet in front of the wreckage. Although burned, both wing lift struts remained attached to their respective wing and fuselage attach points.

Each wing fuel tank was partially consumed by fire. The inboard portion of the left wing, the cockpit and cabin area, and the right wing were destroyed by fire. The right wing had spanwise leading edge aft crushing to about the spar. The right aileron was fire damaged, and attached to the wing. It had extensive crushing and melting, molding itself to the aft side of the wing.

The right cabin door was found lying on the ground, outboard of the burned end of the right wing. It was dented at the lower front edge. The interior, and exterior sides of the door were not fire damaged. The interior of the right door window was undamaged, and not sooted.

The fuselage structure, forward of about five feet in front of the vertical stabilizer attach point, was incinerated. The remaining aft portion of the tail assembly was standing vertically, with the aft end resting on the ground, parallel to the vertical right float assembly. Fire damage was observed on the underside of the left horizontal stabilizer and elevator. Charring and blistering of the paint, and soot was observed on the left side, and underside of the empennage. The vertical stabilizer and the rudder were sooted, but undamaged. The elevator and trim tab were attached to the stabilizer.

The flight control surfaces remained connected to their respective attach points. Due to the impact, and postimpact fire damage, the flight controls could not be moved by their respective control mechanisms. The continuity of the flight control cables was established to the cabin/cockpit area. The instrument panel was destroyed by fire.

The postcrash fire incinerated the entire cabin/cockpit area. The bottom fuselage, at the upper aft float attaching fittings, was destroyed. A lift-lever release type seat belt buckle, was found in the wreckage with two shoulder harness end fittings retained on the latch end of the seat belt, and inserted into the latched buckle. The seat belt and shoulder harness webbing was destroyed by fire.

The forward tips of each float assemble were crushed and folded in an aft and upward direction, back to the forward spreader. Soot was observed emanating from each float compartment inspection cover. Soot was observed on the bottom surface of each float

The engine sustained fire and impact damage. It was resting on about a 45 degree angle to the ground. The propeller assembly separated from the engine crankshaft. One propeller blade was fractured at the outboard end. It had melting of the outboard end, trailing edge gouging, aft bending, and torsional twisting. The second blade had extensive leading edge destruction, "S" bending, torsional twisting, and aft bending of about 30 degrees. No evidence of any preimpact mechanical malfunction was discovered during the wreckage examination.

MEDICAL AND PATHOLOGICAL INFORMATION

A postmortem examination of the pilot was conducted under the authority of the Alaska State Medical Examiner, 5700 E. Tudor, Anchorage, Alaska, on September 2, 1999. The cause of death for the pilot was attributed to multiple impact injuries.

A toxicological examination was conducted by the FAA's Civil Aeromedical Institute (CAMI) on October 4, 1999, and was negative for drugs or alcohol.

FIRE

A postcrash fire incinerated most of the airplane.

WRECKAGE RELEASE

The Safety Board released the wreckage, located at accident scene, to the owner's representatives on November 23, 1999.

NTSB Probable Cause

The pilot's inadvertent stall.