ANC01GA075

A certificated commercial pilot, an Alaska State Trooper, departed from a remote lake in a float-equipped airplane, as the second airplane in a flight of two airplanes. When the accident airplane failed to arrive at the intended destination, the first pilot initiated an aerial search. The airplane wreckage was discovered about a quarter-mile southeast of the departure lake. The first pilot recalled having a conversation with the accident pilot concerning the use of the Cub Crafters main fuel valve installed in the accident airplane. He said that the accident pilot commented that he was not flying the airplane normally assigned to him, which had the original Piper main fuel tank selector valve installed. The accident pilot told the first pilot that he was unsure if the accident airplane's fuel selector valve should be operated in the BOTH position or the LEFT or RIGHT positions. The FAA approved Cub Crafters STC requires the addition of a placard, placed just above the main fuel valve, which states: "TAKE OFF AND LANDING ON BOTH ONLY." The accident airplane had the placard installed. During an on-scene inspection of the airplane wreckage, the fuel selector valve was found selected to the LEFT fuel tank setting, and the left fuel tank was empty. A review of the State of Alaska, Department of Public Safety's "aircraft manual," which outlines general operating policies and standards, disclosed that there were no provisions for differences training for the Cub Crafters fuel system.

History of flight

On June 25, 2001, about 1918 Alaska daylight time, a float-equipped Piper PA-18-150 airplane, N7050, sustained substantial damage when it collided with tundra-covered terrain about 80 miles north of King Salmon, Alaska. The airplane was being operated as a visual flight rules (VFR) cross-country government flight under Title 14, CFR Part 91, when the accident occurred. The airplane was operated by the State of Alaska, Fish and Wildlife Service. The sole occupant, an Alaska State Trooper who held a commercial pilot certificate, but limited to private privileges for single engine sea operations, was fatally injured. Visual meteorological conditions prevailed in the area of the accident, and VFR flight following procedures were in effect.

During a telephone conversation with the National Transportation Safety Board investigator-in-charge on June 25, the supervisor for the State of Alaska's aircraft section reported that the accident airplane was one of two airplanes en route to Iliamna, Alaska, after a brief stop at a remote lake. He added that both airplanes departed the remote lake, and no radio communication was received from the accident airplane after departure. When the accident airplane failed to arrive in Iliamna, the pilot of the first airplane refueled his airplane, and initiated an aerial search along the accident airplane's anticipated route of flight. The airplane wreckage was discovered about a quarter mile southeast of the departure lake.

During an interview with the National Transportation Safety Board investigator-in-charge on July 5, the pilot of the first airplane, also an Alaska State Trooper, reported that the accident pilot had arrived in Iliamna on Sunday, June 24, the day before the accident. He said that the accident flight was to serve as one of the accident pilot's orientation flights since he was unfamiliar with the Iliamna and King Salmon patrol areas. The first pilot added that soon after arriving in Iliamna, the accident pilot refueled his airplane.

The first pilot reported that on the day of the accident, the intended flight route was to depart Iliamna, fly to Igiugig, Alaska, proceed to the accident lake, and then return to Iliamna. The first pilot added that the accident lake had a remote cabin that is utilized by Fish and Wildlife Service enforcement officers during various sport fishing openings, and he wanted to acquaint the accident pilot with the cabin's location. He said that both airplanes arrived at the accident lake about 1840, and both pilots parked their airplanes on the lake, in front of the remote cabin. The pilots remained at the remote cabin for about 30 minutes, as the first pilot acquainted the accident pilot with the cabin. About 1910, both pilots boarded their respective airplanes, and prepared for the return flight to Iliamna. The first pilot said that he started his airplane's engine first, and started a slow taxi to the end of the lake, in preparation for a westerly departure. As he started his takeoff run, he noted that the accident pilot was in the process of starting his airplane's engine. The last time that the first pilot observed the accident airplane, the airplane was slowly taxiing to the end of the lake in preparation for a westerly departure.

As the first pilot flew back to Iliamna, he said that he tried to call the accident pilot on the radio, but was unable to establish radio contact. After arriving in Iliamna, he waited at the parking area for the second pilot to arrive. He said that he waited for about one hour, and then elected to retrace the accident pilot's anticipated flight path. He located the accident site, about a quarter-mile southeast of the departure lake.

Prior to the accident, the first pilot recalled having a brief conversation with the accident pilot concerning the use of the Cub Crafters main fuel valve installed in the accident airplane. He said that the accident pilot commented that he was not flying the airplane normally assigned to him, since his airplane did not have floats installed. He added that the airplane that the accident pilot normally flew had the original Piper main fuel tank selector valve installed. The accident pilot told the first pilot that he was unsure if the accident airplane's fuel selector valve should be operated in the BOTH position or the LEFT or RIGHT positions. The first pilot reported that since his airplane was equipped with the standard Piper fuel system as well, he was also unsure as to the operation of the accident airplane's fuel system.

Crew information

The pilot held a commercial pilot certificate with airplane single-engine land, airplane multiengine land, and airplane instrument ratings. The pilot held an airplane single-engine sea rating, but was limited to private privileges. He also held a commercial helicopter, and instrument helicopter ratings. The most recent second-class medical certificate was issued to the pilot on April 12, 2001, and contained the limitation that corrective lenses be worn while exercising the privileges of his airman certificate.

According to the pilot/operator report (NTSB form 6120.1/2) submitted by the supervisor of the State of Alaska's aircraft section, the pilot's total aeronautical experience consisted of about 4,250 hours, of which 630 were accrued in the accident airplane make and model. In the preceding 90 and 30 days prior to the accident, the report lists a total of 40 and 20 hours respectively. No other personal flight records were located for the accident pilot.

According to pilot records provided by the supervisor, the pilot completed his annual proficiency check ride on December 4, 2000. The check ride was accomplished in another Piper PA-18-150, N5141T, which had the original Piper fuel system and fuel selector valve installed.

Aircraft information

The airplane had accumulated a total time in service of 9,770.0 hours. Examination of the maintenance records revealed that the most recent annual inspection of the airframe and engine was accomplished on March 26, 2001, 80.9 hours before the accident.

The engine maintenance records note that the engine was installed new in the accident airplane on September 27, 1993, 1,533.3 hours before the accident.

Further examination of airframe maintenance records revealed that between January 1999, and October 1999, the accident airplane underwent an extensive airframe overhaul. During the overhaul process, a Cub Crafters, model 103700 fuel system kit was installed in accordance with an approved Federal Aviation Administration (FAA) supplemental type certificate (STC) number: SA00415SE. The Cub Crafters fuel system allows the pilot to select both fuel tanks at once, an option that is not available on the factory installations.

The original Piper PA-18 fuel system uses two 18 gallon, wing-mounted fuel tanks. The two wing tanks supply fuel to the engine via two header tanks to ensure adequate fuel flow to the carburetor during prolonged periods of uncoordinated flight. By installing the Cub Crafters model 103700 fuel system kit, the same 18-gallon fuel tanks are used, but the two header tanks are removed. In addition, the main fuel tank selector valve is replaced, or the existing fuel valve may be retrofitted and reinstalled for use with the new fuel system.

The original PA-18 main fuel tank selector valve has three positions available. If the selector is set to the LEFT tank, fuel is supplied to the engine from the left fuel tank. If the selector valve is set to the RIGHT tank, fuel is supplied to the engine from the right fuel tank. The third position is, OFF, which shuts off all fuel to the engine.

The Cub Crafters main fuel tank selector valve has four positions available. If the selector is set to the LEFT tank, fuel is supplied to the engine from the left fuel tank