NTSB Factual Report

HISTORY OF FLIGHT

On June 13, 1996, at 1129 hours Pacific daylight time, a Piper PA-24-250, N7280P, impacted water 0.5 miles southwest of the Big Bear City, California, airport. The aircraft was destroyed and two passengers were fatally injured, with the private pilot sustaining serious injuries. Visual meteorological conditions prevailed for the personal flight which was destined for Blythe, California.

According to family members of the pilot, the flight originated earlier in the day at Blythe. Following a brief stop at Big Bear to board the two passengers, the aircraft was departing from runway 26 (5,850 feet long by 75 feet wide; elevation 6,748 feet) for the return to Blythe. The aircraft was not serviced while at Big Bear. The temperature at the time was 75 degrees Fahrenheit.

A witness, whose home is abeam the departure end of the runway and 500 feet to the south, observed the aircraft depart. The witness reported that the aircraft's departure appeared normal and the engine sounded normal until the aircraft was directly over the end of the runway, about 200 feet altitude, when the engine sound completely and abruptly ceased. The aircraft then continued west out of view.

Another witness, who was working in a nursery further west and south of the airport, reported that she noticed the aircraft because its flight path was nearer the nursery (further south) than is normal for departing aircraft and it was remarkably silent. She remarked that as she watched the aircraft continue west past the nursery, the aircraft's "chin" pitched up noticeably, after which the left wing dropped and the aircraft fell into the lake. From her position, about 200 feet east of the accident site, there was a strong smell of fuel in the minutes after the accident.

In a telephone conversation with the NTSB investigator on July 24, 1996, the pilot stated his recollection of the accident events. Before departure from Blythe he had the inboard (main) fuel tanks filled. He selected the left main tank for takeoff and flew to Big Bear on that tank. In preparation for landing he intended to switch to the right main fuel tank, but now believes that he accidentally switched to the left auxiliary tank, which contained very little fuel. After picking up his passengers at Big Bear, he took off without rechecking the fuel selector because he thought it was on the fullest (right main) tank. He recalled the engine failure after takeoff and turning left toward the south shore of the lake because his passengers could not swim. He recalled that he was analyzing the fuel selector position at the time the aircraft stalled and spun.

PERSONNEL INFORMATION

The 47-year-old pilot is a professional farmer and acquired his private pilot license in June, 1983. The last entry in his logbook was on November 3, 1995, with a total flying time of 619 hours. Partnership usage records found in the aircraft show one additional flight in the aircraft by the pilot on March 25, 1996, from Blythe to Calipatria and return in 2.1 hours. His biennial flight review was conducted September 29, 1995, and his third-class medical certificate was issued June 3, 1996. According to a family member, the pilot's only flying was done in the accident aircraft, and in the period January to October, 1995, he had flown 10.8 hours.

AIRCRAFT INFORMATION

A review of maintenance records and the aircraft recording tachometer revealed that at the time of the accident the aircraft had accumulated 5,690 hours total time. The last maintenance performed was an annual inspection on April 15, 1996, at 5,675 hours. Prior to the annual, the aircraft had been out of license for 4.5 months. At the time of the accident the engine had accumulated 1,666 hours in service since overhaul, and 987 hours since top overhaul. The pilot's brother reported flying the aircraft 2 weeks before the accident and he stated that there were no discrepancies with the aircraft at that time.

METEOROLOGICAL CONDITIONS

At 1140, the AWOS at Big Bear City Airport reported weather as: no clouds below 12,000 feet; visibility 10 miles; temperature 75 degrees; dew point 11 degrees; wind from 270 degrees at 7 knots; and altimeter setting 30.22 inHg. In remarks, the density altitude was reported as 8,900 feet.

AIRPORT INFORMATION

The Big Bear City Airport is an uncontrolled airport located in a mountain valley at the east end of Big Bear Lake at 6,748 feet elevation. There is one runway (8-26) which is 5,850 feet long and 75 feet wide. The airport is served by a unicom advisory service and AWOS-3 is available. According to airport personnel, the prevailing winds are from the west and departures are usually to the west on runway 26 over the lake.

WRECKAGE AND IMPACT INFORMATION

The accident site is 3/8 mile west-southwest of the departure end of runway 26 in the eastern wetlands portion of Big Bear Lake in an area named Baker Pond. The latitude at the site is 34 degrees, 15.75 minutes north and the longitude is 116 degrees, 52.25 minutes west. The aircraft came to rest oriented on a 280-degree magnetic bearing approximately 20 feet from the nearest shoreline in an area where the water is 3- to 4-feet deep.

The aircraft was substantially damaged in all areas except the empennage. The passenger cabin area retained it's normal volume. Rescue personnel cut open the roof of the cabin to extract the occupants.

When removed from the lake, the aircraft was intact except for the engine cowling, the left main fuel tank, and the left wing outboard of the flap/aileron juncture. Approximately 2 gallons of 100LL fuel was drained from the right wing fuel tanks when the aircraft was brought on shore. The cowling was recovered in several pieces adjacent to the main wreckage. The left wing outboard panel was severed at the flap outboard station, although the aileron remained attached by the control cables. Portions of the wing panel were not recovered from the lake due to poor underwater visibility.

The propeller remained attached to the engine and the blades were bent back approximately 45 degrees in long, smooth bends. There was leading edge damage to one blade and no torsional bends were observed. The transverse muffler was crushed against the firewall and the engine was canted 10 degrees right and 10 degrees down. The lower right-hand engine mount tube exhibited compression buckling. The carburetor was broken from the engine sump, but remained attached to the engine by the mixture and throttle cables and the fuel hoses. The throat of the carburetor was obstructed with mud.

A field inspection of the engine verified mechanical continuity, compression, valve action, and spark output of the magnetos. The ignition switch was in the "both" position and the P-lead circuits were electrically open. The spark plugs exhibited a light grey-brown appearance. The inlet air path and engine exhaust system both had crushing due to impact; however, there was no foreign matter in the inlet duct and the exhaust outlet from the muffler was clear.

The left wing leading edge was compressed back to about the 15 percent chord line. The wing spar and spar carry-through structure was skewed 10 degrees with respect to the longitudinal axis of the aircraft in the left wing aft/right wing forward direction. The aft spar attachment of the left wing had collapsed the left side wall of the cabin inward about 10 inches in the vicinity of the left rear seat. The right wing had compression damage to the leading edge within 4 feet of the fuselage and downward bending outboard.

The left main fuel tank separated from the wing and the bladder was ruptured. The right main and right auxiliary tanks remained attached with both bladders ruptured. The left auxiliary tank remained intact; however, the supply line between the tank exit and the fuselage was missing.

There was compression buckling along 6 feet of the left side of the fuselage centered near the baggage compartment. There was a tear on the opposite side of the fuselage, top to bottom, aft of the baggage door. The aft fuselage was canted approximately 10 degrees tail left with respect to the cabin.

In the cabin the throttle, propeller, mixture, and carburetor heat controls were full forward. All electrical switches were in the off position. Needles on the fuel gauges for the left main, right main, and right auxiliary tanks were trapped between 3/4 and full. The fuel gauge needle for the left auxiliary tank moved freely.

The horns on both the pilot's and copilot's controls were broken off and there were two soft indentations in the instrument panel slightly left of the straight ahead position for the pilot and right front seat passenger. At the right rear seat, the bracket which attaches the passenger seatbelt to the fuselage sidewall frame had broken in front and pulled out rivets in the rear.

The fuel tank selector was in the left auxiliary tank position. A field examination of the fuel supply system between the left auxiliary fuel tank and the engine was performed approximately 7 hours after the accident and 2 hours after the aircraft was recovered from the lake. The fuel system had been submerged while in the lake. The left auxiliary fuel tank bladder was intact and contained approximately 1 inch of water and dirt. The supply line from the bladder to the fuselage was missing. The supply line was blown through from where it enters the fuselage at the wing root to the firewall bulkhead fitting and only water and less that 1 teaspoon of fuel was present. The fuel strainer sump under the fuel selector valve was drained and revealed approximately 3 ounces of fuel and 2 ounces of water. Forward of the firewall the fuel line fittings were broken at 3 of the 4 attachments to the two auxiliary fuel pumps. The fractures exhibited a bright, uniform copper color circumferentially and the pump housings were bent where the fittings were broken off. The aluminum tube which joins the input of the two pumps together was crushed. No fuel was found in the lines forward of the firewall. The fuel line from the engine driven fuel pump to the carburetor contained approximately 1 tablespoon of water. The float chamber in the carburetor contained approximately 4 ounces of water and dirt.

The engine was disassembled and inspected at Lynn's Aircraft Engines, El Monte, California on July 23, 1996. No discrepancies were noted.

TESTS AND RESEARCH

The Piper Comanche Owner's Handbook, dated November, 1961, addresses the use of the auxiliary fuel tanks in three places. In Section II, Design Information, Fuel System, the manual states, "Use auxiliary fuel in level flight only." In Section III, Operating Instructions, both the takeoff and landing checklists require "Fuel on proper tank".

According to The New Piper Aircraft Company, the fuel selector placard was changed in 1964 to add the words "Level Flight Only" adjacent to the auxiliary tank position. The accident aircraft, built in 1961, did not have the late style placard.

ADDITIONAL INFORMATION

The aircraft wreckage was released to Arnold and Arnold, Inc., insurance adjusters for the owner, on July 23, 1996.

NTSB Probable Cause

improper preflight by the pilot, by failing to ensure that the fuel selector was positioned to an approved fuel tank with adequate fuel before takeoff; his failure to reposition the fuel selector (per emergency procedures) after the loss of engine power; and his failure to maintain adequate airspeed, which resulted in an inadvertent stall and collision with the terrain.