CEN09LA605

A loss of engine power during initial climb due to fuel starvation as a result of the pilot's selection of an empty or nearly empty main tank for takeoff.

The pilot reported that, during his preflight inspection, he verified the fuel quantity and its distribution in the airplane's four fuel tanks. He noted that both inboard (main) fuel tanks were essentially empty and that both outboard (tip) tanks were almost full. He stated that he performed the accident takeoff using fuel from the left tip tank. Before takeoff, he verified that no anomalies existed with the engine operation during the engine check and when he applied power for takeoff. The pilot performed a short-field takeoff with 20 degrees of flaps. The pilot stated that, as the airplane approached the departure end of the runway, the engine experienced a "quick loss of power," which was shortly followed by a sustained loss of power. The pilot immediately performed a forced landing in a parking lot just north of the departure threshold. During the forced landing, the airplane impacted a shopping cart corral and a tree and then slid down an embankment. The right wing tip and tank were sheared off during impact, and a postimpact ground fire ensued at the sheared right wing tip. Postaccident examination of the airplane revealed that the left tip tank contained 4.5 gallons of fuel, about 1/4 of its 17-gallon capacity. (The pilot stated in a postaccident interview that the left tip tank contained 1/2 to 3/4 of its total capacity.) The left main tank contained about 0.6 gallons of fuel. The right main tank did not contain any fuel; however, the fuel drain for that tank was separated from the tank during impact. No fuel was observed leaking from the right main tank, nor was there an odor of leaking fuel. The right tip tank was destroyed by impact damage and the subsequent fire. The cockpit fuel selector was found positioned on the left tip tank. During a postaccident interview with a Federal Aviation Administration inspector, the pilot stated that, after the loss of engine power, he reached for the fuel selector but was unsure of what he did because his attention was diverted by the stall warning light. An operational engine test run revealed no anomalies. The pilot stated that he believed the loss of engine power during initial climb was likely due to fuel starvation, as a result of fuel sloshing in the left tip tank during rotation and initial climb. However, calculations, testing, and operational history showed that the left tip tank would not unport and experience fuel starvation leading to loss of engine power if it contained 4.5 gallons of fuel unless maneuvering during a turning takeoff was extreme. The accident airplane did not experience extreme maneuvers during or immediately after takeoff. Global positioning system (GPS) data downloaded from the pilot's handheld receiver showed that ground maneuvering for the accident takeoff was routine and did not achieve the lateral accelerations necessary to disrupt fuel flow from the left tip tank. Thus, a takeoff using the left tip tank containing 4.5 gallons of fuel would not result in fuel starvation and, ultimately, loss of engine power. Additional testing showed that if a fuel tank was depleted of its useable fuel, the engine would continue to run at takeoff power for an additional 35 to 40 seconds. GPS data for the accident flight showed that the loss of engine power likely occurred 22 to 27 seconds after the takeoff roll was initiated. A takeoff on an empty or nearly empty main tank could result in fuel starvation. The accident takeoff was likely performed on an empty or nearly empty main tank.

***This report was modified on 5/3/2011 and 5/23/2011. Please see the docket for this accident for the original factual report and revision history.*** HISTORY OF FLIGHT On September 24, 2009, about 2044 eastern daylight time, a Piper PA-32-260 (Cherokee Six), N4864S, was substantially damaged when it impacted terrain following a loss of engine power shortly after takeoff from Oakland/Troy Airport (KVLL), Troy, Michigan. The pilot sustained minor injuries. The flight was registered to Galt Zone, LLC, and operated by a private pilot under the provisions of 14 Code of Federal Regulations Part 91. Night visual meteorological conditions prevailed for the flight, which operated without a flight plan. The flight was originating at the time of the accident and was destined for Hillsdale Municipal Airport, Hillsdale, Michigan. The pilot reported that he performed a preflight inspection of the airplane, during which he verified the fuel quantity and its distribution between the fuel tanks. He noted that the right and left inboard (main) tanks were nearly empty and that both outboard (tip) tanks were almost full. He stated that he had flown earlier in the day and that his last landing was completed using fuel from the left tip tank. The pilot reported that he did not reposition the fuel selector before the accident flight, and, as such, performed the takeoff using fuel from the left tip tank. The pilot stated that he did not observe any anomalies with the engine operation during his pre-takeoff engine checks. After the engine checks, he positioned the airplane to the approach end of runway 9 (3,549 feet by 60 feet, dry asphalt) and configured for a short-field takeoff with 20 degrees of flaps. Before starting the takeoff roll, the pilot established takeoff engine power and reconfirmed that there were no issues with engine operation. Shortly after liftoff, as the airplane approached the departure end of the runway, the engine experienced a "quick loss of power," which was shortly followed by a total loss of engine power. The pilot noted that the airplane was too low to perform any emergency checklist items. He stated that, after seeing the stall light flicker momentarily, he focused exclusively on performing a forced landing in a parking lot located immediately north of the departure threshold. During the forced landing, the airplane impacted a shopping cart corral and a tree before sliding down an embankment into another parking lot and grassy area. A postimpact ground fire broke out at the right wingtip, which was quickly extinguished by first responders and the local fire department. A witness reported hearing the airplane's engine momentarily "stall" after takeoff but then resume operation for a short period of time before it experienced a complete loss of power. Several witnesses saw the accident airplane impact a shopping cart corral and then descend an embankment into another parking lot and grassy area. The witnesses further noted that the pilot had already extracted himself from the airplane upon their arrival and that he did not appear to be seriously injured. WRECKAGE AND IMPACT INFORMATION After the accident, the pilot and the airport manager visually inspected the fuel tanks at the accident site. Both main tanks were visibly empty. The right tip tank had been destroyed during the impact and fire and contained no recoverable fuel. The left tip tank appeared to be "full of fuel," according to the pilot. A lieutenant with the local fire department reported that he did not observe any fuel leaking from the airplane and that there was no evidence of a fuel spill at the accident site. The airplane was subsequently recovered to a hangar at KVLL for storage and further examination. The hangar was locked, and the airport manager limited access to the hangar. He indicated that the FAA would define who would have access while the wreckage was in their custody (for example, FAA, NTSB, and possibly insurance representatives or the owner). On September 28, 2009, FAA inspectors examined the accident airplane at KVLL. In the hangar, the airplane was resting on its fractured right wing and engine because the right main and nose landing gear had collapsed during the accident. In this right-wing-low, nose-low attitude, a visual inspection of the left tip tank showed that the tank appeared to contain between 1/2 and 3/4 of its total 17-gallon capacity. The left main tank contained no visible fuel. The right main tank was void of any visible fuel, but a damaged fuel drain port compromised the tank's integrity. The right tip tank was destroyed and contained no fuel. The cockpit fuel selector was observed positioned on the left tip tank. On October 6, 2009, FAA inspectors reexamined the accident airplane and conducted an operational engine test run at the NTSB's request. The airplane was lifted to a slightly right-wing-down, near-level pitch attitude for the engine test run. There were no observed fuel leaks when the fuel system was pressurized with the electric fuel pump and using the left tip tank as the fuel source. After an uneventful startup, the engine was run at various engine speeds as the engine throttle was manipulated in the cockpit. Investigators did not note any engine system anomalies on the cockpit engine gauges during the operational test run. According to data downloaded from the accident airplane's engine monitoring system, the engine test run took about 1 minute 17 seconds. The left main tank was drained at the fuel drain port and contained about 1 cup of fuel. The wreckage was released by the FAA but remained in the locked hangar with limited access controlled by the airport manager. On October 26, 2009, an NTSB investigator and two FAA airworthiness inspectors revisited the hangar. The airplane was still in the postaccident attitude. The investigators observed that the left tip tank appeared to be generally 1/2 to 3/4 full. The NTSB investigator had the airplane leveled and then observed that the left tip tank appeared to be generally 1/4 to 1/2 full. There was no loss of fuel between the two observations of "1/2 to 3/4 tank" and "1/4 to 1/2 tank," and there was no evidence of a fuel leak at the accident site or in the hangar where the airplane was stored. The left main and left tip tanks were drained using the airplane's electric fuel pump, and the fuel was collected from the carburetor inlet fuel line. The left main tank contained about 75 fluid ounces (0.6 gallons) of fuel. The left tip tank contained about 4.5 gallons of fuel. (All of the recovered fuel was blue in color, consistent with 100 low lead aviation fuel, and did not contain any water or particulate contamination.) The right main tank was reconfirmed empty of any fuel. The left tip tank was removed, and the 4.5 gallons of fuel previously recovered was returned to the tank. The fuel outlet port was located near the aft, inboard corner of the fuel tank. The fuel tank was rotated about the longitudinal and lateral axes to determine if the position of the tank's outlet port could allow air to enter the outlet fuel line. With 4.5 gallons of fuel in the tank, the tank was rotated 7 degrees to the right to align the tank with the wing's dihedral of 7 degrees. Starting at the 7-degree attitude, the tank was rotated 20.5 degrees to the left until the tank's fuel outlet port became uncovered. The static test was not representative of an airplane that was banked 20.5 degrees while in coordinated flight; however, it provided a measure of the lateral acceleration necessary in uncoordinated flight or a turning takeoff to unport the tank. The position of the fuel outlet did not allow air to enter the outflow line when positioned at positive pitch angles or in a right-wing-low attitude. Above the fuel selector assembly was a black placard with white lettering, part number 69192, which stated the following: "All Weight In Excess of 3112 Pounds Must Be Fuel Weight O