Fuel starvation

 - May 9, 2008, 7:22 AM

RAYTHEON KING AIR B90, WEST PALM BEACH, FLA., SEPT. 3, 1999–Eight people were killed when the King Air ran out of fuel on an IFR flight from Pontiac, Mich. to Boca Raton, Fla. The twin turboprop crashed a half mile short of West Palm Beach (Fla.) International Airport (PBI) at 0325, an alternate requested two minutes earlier. The NTSB cited contributing factors were an over-gross takeoff weight, and inadequate preflight and in-flight planning.

The flight left Pontiac Airport (PTK) at 2231 with the ATP-rated pilot in the left seat and the owner-pilot in the right seat. At 0237 the pilot made radio contact with Miami Center and received a clearance direct to Boca Raton Airport (BCT). Shortly after 0300 the controller issued the initial descent to 6,000 ft. The pilot received a handoff to Palm Beach Tower at 0314 and reported in that he was descending to 6,000 ft. At 0323 the pilot requested a deviation to PBI, which he received along with a descent to 1,500 ft. The controller told the pilot the airport was “10 to 11 o’clock at five miles” and to report the field in sight. He did and the controller cleared him for the visual to Runway 13.

At 0325:27, the pilot transmitted, “Alpha Sierra, we need, ah, we got mayday…” Seconds later a sheriff’s department helicopter pilot reported the downed aircraft and dispatched the fire department. A witnesses who saw and heard the aircraft pass over said the engines sounded like “a fluttering sound as if air passing through the propeller. I was unable to determine if the engine was running at this time. A few seconds later I heard a loud explosion…”

The PIC’s estimated flight time, based on insurance company records, was 11,562 hr TT, 11,062 hr PIC in multi-engine airplanes and 9,800 hr in turbines. An estimate for his time in make and model, provided by the pilot’s associates, was about 200 hr. Post-mortem testing of the pilot revealed no presence of drugs or alcohol.
The aircraft had nearly 9,000 hr TT and was considered airworthy at the time of departure. No mechanical anomalies were found to exist before the crash.

According to line personnel at PTK, the pilot topped off all tanks before departure. The NTSB calculated that the aircraft took off about 6 percent over mtow. With the aid of ATC transcripts, NTSB investigators estimated that the aircraft took about eight minutes longer to reach altitude than the book predicts. Using standard fuel flow tables from the King Air flight manual for a mtow aircraft, the required fuel exceeded the usable fuel, even without the extended climb scenario.

Calculations by NTSB investigators indicated that the fuel-burn rate (assuming a departure at mtow) would have required 2,649.3 lb of jet-A during the flight. The flight departed with all tanks full (2,572.8 lb usable), which was insufficient for the planned flight. The NTSB’s calculations do not consider performance degradation for operating the airplane over mtow, meaning the performance was even poorer than shown on the maximum power chart for climb and cruise. With the aircraft’s payload, only 1,851 lb of jet-A could be legally carried.

The aircraft was found with the crossfeed switch in the open position, suggesting that “the pilot was attempting to operate both engines on one fuel system.” Investigators recovered two gallons of fuel from the right nacelle tank. The fuel was free of contaminants and was determined to be jet-A.