N1224S

On August 17, 1997, about 1820 eastern daylight time, a Cessna 425, N1224S, operated by the Inductotherm Corp. Rancocus, New Jersey, was substantially damaged during a forced landing in Perkasie, Pennsylvania. The certificated commercial pilot was not injured. Six passengers were not injured, and one passenger received minor injuries. Visual meteorological conditions prevailed for the corporate flight which departed Niagara Falls, New York, about 1725, destined for Rancocus, New Jersey. The flight was operated on an Instrument Flight Rules (IFR) flight plan, and conducted under 14 CFR Part 91.

The pilot reported that he requested the airplane to be fueled to a total of 700 pounds per side prior to his departure from Niagara Falls, New York. When he preflighted the airplane, he noticed the fuel gauge for the right side indicated 1,060 pounds, and the fuel gauge for the left side indicated 700 pounds. The pilot stated, "...I knew this gauge [left] to be unreliable and felt positive that the 1,060 pounds showing on the right gauge was an accurate number. At this point I decided to rely on the right gauge for the entire trip...."

The pilot reported that upon arrival at Elmira, the right gauge showed 810 pounds, and upon arrival at Niagara Falls, New York, the right gauge indicated 650 pounds. Based upon the right gauge indication, the pilot cancelled his requested refueling for a total of 100 gallons (680 pounds) that had been ordered for his arrival at Niagara Falls.

The pilot departed Niagara Falls, for Rancocus, with the right fuel tank indicating 650 pounds of fuel remaining. At the top of climb, the right fuel gauge indicated 450 pounds of fuel remaining. In the vicinity of Allentown, Pennsylvania, while in a descent, both low fuel quantity lights illuminated. At that point, the right fuel gauge indicated 390 pounds of fuel remaining. The pilot elected to continue toward his destination, about 50 miles away. The airplane was descended to 9,000 feet. Then after initiating a descent to 3,000 feet, the right engine lost power. About 10 seconds later, the left engine lost power.

The pilot attempted to reach the Pennridge Airport, Perkasie. Unable to reach the Pennridge Airport, the pilot performed a forced landing in an open field, about 1 mile south of the airport, with the landing gear extended. During the touchdown and initial ground roll, all landing gear collapsed, with the left main gear striking the fuselage as it separated from the airplane. The left wing struck a football training device in the field and the outboard 4 feet of the wing was separated from the airplane.

The airplane was examined by an inspector from the Federal Aviation Administration (FAA), who reported that both wing tanks were empty, and there was no evidence of fuel siphoning or a ground fuel spill. In addition, no fuel was found in the collector tanks, fuel filters, or fuel lines to the engines. When electrical power was applied to the airplane, the left wing fuel gauge indicated zero fuel remaining, and the right wing fuel gauge indicated 290 pounds of fuel remaining.

According to maintenance records, the following fuel quantity discrepancies were found:

January 20, 1997 - fuel system calibrated, right fuel quantity signal conditioner replaced.

June 23, 1997 - Incoming discrepancy left fuel quantity indicator, replaced signal conditioner, recalibrated left fuel quantity indicating system.

August 6, 1997 - Left fuel quantity indicator intermittent - could not be duplicated, aircraft taxied for departure and then taxied back in - bent cannon plug pin found, system checked satisfactory, airplane released.

At the time of the accident, the airplane had been operated for 2 hours and 28 minutes, with 3 takeoffs since the last refueling.

The investigation revealed that each wing was configured as a fuel tank, and in addition, a collector tank was located behind each engine, in the nacelle faring. The engines were fed from the collector tanks. The collector tanks were fed from the wing fuel tanks. The wing fuel tank quantity was measured by sensors in the wing tanks, and displayed on fuel gauges in the cockpit. The low fuel quantity sensors were also in the wing tanks. The collector tank did not have fuel gauges, but could be visually checked during preflight.

According to the Cessna Pilot's Operating Handbook, illumination of the low fuel quantity lights indicated that the fuel level had reached 160 pounds on the side indicated. The measurement system was independent of the fuel quantity measuring system.

In the section of the NTSB Pilot/Operator Aircraft Accident Report labeled, Recommendation (How Could This Accident have Been Prevented), the pilot stated:

"By closer monitoring of fuel being put on board, by closer monitoring of its use, and by less reliance on the gages. Most importantly by landing at the first sign of any inconsistencies of reading."