Aviation Accident Summaries

Aviation Accident Summary MIA98FA110

WEST PALM BEACH, FL, USA

Aircraft #1

N22358

Cessna 150H

Analysis

The first two legs were uneventful; the fuel tanks were filled after the first flight. During the final leg, he became 'off' course and was taking longer than anticipated due to strong headwinds; no weather briefing was obtained. The pilot did not ask for assistance and corrected for being 'off' course, and while flying near the destination airport, the engine quit. The left and right fuel gauges at that time indicated less then 1/4 and 1/4 respectively. The engine was restarted momentarily but quit again. While flying over a congested highway, he attempted a forced landing in a parking lot and collided with a power line and trees. The entire fuel system was found to contain about 2.0 gallons of fuel; 3.5 gallons of fuel is the unusable amount. The right fuel tank transmitter was sticking in a position that corresponded with 1/4 tank capacity. The airplane was inspected 18.5 hours and 2 months and 13 days earlier using the manufacturers checklist. The checklist requires inspection of the transmitters and fuel gauges for proper operation and correct travel. The airplane had been operated for about 4.5 hours since the fuel tanks were filled after the first leg.

Factual Information

On March 28, 1998, about 1946 eastern standard time, a Cessna 150H, N22358, registered to private individuals, collided with a power line, trees, then the ground during a forced landing near West Palm Beach, Florida. Visual meteorological conditions prevailed at the time and no flight plan was filed for the 14 CFR Part 91 personal flight. The airplane was substantially damaged and the private-rated pilot and passenger were seriously injured. The flight originated about 1015 from the Palm Beach County Park Airport, Lantana, Florida. The pilot stated that he did not obtain a preflight weather briefing before the flight departed, and the first leg of the cross country flight was uneventful, lasting about 1 hour 30 minutes. After landing, the fuel tanks were filled. The flight then departed and flew along the coast to the second airport where an uneventful landing occurred about 45 minutes later. The pilot stated that the fuel gauges indicated 3/4 capacity before departure at about 1715. While flying by pilotage and arrived at the west side of Lake Okeechobee about 20 miles north of his intended point. He noted that the flight was taking longer than anticipated due to strong headwinds and was "off course." The flight proceeded to the south end of Lake Okeechobee and at that point the flight duration was 1 hour 45 minutes, and it was 1900. He noted that it was getting dark and the left and right fuel tank gauges indicated less than 1/2 and 1/2 respectively. The flight continued and he thought the flight was too far south and he elected to fly a northeasterly heading. He did not request assistance from Palm Beach Approach Control and proceeded northbound. The engine then quit with no sputtering and the left and right fuel gauges indicated less than 1/4 and 1/4 respectively. He restarted the engine momentarily but it quit again while at 1,000 feet over I-95. There were too many cars on I-95 and he maneuvered the airplane toward a dark space. The airplane was determined to have collided with a power line 39 feet above ground level (agl), flew 94.1 feet, and collided with trees at 15 feet agl. The airplane then flew 46.7 feet and impacted the ground, coming to rest 36.9 feet past the initial ground impact on a magnetic heading of 105 degrees. Postcrash examination of the airplane revealed that about 60 ounces of fuel were drained from the left wing fuel tank and 184 ounces of fuel were drained from the right wing fuel tank. About 4 ounces of fuel were drained from the gascolator and 1 ounce of fuel was drained from the carburetor. No evidence of fuel leakage was noted on the ground at the crashsite; oil leakage was noted on the ground beneath the engine and an impact damaged oil sump was also noted. The engine was removed from the airplane and examination revealed no evidence of preimpact failure or malfunction. Also, the emergency locator transmitter (ELT) activation switch was found in the "off" position and the external antenna coax cable was not connected. The fire rescue personnel did not turn off the ELT nor disconnect the antenna. According to the airplane manual, the total unusable fuel capacity is 3.5 gallons which corresponds to 448 ounces. The current owners of the airplane kept in it a paper which recorded the date, pilot's name, tachometer time out and in, and the beginning hobbs meter reading when the airplane was purchased by them on February 18, 1998. The paper indicated in part that the airplane was fueled after a flight that took place on March 22, 1998. According to the person who fueled the airplane, the left tank was full and the right tank in her estimate was about 2-3 gallons less than full. The airplane was reportedly not flown since that date until the accident day. Based on the tachometer time before departure and the tachometer reading at the accident site, the airplane had been operated for a total of 5.9 hours, on the day of the accident. The pilot had estimated that the first leg of the flight lasted about 1 hour 30 minutes, and as previously mentioned, the fuel tanks were filled after that landing. The airplane was calculated to have been operated for a total of 4 hours 30 minutes since the fuel tanks were filled after the first landing. Postaccident testing of the fuel quantity indicating system revealed that the right fuel tank quantity transmitter would not of its own weight, contact the empty tank stop tab. The float assembly would remain at a point that corresponded with 1/4 tank capacity when electrical power was applied and would not move past that point without force. The float assembly was forced past that point to the empty tank stop tab and the gauge indicated empty. Testing of the left fuel tank quantity transmitter revealed that the unit moved freely between the full and empty stop tabs. At the empty stop tab, the left fuel quantity gauge indicated 1 needle width below empty. Visual examination of the right fuel tank transmitter revealed internal damage to the rheostat. Review of the engineering drawing for the transmitter revealed that the float arm is to move freely between the upper and lower stop tabs. It should also return to the lower stop tab of its own weight from all intermediate positions. According to the federal aviation regulations pertaining to the certification standards of the airplane, the fuel gauges are required to read empty with the unusable fuel remaining in the tanks. Review of the aircraft logbook revealed that the airplane was last inspected in accordance with an annual inspection that was signed off on January 15, 1998. The airplane had accumulated 18.5 hours since that inspection. The entry indicates that the airplane was inspected in accordance with the Cessna inspection checklist. There was no entry which indicated that the right fuel tank transmitter had ever been replaced or removed for maintenance. Review of the checklist revealed that, "The 100-hour (or annual) inspection includes everything in the 50-hour inspection...." The checklist indicates that the fuel quantity gauges and transmitter units are required to be checked each 100 hours. The checklist also states that as it pertains to moving parts, check as applicable for proper operation and correct travel. The fuel tank is required in part to be drained each 1,000 hours, or to coincide with engine overhauls. The checklist for that item does not indicate that the fuel quantity gauges are to be checked to verify that they indicate empty with an empty tank. The airplane minus the retained right fuel tank transmitter and the wooden fuel stick was released to Robin Harris, one of the co-owners of the airplane, on April 17, 1998. The retained components were released to Mr. Michael Barrett, of U.S. Aviation Underwriters, Inc., on September 10, 1998.

Probable Cause and Findings

The poor in-flight planning by the pilot-in-command for his failure to ask for assistance after becoming lost momentarily, and his failure to monitor the total time airborne after the fuel tanks were filled. Contributing to the accident was the binding of the right fuel tank quantity transmitter resulting in the incorrect reading of the gauge, and inadequate aircraft manuals by the airplane manufacturer for failure to require testing of the fuel quantity indicating system for accuracy. Also contributing was the failure of the pilot to obtain a preflight weather briefing, and unsuitable terrain encountered by the pilot during the forced landing.

 

Source: NTSB Aviation Accident Database

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