Aviation Accident Summaries

Aviation Accident Summary LAX05FA108

Oxnard, CA, USA

Aircraft #1

N2044S

Cessna 210L

Analysis

As the pilot turned the airplane onto the active runway, he saw white flashes coming from the engine gauges in the instrument panel. He did not believe there was a problem, and continued the takeoff run. About 1,000 feet down the runway, smoke started to enter the cabin, and he stopped the airplane and evacuated the passengers. When he returned to the cabin area, he noted a fire concentrated in the engine gauge instrument cluster area of the panel. He put the fire out, but by the time the fire department arrived, the fire had restarted. The cabin area sustained structural damage during the fire. Investigation found that the wire bundles in the engine gauge area had missing insulation and beading. The engine instrument section was removed for inspection, and a pinhole was found on the steel fuel pressure line. A Safety Board materials specialist examined the fuel pressure line, and noted copper material and damage that was consistent with electrical arcing of a copper wire on another metal surface. The airframe manufacturer issued Service Bulletin SEB98-7 in 1998, which required an inspection of the fuel line between the firewall and fuel flow gauge for abrasion damage. No evidence was found that the service bulletin had been complied with. While the service bulletin was not mandatory, had it been addressed, the damage to the fuel line may have been found in a timely manner before the onset of the fire.

Factual Information

HISTORY OF FLIGHT On March 7, 2005, at 2105 Pacific standard time, a Cessna 210L, N2044S, caught fire on the takeoff roll from runway 25 at Oxnard Airport (OXR), Oxnard, California. The pilot/owner operated the airplane under the provisions of 14 CFR Part 91. The airplane sustained substantial damage to the interior during the fire. The private pilot and four passengers were not injured. Instrument meteorological conditions prevailed for the flight that was destined for Santa Monica Municipal Airport (SMO), Santa Monica, California. An instrument light rules (IFR) flight plan had been filed, but had not been activated. According to airport operations personnel, the tower had issued an IFR clearance to the accident pilot. Prior to the accident airplane's takeoff roll, the tower closed (2100). Airport personnel heard a radio transmission from the pilot that he was taxiing to the active runway. A short time later, airport personnel were notified that Oxnard fire department was responding to a call of a burning airplane at the airport. In the pilot's written statement he reported that he conducted a normal run-up. As he turned the airplane onto the active runway, he turned on the landing light, the transponder, the strobes, and the DME. On the takeoff roll he noticed bright white flashes emanating from behind the instrument panel and then from the top of the panel. At first he thought the flickering was from the lighting system, but then he saw smoke coming out of the top of the panel. The smoke partly obscured his vision. The pilot stated that he cut the power and veered towards the side of the runway. He pulled out the mixture, turned off the master switch, and took the keys out of the ignition. After putting out the fire, he moved the airplane onto the gravel shoulder and off the runway. The National Transportation Safety Board investigator-in-charge (IIC) interviewed the pilot. The pilot stated that during the takeoff roll he saw lights flickering from the top and bottom of the instrument panel. About 1,000 feet down the runway smoke started to fill the cabin area, which obscured his vision. The pilot reported that he went back to the airplane to get the fire extinguisher and noted that the avionics section had become displaced in the fire, so he aimed the fire extinguisher in that area. During this time a 911 call was placed. The pilot believed the fire had been put out; however, smoke was still emanating from the airplane. By the time the fire department arrived the airplane's cockpit was fully engulfed in flames. AIRCRAFT INFORMATION The airplane was a single engine Cessna 210L, serial number 21061011. According to the airframe logbook the airplane had a total time of 7,225.2 hours. An annual inspection had been completed on December 1, 2004, and had flown approximately 30 hours since the inspection. A review of the airframe logbooks showed: On October 25, 2004, the alternator regulator had been replaced. On April 23, 2002, an invoice from Desert Aircraft Maintenance, Bermuda Dunes, California, indicated that wiring damage had been repaired. There was no further description of the type of wiring repaired, nor a corresponding logbook entry. On October 4, 2001, a JPI engine monitor system had been installed, which was located at the right of the engine instrument cluster. On September 15, 2000, a CHT gauge had been replaced and the wiring was reworked. On April 27, 2000, the alternator wiring had been repaired. WRECKAGE AND IMPACT The Safety Board IIC, a Safety Board Fire and Explosion Specialist, and a representative from Cessna Aircraft Company, a party to the investigation, examined the airplane at Oxnard Airport. The interior of the airplane had sustained fire damage. There was no other structural damage to the airplane. Investigators noted that the CABIN LIGHTS circuit breaker had been tripped. Investigators noted that the instrument panel had been heavily fire damaged. The area of concentration was the backside of the engine instrument cluster (CHT, fuel level gauge left and right fuel), ammeter, oil temperature, and oil pressure). The gauges had either melted in the fire, or were heavily sooted. The wire bundles in the engine instrument panel area showed several sections had missing insulation and the conductors were brittle. Investigators also observed beading of multiple wire conductors. Investigators found a pinhole in the fuel pressure line for the fuel flow pressure portion of the manifold pressure/fuel flow pressure gauge. TESTS AND RESEARCH A section of the wire bundles that included the oil temperature gauge, CHT, and fuel quantity gauges were removed for further inspection. The Safety Board's Fire and Explosion Specialist inspected the wires in a laboratory under a microscope (the full report is contained in the public docket for this accident). A pinhole was identified on a stainless steel fuel pressure line that attaches to the fuel quantity center. Blue stains were noted on the surface of the fuel pressure line. The Safety Board Materials Laboratory examined the fuel pressure line and noted copper metal on the surface of the hole. The report also indicated that the pinhole damage was typical of electrical arcing of a copper wire on another metal surface. The Safety Board Fire and Explosion Specialist also noted a section of the fuel line adjacent to the pinhole exhibited marks consistent with rubbing contact with another object. Also submitted to the Safety Board Materials Laboratory was the oil pressure line, which had a hole in the sidewall. Prior to removal, investigators noted that a small group of wires were lying on top of the line. The insulation from the wires had melted and attached to the oil pressure line. After removal of the installation, a hole was discovered. The Materials Laboratory specialist reported evidence of wall thinning from pitting on the interior and exterior surfaces. Another area of pitting was also identified; however, the line had not breached in that area. Cessna issued Service Bulletin (SB), SEB98-7, on October 5, 1998, which required the inspection of the fuel line between the firewall and the fuel flow gauge for signs of abrasion damage. Non-compliance of the SB might result in the failure of the fuel pressure/fuel flow gage supply line, which could allow fuel to be expelled into the cabin, and create a potential for a fire. No corresponding maintenance logbook entries were identified that indicated that the SB had been accomplished.

Probable Cause and Findings

A pinhole leak in the fuel pressure line during the takeoff roll that was ignited by an electrical arc associated with wires adjacent to the fuel line. A contributing factor in the accident was the failure of maintenance personnel to comply with a manufacturer's service bulletin that addressed potential damage to the fuel line.

 

Source: NTSB Aviation Accident Database

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