CRESWELL, OR, USA
N3121K
CESSNA 421
The aircraft occupants observed a fire in the left engine nacelle during the landing roll. The pilot stopped the aircraft and secured it. The occupants exited safely, and the fire was extinguished; however, the fire substantially damaged aircraft structure. Photographs showed evidence of heat distress inside the nacelle aft of the engine, where the turbocharger is located close to fuel lines. The operator stated the airplane had had a left engine fuel leak repaired just before the accident flight. The company mechanic who performed this repair stated that he fabricated a replacement for a leaking fuel line, which as he recalled went 'from the fuel control to the fuel pump', out of '5606 hose with red and blue MS fittings'; and that the replacement line 'looked just like the original.' The aircraft service manual showed that the 'hose assy - metering unit return to pump' is located close to the turbocharger and was in an area of heat distress as shown by the photos.
On August 18, 1995, approximately 1430 Pacific daylight time, a Cessna 421, N3121K, registered to Aerial Communications of America (ACA), Inc. of Eugene, Oregon, experienced a left engine fire which was first observed on landing roll at Hobby Airport, Creswell, Oregon. All four occupants successfully egressed the aircraft; neither the commercial pilot nor any of the three passengers were injured. The fire was subsequently extinguished; however, the fire substantially damaged aircraft structure in the area of the left engine nacelle. The flight was a 14 CFR 91 business flight from Eugene. Visual meteorological conditions prevailed at the time of the accident and no flight plan had been filed. The pilot stated: "After an uneventful fairly good landing and as the aircraft...was slowing through approx[imately] 30-40 MPH the passenger occupying...seat #5 yelled out 'Fire left side!' I looked in that area and sure enough, there was a fire! I continued to slow down the [aircraft] and while this was happening the passenger occupying seat #2 yelled back to the passengers to open the crew door. (main door) I also yelled this...and when the aircraft stopped, we all exited the aircraft with NO hesitation. During roll-out I did shut the fuel switches (valves) to the off position, mixtures...pulled, master [and] mag[neto]s, off, fire extinguishers were brought to us immediately and I and passenger in seat #2 put out the fire. Total fire time [was] approx[imately] 10 min[utes]." Statements submitted by the passengers indicated that the passenger in the seat directly behind the pilot was the first occupant to observe the fire. This passenger stated: "...we were rolling out on the runway and we were nearly slowed to taxi speed and I looked out the window and noticed fire coming out of the top of the engine...." Photographs taken after the accident showed evidence of heat distress inside the left nacelle, in the area behind the engine. This area contains the engine turbocharger along with several fuel lines in close proximity. The left side of the aft firewall inside the nacelle also exhibited evidence of thermal distress. The outer nacelle aft of the firewall was scorched in a pattern running aft along the nacelle top left side for approximately 3 feet. The operator stated in a telephone conversation with the investigator that just before the accident flight, the airplane had developed a left engine fuel leak. He reported that one of his mechanics discovered a leaking fuel line. He stated that the mechanic fabricated a replacement for the leaking line and installed the fabricated line on the aircraft. A Cessna air safety investigator stated that Cessna does not recommend such repairs and that only Cessna parts should be used on the aircraft. The Cessna investigator furnished a 3-page document to the investigator-in-charge which contained technical specifications for medium-pressure hose assemblies. However, the FAA coordinator to the accident, an airworthiness inspector at the FAA's flight standards district office (FSDO) in Hillsboro, Oregon, indicated that this type of repair is authorized under Federal Aviation Regulations. The mechanic who performed the repair was subsequently located and interviewed by telephone. He stated that to the best of his recollection, the line he had fabricated and replaced went "from the fuel control to the fuel pump." He stated that he constructed the replacement line out of "5606 hose, with red and blue MS fittings", and that the replacement line "looked just like the original." He stated that the fire may have occurred on the next flight after he replaced the line but said he was not sure of this. The mechanic stated that he fabricated a replacement line rather than install a Cessna part in order to save money for the operator. A check of the parts list and left engine assembly diagrams in the Cessna 421 service manual revealed that part number CM3758D116A, "hose assy - metering unit return to pump" (figure 134, item 26Q on pages 2-467 and 2-469 of the service manual), passes in close proximity to the engine turbocharger. This line was also located in an area of thermal distress as shown by the photographs of the accident aircraft.
the company mechanic's failure to properly fabricate a fuel line.
Source: NTSB Aviation Accident Database
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