NTSB Identification: LAX01FA160.
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Accident occurred Monday, April 30, 2001 in Casa Grande, AZ
Probable Cause Approval Date: 10/24/2002
Aircraft: Bellanca 14-19, registration: N521A
Injuries: 1 Fatal,2 Serious.
NTSB investigators either traveled in support of this investigation or conducted a significant amount of investigative work without any travel, and used data obtained from various sources to prepare this aircraft accident report.
The airplane was making a precautionary landing due to a fluid leak (most likely fuel) in the cockpit and had an explosive flash fire in the cabin during the landing roll. The pilot stated that a clear fluid was running down the cabin side of the firewall from an area right of center. The right seat passenger reported that the leak appeared to be coming from behind the instrument panel directly in front of her position. The pilot then pulled back the power slowly and headed for the closest airport. A passenger and the ground witnesses described the touchdown and rollout as normal until an explosion occurred, which filled the cabin with flames and blew the entry door off the right side of the airplane. Witnesses on the ground reported seeing flames coming out of the front-bottom of the aircraft before hearing a "pop" in conjunction with the explosion inside the cockpit. The fabric-over-tubular-steel-frame airframe was thermally destroyed except for the steel components. An examination of the thermal damage patterns disclosed that the most extensive thermal damage appeared to be forward of the right front seat where the passenger reported the fluid leak. Also parts of the metal frame were severely warped, especially on the lower right-hand side near the firewall and below where the instrument panel would be. In addition the bottom braces of the engine mount were warped due thermal damage. Furthermore, there was sooting and heat resultant discoloration on the firewall in the engine compartment. On the topside and on the right-hand side of the firewall red and black discoloration without sooting was evident. The color on the right side of the firewall was a mixture of black and tan, with a little red. On the bottom part of the firewall there was minimal sooting and a tan color. The only flammable fluid lines on the right quadrant of the firewall are the pressure measurement lines for fuel, engine oil, and hydraulics. These Mil-6000 hose lines are connected to firewall and pass-through fittings, that are located almost directly in front of the right seat passenger's location on the upper part of the firewall. On the cabin side of the firewall, three other Mil-6000 hoses connect these fittings to a "3-in-1" instrument panel gage that displays the operating pressure of these three systems. No evidence was found in the maintenance records that these fuel lines had ever been replaced. While the fuel related components (i.e. carburetor, fuel pump, and associated lines) attached to the engine were thermally damaged, the degree of damage was significantly less than the fuel components attached to the firewall. The thermal damage and sooting patterns indicate that an accelerant based fire originated on both sides of the firewall near the bottom.
The National Transportation Safety Board determines the probable cause(s) of this accident to be: A fuel leak on the cabin and engine sides of the firewall with a probable origin at the firewall pass-through fitting for the fuel pressure gage line. The fire likely began on the engine side of the firewall near the bottom with the explosive ignition of the pooled fuel/vapors in the cockpit after burn through penetration of the fuselage fabric skin on the bottom aft side of the firewall. Further refinement of the leak source between the pass-through fitting and the lines/connectors could not be established due to thermal destruction of the components. Full narrative available
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