Incident Summary
On July 11, 2010, at about 0915 eastern daylight time, a Beechcraft BE-58 (registration N405RW) sustained substantial damage during a right engine start at LaGrange-Callaway Airport (LGC) in Lagrange, Georgia. The aircraft was owned and operated by private individuals. The pilot was not injured. Visual meteorological conditions prevailed for the Title 14 Code of Federal Regulations Part 91 personal flight.
Flight and Return
According to the pilot, a lineman had filled both wings to capacity and secured both fuel caps. The pilot's preflight check confirmed both caps in place. After takeoff from runway 31, at approximately 700 feet above ground, the right wing fuel cap released from its opening but remained attached via its retaining chain. Fuel was observed exiting the opening. The pilot initiated a return to LGC. With no traffic and no wind, the pilot landed on runway 13 and taxied to the ramp. Both engines were shut down, and the pilot met the lineman. The pilot exited the aircraft, secured the right fuel cap, and visually inspected the wing, observing no signs of fuel spillage. The lineman noted the pilot re-secured the cap and declined a top-off of the right tank.
Engine Fire
Approximately 10 minutes after returning, the pilot boarded and started the left engine, then attempted to start the right engine. The engine backfired on startup, producing a loud bang and whoosh sound, and flames rose from the right wing. The pilot continued cranking and performed the emergency procedure for an engine fire during start. The propeller wash quickly extinguished most flames, but a small flame persisted at the aileron linkage area, which the lineman extinguished with a fire extinguisher. The pilot shut down both engines and exited the aircraft.
Aircraft Examination
A Federal Aviation Administration (FAA) inspector and a manufacturer representative examined the aircraft. An estimated 11 gallons of fuel had vented from the right wing filler neck during the air turn back. The right wing exhibited internal blast damage, causing the upper wing skin to expand and separate from retaining rivets. A soot trail originated at the exhaust pipes and traveled aft to the trailing edge. Both upper and lower skin panels showed bulging and wrinkling, with damage concentrated around the aileron bell crank box structure. Several rivets separated, damaging the wing rib area. The aileron had a bulged area with soot near the outboard hinge. The aircraft's fuel boost pumps operated without leaks. The left fuel cap functioned properly; the right fuel cap did not operate properly—its locking tab could be lowered without being attached to the filler opening, and the lanyard retaining clip was installed backwards.
Additional wing examination found the right wing navigational light power wire rubbing on a lightning hole, landing light wires chafing on a lighting hole edge, and the right wing fuel vent lines unsecured. Three inspection panels had small amounts of fuel residue on their exteriors.
Fuel Cap Examination
The right fuel cap was tested at an FAA-certified overhaul facility with National Transportation Safety Board oversight. The outer o-ring was dry and cracked. The cap leaked under pressure and required excessive force to close and secure the lock tab, while the force to unlock was below specifications. Disassembly revealed a missing washer. After reassembly with all required parts and proper adjustment, the cap met specified forces and passed a pressure test without leaking.
Maintenance and Safety Actions
The aircraft's last annual inspection was on July 7, 2009, with a total time of 3,139 hours. FAA review of maintenance records did not indicate when the right fuel cap last underwent maintenance or overhaul. The aircraft manufacturer's maintenance manual did not specify the required forces to open and close the fuel cap; the cap manufacturer's overhaul process includes such specifications and a pressure leak check, which the aircraft manual lacked. The aircraft manufacturer later added a note to applicable maintenance manuals to inspect the fuel cap outer o-ring for damage and replace or overhaul the cap if damaged.
The aircraft manufacturer had published Safety Communiqué No. 298 in October 2008 regarding interior wing inspections. In December 2010, Revision 1 added areas of concern discovered during this investigation. The FAA issued Special Airworthiness Information Bulletin (SAIB) CE-11-28 on April 8, 2011, addressing these concerns.