Fatigue crack downs bomber

Photo: http://rideswithchuck.blogspot.com.au/

U.S. investigator reports on B-17 crash

A fuel leak that was thought to have been fixed, but wasn’t, caused the destruction of a World War II Boeing B-17 bomber in 2011, the US National Transportation Safety Board, (NTSB) has found.  All on board survived, but the B-17G, named Liberty Belle, was destroyed by flames after a forced landing near Chicago, in the U.S. mid-west.

The NTSB’s final report, released this month, says the aircraft was found to have a fuel leak the weekend before the accident. The leak was repaired, and a final inspection on the morning of the accident flight found no evidence of any fuel leaking.

However, during initial climb, the flight crew noticed a faint smell of fuel. Soon after, the pilot saw a small amount of smoke near the radio room and the crew began a turn back to the airport.

About that time, they heard from a chase plane that there was a fire on the left wing. The B-17 landed in a cornfield about 12 km from the airport. Although the bomber was undamaged by the landing, boggy conditions in the field hampered firefighters and the fuselage and inboard wings were destroyed by fire.

The NTSB found a repair to the No. 1 main fuel tank earlier in the week had partially separated. Metallurgical examination of the repair area revealed a longitudinal fatigue crack along the weld seam. The NTSB concluded that the crack must have grown rapidly during the aircraft’s last flight, because at 18cm it was double the length of the crack reported by the engineer. The aircraft’s fuel bladders had been removed a few months earlier because they were degrading and sometimes blocking fuel flow.

Read the NTSB report here.


Please enter your comment!
Please enter your name here