The FBI is investigating a small hole found in a US Airways 737 jetliner at Charlotte Douglas International Airport in North Carolina. Officials believe it's a bullet hole but are unsure of how it got there, a law enforcement source said.
The round hole is about the size of a nickel and is located on the left side of the aircraft toward the tail, US Airways spokeswoman Michelle Mohr said.
It was discovered Monday during a standard pre-flight inspection by the pilot and the plane was taken out of service for the maintenance team to investigate, Mohr said.
The airline called authorities to investigate the hole because it appeared to be caused by a bullet.
The plane is in maintenance and will likely return to service this evening, a source told ABC News.
The source also said that a "a little bullet hole is nothing" for a plane like this and that it is possible the crew would have noticed no significant changes if the plane were hit in mid-flight.
The direction of the plane's approach to Charlotte is unclear but there is a police firing range in the vicinity of the airport, creating some speculation that the hole might have been caused by an errant bullet from the range.
The plane flew from Philadelphia to Charlotte Monday before the hole was discovered. Because pre-flight visual inspections are standard procedure, the hole either did not exist before takeoff or was missed during the inspection.
The US Airways maintenance crew in Charlotte has experience with bullet holes. A pilot accidently discharged his pistol in 2008 during landing on a trip from Denver to Charlotte. The aircraft was forced to spend days in Charlotte for repairs.