The Air Force Office of Special Investigations booked a man on Thursday for breaking into Joint Base Andrews, Maryland, and entering a C-40 aircraft assigned to the 89th Airlift Wing.

The unauthorized intruder was unarmed and there was no indication he had any links to extremist groups, the Andrews-based 316th Wing public affairs shop said in a press release on Friday.

“The security of our installation is paramount,” said Col. Roy Oberhaus, the vice wing commander of the 316th Wing. “This was a serious breach of security and Joint Base Andrews is investigating the incident to determine how this happened so it doesn’t happen again.”

Air Force media operations chief Ann Stefanek said in a statement that the incident has prompted the Air Force to “launch a comprehensive review of installation security and trends.”

“Once complete, we will publicly share the results of the investigation into the breach at Joint Base Andrews,” Stefanek wrote on Friday. “We are still gathering information and facts, but we can assure you, installation security is of critical importance to the Department of the Air Force.”

Security forces at the base detained the man and interviewed him along with OSI before he was turned over to local law enforcement and given two outstanding warrants, the 316th Wing press release said.

A spokesperson for Andrews said OSI is the lead on investigating the incident, though OSI did not respond to questions in time for comment.

Late Thursday night, Joint Base Andrews announced on Facebook that it was suspending its Trusted Traveler Program, which allows cardholders to vouch for up to 10 individuals in their vehicle without a visitor request form, according to a 2015 press release that was first reported by Air Force Magazine.

Joint Base Andews is best known for transporting senior government and military leaders, according to the base’s website. The base is home to the President’s jet, Air Force One, several different kinds of transport aircraft, and F-16 fighter jets.

The C-40, the aircraft which was boarded illegally on Thursday, is a military version of the Boeing 737-700 business jet and is used to fly combatant commanders and members of the Cabinet and Congress.

“The C-40B is designed to be an “office in the sky” for senior military and government leaders,” the Air Force wrote in a profile of the aircraft. “It gives combatant commanders the ability to conduct business anywhere around the world using on-board Internet and local area network connections, improved telephones, satellites, television monitors, and facsimile and copy machines.”

Featured image: The C-40B’s primary customers are the combatant commanders and C-40C customers include members of the Cabinet and Congress. The aircraft also perform other operational support missions. (DoD courtesy photo)

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