WINDSOR LOCKS, Conn. (WWLP) — A United Airlines plane that departed from Connecticut’s Bradley International Airport had to return due to an issue with a window in the cockpit.

A passenger on United Airlines Flight 1274 on April 18 told WWLP that she heard a loud noise about 15 minutes into the flight, then the plane dropped down and abruptly took a sharp turn. The plane safely landed back at Bradley Airport and passengers were told, according to the passenger that “the co-pilot’s window blew out of the plane.”

Photos sent to WWLP show the missing window, including one that shows the window covered by a box.

United Airlines sent WWLP the following statement:

“On Tuesday, April 18, a flight departing Bradley International Airport returned to the airport to address an unlatched cockpit window. The flight landed safely, and we re-accommodated our customers on another aircraft.”

The passenger called the experience “awful.”

“It was an awful experience and the customer service was horrible, having waited in line over 3 hours and totally stressed out!!” the passenger said.

The FAA told WWLP that the crew reported an open window after departure and that it is investigating.

The Boeing 737 was headed to Washington Dulles International Airport.