May 15 (UPI) -- United Airlines had to change the keypad codes to enter cockpits doors after they were accidentally posted online.
Over the weekend, United sent a memo to pilots to use alternative security measures, the airline said.
One of the flight attendants posted the codes to a public website. The airline said that this particular incident was an accident, rather than an intentional data security breach.
"The risk of a breach of the flight deck door is strongly mitigated by carefully following the flight deck security procedures," the memo obtained by CBS News said. "Remember this information is sensitive security information and sharing this with anyone not authorized or who does not have a need to know is strictly prohibited."
After the 9/1 hijackings in 2001, cockpit doors were fortified and secured.
United informed the FAA of the codes' release.
One pilot told CBS that he suspects the airline needed to manually change the codes on every plane.
The Airline Pilot's Association said the problem was fixed Sunday.
"The safety of our customers and crew is our top priority and United utilizes a number of measures to keep our flight decks secure beyond door access information," spokeswomen Maddie King said Sunday. "In the interim, this protocol ensures our cockpits remain secure."
United has 4,496 departures each day in 215 domestic and 122 international airports across the country, according to the company's website.