American Airlines temporarily has removed from service 14 of its Boeing 737-800 jets because work to add new overhead bins on some aircraft “was not up to our standards,” an airline spokesman said Thursday.

American said it found issues with bin retrofits on two aircraft, but took the rest out of service to ensure those aircraft do not have similar problems. An airline spokesman did not say what was wrong with the work, which he said was done by an “by a long-time FAA-licensed vendor.” An official with American’s maintenance union told the NBC news affiliate in Dallas television station that bins were “popping open continuously.” 

American said it notified the FAA of the issue, but said it would not affect the safety of the aircraft. It has, however, affected operations: By mid-day Thursday, American said it had canceled nearly 40 flights.

The news was first reported by View From the Wing, an airline-business blog.

American is retrofitting most of the 304 Boeing 737-800s in its fleet to match the seating configuration in its new Boeing 737-8 Max jets. American is increasing seating capacity from 160 passengers to 172, mostly by reducing legroom for each passenger and shrinking the size of bathrooms.

The retrofit work is being done in several places, and American found improper work from just one vendor, an airline source told Skift.

Passengers have complained about the new configuration, and some have speculated American might walk it back, because it is not competitive with other U.S. carriers. United has 166 seats on its Boeing 737-800s, and it does not seem likely to adds seats to match American.

Because the planes will fit more passengers, who will bring more bags, American decided to rip out the old bins, replacing them with what Boeing calls Space Bins. According to Boeing, each bin can now fit six full-sized bags, up from four.

Also as part of this project, American will remove in-seat television screens for aircraft that have it.

Photo Credit: Boeing developed Space Bins for 737 jets so aircraft can hold more bags. Boeing