The Federal Aviation Administration (FAA) announced investigations are being made on the Boeing 777 airplanes after an incident in Denver where an engine failure dropped debris on Broomfield. According to Steve Dickson, FAA Administrator, the airplanes equipped with certain Pratt & Whitney PW4000 engines are likely to be removed from service.

The plane with 231 passengers and 10 crew members on board had to make an emergency return to Denver airport after an engine failure. The flight 328 from United Airlines was headed to Honolulu when the incident occurred.

Following the FAA announcement, United Airlines said in a statement that they are immediately removing 24 Boeing 777 planes that are powered by Pratt & Whitney 4000 series engines. The 24 aircrafts are portion of the 52 of the model in the United fleet; the other 28 remain in storage. Their statement said the move is voluntary and temporary, and that it should only disrupt a small number of costumers.

The FAA’s directives states that Boeing 777 in other airlines’ fleets may be removed from service due to increased inspections.