In LOUISVILLE, Ky., aviation officials extended the emergency directive on Friday to include additional Boeing Company models, following the tragic incident at the UPS global aviation hub in the state.

Initially issued on November 8 for McDonnell Douglas MD-11 planes, the Emergency Airworthiness Directive now also applies to the older McDonnell Douglas DC-10 models.

The directive states, “The FAA is issuing this emergency AD because the agency has determined the unsafe condition described previously is likely to exist or develop in other products of the same type design.”

This order mandates that the aircraft remain grounded until thorough inspections are conducted.

DC-10 aircraft are mostly retired and now only eight are in operation, working as water bombers, tankers and cargo holders, according to Simple Flying. This updated directive expands the previous order due to concerns about the models are “subject to the same unsafe condition,” the order said. 

The updated directive is unlikely to impact day-to-day travel. 

UPS and FedEx previously said they were grounding their fleets of McDonnell Douglas MD-11s “out of an abundance of caution,” and the Federal Aviation Administration’s directive the following day sidelined the planes until inspection and correction of any problems. In the Louisville crash, the jet’s left engine detached during takeoff.

MD-11 aircraft make up about 9% of the UPS airline fleet and 4% of the FedEx fleet, the companies told the Associated Press. UPS said they no longer operate DC-10s and FedEx retired their last of the model in 2022.

The Nov. 4 crash at UPS Worldport killed 14 people including the three pilots on the MD-11, which was headed for Honolulu.

The UPS cargo plane, built in 1991, was nearly airborne when a bell sounded in the cockpit, National Transportation Safety Board member Todd Inman said in a Nov. 7 press conference. For the next 25 seconds, the bell rang and the pilots tried to control the aircraft as it barely lifted off the runway, its left wing ablaze and missing an engine, and then plowed into the ground in a spectacular fireball.

The cockpit voice recorder captured the bell, which sounded about 37 seconds after the crew called for takeoff thrust, Inman said. There are different types of alarms with varying meanings, he said, and investigators haven’t determined why the bell rang, though they know the left wing was burning and the engine on that side had detached.

Inman said it would be months before a transcript of the cockpit recording is made public as part of that investigation process. 

Jeff Guzzetti, a former federal crash investigator, said the bell likely was signaling the engine fire.

“It occurred at a point in the takeoff where they were likely past their decision speed to abort the takeoff,” Guzzetti told The Associated Press after Inman’s news conference. “They were likely past their critical decision speed to remain on the runway and stop safely… They’ll need to thoroughly investigate the options the crew may or may not have had.”

Dramatic video captured the aircraft crashing into businesses and erupting in a fireball. Footage from phones, cars and security cameras has given investigators evidence of what happened from many different angles.

Flight records suggest the UPS MD-11 that crashed underwent maintenance while it was on the ground in San Antonio for more than a month until mid-October. It is not clear what work was done.

The UPS package handling facility in Louisville is the company’s largest. The hub employs more than 20,000 people in the region, handles 300 flights daily and sorts more than 400,000 packages an hour.

The Associated Press contributed to this report.