United Airlines mentioned Tuesday that the Federal Aviation Administration has cleared the trail for the return of 52 Pratt & Whitney-powered Boeing 777s that had been grounded after an engine failure in February 2021.

“Late last night, the FAA issued the final paperwork on our Pratt & Whitney-powered triple sevens,” United’s chief business officer Andrew Nocella mentioned at a Bank of America business convention.

The planes characterize 10% of United’s capability, “so it’s really, really material,” Nocella added. ‘You actually cannot rush security.”

“The FAA authorized the service bulletins that will likely be used to make the required adjustments outlined within the Airworthiness Directives to the Boeing 777-200 with Pratt & Whitney PW4000 engines,” the FAA said in a statement.

United last week said it plans to bring the planes back gradually once they were cleared, starting later this month, and later expand them to international routes.

The planes were grounded after one of United’s 777-200s heading for Honolulu from Denver suffered an engine failure. It dropped debris in a residential area before returning to Denver’s main airport. No injuries were reported.

The planes’ return had been delayed through at least May 13 from an expected return in April, CNBC reported last month.

United shares were sharply higher in premarket trading Tuesday after the carrier reported it expects second-quarter revenue per seat mile, a gauge of how much it’s bringing in for each seat it flies a mile, to rise as much as 25% over 2019, even though it would fly about 14% less.

The trend shows higher fares for travelers, who have returned in droves after two years of pandemic.

“We’re not seeing any indicators of resistance to pricing,” United CEO Scott Kirby said in an interview on CNBC’s “Squawk Box” on Tuesday morning.