New York CNN  — 

The Federal Aviation Administration plans to dramatically accelerate replacing the safety system whose failure led to a nationwide air travel grounding earlier this month. The regulator also said it has taken steps to prevent a repeat of the meltdown in the interim.

The FAA outlined the new timeframe and procedures in a letter to Congress Monday.

The 30-year-old NOTAM, or Notice to Air Missions, system provides potential flight hazard information to pilots and air traffic controllers. Under previous plans the FAA would have taken at least six years to replace it. But now the system will be replaced by “mid-2025,” the FAA said in the letter.

The FAA said it now requires “at least two individuals to be present during the maintenance” of the NOTAM system. One of the individuals must be a FAA manager, the letter says.

CNN first reported the failure was due to a corrupt file in the system. The FAA later confirmed that problem. It said a contract employee unintentionally deleted a file from the database.

In the future, changes to the NOTAM system will not be immediately synchronized to the backup system, which “will prevent data errors from immediately reaching that backup database,” the letter said. CNN previously reported the issue was discovered on both the main system and a backup system, complicating the recovery.

“Contractor personnel directly involved in the deletion no longer have access to FAA buildings and systems while we complete our investigation,” the agency wrote.

NOTAM is not the only FAA computer system that needs to be upgraded, Transportation Secretary Pete Buttigieg told Reuters in an interview Monday. The Biden administration will seek funding to improve air travel computer systems beyond NOTAM, he added, because of the need to “pick up the pace” of modernization.

“The broader context is aging systems and growing demand,” Buttigieg said. “I don’t want this to be ‘whack-a-mole’ where we figured out one flavor of problem on one system … only to face another one later on.”

The agency reiterated that the ongoing investigation has found “no evidence of a cyber-attack.”

The NOTAM system is separate from the air traffic control system that keeps planes a safe distance from each other. Still, it’s another critical tool for air safety. Its messages could include information about a runway lighting outage, nearby construction or unusual flight activity for an air show.

“It’s like telling a trucker that a road is closed up ahead. It’s critical information,” said Mike Boyd, aviation consultant at Boyd Group International.

But the NOTAM system has problems beyond those that caused the failure. The system’s notices are not as efficient and useful as they should be, according to Kathleen Bangs, a former airline pilot and aviation expert.

“It’s a clumsy system that often over-burdens pilots with pages and pages of less-than-urgent notices, written in archaic code that sometimes buries that one, critical piece of safety information a pilot really needs.”

The incident on January 11 caused more than 9,500 flight delays and 1,300 cancellations, according to data from the tracking service FlightAware. It was the first nationwide grounding of the nation’s air traffic system in 20 years, since the days following the September 11 attacks.