Washington CNN  — 

The nation’s top aviation official talked about the safety risks of “complacency” in a Senate hearing Wednesday, and said the Federal Aviation Administration is juggling three competing systems of controlling US airspace.

Billy Nolen, the acting FAA administrator, appeared before the Senate Commerce Committee to address the software outage that halted flight departures nationwide last month, a near miss between an American Airlines plane and a Delta Air Lines plane on a JFK airport runway last month, another close call between a FedEx cargo plane and a Southwest plane in Austin, Texas, earlier this month, and other recent safety problems plaguing the aviation industry.

Billy Nolen, the acting FAA administrator, appeared before the Senate Commerce Committee to address the software outage that halted flight departures nationwide last month.

He said efforts to upgrade the NOTAM safety messaging system that failed in January will be mostly completed “by mid-2025,” an acceleration of work that he previewed in a letter last month.

In a letter to Congress in early February, the FAA said it plans to dramatically accelerate replacing its outdated Notice To Air Missions (NOTAM) safety system, whose failure led to a nationwide air travel grounding in January. The software failure and ground stop led to thousands of delayed and canceled flights a month ago. The regulator also said it has taken steps to prevent a repeat of the meltdown in the interim.

A contractor working for the FAA unintentionally deleted files related to the key pilot safety system, the FAA said. NOTAM messages could include information about lights being out on a certain runway, or a tower near an airport not having the required safety lights working, or an air show taking place in the air space nearby.

The FAA has found no evidence of a cyberattack or malicious intent, and the agency says it has taken steps to make the system more resilient.

The near collisions have also raised concerns that the FAA’s safety systems may be insufficient.

Nolen told the Senate Commerce Committee that he believes that “the fixes that we have in place today will prevent the reoccurrence of the event that we saw in January,” but under pressure admitted that vulnerabilities remain in the NOTAM safety messaging system.

“Can I sit here today and tell you that there will never be another issue on the NOTAM system? No, I cannot,” Nolen said.

The FAA instituted changes that require two people to be present when programming changes to the system, and a delay before syncing changes between multiple redundant systems.

Nolen said the older system that initially failed is used by only about 20% of the total users of NOTAMs. Many airlines and pilots, he indicated, use a newer system that also suffered an outage when changes to the older database were synced with the new system.

Nolen also said the FAA is handling three overlapping methods of managing the nation’s airspace, including the long-standing air traffic control system, an upgraded system dubbed NextGen, and systems for handling drones, space launches, and future aircraft.

“For us to sustain, implement, and plan for all of these systems, we have a lot of work ahead,” Nolen said.

A recent National Transportation Safety Board report said an American Airlines widebody Boeing 777 jet crossed an active runway without clearance from air traffic control, causing a narrowbody Delta 737 to abort its takeoff last month. The NTSB is also investigating the FedEx and Southwest incident involving two aircraft at Austin-Bergstrom International Airport. That near collision happened after air traffic controllers cleared the FedEx Boeing 767 to land on Austin’s Runway 18 Left, according to the FAA.

Nolen on Tuesday said he has ordered a sweeping review of the agency, and asked in prepared testimony to the Senate Commerce committee for additional funding to meet the demands, including modernizing the legacy computer system that failed.

“We are experiencing the safest period in aviation history, but we cannot take this for granted,” Nolen wrote in a memo. “Recent events remind us that we must not become complacent.”

One focus of the safety review team will be determining “whether there are other incidents that resemble ones we have seen in recent weeks.” It will also look at ways to better integrate the FAA’s air traffic control arm into the agency’s broader safety efforts.