A watchdog for the U.S. Transportation Department is investigating the decision to relocate a key piece of Newark Liberty International Airport’s air traffic control to Philadelphia, after outages earlier this year disrupted operations at the New York-area hub.

The outages — one occurring in late April and one in May — temporarily left air traffic controllers unable to communicate with or see aircraft as they guided planes in and out of the busy airport.

“These events have raised questions about FAA’s management of the relocation, including impacts on system redundancy, controller staffing and training, and operational resilience,” the Transportation Department’s Office of Inspector General said in a memorandum on July 28 announcing the audit. 

The U.S. Federal Aviation Administration said in a statement that it welcomes feedback and will cooperate fully with the audit.

Transportation Secretary Sean Duffy said in May he would ask the watchdog to investigate the move, which occurred in July 2024. 

The OIG said it would begin the audit in August and would conduct its work at the FAA’s headquarters, and at air traffic facilities in Newark, New York and Philadelphia. The review will look at the FAA’s planning and risk assessments, and the regulator’s response to the move’s “operational impact on flight delays, cancellations, and safety incidents,” according to the memo.

Franklin McIntosh, acting chief operating officer of the FAA’s Air Traffic Organization, defended the relocation to Philadelphia at a congressional hearing in May. He told lawmakers it was necessary to improve staffing because there weren’t enough controllers who wanted to work at the facility in New York that previously handled the Newark airspace.