US FAA investigating false collision alerts at Washington DC airport

The Federal Aviation Administration is investigating why several flight crews on Saturday received faulty alerts of potentially nearby aircraft on arrival at Washington's Reagan National Airport.

The FAA said Monday that some of the crews executed go-arounds as a result of the alerts that aim to prevent collisions and is investigating why the alerts occurred. A go-around is when a plane aborts a landing as it nears the airport.

There has been intense focus on traffic at the airport after a January 29 fatal collision between an Army helicopter and an American Airlines regional jet near the airport that killed 67 people.

Reagan National has the single busiest runway in the United States.

Airplanes use alerts to warn of potential collisions, with pilots using various Traffic Alert and Collision Avoidance System alerts. The system functions independently of ground-based air traffic control.

In October, the FAA said it was opening an audit into runway incursion risks at the 45 busiest U.S. airports.

The FAA has taken a series of steps since the fatal incident including limiting helicopter traffic around the airport, barring airplanes from taking off when a presidential helicopter is present and slowing the rate of arrivals.

Over the last two years, a series of troubling near-miss incidents has raised concerns about U.S. aviation safety and the strain on understaffed air traffic control operations.

A persistent shortage of controllers has delayed flights and, at many facilities, controllers are working mandatory overtime and six-day weeks to cover shifts.

The FAA, which has aging technology and facilities and needs billions of dollars to modernize, is about 3,500 air traffic controllers short of targeted staffing, prompting the aviation industry and lawmakers to call for action.