Several times over the last year, Newark controllers lost radar or radio service, leaving them unable to talk with planes they were tracking.

A deadly midair collision in January between a military helicopter and a commercial airliner, several additional crashes and technical problems that resulted in mass cancellations at New Jersey's biggest airport have prompted officials to pledge a fix for the nation’s outdated air traffic control system and vow to hire more controllers.

Audio between air traffic controllers and pilots at Newark Airport reveals the moment the tower lost radio contact with planes.