The National Transportation Safety Board said Tuesday that LaGuardia Airport’s ASDX runway safety system did not generate an alert before Sunday night’s runway collision.
NTSB Chair Jennifer Homendy said at the board’s Tuesday press conference that the system “did not generate an alert due to the close proximity of vehicles merging and unmerging near the runway, resulting in the inability to create a track of high confidence.”
Homendy also said Truck 1, the aircraft rescue and firefighting vehicle involved in the collision, did not have a transponder.
The board also released preliminary timing from the cockpit voice recorder during the final three minutes of the flight. According to investigator-in-charge Doug Brazy at the Tuesday NTSB press conference, the tower cleared the airplane to land on Runway 4 and later cleared Truck 1 to cross Runway 4 at Taxiway Delta 20 seconds before the end of the recording. Nine seconds before the recording ended, the tower instructed Truck 1 to stop. Brazy said a sound consistent with the airplane’s landing gear touching down was recorded at eight seconds, followed by a transfer of controls from the first officer to the captain at six seconds and a second instruction for Truck 1 to stop at four seconds.
Brazy also said an airport vehicle transmission 1 minute, 3 seconds before the end of the recording was stepped on by another radio call, and investigators have not yet identified the source of the overlapping transmission.
Investigators said the firefighting vehicles were responding to a United Airlines flight at the gate after two aborted takeoffs and a report of fumes, smoke or another odor in the cabin. Homendy said other vehicles were behind Truck 1 but did not begin to cross the runway, and she said investigators were still working to verify staffing records and controller duties in the tower. She also said interviews with controllers began Tuesday afternoon and that the board was reviewing conflicting information in staffing logs, including dates and times.
