The National Transportation Safety Board (NTSB) has stated that investigators will need to manually build a timeline for data retrieved from the flight data recorder (FDR) of the Black Hawk helicopter involved in last week’s mid-air collision in Washington.
The recorder lacked timestamps, complicating efforts to reconcile discrepancies between radar readings and data from the CRJ700 aircraft also involved in the incident.
The radar display for the air traffic controller handling both aircraft showed the Black Hawk at 200 feet, a figure transmitted directly from its Mode S transponder. However, the CRJ700’s FDR and Automatic Dependent Surveillance–Broadcast (ADS-B) placed the aircraft at 325 feet, with a margin of error of 25 feet. Determining the source of this discrepancy is a critical focus of the investigation.
“NTSB investigators are working to synchronize flight data recorder and cockpit voice recorder data from both aircraft, ATC communications, and radar scope data to obtain a detailed timeline,” the NTSB said in a Monday update. “The flight data recorder for the Black Hawk did not have timestamps. Investigators will have to manually create timestamps, which requires additional time to validate.”
Meanwhile, the NTSB and the Navy Supervisor of Salvage have deployed a barge-mounted crane to the Potomac River to recover the largest pieces of the CRJ700’s wreckage. As substantial debris is retrieved, FBI divers are searching for smaller fragments, all of which will be transported to a hangar at Reagan National Airport for reconstruction. Once the CRJ700’s remains are secured, recovery efforts will shift to the Black Hawk.
The investigation remains ongoing as officials work to piece together the events leading up to the fatal collision.
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