Pentagon Plane, page-546

About 03:40 on September 14, a paramedic and a firefighter who were searching through the debris of the impact site found two dark boxes, about 1.5 by 2 feet (46 by 61 cm) long.
They called for an FBI agent, who in turn called for someone from the National Transportation Safety Board (NTSB).
The NTSB employee confirmed that these were the flight recorders ("black boxes") from American Airlines Flight 77.^[114]

Dick Bridges, deputy manager for Arlington County, Virginia, said the cockpit voice recorder was damaged on the outside and the flight data recorder was charred.
Bridges said the recorders were found "right where the plane came into the building".^[115]
The cockpit voice recorder was transported to the NTSB lab in Washington, D.C., to see what data was salvageable.

In its report, the NTSB identified the unit as an L-3 Communications, Fairchild Aviation Recorders model A-100A cockpit voice recorder – a device which records on magnetic tape.
There were several loose pieces of magnetic tape that were found lying inside of the tape enclosure.
No usable segments of tape were found inside the recorder; according to the NTSB's report, "[t]he majority of the recording tape was fused into a solid block of charred plastic".^[116]
On the other hand, all the data from the flight data recorder, which used a solid-state drive, was recovered.^[117]