On September 14, the DoD announced that they had found the black boxes for Flight 77, and that they have been tuened over to the NTSB. However, the data of the flight data recorders, or the voice from the voice recorder from Flight 77 have never been released:
September 14, 2001 -- Searchers found the flight data and cockpit voice recorders about 4 a.m. today in the wreckage of the hijacked plane that slammed into the Pentagon on September 11, defense department officials said. The two "black boxes" will help investigators put together the puzzle of what happened during the doomed flight, said DoD spokesman Army Lt. Col. George H. Rhynedance. "The voice recorder will tell what was going on in the cockpit," he said. The data box, he said, will tell what was happening with the aircraft as it headed toward the Pentagon, such as its rate of turn. Information from the two boxes will help determine what actually happened during the flight, he said. The recorders were turned over the FBI. The recorders are now at the National Transportation Safety Board laboratory in Washington, where technicians are working to recover data on the recorders. DoD
September 14, 2001 -- Dick Bridges, deputy manager for Arlington County, Va., said the voice recorder was damaged on the outside and the flight data recorder was charred. But he said the FBI still was confident the data can be recovered from both devices." "Bridges said the recorders were found "right where the plane came into the building." Albuquerque Tribune
September 14, 2001 -- FBI Director Robert Mueller said Friday investigators have recovered some information from the flight data recorder from American Airlines Flight 77, the hijacked jet that slammed into the Pentagon. CNN
A damaged voice recorder and the charred flight data recorder from the hijacked have been sent to the FBI. Wired News
Feb. 25, 2002 --FBI Director Robert Mueller said Flight 77's data recorder provided altitude, speed, headings and other information, but the voice recorder contained nothing useful. CBS
FBI Director Robert Mueller said that the voice data recorder contained nothing useful, it would imply that there are no words of the hijackers on the tape, which would once again reinforce our feeling that there is no evidence of hijackers. We'd like to have a independent and reputable expert look at the originals - perhaps what they do or do not contain is useful. Because, as we shall see below, we are deeply suspicious of the FBI's withholding or burying all evidence related to Flight 77.
Secretary of Defense Rumsfeld said the data on the cockpit voice data recorder was unrecoverable.
If the cockpit voice data recorder was unrecoverable, it would be the first time in aviation history a solid-state data recorder (the type used on Flight 77) was unrecoverable after a crash. From a Scientific American feature article lauding the "Better Black Box" in their September 2000 issue:
Nearly 100,000 flight recorders have been installed in commercial aircraft over the past four decades. The prices of the latest models generally range from $10,000 to $20,000. Their survival rate has greatly improved in recent years as the FAA has raised the certification requirements. Although older recorders using magnetic tape were susceptible to fire damage, no solid-state device has been destroyed in an accident to date.
Lawyers representing 9/11 victim families are attempting to use the Freedom of Information Act to obtain transcripts of the black-box data. See 9/11 Lawyers Seek Black-Box Data on Saudi Hijackers by Tom Flocco, which indicates the FBI are obstructing the NTSB review of the black box data.
Of course, as Flight 77 was not the plane involved in the Pentagon Attack, it's black boxes would presumably show that, and the government would be very reluctant to allow the data to be examined, or allow the NTSB to carry out the investigation of the crash that is required by law.