NTSB to Finally Examine Long Lost Black Box of Eastern Airlines Flight 980

— -- The National Transportation Safety Board is arranging to retrieve the remains of a black box belonging to Eastern Airlines Flight 980 from a Boston apartment, according to an email from an NTSB official that was shared with ABC News.

The email says Bolivian authorities have requested that the NTSB obtain the evidence and examine it in its lab in Washington, D.C.

In May 2016, best friends Dan Futrell and Isaac Stoner of Boston climbed Bolivia's Mount Illimani and, at an elevation of 16,000 feet, recovered remains of what appears to be a black box from the doomed U.S. airliner.

Flight 980 crashed on Jan. 1, 1985, on its approach to the airport outside La Paz, Bolivia. There were 29 people on board, including eight Americans. No one survived, and multiple international efforts to recover the flight recorders ended fruitlessly because of the inaccessibility of the crash site, the NTSB previously said.

International regulations dictate that the nation where an accident occurs is in charge of any investigation. After the discovery by Futrell and Stoner this spring, the NTSB offered its services, but the agency needed the green light from Bolivia before proceeding.

Futrell and Stoner said their phone calls, emails and certified letters sent to the Bolivian Embassy in Washington went unanswered.

ABC News' efforts to reach Bolivian diplomats in the United States were unsuccessful.

On Dec. 1, Capt. Edgar Chavez, the operations inspector at the General Directorate of Civil Aviation of Bolivia, told ABC News that the Bolivian government would allow the NTSB to look at the tape found by Futrell and Stoner.

He was unable to say when that would occur, however, adding that his agency was "still working on the paperwork."

Chavez did not responded to follow-up calls and emails from ABC News requesting an update or another interview.

Wednesday's news that the NTSB received permission to examine the black box is a significant step forward in the search for answers to what many call the biggest aviation mystery of the 20th century. Many experts, including those at the NTSB, thought finding the flight recorders would be impossible, given the conditions on Mount Illimani.

It is unclear when, where or how the evidence will be handed over to the NTSB. The recorders remain in Futrell's apartment in a suburb of Boston.