Several “pings” believed to be from AirAsia Flight 8501’s so-called black box recorders were detected Friday, reigniting hopes that investigators might uncover the vital pieces of equipment that could explain what led to the plane’s crash. The pings were detected near the spot where search and rescue workers were deployed to raise the aircraft’s tail, which was discovered earlier this week.

A plane’s black box is typically located near the rear of the aircraft, but this time it could have become separated from the wreckage. "We received an update from the field that the pinger locator already detected pings," Santoso Sayogo, an investigator at the National Transportation Safety Committee, told Reuters. "We have our fingers crossed it is the black box. Divers need to confirm. Unfortunately it seems it's off from the tail.” The tail was found partially buried in the sea floor about 30 kilometers (20 miles) from the aircraft’s last known location.

Fransiskus Bambang Soelistyo, head of the search and rescue agency, said, “Looking for victims is still our main priority besides the black box.” No survivors have been found after Flight 8501 plunged into the Java Sea on Dec. 28 with 162 people on board. Forty-eight bodies have been recovered from the waters near the island of Borneo.

An aircraft’s black box – a misnomer, given that the boxes are actually orange – is a catchall term for an aircraft’s voice recorder as well as its flight data recorder. A plane’s voice recorder captures all communication inside the cockpit. The data recorder tracks a plane’s every movement, including its air speed, altitude and flight path. Modern data recorders also monitor movements on the wings’ individual flaps and when a plane is in or out of auto-pilot. Any corporate jet or commercial aircraft is required to have a black box. Finding the aircraft’s black box could help investigators determine exactly what went wrong with Flight 8501.

AirAsia Flight 8501 disappeared from radar en route from Surabaya, Indonesia, to Singapore. All 155 passengers and seven crew members are presumed dead.