NTSB Is Helping China Decipher Black Box Clues to 737 Crash

(Bloomberg) -- The U.S. National Transportation Safety Board has been helping Chinese officials download two black-box recorders that were damaged in the mysterious crash of a Boeing Co. 737 jetliner on March 21.

The work to decipher the final sounds caught by cockpit microphones on the doomed jetliner is being carried out in the NTSB's lab in Washington, spokesman Peter Knudson said in an email. He declined to discuss how or when the cockpit recorder was brought to the lab, which is routinely used by investigators around the world after accidents.

The second so-called black box is the flight data recorder, which captures hundreds of data parameters tracking an aircraft's path and how its systems are performing. It was also brought to the U.S., said a person familiar with the effort.

Another NTSB spokesman, Eric Weiss, said he couldn't comment on any information involving the second recorder.

The work is being assisted by technicians from Honeywell International Inc., which made the recorders, according to another person familiar with the work. The people were granted anonymity to discuss the sensitive inquiry.

Both devices were damaged in the high-impact crash, Chinese investigators have said.

Separately Friday, teams of NTSB investigators and Boeing technical experts from the U.S. departed for China, underscoring the cooperation between the two nations as they look into the accident, which killed all 132 people aboard.

Earlier: China Crash Mystery Grows as Evidence Signals Midair Breakup

The NTSB, along with technical experts from Boeing and the U.S. Federal Aviation Administration, is assisting the Civil Aviation Administration of China under a United Nations treaty that allows participation from the country where an aircraft was built. The FAA team isn't traveling at this time, the NTSB said.

China notified the NTSB about the crash of the China Eastern Airlines Corp. 737-800 the day it occurred, triggering American participation. But restrictions because of the coronavirus delayed travel arrangements, according to earlier NTSB tweets.

The investigators will follow similar safety protocols to those used by participants in the Beijing Olympics earlier this year, limiting interactions with those not involved in the probe, the NTSB said in a tweet. The measures will allow them to begin working immediately without quarantining. The NTSB didn't specify the number of people on the team bound for China.

The CAAC is leading the investigation. Traditionally in such cases, the NTSB can help search the wreckage for clues about what happened to a plane and assist in obtaining data from the two black boxes.

Modern crash recorders store data on computer chips that have proved highly resistant to impacts and fires, but they sometimes require repairs to retrieve the information.

China Eastern Flight 5735 from Kunming to Guangzhou was flying at about 29,000 feet when it suddenly dove at high speeds. It slammed into a forested hillside about 100 miles from its destination, according to the CAAC.