By Martin Quin Pollard

WUZHOU (China) -Recovery teams expanded Friday’s search area for the China Eastern Airlines (NYSE) crash. The second black box on the plane was not found by search-and rescue workers, and the crews continued to search the wreckage.

The flight MU5735 was enroute from Kunming in the southwest to Guangzhou along the coast Monday. On Monday, the Boeing (NYSE.) 737-880 crashed from cruising height at the exact time it needed to begin its descent towards its destination.

Although the remains of the survivors and human remains were discovered, no debris was found on the steep slopes of China’s Guangxi.

The incident was China’s first serious air accident in twelve years. Although the reason for the tragedy is still unknown, it has forced the government to strengthen safety inspections in other areas.

Lao Gaojin (local government official) said that the area for search and rescue has been increased to 200,000 square metres. He also added that 2,248 residents joined in on Friday’s search.

Another black box, the cockpit voice recorder, was located on Wednesday and has been sent by Beijing to be examined by experts.

According to Chinese state media, it could take between 10 and 15 days for a preliminary analysis to be completed, and even longer to reach a final conclusion.

Mao Yanfeng from the Civil Aviation Administration of China (CAAC), stated, “Currently, it is not possible to determine the exact duration for the data download and analysis of the blackbox already recovered.” He added that the external of the device had been destroyed.

China leads the investigation into the crash, however the United States was asked to join the fray because the Boeing 737-8800 was made and designed in China.

U.S. Transportation Secretary Pete Buttigieg claimed Wednesday that Chinese authorities have invited the U.S. National Transportation Safety Board, (NTSB), to join the investigation. Buttigieg also stated that he is encouraged by the invitation of being on the ground with China.

However, the NTSB later stated that it was not certain if investigators will travel to China due to visa and quarantine restrictions.

Anthony Brickhouse of Embry-Riddle Aeronautical University, a safety expert in air safety, stated that it would be crucial for the NTSB’s participation in downloading the cockpit voice and data recorders.

He said, “Just to be open, whenever you do downloads, it is important that other people are in the room.”

DISTRAUGHT

The crash site has been visited by more than 200 of the grieving relatives of the victims, who were 132 in total.

Lao stated that rescue workers had so far recovered human remains and collected 18 fingerprint samples as well as 101 personal belongings from the passengers.

He said that more than 230 DNA experts also took DNA samples at the crash site and from relatives.

The debris from the jetliner, including the engine blades and horizontal tail stabilisers, was concentrated to within 30 meters (90 feet), of the main impact site, which was 20m (60 feet).

An alleged fragment measuring 1.3 metres in length and believed to have come from the plane was discovered about 10 kilometers (six miles), prompting an expansion of the area for search.

Flight tracking site FlightRadar24 reports that the aircraft briefly pulled out from its nosedive before plummeting back.

According to authorities, the pilots failed to respond repeatedly during rapid descent to air traffic controllers’ repeated requests.