Chinese transportation officials say they have found one of the two “black boxes” in the wreckage of the plane that dived 30,000 feet nose-first into the ground, but that it could take “years” to find a reason for the mysterious and very uncommon crash.

The crash site investigators, who have remained quite secretive since the crash, now say that one of the “black box” flight recorders from China Eastern Flight MU5735 has been found and is “relatively intact.”

The search for a second black box continues, allegedly hampered by heavy rain in the area. Chinese state media continues to provide few serious details about the crash, beyond confirming that none of the 132 passengers or crew survived it.

Flight MU5735, a Boeing 737-800 NG aircraft with good individual and class safety records, bizarrely plunged from its 29,000-foot altitude to crash in the mountainous Guangxi area on Mar.21, shortly before it should have commenced a routine descent into the regional air hub of Guangzhou to conclude its two-hour flight. 

A handful of local eyewitness accounts and smartphone videos posted on social media suggest the plane was intact when it began its crash-dive. Independent flight tracking systems showed the plane diving at roughly 31,000 feet per minute. A curious anomaly in the data showed the plane halting its dive at 7,425 feet, regaining about 1,200 feet of altitude, and then diving again until it crashed into a mountain.

The plane plummeted nearly straight down nose first, which is a highly suspicious and unusual way for any airplane to crash – but particularly a passenger jet – since they are designed to “glide” even in the face of total engine failure. This was a very strange position for the plane to strike the ground in, particularly with its wings intact, which prompted some to speculate that the nose-dive could have been intentional.

The New York Times quoted data from Boeing that show cruising and initial descent are normally the safest phases of air travel, accounting for only 13 and 3 percent of fatal crashes, respectively.

A video posted by China’s state Xinhua news service on Wednesday, Mar. 23, showed investigators retrieving the black box (which is actually painted orange) from a muddy hillside and sealing it inside a plastic evidence bag.

Aviation safety director Zhu Tao of the Civil Aviation Authority of China (CAAC) told reporters on Wednesday that the recovered black box will be taken to Beijing for “decoding and analysis” so investigators can “provide even more comprehensive data support to reconstruct the entire incident.” 

Zhu provided no estimate for how long this process might take, but analyzing black boxes usually takes a matter of days, depending on how badly damaged they are. Other Chinese officials have suggested the investigation could take “years,” and minimal information will be released to the public until it is completed, a position that has not been well-received by the Chinese public.

According to Reuters, quoting a Chinese state media source China Eastern is now requiring “two senior captains and a senior co-pilot on a three-person crew on some aircraft types” after the MU5735 crash. The airline has also temporarily grounded all of its 737-800 planes.

It is important to note that the Boing 737-800 has a very good safety record, and it should not be confused with the Boeing 737 MAX that was grounded worldwide in 2019 after two crashes with similar equipment failures.