BEIJING (AP) -- Add rain to the challenges facing Chinese investigators as they try to determine why a jetliner with 132 people aboard crashed in remote mountains.

One of the China Eastern Airlines plane's two “black box” flight recorders was found Wednesday. The search was temporarily suspended due to a downpour.

The Boeing 737-800 was flying at 29,000 feet (8,800 meters) when it nosedived Monday into a gap in the mountains outside the southern city of Wuzhou.

WHAT HAVE RESCUERS FOUND?

Searchers found one “black box” recorder with its exterior “severely damaged,” said Mao Yanfeng, director of the accident investigation division of the Civil Aviation Authority of China, at a news conference.

One recorder captures conversation in the cockpit and other sounds. The other records information about speed, altitude, direction up or down, pilot actions and performance of key systems. Mao said the one that was found was being analyzed to see which box it is.

Rescuers with sniffer dogs and drones also found wallets, identity cards and debris.

Authorities gave no indication they found survivors.

Debris is scattered over a wide area that includes the other side of the mountain, state broadcaster CCTV said. The main crash area, now a barren pit in the forested mountainside, is about half the size of a football field.

Searchers must climb steep inclines in the area, which is surrounded on three sides by mountains and reached by a dirt road.

WHAT ARE INVESTIGATORS SAYING?

Investigators have declined to discuss possible reasons for the crash.

Damage to the aircraft was severe, which makes the investigation “very difficult,” said Zhu Tao, director of CAAC's Office of Aviation Safety.

“We cannot have a clear assessment of the cause of the accident with the information currently available,” Zhu said Tuesday at a news conference.

Authorities are “carrying out in-depth investigation” of the aircraft's design and maintenance, air traffic control, weather and other issues, he said.

WHAT IS KNOWN ABOUT THE PLANE?

The 6 1/2-year-old plane's “technical condition was stable” and met requirements to fly, said Sun Shiying, the chairman of the Yunnan provincial branch of China Eastern Airlines.

The plane was flying from Kunming, the capital of Yunnan province in the southwest, to Guangzhou in the southeast.

The 737-800 has an excellent safety record, said Hassan Shahidi, president of the Flight Safety Foundation. It is from an earlier generation of the 737 series than the Boeing 737 Max jets, which were grounded after crashes in 2018 and 2019. The 737-800 does not have the flight control software that was blamed for the 737 Max crashes.

HOW HAS THE CHINESE GOVERNMENT RESPONDED?

The central government sent a team led by Vice Premier Liu He and a senior Cabinet official, State Councilor Wang Yong, to the site to “guide rescue work” and the investigation of the crash.