Four days after a jet crash in northeast China's Heilongjiang Province that killed 42 people on board, rescue for survivors continued at several hospitals in the remote city of Yichun, the provincial capital Harbin and Beijing.

By Saturday, 45 of the total 54 survivors on board the Brazil-made ERJ-190 that crashed upon landing Tuesday night have been transferred to big hospitals for better treatment.

Ten of them arrived in Beijing Friday night and were hospitalized at Jishuitan Hospital and the No. 3 Hospital affiliated to the Peking University, Beijing Health Bureau said in a statement Saturday.

Thirty-five are being treated in Harbin.

Doctors in Harbin said 17 of the victims still faced life threatening dangers with serious burns or head and chest wounds.

Among them were five children, aged from 6 to 10.

Nine people with slight injuries stayed in Yichun for treatment, a spokesman with the Yichun city government said Saturday.

The next of kin of at least 40 dead are hoping to identify their loved ones Saturday, as DNA test results have been published, the official said.

The Lindu Airport of Yichun, where the deadliest commercial plane crash in China in nearly six years happened Tuesday night, resumed operation Thursday.

The aviation industry watchdog, the General Administration of Civil Aviation (CAAC) said Saturday investigation of the crash would take a pretty long period.

"The probe involves every aspect of the jet -- its manufacturer, operator, pilot, crew, maintenance record as well as the air traffic management and airport authorities," said Li Jian, CAAC vice director who arrived at the scene shortly after the disaster.

Li said the CAAC had to be scrupulous in publishing any results of the investigation. "They (such results) will have to withstand the test of time and history. We therefore need more time for that."

At a meeting attended by all investigators of the plane crash in Yichun Saturday morning, Li said rescue work remained vital. "Some patients may suffer complications after the first 72 hours, and we have to watch out for that closely."

According to a Henan Airlines flight schedule, the crashed ERJ-190 was its only aircraft serving on all 10 routes in Heilongjiang Province, connecting Harbin with five small airports including Yichun, Mohe, Mudanjiang, Jiamusi and Jixi.

It flew all 10 routes every Tuesday, Thursday and Saturday, covering about 7,000 km from 8 a.m. to 11 p.m.

When it crashed in Yichun Tuesday, it had flown nine routes, adding up to more than 6,000 km.

It was unclear how many hours the pilot had been flying when the accident happened.

Yangtze Evening News, a newspaper based in the eastern Jiangsu Province, reported Saturday that CAAC had ruled out pilot's fatigue, quoting CAAC press official Zhong Ning.

The same official refuted the report with Xinhua reporters Saturday morning, saying she had never made such a comment.

On Friday, the provincial government of Henan -- after which the ill-fated carrier of the crashed plane was named -- revoked the company's name to protect its own reputation.

The Henan Administration for Industry and Commerce said late Friday it had revoked the name change of the airline from Kunpeng Airlines to Henan Airlines, which was approved in September 2009, adding that the name misled the public and tarnished the province's image.

It said the administration was justified by law to revoke any name change of a company which was either misleading or harmed the province's interest.

Henan Airlines was previously known as Kunpeng Airlines. It was re-launched as Henan Airlines after its headquarters was moved to Zhengzhou, capital of Henan Province, in September 2009.

The company was founded by China's Shenzhen Airlines and two overseas companies in 2007. The re-launch in 2009 did not affect the company's portfolio and the provincial government never invested in it, Henan commerce authorities said.