SHANGHAI - China Eastern Airlines has pledged to improve the English language skills of its flight crew amid investigations into claims that one of its planes took off in Japan without clearance from air traffic control.

Details of what happened on Monday in Osaka remain unclear, yet initial reports suggest that an Airbus 330 operated by the Shanghai-based airline used a runway at Kansai International Airport before getting authorization to do so.

According to Kyodo News Agency, the airport's air traffic coordinator had told the pilot of flight MU516 in English to taxi to a runway and await further directions. However, the aircraft, which was carrying 245 passengers, instead took off.

The airplane landed safely later that afternoon at Shanghai's Pudong International Airport.

Japan's Ministry of Land, Infrastructure, Transport and Tourism said the pilot's actions could be considered a breach of the International Civil Aviation Covenant, even if the plane was kept at a safe distance from other aircraft landing and taking off.

Authorities in Japan are trying to determine whether the pilot intentionally ignored the order to wait.

However, the ministry said the probe is intended largely to prevent similar cases from happening, adding that there will be no punishment for the pilot, regardless of the results.

China Eastern on Wednesday issued a statement saying it will actively cooperate with investigators.

The company said it will also "further improve the English communication skills of its crew to assure flight safety", indicating that the incident may have been caused by a simple misunderstanding.

An industry insider who spoke on condition of anonymity said that although receiving orders from airport coordinators is one of the most basic skills for a pilot, accents and the varying usage of English can cause misunderstandings.

In October, an Hawaiian Airlines flight leaving Kansai International Airport for Honolulu also failed to follow orders from air traffic control and mistakenly entered a runway where a cargo jet was approaching to land.

The insider said the pilot of Monday's MU516 flight is unlikely to have disobeyed orders deliberately, as "ignoring such instructions benefits nobody".

In determining what actually happened that day, recordings of communication between the China Eastern crew and the control tower in Osaka will likely prove to be vital evidence.

"We've written to our Japanese counterparts asking for materials to help us look into the case," said a Civil Aviation Administration of China official surnamed Zhang.

Experts say that if the pilot is found at fault, he or she will face severe punishment from the Chinese authorities, as safety is regarded as being essential to the air transport industry.

According to media reports, China Eastern has so far taken no action against its crew.