ALL-OUT EFFORT: Chinese naval vesselJinggangshan, the largest amphibious landing ship in the Chinese Navy, taking part in the search-and-rescue operation in the Gulf of Thailand on March 11 (BAI RUIXUE)

In the meantime, assistance to the families in Beijing that have been affected has been intensified. Besides accommodation and medical services, MAS promised 31,000 yuan ($5,059) in financial aid to the family members of each missing passenger.

The Beijing Municipal Government offered one-on-one legal consultancy, ambulances as well as psychological counseling and guidance to some 120 passenger family members and friends.

"I won't need a passport if my daughter were to stay with us in our hometown in Hebei," said a middle-aged man surnamed Zhang, father of a missing passenger on the scene of passport accreditation at 9:30 p.m. on March 9. "I did not have the courage to tell my wife about the truth. I wish it were just a nightmare."

Similar to Zhang, most of the passenger's family members did not have a passport before the incident happened. It took only 40 minutes for Zhang to get his travel document. Normally, the process for a first-time applicant is seven to 10 business days and requires numerous documents.

The Malaysian embassy in Beijing issued more than 300 visas so affected families could go to Kuala Lumpur. "I don't see any need to go there. I'd rather stay in Beijing for updates," said newlywed Zhang Zhiliang.

A 13-member joint working group sent by the Chinese Government arrived in Malaysia on March 10 for handling the aftermath of the incident.

A total of 23 family members of the missing Chinese passengers had arrived in Kuala Lumpur as of March 13, according to the group's verified Sina Weibo account which received 190,000 followers in nearly three days.

"Any search-and-rescue effort is worth undertaking. The cost is not an issue," said the working group at a press conference in Chinese Embassy on March 12. "There is no end to the work until the aircraft is found."

The MH370 and MH371 flight codes retired from MAS after new codes ---- MH318 for flight from Kuala Lumpur to Beijing and MH319 from Beijing to Kuala Lumpur –-- used effective since March 14 "as a mark of respect to the passengers and crew of MH370 on March 8," the carrier said in a statement.

Unknown whereabouts

Unfortunately, no traces of the flight have been found as of March 13, the sixth day of search-and-rescue operations.

All communication systems cut off at 1:30 a.m., but the MH370 may have been tracked by the military's air defense radar 45 minutes after the aircraft disappeared from civilian radar. The discovery raised the possibility that MH370 could have turned back after all radio and civilian radar contact was lost, according to the online versions of newspaper The Star.

Tan Sri Khalid Abu Bakar, Inspector-General of the Malaysian Police, said on March 11 that they were looking into four possibilities, "hijacking, sabotage, psychological problems as well as personal problems of passengers and crew members."

"The last transmission from the aircraft was at 1:07 a.m., which indicated everything was normal," said Malaysian Acting Transport Minister Hishammuddin Hussein at a press conference on March 13. "Rolls Royce and the Boeing team are here in Kuala Lumpur, and have been working with us and the investigation team since Sunday [March 9]. These issues have never been raised."

The most likely explanation for its disappearance, according to Zhou Jisheng, chief designer of Changsheng Aircraft Design Co., Ltd, was a sudden collapse that left the pilots no time to place a distress call or handle the emergency.

"A search at sea is very difficult, especially when you do not know exactly where the plane disappeared," said Jean-Paul Troadec, former director of French Bureau of Enquiry and Analysis for Civil Aviation Safety.

It took six days to find the first piece of debris of Air France Flight 447, which slammed into the Atlantic Ocean enroute from Rio de Janeiro to Paris, killing all 228 people on board on June 1, 2009.

"It took the French two years to find them [the aircrafts black boxes] -- only they were able to reveal what really happened," Troadec said.