By Sugita Katyal and Victoria Bryan
TOKYO/FRANKFURT (Reuters) - Airlines pulled in extra, larger aircraft on Thursday to help thousands of people leave Tokyo, and some began screening planes, passengers and crew for radiation as Japan raced against nuclear disaster.
As an increasing number of governments from Britain to New Zealand to South Korea advised citizens to leave quake-affected northern Japan, airlines mobilized for a stream of mainly outbound traffic from one of the world's biggest cities.
Japan has been taking desperate measures to contain a crisis at the Fukushima nuclear power plant, crippled by the earthquake and tsunami that devastated the northeast on Friday.
"We can keep flying even if the situation deteriorates further. But never say never; we don't know what will happen there over the coming days and weeks," Christoph Franz, chief executive of Germany's Lufthansa, said in Frankfurt.
The U.S. State Department said the government had chartered aircraft to help Americans leave Japan and had approved the voluntary departure of family members of diplomatic staff in Tokyo, Nagoya and Yokohama -- about 600 people.
The U.S. travel advisory came after Australia urged citizens with nonessential roles in Japan to consider leaving Tokyo and the eight prefectures most damaged by the earthquake. Australia cited infrastructure problems rather than nuclear concerns.
"We have a real problem in terms of the infrastructure in Japan. We have uncertainty of power supply, we have problems with train services, we have problems with public transport services, many schools have closed, and there is this repeated series of aftershocks," Australian Foreign Minister Kevin Rudd said.
Authorities worldwide responded to concerns about the possible health impact from radiation by starting checks on people, planes and boats. Authorities worldwide responded to concerns about the possible health impact from radiation by starting checks on people, planes and boats.
About 25 passengers arriving in Taiwan from Japan were found to have radiation levels slightly higher than normal, a government official said on Thursday.
Authorities in South Korea reported unusually high radiation levels on three passengers arriving from Japan. Malaysia, which has been screening air passengers, bags and aircraft since Monday, said it would scan ports.
A trace amount of radiation was found on cargo packaging aboard a United Airlines jetliner from Tokyo on Wednesday but officials said the amount was not harmful. Authorities found nothing out of the ordinary on Thursday at U.S. airports.
The U.S. Customs and Border Protection (CBP) said it was monitoring developments in Japan checking for radiation contamination on aircraft entering the United States.
"No aircraft entering the United States has tested positive for radiation at harmful levels," the CBP said in a statement.
Gordon Thompson, a plasma physicist and executive director of the Institute for Resource and Security Studies in Cambridge, Massachusetts, said the danger from flying through a radiation plume depends on the amount of releases into the atmosphere.
He said the typical flight speed of a commercial airliner means it would probably travel through a radiation plume relatively quickly, and added risk of exposure would likely be greater when a plane is taxiing on a runway.
"For commercial travel, the concern would be in the takeoff and landing and ground phases," he said.
"If a plume were to pass across an airport that could be of considerable concern," he added.
Lufthansa extended plans to divert flights away from Tokyo to Osaka and Nagoya until March 27 and said it was scanning aircraft arriving from Japan but that all results had so far come back negative.
Air France said it was checking planes and offering medical advice to crew, 10 of whom agreed to be scanned for radiation by France's nuclear safety agency. The results of all the tests were negative, a spokeswoman said.
TRAFFIC OUT OF JAPAN
Meanwhile, Britain said it was chartering flights from Tokyo to Hong Kong, which would cost 600 pounds ($967) per person. Britons directly affected by the tsunami would not be charged.
France and Germany have also advised citizens in Tokyo to get out or head to southern Japan. France's ambassador in Tokyo, Philippe Faure, said he expected about 500 nationals to be flown out on two special Air France planes on Thursday, with 700 to 800 leaving the following day.
Air India increased flights and used bigger planes to help bring back Indians from Japan. It has been using a Boeing 747-400 jumbo jet with a capacity of 423 passengers, a spokesman said [ID:nL3E7EH1D1].
Airlines did not provide much information on passenger loads in and out of Japan, but travelers reported nearly one-way traffic out of the country. Japan-bound passengers said flights were nearly empty.
Airport staff at London's Heathrow and Amsterdam's Schipol airports said fewer people were buying tickets going to Japan.
"We have seen a modest decline in demand for Japan travel since the earthquake. However, there is a measurable decline on U.S.-to-Japan routes," United Continental Holdings spokeswoman Megan McCarthy said.
Delta Air Lines, which runs more flights to Japan than any other U.S. carrier, said it would suspend its daily flights from Tokyo's Haneda Airport to Los Angeles and Detroit beginning next week. The move was taken "to maximize operational efficiency," the carrier said.
AMR Corp, parent of American Airlines, said its traffic was lighter going into Japan. "Outbound from Japan is heavy," said spokesman Tim Smith.
($1 = 0.6203 pound)
(Reporting by Isabel Coles, Ivana Sekularac, Maria Sheahan, Karen Jacobs, John Crawley and Kyle Peterson in the United States and other Reuters bureaus; Writing by Sugita Katyal and Victoria Bryan; Editing by Tim Hepher, Jon Loades-Carter and John Wallace, Gary Hill)