TOKYO (AP) _ Someone posing as an air traffic controller illegally instructed an Air France pilot to dump fuel over Japan's capital and fly at a dangerously low altitude, the Transport Ministry said Wednesday. The pilot ignored both commands.

As the Paris-bound jumbo jet was returning to Narita airport on Sept. 22 last year to fix mechanical trouble, a male voice suddenly ordered the pilot to dump the fuel, a ministry official said.

And when the plane approached the 12,460-foot Mount Fuji, there came another command, this time to lower altitude to about 4,950 feet.

The pilot, who later reported the orders to aviation authorities, said he thought something strange was going on and ignored the commands, which were given, just like the real ones, in English, the official said.

The plane landed safely at the Tokyo International Airport in Narita.

The ministry official, speaking on condition of anonymity, said the fake commands were on a radio frequency for communications used by air traffic controllers to contact pilots.

But he said there was little authorities could do because such frequencies are not kept secret. Air traffic communication frequencies are published in specialized manuals, although their unauthorized use is illegal.

The Post and Telecommunications Ministry is investigating the case.