SYDNEY, Australia (AP) _ A fuel contamination scare that has crippled Australia's light aircraft industry may end soon, thanks to a new test to tell if a plane is safe to fly, aviation officials said Sunday.

Some 5,000 small aircraft in Australia's eastern states have been grounded for 13 days over concern that batches of airplane fuel made by Mobil Oil Australia Ltd. could clog engines.

In response, Mobil has developed a test to determine if a plane's fuel system has been contaminated, said Mick Toller of the Civil Aviation Safety Authority.

Until now, operators had no way of knowing if their plane's engine had been damaged.

Mobil has begun distributing the test to small aircraft operators across southeastern Australia, and some planes could be flying as soon as Monday, Toller said.

If the test detects contaminated fuel, the fuel system will have be cleaned, he said.

On Jan. 10, CASA grounded all aircraft running on fuel made at Mobil's Melbourne plant between Nov. 21 and Dec. 23, throwing an industry worth $330 million a year into crisis.

Small regional airlines, charter services and flight schools were affected. Crops were left undusted, and some medical and wildfire fighting services scaled back.

Turboprop planes, such as jet airliners, are not affected.

Mobil Oil Australia, a subsidiary of U.S.-based Mobil Exxon Corp., says the contamination was a result of a mistake in the production process, but it has not admitted liability for losses. It has offered operators a $10 million assistance package.

The Aircraft Owners and Pilots Association has launched a class action suit on behalf of operators against Mobil, seeking an unspecified amount of damages for financial losses since the planes have been grounded.