A military hearing for two U.S. pilots blamed in the accidental bombing deaths of Canadian soldiers in Afghanistan will take place on Jan. 13, a U.S. air force spokeswoman announced Tuesday.

Maj. Harry Schmidt, 37, and Maj. William Umbach, 43, will face an Article 32 hearing at the Barksdale Air Force Base in Louisiana to determine if there is enough evidence to go ahead with a trial.

The two men have been charged with involuntary manslaughter, aggravated assault and dereliction of duty for the April 17 accidental bombing that killed four Canadian soldiers and injured eight others.

The troops, all members of Edmonton's Princess Patricia's Canadian Light Infantry, were conducting a live-fire nighttime exercise south of Kandahar when Schmidt dropped a 225-kilogram bomb on the group.

A Canadian and joint Canada-U.S. military inquiry accuse the pilots of not following procedure before dropping the bomb. The pilots claim they were acting in self defence.

An unidentified Canadian officer who served as mission crew commander to a U.S. Airborne Warning and Control System (AWACS) the night the troops were bombed is also expected to take part in the hearing.

"Canadian witnesses will be involved," said David Beck, Umbach's civilian lawyer in Knoxville, Tenn.

The officer told the F-16 pilots not to drop the bomb, but that order was overridden when one of the pilots declared self defence.

Many have come to the aid of Schmidt and Umbach, who are facing six-figure legal bills.

Recently, Illinois Gov. George Ryan threw the pair an opulent $50-a-person fundraiser.

Several other fundraising events, such as community barbecues, have been held to help cover the pilots' mounting legal costs, which are expected to exceed $100,000 each. A 183rd Pilots' Defence Fund website has also been created to promote their case.