ABBOTSFORD, B.C. - The oft-maligned F-35 has passed an important development milestone by dropping its first test bomb.

The practice run happened Wednesday at an air test range along the Patuxent River in Maryland.

The stealth fighter has been the subject of raging controversy in the U.S. and abroad including in Canada, where the auditor general slammed the Harper government last spring for its planned purchase of 65 jet fighters.

A vertical take-off and landing version of the multi-role fighter the 'B' variant successfully dropped an inert, 453-kilogram smart bomb on a target.

Steve O'Bryan, Lockheed Martin s vice president of F-35 business development, says the program is hitting its benchmarks and remains ahead of its plans in the flight test program.

The U.S. defence giant has been criticized for delays and huge cost overruns in the $389-billion program, the largest single defence procurement in U.S. history.

If and when Canada formally signs a contract for the "A' variant, the F-35 would also become this country's largest defence acquisition.

Much of the debate over the aircraft has revolved around the price tag for individual aircraft, a figure that is tied to the number of orders in any given year.

There has been rampant speculation in the U.S. that the Pentagon plans to carve between 10 and 30 per cent out of its order of 2,443 aircraft effectively driving up the price for itself and everyone else.

O'Bryan dismissed it as just speculation and pointed to the Obama administration's recent budget and a Pentagon assessment that indicates the order has not changed.

Note to readers: This is a corrected story. A previous story wrongly said the practice run occurred off Atlanta

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