Availability of Canada's CH-149 Cormorant search-and-rescue helicopters is less than 50 percent, and minimum operational requirements can only be met by buying more aircraft or reducing maintenance inspections, says an official report.

Canada purchased 15 of the AgustaWestland EH101 helicopters in 1998 on the assumption of 75 percent availability, but a study by Defence Research and Development Canada (DRDC) found actual figures vary from 37 to 50 percent.

Lower than expected availability and the loss of an aircraft in 2006 has restricted the Canadian Forces to flying Cormorants from only three of the four planned main operating bases (MOBs) and to use smaller Bell CH-146 Griffons at the fourth.

As recently as late October, all four Cormorants at the Gander MOB were out of service at the same time: one with a maintenance issue, one with damaged blades after a training incident and two in scheduled maintenance.

Canada's Department of National Defense says it is still evaluating the report, which was completed in June. Just released publicly, the report warns the 14 helicopters may not be able to operate indefinitely without changes to inspections.

DRDC studied whether the Cormorant's low availability could be overcome by improving logistic support, but even with ideal access to spares 25 aircraft would be needed at four MOBs, or 19 at three, to meet the availability requirements, it concluded.

If the duration of major, minor and out-of-sequence maintenance inspections could be trimmed by 25 percent, the study found, the number of aircraft required would be reduced to 20 for four MOBs, or 15 for three.

"It should not be expected that the current fleet of 14 aircraft can operate indefinitely from four, or even three, MOBs without significant changes to the fleet's maintenance program," the report concludes.

Photo: Canadian National Defense Ministry