Ontario's troubled air ambulance service was forced to ground some of its helicopters for tens of thousands of minutes over a three-month period because of a shortage of pilots and medics, CTV has learned.

Internal Ornge documents obtained by CTV show that some of the service's helicopters sat idle at bases across the province as the agency scrambled to find qualified staff.

The documents show that from Dec. 1, 2011 to Feb. 22, 2012, the helicopters sat for some 25,625 minutes due to a lack of pilots and 21,091 minutes due to a lack of medics for a combined total of nearly 47,000 minutes.

The shortages were caused by an increasing number of pilots calling in sick, while others were scheduled for training with no replacements available. The data is contained in so-called "down staff reports."

Meanwhile, the grounded helicopters sat idle at bases in Toronto, Ottawa and London in the south, and Kenora, Moosonee and Thunder Bay in the north.

Officials at Ornge were unable to confirm the numbers, but the company said in a statement it takes time to find replacements when two pilots are needed to fly the aircraft.

"On occasion, a replacement may not be found due to the limited number of pilots in the system. The same applies to Ornge paramedics," Ornge said in a statement.

Conservative MPP Frank Klees said the alarming numbers suggest Ornge is not fulfilling its role.

"The bottom line is that patients were put at risk over that period of time," he said. "The expectation is that an emergency air ambulance service is that; it's available on-call for emergencies. Something is fundamentally wrong at the operations centre of Ornge."

Ontario Health Minister Deb Matthews vowed to fix the problems at Ornge.

"Patient safety is number one. We can have the best helicopters, but if we don't have pilots and we don't have paramedics, then they can't fly to their full capacity. So this is very much a very important issue," she told CTV Toronto.

Last week, the Conservatives charged that Ornge faced at least 13 disruptions over the last three weeks alone putting patient safety at risk.

This latest findings comes on the heels of revelations that Ornge does not have permission from the Federal Aviation Administration for its helicopters to cross the border into the United States. In the event of an emergency, a patient has to be flown by airplane or driven by land ambulance.

The provincially-funded air ambulance organization has come under scrutiny in recent months, causing a shakeup of top management and its board. Earlier this month, the Ontario Provincial Police was called in to investigate alleged misuse of public funds.

With a report from CTV Toronto's Paul Bliss