CBC News has learned that an Emergency Health Services flight between Halifax and Sydney, N.S., had a brush with disaster after severe weather triggered a mid-air emergency.

Sunday, Dec. 15 was a day of heavy rain and snow in Nova Scotia, with temperatures fluctuating wildly from -16 C to above the freezing mark. Many flights across the Maritimes were delayed or cancelled that day, but an EHS flight leaving from Sydney bound for Halifax took off.

The Beechcraft Super King Air 200 is operated for EHS by Provincial Airlines, and is used to transfer critically-ill patients to other facilities.

The plane took off from Sydney airport that night carrying two pilots, two medical personnel, one passenger and one patient. Right away, ice began to build up on the plane’s fuselage.

A report from Transport Canada said pilots wanted to climb to 5,000 metres (16,000 feet), but they lost control twice, suddenly plunging about 300 metres (1,000 feet) and declaring a mayday.

EHS plane

The flight took off from Sydney airport on the night of Dec. 15 carrying two pilots, two medical personnel, one passenger and one patient. Right away, ice began to build up on the plane’s fuselage. (Photo: Michael Durning)

On the advice of air traffic control, the pilots headed to the coast, and lower altitudes, where warmer air melted the ice away.

The flight continued safely to Halifax without further incident.

According to Transport Canada, the aircraft's anti-icing equipment was functioning properly. The loss of control was likely due to ice accumulation on the tail of the plane.

CBC News contacted Transport Canada, EHS and Provincial Airlines about this incident.

EHS and Provincial Airlines declined an interview.

In a written statement, EHS said the aircraft was not at risk, and that an in-depth review of the incident is underway.