A Sea King helicopter sits in a field off Highway 101 in Lower Sackville, N.S., where it landed after a hydraulic problem surfaced. (Phonse Jessome/CBC)

A Sea King helicopter made a precautionary landing in a grassy field off a Nova Scotia highway Tuesday because of a hydraulic problem, a military official said.

The aircraft set down off Highway 101 in Lower Sackville, north of Halifax, at about 8 p.m. The three crew members were not hurt.

Capt. Paul Finnemore, spokesman for 12 Wing Shearwater, said the crew members were on a training flight when they detected something wrong with the hydraulic system.

"It would be the equivalent of having an indicator light go off on your dashboard when you're driving your car," Finnemore told CBC News.

This meant the crew had to make a "precautionary landing" and choose a suitable place to put down, he said.

People in the residential neighbourhood gathered as technicians from the Shearwater airbase arrived to work on the helicopter.

Finnemore said the technicians discovered a loose connection on one of the hydraulic lines.

"They were able to repair the problem in relatively short order and top up the hydraulic fluid," he said.

Darlene Jollymore stayed up late to watch the technicians work and even got up at 4 a.m. so she wouldn't miss anything.

"I tell you, I'd do it all over again," she said. "It was really nice to see that power right in front of you like that and the adrenalin just going through you as you hear the noise."

The helicopter took off just before 7:30 a.m. The pilot lifted the aircraft about 10 metres off the grassy field, hovered for about two minutes, then flew away.

The Sea King is back at home at 12 Wing Shearwater.