The chopper was on a training flight from Canadian Forces Base Shearwater when it encountered the problems, navy Lt. Len Hickey said.
"In accordance with procedure, this requires a landing as soon as possible to limit any risk," Hickey said in an interview.
The helicopter made a controlled emergency landing in a vacant gravel lot near a Sobeys grocery market in the Halifax suburb of Bedford around 2:20 p.m., he said. Five military personnel were on board, but no one was hurt.
Crystal Forhart, a front-desk worker at a nearby dental clinic, said she heard a loud, startling noise as the helicopter suddenly descended.
"We all stopped and said, 'Did you hear that? It sounds like it is right on top of us,'" she said in a telephone interview.
"I'm just glad it didn't land on us."
Hickey said an investigator was sent to the scene at Peakview Way off Larry Uteck Boulevard, and officials will repair the helicopter on site if possible.
"Right now, we're just following up to find out exactly what happened," he said. "We don't know exactly what the issue is."
Hickey said the military goes to great lengths to ensure its fleet of helicopters is safe.
"Old or new, aircraft flying has an element of risk attached to it just by its nature," he said.
"We do everything we can to minimize the risk, but sometimes these things happen."
The Sea Kings have been at the centre of controversy for years as Ottawa's bid to replace the aging helicopters has been repeatedly delayed.
The federal government is currently renegotiating its contract with helicopter manufacturer Sikorsky Aircraft Corp., which was selected eight years ago to supply 28 new helicopters.
A $5.7 billion contract to acquire the CH-148 Cyclones was signed by the Liberal government of Paul Martin in 2004, a milestone event in the two-decade fight to find a replacement for the CH-124 Sea Kings after former prime minister Jean Chretien cancelled the first deal in 1993.
Sikorsky was required to deliver new state-of-the-art aircraft within four years, but the Harper government was forced to extend the contract in 2008 and toss in an extra $117 million after the program bogged down.
The Sea Kings began flying for the military in 1963.
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