A Cougar helicopter flight that left Monday morning destined for an offshore rig east of Newfoundland turned around and made an emergency landing in St. John's without incident.

Emergency vehicles were called to the Cougar airbase at the St. John's International Airport before the Sikorsky S-92A chopper landed after noon.

The flight was originally scheduled to land on the Henry Goodrich offshore drilling rig, which is currently working for Statoil.

Flight 141 was travelling with 6 passengers onboard Monday when the flight turned around.

About 20 minutes after leaving the airport, pilots noticed a "higher than normal vibration", so they decided to return to base as a precautionary measure. No alarms went off and the decision to return was made by the helicopter's pilots.

Late Monday afternoon, a Cougar spokesperson told CBC News that the helicopter was returned to service after mechanics inspected and tested the chopper and found nothing wrong with it.

Statoil is drilling a second exploratory well in its Mizzen prospect field in the Flemish Pass area, about 500 kilometres northeast of St. John's. It drilled its first well there in 2009.

A Cougar helicopter crashed into the ocean east of St. John's on March 12, 2009, killing 17 of the 18 people onboard.

That helicopter was also returning to St. John's on an aborted flight to offshore oil production facilities.