A helicopter en route to ExxonMobil’s Hebron platform off eastern Canada was forced to abandon its flight and return to base after an indication of a potential pressure loss in a pressure system.

The Cougar helicopter was en route from St John’s in Newfoundland to the facility when there was “an indication of potential pressure loss on one of its redundant hydraulic pressure systems”, the Canada- Newfoundland Labrador Offshore Petroleum Board (C-NLOPB) said in an incident report on Monday.

C-NLOPB said ExxonMobil reported the incident on Monday, although it is unclear if this is the day the incident occurred.

There were 11 passengers and crew on board Cougar flight CGR151 at the time, it said.

“The helicopters flown offshore by Cougar have multiple, independent hydraulic systems and can fly safely with one system inoperable,” C-NLOPB added.

“Flight CGR151 returned to St John’s and landed safely, with the Cougar SAR helicopter having been dispatched as per Cougar protocols.

“Local emergency crews were on stand-by in accordance with St John’s International Airport procedures. These are standard precautionary measures in response to this type of indication.”

The aircraft will be repaired and returned to service, with Cougar confirming there is no fleet-wide issue.

“Transport Canada and the Transportation Safety Board are aware of the event and the C-NLOPB is monitoring ExxonMobil’s continued investigation,” C-NLOPB said.

Hebron is about 200 miles (350 kilometers) off Newfoundland and Labrador and sits in some 300 feet of water (92 metres).

ExxonMobil operates Hebron on 35.5% and is joined by fellow US supermajor Chevron on 29.6%, Canadian giant Suncor on 21% percent, Norway's Equinor on 9% and Nalcor Energy Oil & Gas on 4.9%.

The facility - which is comprised of platform topsides are supported by a gravity-base structure (GBS) - came online at the end of November last year.

It will produce up to 150,000 barrels per day at its peak, with an estimated recoverable resource of 700 million barrels.

Storage capacity is for up to 1.2 million barrels of oil. The GBS is a reinforced concrete structure designed to withstand sea ice, icebergs and extreme meteorological and oceanographic conditions.