Aircraft Flight Operation Regulations Article 88

Performance of helicopters during en-route phase shall meet the following requirements:1. Operations in performance Classes 1 and 2. The helicopter shall be able, in the event of the failure of the critical power-unit at any point in the en-route phase, to continue the flight to a site at which the conditions of the first or the second subparagraph in the first paragraph of Article 89 can be met, without flying below the appropriate minimum flight altitude at any point.2. For performance class 3 helicopters. The helicopter shall be able, with all power-units operating, to continue along its intended route or planned diversions, without flying at any point below the appropriate minimum flight altitude. At any point below the flight path, failure of a power-unit with cause the helicopter to force landing, therefore the conditions stated in Article 85 shall apply.A helicopter equipped with 3 or more power-units shall be able, with the failure of any 2 power-units, to continue the flight to an appropriate site for landing.