An Alternative and Safer Approach to Takeoff and Landing Acceptable Means of Compliance (AMC/AC 27 and 29) and Air Transport Offshore Operations Regulation

The current certification requirements for multiengine rotorcrafts for takeoff and landing performance do not always provide a safe approach to the scenarios where the helicopters actually operate if compliance demonstration is achieved with the current accepted methods. Several critical aspects of these methods do not to produce "safe" flight envelopes and provide insufficient or inadequate operational information. The current regulations are long dated and not updated to reflect the advance in technology. The current accepted methods of compliance for the definition of the H-V envelope for multi-engine helicopters do not ensure the airworthiness required for all possible operations. For this reasons, the H-V envelope should not be considered a limitation for all CS29 multi-engine configurations and substituted by performance that would allow defining a safer envelope. Particular attention should also be given to operations over elevated helidecks and oilrigs where the environment is extremely demanding and not predictable. In order to get approval for these kinds of operations, specific testing methodology should be developed and approved. A detailed list of proposed changes for the Advisory Circular and applicable regulation is considered and new acceptable compliance methods for the following subjects are proposed for: Cat B Take Off; H-V envelope; Cat A performance for elevated/oilrig helidecks; Takeoff performance influential factors. The incorrect definition of the applicability of the H-V envelope has created an unsafe regulatory case also in the operational rules (AIR-OPS) for Operations in performance class 2 with exposure from helidecks.