Development and qualification of S-76B category 'A' takeoff procedure featuring variable CDP and V2 speeds

Abstract

Most if not all twin engine Transport Category helicopters are designed to FAR Part 29 Category standards, but few are actually certificated for Transport Category Operations. Although recent FAR Airworthiness and Operations legislation sets minimum one engine inoperative (OEI) enroute performance standards, helicopter operators are still not required to follow FAA Certified Category takeoff and landing procedures, and it is doubtful many operators utilize helicopter manufacturers' published procedures which habe historically been inflexible with respect to optimization of payload and field lengths. This paper discusses the development and qualification of a Transport Category takeoff and landing procedure for the S-76B helicopter which provides the flexibility necessary to encourage helicopter operators to use the Rotorcraft Flight Manual zero exposure time takeoff and landing procedures thus improving overall safety. The takeoff procedure features variable critical decision point (CDP) and takeoff safety speed (V2). Rejected and continued takeoff distances are directly proportional to CDP and V2 speeds respectively, therefore lower CDP and V2 speeds equate to shorter field lengths. Maximum takeoff and landing gross weight is also directly proportional to CDP/V2 speeds, therefore higher CDP/V2 speeds can equate to higher maximum takeoff gross weights. This coupled with published headwind influence permits payload to be traded off against available field length in such a manner that Category OEI climb performance minima are maintained over a wide range of environmental conditions. The landing procedure features two different approach profiles. The primary landing approach path is intended for VFR approaches to airfields with minimum available space, with an alternate approach path providing a more shallow profile to address transition from instrument approach or where landing space is not critically short. A reduced gross weight and power single engine pilot training procedure was developed whereby the basic aircraft response and handling characteristics are preserved to provide a realistic training scenario by duplicating the all-up Category WAT limited power/weight ratio, but with the added safety advantage inherent when operating at a reduced gross weight. Timely development/qualification of this procedure was facilitated by newly developed real-time telemetry capabilities also discussed, Copyright @ American Institute of Aeronautics and Astronautics, Inc., 198f. All rights resewed. which include a microwave ranging aircraft position and tracking system (APATS) and CRT displays which permitted instantaneous flight maneuver validation and pilot technique modification decisioning. Also discussed are the potential for further technique enhancements for added operational flexibility, and the adaptation of the FAA certified procedure to CAA Group operations including the effect on paylbad segment APATS BCAR BL CAA CDP CG CRT CTO EAPS FADEC FAA FM FPM Gross IFR IGE ILS LDP MCP Net N1 OEI PCM Q RFM RTO T5 V ~ P P Vblss VFR VY Vl v2 Av WAT ofthe more stringkt 1st and 2nd CAA OEI climb performance minima.