In 1987, HeliAir, an operator of Bell 222s, initiated development of an STC to replace the Lycoming LTS101 engines on the Bell 222A with Rolls-Royce (then Allison) 250 series engines. The purpose of the engine change was to replace the unreliable standard engines with the more reliable Rolls-Royce engines. No other changes were made and thus, other than the engine change, the Bell 222SP is the same as the Bell 222A.
The Bell 222 had its genesis in the early 1970s when it became clear that there was a demand for a medium twin-engine turbine helicopter for the offshore and corporate market. Bell, among others, launched a series of design studies that resulted in a decision to launch the Bell 222 in 1974. The subsequent design represented many firsts for Bell. It was Bell's first helicopter designed from scratch for the civilian market; it was not based on any military design; it had a retractable, wheeled landing gear; its rotor system design was the first to depart from the teetering rotor developed in the 1940s by Art Young; and it used a newly developed engine, the Lycoming LTS 101. On paper this was a great engine, with a high power-to-weight ratio and modest fuel consumption. Unfortunately, even in the upgraded form used on the Bell 222B, it proved to be less reliable than the customers expected and this was one of several factors, including a serious recession in the helicopter industry, which severely limited the market potential for this helicopter.
The Bell 222A uses a two-bladed rotor attached to the hub with elastomeric bearings for the flapping, lagging and pitch change motions. The main transmission uses a “nodamatic” suspension system to reduce vibration levels. The engines used on the Bell 222SP are the Rolls-Royce (then Allison) 250-C30G. A two-bladed tail rotor provides directional control. The fuselage provides two compartments, with the pilot compartment seating two and the passenger cabin seating up to eight. The fuselage is made of conventional aluminum alloys. The passenger cabin is available in three basic configurations. One is a corporate interior with two comfortable seats facing aft and a three-place bench facing forward. The second, the utility configuration, has three forward-facing seats rows (two with three seats and one with two seats). The third configuration is for EMS operators. This configuration puts two stretchers, two medical attendants and medical gear in the cabin.
Development of the Bell 222SP was initiated in 1987 and the STC was obtained in 1990, as was IFR certification. The STC is applicable to the roughly 85 Bell 222As produced between 1992 and 1995. It is not known how many of these Bell 222A were upgraded to 222SP models.