UH-60 Partial Authority Modernized Control Laws for Improved Handling Qualities in the Degraded Visual Environment

The U.S. Army's helicopter fleet consists chiefly of aircraft developed in the 1960's and 1970's with flight control systems based on the requirements of that time. Since then, Army helicopter operations have changed from predominantly daytime, good visual environment (GVE) operations to night and degraded visual environment (DVE) operations. Rotorcraft handling qualities and flight control requirements did not address DVE operations until the introduction of ADS-33 in 1985. Numerous attempts to improve the handling qualities of rotorcraft in the DVE through flight control upgrades have been studied with the CH-47F DAFCS representing a successful partial-authority solution. In 2000, AFDD and Sikorsky developed the UH-60 Modernized Control Laws (MCLAWS) which were intended to satisfy the ADS-33 DVE requirements using the existing limited-authority actuators. While the original program ended in 2003, the effort was resumed at AFDD in 2012 with numerous improvements incorporated into the MCLAWS. Flight tests in brownout conditions at Yuma Proving Ground demonstrated that the MCLAWS resulted in reduced the pilot workload when compared to the legacy UH-60 SAS/FPS control system. A handling qualities evaluation conducted at Moffett Field in simulated DVE conditions on five ADS-33 mission task elements demonstrated Level 1 handling qualities.