HeliSASTM Stability Augmentation System and Autopilot for Helicopters
The links shown below provide detailed information about the HeliSASTM stability augmentation system and autopilot developed and certified by Hoh Aeronautics, Inc. HeliSAS is approved by the FAA for installation on Robinson 44s with hydraulic controls, Bell 206B, L, L-1, L-3, L-4, 407 helicopters, and Eurocopter AS350B, BA, D, B1, B2, B3, and EC130B4 helicopters. HeliSAS is licensed to Cobham and may be purchased from S-TEC, a division of Cobham in Mineral Wells, TX. Also see the S-TEC HeliSAS.com website.
Please click on the following links for more detailed information on HeliSAS.
Overview of HeliSAS System
Pilot Operating Handbook for the HeliSAS SAS/AP system.
Rate vs. Attitude-Command-Attitude-Hold (ACAH) Stability Augmentation. This article is intended to clarify misconceptions regarding the definition of a stability augmentation system. A technical paper that quantifies the safety advantages of ACAH stabilization was presented to the American Helicopter Society in 1998 – “ACAH Augmentation as a Means to Alleviate Spatial Disorientation for Low Speed and Hover in Helicopters”.
HeliSAS Article from Vertical Magazine
HeliSAS as “Editors Choice” from Rotor and Wing
FAA Approved Rotorcraft Flight Manual Supplements may be accessed from the following links,
· Bell 206B, 206L, 206L-1, 206L-3, 206L-4
· Bell 407
· Eurocopter AS350B, AS350BA, AS350D, AS350B1, AS350B2, AS350B3, EC130B4.
With the exception of the R44, the HeliSAS STCs have been transferred from Hoh Aeronautics, Inc. to S-TEC/Cobham in Mineral Wells, TX. All sales, installation, and maintenance enquiries should be directed to S-TEC. Hoh Aeronautics, Inc. is available to answer technical questions regarding HeliSAS on any helicopter.
The R44 HeliSAS is currently not available for sale due to product liability insurance issues.
HeliSAS is installed on the Bell 212 (UH-1N) at the National test pilot school. It is not FAA certified on this aircraft, because its Certificate of Airworthiness is permanently in the Experimental category. The version of HeliSAS installed in this helicopter is integrated with the S-TEC/Chelton Flight Logic EFIS and is called HeliSAS-E. All interfaces for HeliSAS-E installations are via ARINC 429. HeliSAS-E provides additional functionality such as airspeed hold, vertical speed hold, and enroute V-NAV functions. HeliSAS-E (Version 50 software) has completed V and V testing and is fully FAA approved.
HeliSAS is offered by Bell Helicopter Textron on the new BHT 407GX, where it is integrated with the Garmin G1000 EFIS.
The originally certified versions of HeliSAS did not offer beep trim as an option. However, this is now available on new installations and as a retrofit to existing installations.
A safety feature sometimes referred to as “return to level flight” is offered on some new autopilots. HeliSAS does not have a “return to flight” button because it is an implicit feature of the system. If HeliSAS is engaged it will return to level flight if the controls are released. Even if HeliSAS is not engaged, it will return to level flight if the pilot simply engages the system by pressing the trim button on the cyclic or pushing the SAS button on the autopilot control panel. HeliSAS is always in standby mode (there is no “off” switch), so engagement is immediate. HeliSAS has been demonstrated to return to level flight from bank angles up to 90 degrees in the test R44 helicopter.