'Heading Preset Mode' as a Means to Allow the Use of Modern AHRS in Helicopters for Operations in Areas of Severe Magnetic Disturbance

摘要

Helicopters have traditionally used DG mode (un-slave directional gyro mode) as a means to avoid the influence of severe magnetic disturbance when operating from affected helipads. Helipads, by the nature of their location and construction, will continue to be affected by severe magnetic disturbance. Modern Attitude and Heading Reference Systems (AHRS) are now using "MEMS" technology to achieve low-cost glass cockpits. This technology, with few exceptions, does not allow for a DG mode. In addition, AHRS manufacturers are adding smart validation features that shut down the heading solution when faced with a severe magnetic disturbance. Bell Helicopter has developed and certified a methodology called "Heading Preset Mode" as a solution for the issue. In addition to dealing with the technological problems, the solution is implemented with a crew interface specifically designed for the way helicopters are flown into and out from helipads with severe magnetic disturbance.