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Accident Sikorsky CH-148 Cyclone
Although the case of the Boeing 737 MAX is perhaps the most popular case of accidents caused by the flight control, it is not the only one. This report presents a brief study on the CH-148 Cyclone accident from the Royal Canadian Air Force that left 6 fatalities behind.
Few information is available due to the confidentiality of the Royal Canadian Air Force, two reports’ state that the autopilot was left on as the pilot executed a sharp turn, and as a result the software built up commands, preventing the pilot from resuming manual control at the end of his turn.
The first military report (the Board of Inquiry report) referred to this accumulation of calculations from the automated software as “attitude command bias.” This report said these commands in the software “can accumulate to such a degree that it severely diminishes, or even exceeds,” the pilot’s ability to control the aircraft manually.
This description of “accumulation bias” is unclear. However, it pretty much sounds like a antiwind-up problem that shows up in integral controllers where the control action is insufficient to correct the path.
