From US Army Mi-17 Operators Manual. (2007)
2-31.1 Pilot’s Collective Stick
The pilot’s collective stick (Figure 2-2) is mounted on the cockpit floor to the left of the pilot’s seat. The stick includes the twist-grip throttle control with friction adjustment (11), covered control buttons for external cargo emergency jettison (9) and normal release (12), a spring-loaded N2 trim INCR/ DECR switch (7), a searchlight control button (10), and a CLUTCH RELEASE button (13). A hydraulic clutch holds the stick securely in any position, allowing the pilot to make smooth pitch adjustments and preventing the stick from creeping. Ordinarily, the clutch is adjusted manually using the handwheel (5) to allow the stick to be moved, without releasing the clutch, with a force of 45 to 55 lb. The CLUTCH RELEASE button activates the hydraulic clutch release system, allowing the stick to be moved with a force no greater than 3.3 lb. When the button is released, the clutch re-engages. The CLUTCH RELEASE button also disengages the autopilot altitude channel. The clutch release circuit is powered by 27 VDC. The ECLs are mounted on the left side of the collective bracket.