Chinook CH-47/Systems

SECTION 2. SYSTEMS

1 Helicopter

1.1 General

The Shergood CH-47D is a twin-turbine engine tandem rotor helicopter designed for transportation of cargo, troops and weapons during day, night, visual and instrument conditions. The heicopter is powered by two T550GA-714A shaft-turbine engines on the aft fuselage. Each engine drives a separate engine transmission. Drive shafts from each engine transmission is connected to a shared combining transmission which in turn drives the forward and aft transmissions. The forward transmission is housed in the forward pylon above the cockpit, the combining transmission is housed on the forward side of the aft pylon, and the aft transmission is also housed in the aft pylon behind the combining transmission. When the rotors are not turning, and APU (Auxilary Power Unit) can be used to supply electrical power and hydraulic pressure. Fuel is carried in pods on the sides with main, forward auxilary and aft auxilary tanks on each side. An entrance door is located on the forward right side of the main cabin, while a hydraulically powered ramp is in the back.

1.2 Gross Weight

The maximum gross weight is 50,000 pounds.

1.3 Landing Gear Systems

The landing gear system consists for four non-retractable landing gears mounted on the fuselage pods. The forward gear a fixed with twin wheels. The aft landing gears are single wheels mounted on swivels. In addition, the aft right gear can be steered from the cockput to improve ground handling. Landing Gear Proximity Switches Proximity switches are mounted on each aft landing gear. GROUND CONTACT lights on the maintenance panel in the aft rear of the helicopter indicate when the switches have been activated. While ground contact switches are activated, the trim system will position the forward and aft rotors on GND position for better ground handling.

1.4 Steering and Swivel Lock System

The ground steering control panel (see ) is located on the center panel between the pilot and co-pilot seats. The ground steering mode is controlled by a three position switch with the following positions:

• STEER - Active steering of the right rear wheel.
• UNLOCK - Free castering of the rear wheels.
• LOCK - Rear wheels locked in straight forward position.

The steering system is powered by the utility hydraulic system. In addition the PWR STEER switch on the upper console must also be in the ON position to use ground steering, or change the active steering mode. When the STEER steering mode is selected, the "keyboard" control mode is active, and the helicopter is in ground contact, the left/right arrow keys that normally control lateral cyclic will switch to controling the wheel position displayed as pedal inputs.

1.5 Parking Brake

A parking brake is located below the lower left corner of the pilot-side instrument panel. Click the parking brake to pull or push the handle. A green "PARK BRAKE ON" capsule will illuminate to indicate the parking brake is engaged. The parking brake requires hydraulic pressure from the utility system, and for the PWR STEER switch to be in the ON position to activate or deactivate. If there is no hydraulic pressure, the parking brake handle can still be pulled or pushed, but the brakes will not engage.