YC-14 FCS Control & Display Panel (space model)

Marconi-Elliott Avionics
Control and Display Panel
Part No. 25-015-01
Serial No.
Boeing Part No. 748-253120-5
Date

The YC-14 was an experimental STOL aircraft made by Boeing. It had a high wing with the twin engines mounted above the wing and Blown Flaps to give the STOL performance. The Digital Flight Control System provides full control of all primary aerodynamic control surfaces and engine thrust. The objective was to reduce crew workload during the busy STOL mode to a level compatible with a two-man crew. The system has full fly-by-wire control and has a variety of operating modes such as STOL, high Mach or high altitude cruise, low altitude, stores delivery and single engine operation. The system is triple redundant to meet mission and safety reliability requirements. Data is transmitted between channels via a single time multiplexed fibre-optic link which provides complete electrical isolation between redundant channels and eliminates electromagnetic interference.

A full aircraft set of equipment comprises three Computer Units (CU), three Interface Units (IU), three Optical Coupler Units (OCU), three Optical Data Links (ODL), a Control and Display Panel (CDP) and a Test/Fail Ident Panel (T/FIP).

The flight crew manage the operation of the EFCS through the glare shield mounted Control and Display Panel. As much a computer as a panel, the Control and Display Panel (CDP) contains three channels of failure logic as well as switches and displays. Triple, segregated contact switches are employed except for the channel isolate switches, which are simplex one/channel. The indicators are dual redundant, being driven from pairs of channels. Discrete signals are transmitted between the redundant channels via optical isolators. From left to right across the front panel, CWS (Control Wheel Steering) is available with pitch attitude hold or flight path angle hold, and roll attitude hold or track hold. Conventional altitude and heading hold modes are also available as selectable modes. The C-STOL HOLD provides the capability to hold automatically the aircraft at a pre-selected speed during STOL operation.

Configuration and redundancy management controls and displays are provided in the next part of the presentation. The three channel isolate switches provide manual isolation facilities together with displays of channel FAULT and OFF states. First failures may be reset by depression of the RESET switch, which re sets the outputs from the failure monitors. The SYS START Switch is used to engage the EFCS following power up. NOT READY is displayed and system start is inhibited if the system is not in a valid state for flight. The CRUISE/C-STOL display indicates the system configuration for these flight regimes.

The FLIGHT TEST PROGRAMMER enables pre-programmed modifications to the control laws to be selected in flight. These modifications may be changed between flights by reprogramming the appropriate part(s) of the computer memories.