EICAS-4000: Engine Indication and Crew Alerting System

The Engine Indication and Crew Alerting System (EICAS) is designed to provide all engine instrumentation and crew annunciations in an integrated format. The information supplied includes display of torque, interstage turbine temperature, high and low pressure gas generator RPM, fuel flow, oil temperature and pressure.

As part of the EICAS, graphical depiction of aircraft systems can be displayed. Such systems as electrical, hydraulic, deicing, environmental and control surface position can be represented.

All aircraft messaging relating to the above systems are displayed on the EICAS.

A typical EICAS contains one or two large color displays, EICAS control panels, two or three EICAS data concentrator units and a lamp driver unit. Each line replaceable unit is described below.

The primary EICAS display presents the primary engine indication instruments and crew alerting messages. The primary display is a fixed format providing engine data including RPM, temperature, fuel flow and quantity and vibration. Gear and flap annunciations are displayed when applicable. The upper right-hand area of this page is reserved for Caution Alerting System (CAS) messages. The CAS messages appear color coded to indicate the level of importance.

The secondary EICAS display provides a wide range of information options to the flight crew and serves as a backup to the primary display. Information options include status indications of landing gear position, flaps, trim, auxiliary power unit, cabin pressurization or aircraft system synoptic diagrams. Aircraft systems graphically depicted in Collins synoptic diagrams include anti-ice, fuel, flight control positions, hydraulics, doors, AC and DC electrical and pressurization/environmental. The pages are selected using the EICAS control panel. Selection of synoptic diagrams is dependent on aircraft type and mission, and is an integral part of the airframe design.

The EICAS displays receive data bus inputs from the EICAS DCUs and the ECP. The EICAS displays provide data bus output to the Integrated Avionics Processing System data concentrators.

A remote EICAS reversion switch allows the pilot or copilot to select either display. Selecting one display blanks the other tube and allows data pages to be selected on the remaining display using the ECP. The panel push buttons select data pages. The ECP applies this information on the data buses to both EICAS displays and both multifunction displays.

The DCU collects and formats aircraft data for display on the EICAS. The DCU performs the flight data acquisition functions for the flight data recorder. The crew alerting logic is processed in the DCU. The DCU receives high- and low-speed ARINC 429 buses, analog inputs and discrete inputs from the engines and other aircraft systems. The data inputs are concentrated and processed for transmission on ARINC 429 buses. The DCU outputs engine data to the displays; maintenance, diagnostic and aircraft data to the IAPS data concentrators; annunciator lamp data to the LDU; aircraft system data to the flight data recorder and data link management unit.

The LDU is a dual-channel unit capable of driving up to 120 annunciator lamps. Channels 1 and 2 receive digital buses from all the DCUs. The buses contain lamp activation words from the DCUs. Channels 1 and 2 are identical and the outputs from each side are tied together (OR logic). If one channel lamp sink fails, the other channel lamp sink will provide the annunciator function. The LDU monitors the lamp sinks to verify correct function and outputs the lamp sink states on a digital bus to the DCUs.

The ERUs are junction boxes for the data concentrator units. The ERU splits each input signal to three output pins. The pilot ERU routes left side airplane data and the copilot ERU routes right-side airplane data.