Comm/Nav Flashcards
EGI
Embedded GPS Inertial Navigation System
consists of a 12 or 24 channel coarse acquisition system and precise (P) code GPS receivers with full selective availability/anti-spoofing (SASSM) capability embedded in an all attitude ring laser gyro
SAASM EGIs have direct Y code acquisition
INS? Disadvantage?
Worldwide, passive and self contained, provides heading/attitude data
precisely accurate for only a short amount of time
GPS? Disadvantage?
worldwide, passive, updates INS
not self contained, vulnerable to jamming and spoofing, incapable of providing aircraft heading and attitude info
GAS 1
7 element anti-jam controlled reception pattern antenna with an antenna electronics (AE) unit that nulls out suspected erroneous signals
backup unit provides GPS signal to EGI 2 if AE fails via DTIU
Which EGIs connected to GAS 1?
Both; in event of SATCOM (AE) failure, EGI 2 auto connects to backup unit
EGI modes
- Default HNAV
- Commanded HNAV
- Gyro compass
- Stored Heading
- Directional gyro
- data link/manual
Stored heading requires what?
completion of GC alignment, orderly shutdown, parking brake set
Shore only EGI modes?
Gyro compass, stored heading
Which EGI mode is used for quick launch?
Directional gyro
Comms B/U/Failure Modes
- Single mission computer failure
- 1553 data bus failure
- AMC or OCP failure
- Battery mode
Single Mission Computer failure
amc operational, ac power available, no impact on radio or ics
1553 Data Bus Failure
amc operational, ac power available, No impact on ICS, radios function normally but can only be selected via OCP and only tuned via RCU
AMC or OCP Failure
mission computers are operational, ac power available
after a/c power transients
RAD 1 is hardwired to pilot station, 2 to copilot, both controlled by RCU, PTT only
ICS Call available all stations
Battery mode
electrical problem or prior to APU start; dc battery power available
only radio 1 available, controlled by RCU, PTT only
ICS PTT (fixed volume) available to pilots
ICS available to aft stations
