NATOPS Chapter 15/16 Comm/Nav HSM-50

Question 1

EGI

Answer 1

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

Question 2

INS? Disadvantage?

Answer 2

Worldwide, passive and self contained, provides heading/attitude data

precisely accurate for only a short amount of time

Question 3

GPS? Disadvantage?

Answer 3

worldwide, passive, updates INS

not self contained, vulnerable to jamming and spoofing, incapable of providing aircraft heading and attitude info

Question 4

GAS 1

Answer 4

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

Question 5

Which EGIs connected to GAS 1?

Answer 5

Both; in event of SATCOM (AE) failure, EGI 2 auto connects to backup unit

Question 6

EGI modes

Answer 6

1. Default HNAV
2. Commanded HNAV
3. Gyro compass
4. Stored Heading
5. Directional gyro
6. data link/manual

Question 7

Stored heading requires what?

Answer 7

completion of GC alignment, orderly shutdown, parking brake set

Question 8

Shore only EGI modes?

Answer 8

Gyro compass, stored heading

Question 9

Which EGI mode is used for quick launch?

Answer 9

Directional gyro

Question 10

Comms B/U/Failure Modes

Answer 10

1. Single mission computer failure
2. 1553 data bus failure
3. AMC or OCP failure
4. Battery mode

Question 11

Single Mission Computer failure

Answer 11

amc operational, ac power available, no impact on radio or ics

Question 12

1553 Data Bus Failure

Answer 12

amc operational, ac power available, No impact on ICS, radios function normally but can only be selected via OCP and only tuned via RCU

Question 13

AMC or OCP Failure

Answer 13

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

Question 14

Battery mode

Answer 14

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