Navigation - NATOPS CH. 17 Flashcards
Air Data Transducer
Receives analog data from the pitot static system and retransmits it digitally to the AFCC.
Airspeed Transducer
Receives analog airspeed data from the pitot static system and retransmits it digitally to the AFCC.
EGI
Embedded GPS Inertial Navigation System - utilizes GPS satellites to compliment our all attitude ring laser gyro INS.
How many channels are our EGIs?
12 channel or 24 channel
What is a P code receiver? C/A?
P code is precise code. It is military only and requires EGIs to be keyed with the correct codes. C/A is course acquisition.
What is SAASM?
Selective availability anti-spoofing capability.
What configurations of EGIs can we have?
2 legacy
1 legacy, 1 SAASM
2 SAASM
What is the GAS-1?
Seven element anti-jam controlled reception pattern antenna.
Why is EGI #2 important?
Has a fixed reception pattern antenna in the result of an antenna electronic unit failure (SATCOM/GPS).
EGI #1 has no backup.
What may a failure of EGI #1 to receive information indicate?
A GAS-1 failure, because EGI #1 has no backup.
What are the two EGI navigation modes?
HNAV - Hybrid navigation
INAV - Inertial navigation
What must you do in a manual initialization to ensure attitude goes valid? What indicates valid attitude? What aids in HNAV after attitude is valid?
Fly a straight and level course.
ALGN-G
30-90 degree heading changes using 10-20 degree AOB turns.
How long can HNAV withstand GPS drop outs?
65 seconds
How do you know if GPS is available in INAV mode? How to you initiate the swap to HNAV?
You will see INAV-G as the alignment type. You can “GPS ACCEPT” in the nav menu.
What are the five alignment types?
GPS/INS - ground or flight
Gyrocompass - ground only
Stored Heading - ground only
Directional Gyro - ground, flight, ship
Data Link - shipboard
What manual entries help with commanded alignments?
Lat, long, date, time
What EGI is used for coupled approach and hover function?
EGI 2
Valid _________ and __________ data from EGI 2 is required for coupled approach and hover function.
Heading and velocity
When aboard a ship, what is the only way to obtain valid velocity data?
GPS alignment
Valid heading can only be obtained after a full inertial alignment, which includes…
GPS, GC, DL, or SH
What is the minimum number of satellites needed for a GPS/INS alignment?
Four
What will GPS EHE and FOM show if the EGI is not aligning properly?
EHE of 32765, and FOM of 9
What is the minimum EGI status allowed for taxi/flight?
HDGV-___ (G, GC, SH, DL)
Valid attitude and heading are available.
What is the difference between DG-HI and DG-LO?
Magnetic heading is entered by operator in HI. LO has no heading information available.
How do you know if an alignment is complete?
CMPL-_____ (GC, SH, DL)
Will automatically transition to HNAV once weight off wheels
What does it mean if HNAV turns white?
Comes on within 4-12 seconds of losing GPS signal. White text displayed for 15 minutes, and then transitions to INAV.
What is the difference between INAV and INAV-G?
GPS is available. Pilot can accept GPS in the nav menu and transition to HNAV.
INS VEL ERR
INS velocity error is greater than 50 feet per second for 60 seconds
What is RAIM?
Receiver Autonomous Integrity Monitoring
Determines integrity of space vehicle data
How many satellites can an EGI track simultaneously?
24 satellites
What is required for a Stored Heading alignment?
Parking brake - set
CMPL-GC prior to shutdown
Perform orderly shutdown of EGIs via CMP
Manually command SH alignment on start up with parking brake still set
The helicopter can not be moved between shutdown and startup.
What does a FOM 2 guarantee you?
EHE less than 25 feet
Are both EGIs required for full AFCS functionality?
Yes
When will you get a miscompare advisory between the EGIs?
When attitude differences are greater than 3 degrees
What is TACAN? How many channels?
Tactical air navigation. 126 X channels for FAA use, 126 Y channels for tactical use (252 total).
How many channels apart do you have to be for Air to Air TACAN to work?
63 channels apart
What are the three methods of wind calculation?
Steady state - finds difference between ground track and air track vectors
Turn estimate - four 180 degree turns at a steady bank angle
Cycloid - 360-390 degree turn at a steady bank angle
