Describe acceleration errors in Compass systems?
Are maximum in East and West headings and zero on North and South Headings
Northern hemisphere:
On hdg 270 it will show 280
On hdg 090 it will show 080
ANDS in the North
DNAS in the South
Describe turning errors in Compass systems?
ONUS in the North
UNOS is the South
No turning errors on East and West
Over-shoot North, under-shoot South (Northern side)
What’s a remote indicating compass system?
Combines the use of a gyroscope with the earths lines of flux to give the best of both a DI and a remote indicating compass
What are the advantages of a Remote Indicating Compass system?
- Detector unit can be installed in a remote part of the a/c well away from electrical circuits
- Flux valve technique senses rather than seeking the earths magnetic meridian which means it’s more sensitive to small changes in H
H is the horizontal component of magnetic fields
Greatest at the equator and smallest over the poles - Turning- and acceleration errors are minimized
- Automatically compensates for real and apparent drift. Needs no re-setting
What’s the difference between Slaved- and Free Gyro modes?
Slaved: Gyro is monitored by the detector unit element
Free: Gyro is isolated from the detector unit and functions as a straight forward DI
When would the Free Gyro mode be used?
Used when flying at latitudes where the value of H is too small to use as a reliable source. That is closer to the poles at high latitudes
