Summary of compass errors
Acceleration error - Affect us on East/West headings
In the Northern hemisphere use the pneumonic
NADS
Meaning
Compass indicates turn to NORTH on ACCELERATION and a turn to SOUTH on DECELERATION
In the Southern hemisphere use the pneumonic
SAND
Meaning
Compass indicates turn to SOUTH on ACELERATION and a turn to NORTH on DECELERATION
NB No errors on N / S headings (both hemispheres)
No errors at the magnetic equator (pivot/CG in line)
Example Question
When on approach to RW 10R at London Heathrow the aircraft decelerates to lower gear and flap. What is the effect on the direct reading compass (DRC)?
a) A turn to the South
b) A turn to the North
c) No apparent turn
d) The magnetic element rocks
Solution
London Heathrow in Northern hemisphere so use NADS
We are decelerating so compass indicates turn to the South answer a