Magnetism And Direct Reading Compass Flashcards
(31 cards)
What are the properties of a magnet
If its cut new poles are made
Force is strongest at the extremities
Force of attraction between 2 magnets is inversely prop to the distance squared
What is an isognal/isonic line
A connection between two points with equal variation
What is an agonic line
A connection between two places with 0 variation
What happens if increased dip
More acceleration and turning erros
What happens to dip with an increase in latitude
It increases
What is a secular change or movement
The annual movement of 15km that the earths magnetic North Pole does
How does an aircraft aquire a magnetic field
Through the manufacturing process with ferrous materials and electrical fields and also depends on what hemisphere it was built in
What is deviation
The difference between magnetic and compass heading
What is the acronym to remember var/dev/headings
Can Dead Men Vote Twice During Time At Elections
Compass Hdg, Deviation, Magnetic Hdg, Variation, True Hdg, Drift, True Track, Add East
What are the two types of magnetism
Permanent
Electromagnetism
Why do you do a compass swing
To determin any residual deviation on any given heading or any heading
When should a compass swing be done
If in long time storage without turning facilities
Fitted new equipment
During normal maintenance ect…
What does steer mean on a compass card
Where you to be heading to ensure your on the right heading
Eg. For 360 then steer 358
What is the direct reading compass
Uses the horizontal component as a datum for earths magnetic field
Indicates direction, completely independent of other instruments
How do you correct for deviation on a DRC
With compensating screws and magnets
What do you check to see if a DRC is working
No cracking in glass
No bubbles
Need indicstions within 5° of known heading (allowed 10°dev)
What are the three limitations of a DRC
- Turning and Acceleration Errors due to dip
- Closeness to sources of deviation
- It is self contained so doesn’t help anything else
What is the dip angle
Between the needle point and horizontal component
What does DEAP stand for
(Acc errors)
Decelerating then turn to Equator
Accelerating then turn to Poles
When your accelerating where do you turn ton
The nearer pole
If accelerating east west then error is
MAX
If accelerating north south
Error is 0
What does a turning error relate to
The result of inertia on a magnet with dip
So the vertical component on a magnet
When turning East west error is
0
