Thanks to the magnets' interaction with Earth's magnetic field, the assembly wants to point to the north, and the compass card
is attached 180 degrees opposite that indication.
So, the difference between a rather challenging NDB approach and one that you could fly with relative ease was a fixed or manually adjustable compass card
behind the bearing pointer versus a compass card
that turned with your heading.
As I went to pull out the checklist, my pilot told me the compass card
was spinning freely, ratcheting, and randomly reversing direction of spin.
Yes, pricey, but just a beautiful prismatic hand-bearing compass with a mother of pearl compass card
readable in even the lowest light The solid brass housing shines like gold, and the 25X magnifying prism helps you read small print The compass is liquid filled, with mineral crystal glass, plus features a rotating bezel with lock and thumb loop.
Pivoting the needle on an axis, adding a compass card
and later, when metal hulls interfered with the magnetic needle, magnetic compensation systems were invented.
A small piece of cardboard served as compass card
. Al painted the compass points with a brush made of his own hair.
A light blue heading bug is displayed on the heading tape and on the dedicated HS1 page, which is a familiar rotating compass card
in a heading-up orientation.
Simply put, think of an HSI as a directional gyro with a course deviation indicator mounted on the compass card
. It displays left/right/vertical course and steering guidance, to/from and heading-valid flags, a compass card
and a heading bug for interacting with an autopilot.
The corrective-heading readings on the standby compass card
is vital and will let the pilot know which direction to navigate should both embedded INS systems be lost.
Thanks to less-than-adequate instrument lighting, I barely could read my BDHI compass card
and couldn't see the DME.
Heading mode orients the HSI to display aircraft heading in a conventional manner, with the current heading value shown at the top of the compass card
as indicated by the lubber line.
The answer was the horizontal situation indicator (HSI) that put a VOR/LOC indicator inside the heading indicator compass card
. In this fashion, the VOR indicator's course pointer and CDI would rotate with the heading.