BOMBARDIER BD-100-1A10, Operating Manual

Page: 340 / 544

FLIGHT INSTRUMENTS
Volume 2 Flight Crew Operating Manual Dec 05/2006
11-01-34
CSP 100-6
REV 7
STANDBY COMPASS
DESCRIPTION
The standby compass supplies the flight crew with the magnetic heading data. This system is in constant operation and is
used as an auxiliary display.
COMPONENT AND OPERATION
The standby compass is installed in a bracket on the center post of the windshield, above the flight guidance panel. The
compass is aligned with the aircraft longitudinal axis.
The standby compass is a self-contained unit that has a transparent and molded bowl and is filled with silicon fluid. In the
fluid is a sphere with a compass dial. Silicone fluid is used to insure free and smooth movement in order to provide an ac-
curate indication. Metal bellows in the compass let the fluid volume expand and contract to changes in temperature and
altitude.
The standby compass is lighted and uses a special non-magnetic bulb. The light unit is powered by 5 vdc from the integral
light controller.
The compass dial shows markings for the four cardinal heading (N, E, S, W) and has numerals every 30
°
, with bars every
10
°
. The last numeral is not shown (for example “24” means “240”). Heading of the aircraft is read against the vertical
lubber line.
To operate correctly, the compass needs installation adjustments and also corrections for heading indication errors caused
by magnetic interference from the aircraft electrical and avionics system. During the adjustment procedure, the heading
reference is supplied by the attitude and heading references system (AHRS).
The standby compass is adjusted in the vertical axis with two adjustment screws that attach the compass to the mounting
bracket through two extended holes. At the top of the compass there is an index error adjustment scale. The center major
index mark on this scale is used as a reference point during the adjustment procedures.
The standby compass has also two compensators (B and C) installed at the top area of the compass. They are used to adjust
the readings for the magnetic interferences.
COMPASS CORRECTION CARD
The standby compass system includes a compass correction card installed on a bracket above the standby compass. The
compass correction card has a STEER row used to write the corrected heading for each of the cardinal headings and for the
30
°
increments.