(2)
Non-magnetic tools to adjust the standby magnetic compass.
(3)
One compass correction card - AN5823-1.
(4)
Standby Compass Calibrator Kit, Honeywell
2591553-901
(5)
Non-Magnetic Tripod
B. References
(1)
AMM 9-11-00/201, Towing
(2)
AMM 21-58-00/501, Equipment Cooling System
(3)
AMM 24-22-00/201, Manual Control (Apply Power)
(4)
AMM 34-41-00/501, Inertial Navigation System
C. Access
(1) Location Zones
221 Control Cabin, LH
D. Calibrator Adjustment (Fig. 201)
(1) Do this procedure to calibrate the standby compass calibrator (SCC) to the magnetic field at the location of the compass swing area
(a)
Make sure that there are no vehicles or airplanes less than 250 feet away.
(b)
Make sure that there are no buildings less than 250 feet away.
(c)
Put a nonmagnetic tripod at the center of the compass swing area.
(d)
Remove the magnet assembly from the SCC.
EFFECTIVITY
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MAGNETIC FIELD CANCELLATION ADJUSTMENT SCREW
Standby Compass Calibrator Figure 201
EFFECTIVITY
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(e) Attach a master magnetic compass to the SCC with two mounting screws.
NOTE: You can use an accurate standby magnetic compass for a
____ master magnetic compass. Make sure that the N-S and E-W adjustment screws are at neutral.
(f) Put the SCC/master compass assembly on the tripod.
NOTE: Make sure the assembly is level.
____
(g)
Turn the assembly until the master magnetic compass shows an indication of magnetic north (N).
(h)
Install the magnet assembly onto the SCC/master compass assembly.
(i)
Turn the top and bottom SCC dials to show an indication of E at the index line.
(j)
Make a record of the heading shown on the master magnetic compass.
(k)
Turn the top and bottom SCC dials to show an indication of W at the index line.
(l)
Make a record of the heading shown on the master magnetic compass.
(m)
Turn the magnetic field cancellation adjustment screw on the SCC to decrease the heading errors in each direction (E and W) to a minimum.
(n)
Continue to adjust the SCC dials for each direction (E and W). Then use the field cancellation adjustment screw until the errors are at a minimum.
NOTE: Continue to do this procedure until the error in each
____
direction is at a minimum.
Do not move the field cancellation adjustment screw before the compass swing is completed.
E. Prepare for a Compass Swing of the Standby Compass
NOTE: Ferromagnetic parts installed near the standby compass can cause
____ compass heading errors. Make sure no ferromagnetic parts are near the captain's and the first officer's window frames. If found, replace the parts with non-magnetic, corrosion-resistant steel (CRES) parts.
EFFECTIVITY
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(1) Tow the airplane to the compass swing area (AMM 9-11-00/201).
NOTE: The compass swing area must be a level area with a smooth
____ surface. It must be sufficiently strong to hold the weight of the airplane. The area must be large enough to tow or taxi the airplane. Make sure all vehicles other than the tow vehicle are not less than 250 feet from the airplane.
The horizontal component of the earth's magnetic field must be constant (|1 degree) in the test area. Measure the horizontal component if magnetic material (such as a new building) is less than 600 feet from the compass rose. Do not use the compass rose if the horizontal component is not constant (|1 degree).
(2)
Supply the electrical power (AMM 24-22-00/201).
(3)
Energize all of the electronic equipment, radios, and control cabin lighting for the usual conditions that occur in flight.
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