AircraftTroubleshooting

Compass swing notes from Collins avionics

 

 

Rockwell Collins Compass Swing Demonstration for the AHS-85 and MCS-65 Systems

Course Summary

This course demonstrates some different compass swing techniques that can be used to align either the MCS-65 system or the AHS-85 system.

Content Topics

  1. Checking the Compass Site

      1. Visual Check

        1. 300 feet from other aircraft

        2. 600 feet from all large visible magnetic objects

        3. Not close to fuel tanks, power lines, buildings, light poles, railroad tracks, or underground fuel lines or tanks

        4. Check for underground power cables, reinforcement rods, and natural magnetic changes

      2. Marking the Site

        1. Find center and mark

        2. Center tripod and level over mark

        3. Align north mark to magnetic pointer

        4. Mark a spot 125 feet north from center

        5. Mark other cardinal points 125 feet from center

      3. Checking the Site Marks

        1. Move transit to north mark, center and relevel compass

        2. Place rod on east point and measure angle from north

        3. Should be 135 degrees to east mark, 180 degrees to south and 225 degreesto west

        4. Repeat from all cardinal points

        5. From east, north should be 315 degrees, west – 270 degrees, and south – 225 degrees

        6. From south, east – 45 degrees, west – 315 degrees, north – 0 degrees

        7. Alternate method – ramp squares

  1. System Components

      1. Compass Basics

        1. Components

          1. Combined gyro and electronics unit

          2. Flux detector

          3. Compensation units

        2. Global compass operation

        3. Flux detector operation

        4. Magnetic effects of aircraft

        5. Correcting errors using compass card

        6. Compensation units

          1. RCP-65

          2. CCU-65

          3. ICU-85

  1. Review Basics

      1. Sine compensation control

      2. Cosine compensation control

      3. Index compensation control

  1. Compass Swing Using Voltage Method

      1. Aircraft positioned accurately

        1. North heading

        2. Set sin voltage at test point 1 to 0 V, test point 2 for cosine compensation, and test point 6 for the index compensation to 0 V.

      2. Set-up mode

        1. Connect meter to test point 3

        2. Record voltage 4 seconds after it comes on

      3. Use the correct meter

        1. Fluke 8062

          1. Three decimal places after voltage readings

          2. Good sampling rate

        2. Fluke 87

          1. Three decimal places

          2. Analog voltage scale

          3. Hold mode

        3. Windspeed

          1. Less than 15 knots

      4. Read 8 voltages

      5. Computer calculations

        1. Minimum system requirements

        2. Installation

        3. Order program disk from Collins order admin. in Melbourne, FL

        4. Data entry

        5. Setting compensation/index controls

      6. Calculations by hand

      7. Position error method

      8. Computer calculations

      9. Hand calculations

      10. Summary