Title
L-880(L), L-881(L) Precision Approach Path Indicator Lights (PAPI) - Leveling and Tilting the Light Head (Setting the glide slope)
URL Name
L-880-L-L-881-L-Precision-Approach-Path-Indicator-Lights-PAPI---Leveling-and-Tilting-the-Light-Head-Setting-the-glide-slope
Summary
This article describes how to Leveling and Tilting the Light Head (LHA) on a L-880(L), L-881(L) Precision Approach Path Indicator Lights (PAPI)

Content

Leveling and Tilting the Light Head (LHA)

Prerequisites / Safety Notes

  • Work only when authorized and with proper lockout/tagout procedures if required.
  • Handle the Photosensor harness on the Primary unit with extreme care to avoid stress or damage.
  • Use appropriate PPE (gloves, eye protection) when working around energized equipment.

Step-by-Step Instructions

  1. Remove the Top Cover
    • Carefully remove the top cover of the LHA.
    • Caution: On the Primary unit, avoid stressing or pulling on the photosensor harness.
  2. Set Dip Switches to Test Mode 1
    • Configure dip switches as follows:
      • SW1-6: ON
      • SW1-8: ON
      • SW2-8: OFF
    • This mode allows the system to operate while ignoring Tilt or Communication failures.
  3. Loosen Mounting Hardware
    • Remove the top flange nuts on each mounting leg (front and rear legs).
    • Leave the lower flange nuts in place for initial adjustments.
  4. Energize the System
    • Use the circuit breaker in the PDU
  5. Perform Horizontal Leveling
    • Press the LEVEL button on the control/display panel to initiate horizontal leveling.
    • Using the lower flange nuts on the two front legs, adjust the LHA until the display reads 0.00 (perfect level).
  6. Set Glide Slope Tilt/Angle
    • Press the GLIDE button.
    • Using the lower flange nut on the rear leg, adjust the tilt/angle of the LHA until the display shows the desired angle in Decimal Degrees
  7. Secure and Fine-Tune
    • Reinstall and hand-tighten the upper flange nuts on all legs.
    • Make minor adjustments as needed to maintain the display reading of 0.00 (level) or the exact desired glide slope angle.
    • Fully tighten all upper flange nuts once satisfied.
  8. Save the Configuration
    • Press SET repeatedly until the display reads SAVE.
    • The LHA is now calibrated to detect deviations from the desired glide slope.
  9. Return to Normal Operation Mode
    • Reset all dip switches to Normal mode:
      • SW1 positions 6, 7, and 8: OFF
      • SW2: All OFF
      • SW1 positions 1–5: Set to normal field settings (as per site configuration).
    • The system will now resume full operational functionality, including tilt and communication monitoring.
  10. Final Steps
    • Replace and securely fasten the top cover.
    • Verify system status on the display/control panel.
    • Perform a functional check or log the calibration if required by maintenance procedures.

Additional Notes

  • Always confirm the desired glide slope angle matches airport specifications
  • If system does not function as it should recheck dip switch settings.
  • Document all adjustments, including before/after readings and any deviations noted.

 

Airport Lighting Company | L-880(L), L-881(L) Precision Approach Path Indicator Lights (PAPI)

Precision Approach Path Indicator Lights

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