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ILS Glide Slope Standards: Part 1. A Review of Flight Inspection Standards Affecting Landing Performance and Comparison with Limits Evolved from System Analysis

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Final rept. 20 Aug 1973-20 Aug 1974, on Phase 1

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System analysis techniques are used to determine maximum levels for ILS Glide Slope beam structure characteristics which will result in acceptable approach and landing outcomes. Results are based upon a power spectral density signature for ILS Glide Slopes obtained from a nonstationary statistical analysis of flight inspection data for 17 Category II and II-training facilities. Maximum levels and standard deviation time historics for typical aircraftcontrol system response indicated glide path deviation, actual glide path deviation and actual glide path deviation rate are used as the basis for recommending revisions to the ILS Glide Slope flight inspection data processing procedures, and for recommending relaxed flight inspection standards. The maximum extent to which current Glide Slope flight inspection standards might be relaxed is indicated to be very considerable along the entire approach path for Category I service. Relaxation of the standards in ILS Approach Zone 3 is also possible for Category II service. An additional finding is that the maximum extent to which flight inspection standards might be relaxed is exactly the same for Category II and III services. Further findings are that any distinctions between the approach performance obtained using manual flight director controlled approach coupling, automatic approach coupling, or inertially augmented automatic approach coupling do not warrant ILS Glide Slope flight inspection standards which are specific to the airborne users method of coupling. Glide Slope approach couplers incorporating inertial augmentation produce significantly lower touchdown dispersion, but comparable missed approach rates.

Subject Categories:

  • Terminal Flight Facilities
  • Air Navigation and Guidance

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