TP 13706 - Technical Evaluation Engineering

INTRODUCTION

Pursuant to a request from Transport Canada – Civil Aviation, a frost study was conducted on a number of designs of Precision Approach Path Indicator (PAPI) light units. The objective for the project is to eliminate the possibility of a false signal being presented to aircraft from a frosted PAPI, and thus to prevent a potential hazard. For more details, see terms of reference
(Appendix "A").

The project is separated in 4 parts:

  1. Determine the amount of operating time required to eliminate frost 1/16" (1.6 mm) from the PAPI lens or cover glass at different temperatures (-5, -10, -20, -30°C).
  2. Determine the minimum current level for the PAPI lights to function with a partial frost accumulation on the lenses or cover glass at the same temperatures as in 1.
  3. Determine the minimum current level for the PAPI lights to function without frost accumulation on the lenses or cover glass at the same temperatures as in 1.
  4. Determine what is the effect of dew on PAPI signal at 0°C.

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