Aviation In Canada

Sunday, January 16, 2005


I mentioned before about ILS being protected by ICAO as the primary precision approach aid until 2010. Many of us are quite eager to see more changes sooner, rather than later. A few airlines are taking leading roles in flight checking GPS precision approaches. From my perspective, something new can't come soon enough.

ILS is great, I agree, but why is it that when the worst weather comes, the first thing to go is the ILS? Snow is bad for that, especially heavy wet snow. Each transmitter carries with it a self-monitoring device which verifies that the signals are being sent out within acceptable tolerances. When heavy, wet snow falls in front of the glidepath antenna, it affects the radiation of the radio signals being sent out, therefore altering the glidepath angle. If it's out by too much, the equipment fails itself. Good safety device, in that respect. But now the weather is still dirty and pilots have no ILS, just a localizer -- for as long as that holds.

GPS is an example of a type of navigation that doesn't rely on snow-covered antennas to deliver it's signals. The future for GPS in aviation certainly looks bright, especially with new satellites being launched that will transmit the same codes on two different frequencies for civilian use. A more accurate system stands to come from it, enhancing what is already a good thing. It's not too soon from an ATC standpoint to see an improvement to methods used to get aircraft where they want to be.