Wednesday, April 11, 2007

on the road

Andrew's wedding is this weekend! It's like the last six months never happened. I'm about to get packin', but before I do a tidbit on air travel:

The sky is measured with invisible lines called "Victor airways." These are direct vectors between points of navigation called VORs. From 1,200 to 18,000 feet, planes use these vectors like roadways. Traffic is stacked vertically, and opposite directions are alternated. The minimum vertical clearance is 500 feet. Jet travel is above 18,000 feet, and these planes generally have sophisticated enough avionics to be cleared for direct navigation, triangulating between VORs to make their own route.

This system is built on technology over 50 years old. In many cases GPS is just as accurate; with the direction things are going VORs will probably be obsolete within the decade. This marks a phase shift in navigation; we are no longer marking out lay lines on the globe; once again we are turning to the sky to find out where we are. The points of reference are in constant motion above, instead of fixed below. Distance is once again relative, not absolute.

The older VORs cone-shaped housings for antennas that spin at 1,800 revolutions a minute, changing its broadcast continuously to mark different directions. One of these sits just up the hill from our house at the Santa Monica Airport. Pretty soon it will stop marking the earth, and its continuous whine will stop, replaced by silent points of reference above.

No comments: