En route altitudes and safety

On Wed, 27 Aug 2008 21:09:01 GMT, "JGalban via AviationKB.com"
u32749@uwe wrote:

John Smith wrote:

The problem is, FAA HQ has recently state that the controller is being
taken out of the loop and the deviations are being automatically
recorded. The controllers don't like it and have voiced their concerns
in the past few weeks.

If that is the case, they are probably not nit picking 100 ft. deviations.
Since altitude is reported in 100 ft. increments by the encoder, it's pretty
normal for a controller to see +/- 100 ft. when someone is flying right on
the altitude. If you're flying 1 ft. above your assigned altitude, a
properly working encoder could show you to be 100 ft. high. Last time I
visited a TRACON, there were numerous targets that were +/- 100 ft. and the
controller assumed they were flying the correct altitude.

A properly set encoder will not switch to the next altitude until 50'.
So 1149 will read 1100, 1150 will read 1200. That doesn't even
include the allowable instrument error in the altimeter.