View Single Post
  #4  
Old April 3rd 07, 01:59 PM posted to rec.aviation.piloting
Kev
external usenet poster
 
Posts: 368
Default Altimeter Calibration Height

On Apr 3, 12:11 am, TheSmokingGnu
wrote:
The imaginary aircraft is sitting at Imaginary Airfield (KIMG), which
sits at a billiards-table-flat 50 MSL. The aircraft's static port is
mounted at the centerline of the fuselage, which is 10 feet from the
ground. The instrument in question is mounted 4 feet above the centerline.

What will the gauge read when set to the proper barometric scale? 50,
60, or 64 feet?


Any of the above ;-) To repeat what I posted back on March 9th...

The actual altimeter test is described in FAR 43 CFR Appendix E, and
allowable error varies from 20' at sea level, to much more at higher
altitudes.

http://www.flightsimaviation.com/dat...t_43-appE.html

In theory, the instrument is calibrated on the bench to read at its
own height, but can later be adjusted in the aircraft to read wheel
height. Whether it should be or not, doesn't seem to be addressed in
the regulations that I could find.

There's an old saying, that "hell for scientists" is defined as a
place where all the conditions are perfect, but none of the
instruments are.

Kev