On Mar 8, 6:56 am, Michelle P
wrote:
TheSmokingGnu wrote:
Here's one that may seem silly: to what height, precisely, is an
altimeter calibrated to?

The bottom of the landing gear? The height of the static port? the chord
line of the fuselage? In a Cessna, the difference between these is
minimal, but on an airliner, you're talking about a possible +/- 10-15
feet (even discounting the radar altimeter).

What is the answer, o Swammi of Salami?

TheSmokingGnu

When doing the bi-annual? the calbration is at the height of static port.

Michelle

But a static port at a lower level won't result in a higher
static pressure at the altimeter. There's a pressure drop with
altitude inside the line, too, just as there is in a water-filled
tube. I would imagine the pilot of a machine with its altimeter 20
feet off the ground would note a 20-foot discrepancy with the field
elevation once the altimeter has been set to the controller's numbers.

Dan