Altimeter

Question 1

How does an altimeter work in principle?

Answer 1

senses the change in static pressure and displays it in altitude units.

Question 2

How does an altimeter work technically?

Answer 2

a partially evacuated aneroid capsule inside a container is subject only to outside static pressure. The change in static pressure as we clib/descent causes the capsule to expand or contract. This is transformed into a mechanical movement to the dial.

Reference data is needed as a fixed datum to measure from. This is set in the subscale window in the form of current atmospheric conditions.

Question 3

QFE?

Answer 3

current pressure at airport. Reading will be 0ft

Question 4

QNH

Answer 4

Derived MSL pressure. Airport elevation.

Question 5

QNE/standard (SPS)

Answer 5

standard pressure setting used for ISA conditions. 1013hPa. altidue becomes pressure altitude/flight level in accordance with ISA standard pressures.