Altimetry

Question 1

Altimetry

Answer 1

read pressure difference between Ambient pressure(inside the case) and the pressure set

Question 2

Altimetry Error

Answer 2

Barometric QNH Different
Temperature 4% per 10°
Instrumental manufact imperfection
Position Error static ports
Manouver

Question 3

Altimetry Type

Answer 3

Simple
Sensitive
Servo-Assisted

Question 4

Simple Altimetry

Answer 4

Static pressure is fed into the case of the instrument from the static source.
As height increases, static pressure decreases and the capsule expands under the control of a leaf spring.

Question 5

Sensitive Altimetry

Answer 5

•A bank of two or three capsules gives the increased movement necessary to drive three
pointers.
• Jewelled bearings are fitted, reducing friction and the associated lag in indications.

Question 6

Servoassisted

Answer 6

This servo-assistance not only gives the altimeter an increased operating range but also improves the instrument accuracy, particularly at high levels.
The principle of the servo altimeter is that the small movements of the capsules are detected by a very sensitive electromagnetic pick-off. This produces an electric current which is amplified and used to drive a motor which rotates the counters and pointer.

Question 7

Tollerance Simple

Answer 7

simple 0’ +-100 - 35000 +- 1000

Question 8

Tollerance Sensitive

Answer 8

sensitive 0’ +- 70 - 40000 +- 600

Question 9

Tollerance Servoassisted

Answer 9

ServoAss 0’ +-30 - 40000 -+ 100

Question 10

Blockage

Answer 10

Altimetry freez at level when incident happen

Question 11

Leak

Answer 11

• Non pressurize over-read because pressure inside is
  less than the one oudside
• Pressurize read the cabin altitude (pressure set by the pilot)