Aeroplane Aerodynamics: Altimeter Mechanism

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What is the primary function of a bimetallic strip in temperature sensors?

To measure the pressure of a system

To detect changes in humidity

To regulate the flow of liquids

To compensate for temperature changes (correct)

What is the main purpose of a bimetallic U-shaped bracket in an altimeter?

To increase the accuracy of the altimeter

To compensate for changes in temperature (correct)

To amplify the pressure signal

To reduce the weight of the altimeter

What happens to the elasticity of the capsule material when the temperature decreases?

It remains the same

It becomes zero

It increases (correct)

It decreases

What is the effect of a decrease in temperature on the U-shaped bracket?

It causes the limbs to bend inwards (C) Signup and view all the answers

What is the primary cause of the temperature coefficient of the instrument?

The change in elasticity of the capsule material (B) Signup and view all the answers

What would happen to the altimeter reading if the temperature were to decrease and there were no temperature compensation?

It would over-read (D) Signup and view all the answers

What is the primary purpose of the 10 000-foot pointer in an altimeter?

To serve as a passive low-altitude warning device (C) Signup and view all the answers

What occurs to the striped disc in the 10 000-foot pointer as the aircraft climbs above 10 000 feet?

It gradually retracts from view (B) Signup and view all the answers

What is the purpose of the vibrator in some aircraft's altimeter?

To prevent the delicate gearing from sticking (C) Signup and view all the answers

What causes the aneroid capsules to expand in an altimeter?

A decrease in air pressure outside the aircraft (C) Signup and view all the answers

What is the purpose of the tubing and hose in an altimeter?

To conduct the static pressure outside the aircraft to the instrument case (D) Signup and view all the answers

What is the significance of the 10 000-foot segment in the 10 000-foot pointer?

It represents 10 000 feet (B) Signup and view all the answers

What is the approximate expansion of the capsule for an ascent from sea level to 30,000 ft?

7 mm (A) Signup and view all the answers

What is the purpose of stacking aneroid capsules in an instrument?

To increase the sensitivity of the instrument (D) Signup and view all the answers

What is the difference between an aneroid capsule and a bellows?

A bellows is generally not evacuated and made from more rugged material (B) Signup and view all the answers

What is the purpose of an aneroid capsule in an aircraft?

To measure atmospheric pressure and altitude (A) Signup and view all the answers

What is the mechanism used to transfer linear movement into rotary movement in an altimeter?

A combination of pivoted levers, sector gears, and flexible cord or linked fusee chain (A) Signup and view all the answers

What can happen to a pitot probe if it is operated for too long on the ground?

The heating element can burn out (B) Signup and view all the answers

Why is it important to keep the area around fuselage-mounted static ports clean?

To ensure accurate air pressure readings (D) Signup and view all the answers

What is the relationship between the pressure change and the expansion of the aneroid capsule?

The capsule expands 0.01 mm for each millibar of pressure change (A) Signup and view all the answers

What can happen if pitot heaters are operated with protective covers fitted?

There is a risk of fire (B) Signup and view all the answers

Why should you always test the temperature of a pitot probe with the back of your hand?

To prevent burn injuries (A) Signup and view all the answers

What can cause damage to the profile of all openings on a pitot probe?

Excessive heat (A) Signup and view all the answers

What is the purpose of a 'salt shaker' design on some static ports?

To prevent wasps from entering the port (B) Signup and view all the answers

What is the purpose of the two screws in the unpainted area?

To attach a test adaptor for static system testing (B) Signup and view all the answers

What material is used to make the pipelines to prevent corrosion?

Light alloy and/or Tungum (C) Signup and view all the answers

Why are the pitot lines usually smaller in diameter than the static lines?

To prevent cross connection (C) Signup and view all the answers

What is used to identify a pipeline at regular intervals along its length?

Appropriately coded tape (B) Signup and view all the answers

Why is it necessary to guard against water accumulation in the system?

To prevent water restriction and indication errors (B) Signup and view all the answers

What is the purpose of the colour coding of the pipelines?

To guard against cross connection (C) Signup and view all the answers