Aircraft Systems and Instruments: Temperature Measuring Devices

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What is the total pressure change that pitot static instruments are required to measure?

20 psi

10 psi (correct)

30 psi

5 psi

How many revolutions of a 100-foot pointer on an altimeter would a 1 psi change in pressure translate to?

2 revolutions

5 revolutions

3 revolutions

4 revolutions (correct)

What is the atmospheric pressure at 10 000 feet compared to sea level?

¼ that of the pressure at sea level

½ that of the pressure at sea level

¾ that of the pressure at sea level

⅔ that of the pressure at sea level (correct)

Who discovered that the pressure of air bearing down on a liquid in a container forces it up a tube?

Evangelista Torricelli Signup and view all the answers

What is the advantage of using mercury in barometers?

Mercury is the heaviest of all liquids Signup and view all the answers

What is a limitation of mercury barometers?

They require special care in handling Signup and view all the answers

What is the primary function of bimetallic temperature sensors in circuit breakers and thermostats?

To operate switch contacts Signup and view all the answers

What is the main reason for the temperature coefficient of the instrument in an altimeter?

The change of elasticity of the capsule material with change of temperature Signup and view all the answers

What happens to the elasticity of the capsule material if the temperature decreases at sea-level?

It increases, causing the capsule to expand Signup and view all the answers

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

The limbs of the bracket bend inwards Signup and view all the answers

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

To compensate for changes in ambient temperature Signup and view all the answers

What is the result of the downward force exerted on the capsule assembly by the U-shaped bracket in an altimeter?

The error-producing expansion of the capsule is opposed Signup and view all the answers

What is the primary function of a pitot probe?

To measure airspeed Signup and view all the answers

What is the purpose of the calibrated drain hole in a pitot probe?

To allow moisture to escape without affecting the sensed pressure Signup and view all the answers

What is the function of the electrical heater element in a pitot probe?

To negate the possibility of moisture freezing Signup and view all the answers

What is a static port used to measure?

Static pressure Signup and view all the answers

In what location is a static vent often found in some light aircraft?

In the fuselage skin Signup and view all the answers

What type of plates are used in more complex aircraft systems?

Specially contoured metal vent plates Signup and view all the answers

At approximately what Mach number do commercial jet aircraft typically reach their critical Mach number?

M.73 Signup and view all the answers

What is the purpose of determining an aircraft's Maximum Operating Mach Number?

To avoid loss of control due to shock waves Signup and view all the answers

What is the function of a Machmeter?

To compute the Mach number from airspeed and altitude Signup and view all the answers

What is the purpose of the lubber mark on a Machmeter?

To show the critical Mach number and Maximum Operating Mach Number Signup and view all the answers

Why do commercial jet aircraft typically have a Maximum Operating Mach Number around M.8 to M.87?

To provide a safety margin before shock waves cause loss of control Signup and view all the answers

What happens to the air flowing over the top of the wing as an aircraft approaches the speed of sound?

It approaches the speed of sound Signup and view all the answers

What type of construction is the ranging bar made of?

Bimetal Signup and view all the answers

What is the purpose of the invar portion in the ranging bar?

To counteract the capsule expansion Signup and view all the answers

What does the red radial line on the airspeed indicator represent?

The never exceed speed Signup and view all the answers

What determines the stall speed on an airspeed indicator?

Flap and/or landing gear configuration Signup and view all the answers

What is the purpose of the amber caution speed range on the airspeed indicator?

To indicate smooth turbulent-free conditions Signup and view all the answers

What is the typical color of the normal operating speed range on an airspeed indicator?

Green Signup and view all the answers