Chapter 5.6 - Flight Instruments Flashcards
Which Flight Instruments are pressure-operated by utilising the Pitot-Static system (3)?
- Airspeed Indicator (ASI).
- Altimeter.
- Vertical Speed Indicator (VSI).
What is the purpose of an Aircraft’s Altimeter?
To measure the height and vertical distance above a specified datum.
How is a specified datum set in order to provide the Altimeter?
Pressure-setting Subscale.
What is the Altimeter measured in?
Feet.
What does ISA stand for?
International Standard Atmosphere.
What is the Hectopascals at Mean Sea Level?
1013 hPa.
At Mean Sea Level, for every 30 ft gained in Height, how many Hectopascals is decreased from MSL?
1 hPa.
For every 1000 ft gained, how many Hectopascals is decreased from MSL?
30 hPa.
What is the pressure in Hectopascals at an Altitude of 10 000ft?
697 hPa.
What is the temperature at Mean Sea Level?
15°C.
For every 1000ft gained, how much temperature is deceased from MSL?
2°C.
Describe Elevation?
Height (vertical distance) of something on the Earth above mean sea level.
Describe Altitude?
Height of an Aircraft above mean sea level.
When should a Pilot set Local QNH (2)?
- Prior to Takeoff.
- Top of Descent.
When should a Pilot set Area QNH?
Top of Climb.
If a Pilot uses Area QNH at the top of a descent, how much error can be expected?
150+/- ft.
If Local QNH is unavailable, how can a Pilot obtain this information at an Aerodrome?
By setting the elevation of the Aerodrome.
True or False. Vertical Speed Indicator will have a small lag in instrument reading due to the changes in Static Pressure?
True.
How can a Pilot check if the Altimeter is working correctly?
With an accurate QNH in place, the reading should be the same as the Aerodrome Elevation within 100 ft.
How can a Pilot check if the Airspeed Indicator is working correctly?
To monitor changes in reading when taking off.
How can a Pilot check if the Airspeed Indicator is working correctly during flight?
To measure the Stall speed and see if it matches the speed found in the Pilot’s Operating Handbook.
How can a Pilot check if the Vertical Speed Indicator is working correctly?
The pointer should read on ground.
True or False. When Static Vents are blocked during Straight and Level Flight, the Airspeed Indicator will read correctly, providing the height remains constant?
True.
When Static Vents are blocked during a climb, the Airspeed Indicator will show what?
Under-read (lower than actual ASI).
When Static Vents are blocked during a descent, the Airspeed Indicator will show what?
Over-read (higher than actual ASI).
When Static Vents are blocked during Straight and Level Flight, what happens to the Altimeter?
The Altimeter will read the Height at which the blockage occurred.
When Static Vents are blocked during a climb, the Altimeter will show what?
Under-read (lower than actual Altitude).
When Static Vents are blocked during a descent, the Altimeter will show what?
Over-read (higher than actual Altitude).
When Static Vents are blocked, what happens to the Vertical Speed Indicator?
Read Zero despite changes in Altitude.
When Pitot Tube is blocked on ground, what happens to the Airspeed Indicator?
Will read Zero on Takeoff.
When Pitot Tube is blocked during Straight and Level Flight, what happens to the Airspeed Indicator?
Airspeed Indicator will remain constant, despite changes in Indicated Airspeed.
When Pitot Tube is blocked during a climb, the Airspeed Indicator will show what?
Over-read (higher than actual ASI).
When Pitot Tube is blocked during a descent, the Airspeed Indicator will show what?
Under-read (lower than actual ASI).
True or False. Alternative Static and Static Pressure are the same?
False.
What is the ‘worst case scenario’ with the Alternative Static Pressure?
If this Pressure is lower than the actual Static Pressure.
In the event of Alternative Static Pressure being lower than the actual Static Pressure, what happens to the Altimeter?
Over-read (higher than actual Altitude).
In the event of Alternative Static Pressure being lower than the actual Static Pressure, what happens to the Airspeed Indicator?
Over-read (higher than actual ASI).
Which Flight Instruments are Gyro-operated (3)?
- Attitude Indicator (AI).
- Heading Indicator (HI).
- Turn Coordinator.
Name 2 ways gyroscopes are powered in an Aircraft?
- Electronically.
- Vacuum System.
If the Suction Gauge is indicating high or low readings, what will happen to the Gyro-operated Instruments?
The accuracy can no longer be reliable.
Name three ways to check the Attitude Indicator on ground?
- Suction Gauge has the recommended Vacuum Pressure.
- Check the dial glass is undamaged.
- The miniature aircraft retains laterally during Taxiing.
How can a Pilot check the Attitude Indicator during flight?
By banking and/or pitching the Aircraft to see if the Instrument reads the same action.
Why must a Pilot check the Directional Indicator during flight?
The instrument will drift off alignment from the Magnetic Compass.
How can set the DI with the Magnetic Compass?
With a Compass Card.
When should a Pilot align the DI with the Magnetic Compass (2)?
- Prior to Takeoff.
- Every 15-20mins during flight.
What Attitude should be used when aligning the DI with the Magnetic Compass?
Straight and Level Flight.
How can a Pilot check the serviceability of the Directional Indicator?
By checking the power source (the suction gauge).
How can a Pilot check the operations of a DI is working on the ground?
When Taxiing check the reading is the same as the Magnetic Compass after turning.
Name two functions of the Turn Coordinator?
- Rate of Turn.
- Whether Aircraft is balanced.
True or False. The Rate of Turn Indicator uses a Gyro for its operations?
True.
True or False. The Balance Ball uses electric power for its operations?
False. It’s a mechanical device.
How can a Pilot check the serviceability of the Turn Coordinator on the ground (2)?
- Check that no electrical failure flags are showing.
- When parked both Turn Coordinator and Balance Ball should be centred.
How is the gyroscope in the Turn Coordinator spun?
Electronically.
What’s the difference between the new and old style of Turn and Balance Coordinator?
The new style has a miniature Aircraft to describe the rate of turn. The old has a needle.
What is a Lubber Line?
Lines of reference found in a Compass.
What are deviations in the Magnetic Compass caused by?
Magnetic influences on the Aircraft (such as Radios and metal components).
Where can a Pilot locate a Deviation Card?
Near the Compass.
Which factors are considered in making a Compass unserviceable (3)?
- Discoloured Fluid.
- Air bubbles in the Fluid.
- Cracked/Broken Glass on the Compass.
How can a Pilot check if the Compass is working properly (3)?
- Turning the Aircraft and monitor if the heading changes.
- Measuring the Compass on a known heading such as a Runway.
- Checking Compass Card is level.
