ACFT - Flight Instruments Flashcards
What are the 6 Traditional flight instruments on an A/C? (6)
- Altimeter
- Vertical Speed Indicator (VSI)
- Air Speed Indicator (ASI)
- Attitude Indicator/Artificial Horizon
- Heading indicator/Gyrosyn compass
- Turn Co-ordinator
Which 3 instruments are from air pressure / altitude? (3)
- Altimeter
- Vertical Speed Indicator (VSI)
- Air Speed Indicator (ASI)
Which 3 instruments are Gyroscopic? (3)
- Heading indicator/Gyrosyn compass
- Attitude Indicator/Artificial Horizon
- Turn Co-ordinator
”HAT”
How does a Pitot system work? (5)
- Uses atmospheric pressure
- Senses Dynamic & Static air pressure
- Works out the variation with altitude
- Dynamic air - When the A/C is moving forwards
- Static air - is not in the direct flow of air over the aircraft in flight
What is an Altimeter? (1)
An instrument used to measure the altitude of an aircraft above a fixed level
What can the implications be of an incorrect Altimeter subscale? (3)
Mis-setting the subscale will cause the instrument to under or overread
Higher pressure on subscale - Altimeter to Overread
Lower pressure on subscale - Altimeter to Underread
What is the VSI? (2)
VSI - Vertical Speed Indicator
- Measured in 100 fpm intervals
- Always a slight lag in the instrument and between six and nine seconds of steady climb, descent or level flight must elapse before an accurate reading is displayed
What is ASI?
ASI - Air Speed Indicator
Measures the difference between STATIC pressure and the DYNAMIC pressure received from an aircraft’s pitot tube
What are the V-Speeds for Airspeed Indicators? (4)
What types of ASI errors are there? (4)
- Compression errors
- Instrument error
- Position errors
- Density errors
What types of Pitot system blockages are there? (2)
- A Static blockage - Overread in Descent
- A Pitot blockage - Underread in Descent
“PUD - SOD”
Why do Aircraft use Mach Number? (2)
- In order to overcome the problem of the
difference between IAS and TAS at high altitudes - Expressed as fractions (or multiples) of the Local Speed of Sound
What errors can Mach meters suffer from? (2)
- Instrument error
- Pressure error
What are the 2 important properties of a Gyroscope? (2)
Inertia - The tendency of the gyro to keep a fixed position relative to space, often referred to as rigidity in space
Precession - When subjected to a force, the gyro acts as though the force has been applied at 90 degrees to the rotor, at a position 90 degrees forward in the direction of rotation of the rotor
Positions of an A/C vs Attitude Indicator diagram
What will a failure of a vacuum system cause? (1)
The Attitude Indicator to fail
Turn & Turn-and-Slip indicators diagram
What is a Rate turn? (1)
3° /sec
(360° in 2 mins)
Turns using a Turn & Turn-and-Slip indicator diagram
What is a Heading Indicator? (3)
- It is tied to the vertical/yaw axis to indicate the aircraft’s heading on a rotating compass card
- Remains aligned with the Yaw axis
- Earth’s rotation (approx. 15° per hour) will cause the reading to gradually drift
Is a Magnetic Compass mandatory on an aircraft? (1)
Yes
What types of Magnetic compass Errors are there? (3)
- Deviation
- Dip
- Acceleration error
What is deviation error? (1)
The compass needle is affected when aircraft electrical equipment is operated and by the ferrous metallic components in the aircraft
How are Deviation errors mitigated? (1)
By calibrating the compass on a Compass Swing
