1. 6.11 Flight Instruments
Refs: FTGU pp 33-45

2. Class Outline Review of The Magnetic Compass Pitot-Static Instruments
Gyroscope-based Instruments

3. Review What lines does a magnetic compass point along?
The compass points along magnetic field lines that are generally perpendicular to the surface of the Earth
What is the difference between the North Pole and where a compass points?
Magnetic and True North are located in different positions, the difference is known as variation
What happens to the compass as you get closer to the magnetic poles
The magnet ‘dips’ to follow the field lines and can act erroneously

4. Review What occurs when turning from a Northerly heading?
The compass lags due to magnetic dip effects
What if you accelerate on an Easterly heading?
The compass registers a turn to the North
Why do we perform a compass swing? What is this effect we are correcting for called?
To remove the effects of any internal magnetism of the plane (magnetic and electrical components). The effect we are counteracting is magnetic deviation

5. The Pitot-Static System
Theory of Flight 6.11
The Pitot-Static System

6. The Pitot-Static System

7. Altimeter Measures height based on internal, sealed pressure
Pressure Error
Temperature Error
Mountain Effect
Types of Altitude
Indicated
Pressure
Density
True
Absolute
Radar Altimeter

8. Airspeed Indicator
Difference between static and dynamic (ram) pressure
Density Error
Position Error
Lag
Ice and Water Errors
Airspeeds
Red – Vne
Yellow – Va
Green – Vno
White – Vfe
ICE-T: Indicated, Calibrated, Equivalent, True
Pretty Cool Drink – Position, Compression, Density

10. Inside an Airspeed Indicator:

11. By the way, there is more than one type of “airspeed”:

12. Vertical Speed Indicator
Change in outside, static pressure
Small hole vents pressure difference over time
LAG

13. The Magnetic Compass - Review
Construction
True Direction
Magnetic Direction
Compass Direction
Errors
Deviation
West is Best, East is Least
Magnetic Dip
Northerly Turning Error
Acceleration Error
Acceleration North, Deceleration South

14. Gyroscopic Instruments
Theory of Flight 6.11
Gyroscopic Instruments

15. Gyroscopes
Electrical
Engine
Venturi
Precession: define =

16. Heading Indicator, aka Directional Gyro
Set on ground, reset in air to match compass when level
Precession (because of, reset every 15 minutes)
Apparent Precession

17. Attitude Indicator Artificial Horizon, driven by vacuum system
Takes ~5 minutes to ‘spin up’
Degrees of bank angle
Degrees of pitch, up
Degrees of pitch, down

18. Examples of attitude indicator readings:
Note: for a test one of these instrument indications will be shown and you will have to answer as to what the aircraft is doing.

19. How many degrees of left bank is this airplane at?45

20. Turn and Bank (Slip) Indicator and Turn Co-ordinator
Needle/Aircraft attached to electric gyro (usually)
Ball subject to gravity/other acceleration, shows a skid or a slip in a turn, “step on the ball” to correct
Turn co-ordinator senses ‘yaw’ and ‘roll’

21. This T&BI is showing a right turn…
... and where the ball will move in a properly coordinated turn with the correct input of rudder, then in a skid, then in a slip.
By the way, how long will it take this aircraft to complete a 360 degree turn at this angle of bank?

22. Also remember the loading of gravity plus the increase of stall speed on an airplane in a turn/bank:

23. Summary Review of: Pitot-Static System Gyroscopic Instruments
The Compass
Pitot-Static System
Altimeter
Airspeed Indicator
Vertical Speed Indicator
Gyroscopic Instruments
Heading Indicator
Attitude Indicator
Turn and Bank/Turn Co-Ordinator

24. Next Class
Homework:
Complete Instruments question sheet, use FGU to answer.
Skim Read FGU Chpt. 9 pp to familiarize for Radio Navigation Instruments