Regional Gliding School Pitot/Static System l Pitot Tube –measures dynamic and static pressures and is positioned to be clear of the slipstream and.

Regional Gliding School

Pitot/Static SystemPitot/Static System Pitot Tube

– measures dynamic and static pressures and is positioned to be clear of the slipstream and facing the line of flight.

THE AIRSPEED INDICATOR IS THE ONLY INSTRUMENT CONNECTED

TO THE PITOT PRESSURE SOURCE.


Pitot/Static SystemPitot/Static System Static Tube

– measures static pressure. The tube is vented to allow air pressure inside the instrument case to equalize with the outside air pressure. The vents are located on opposite sides so as to not be affected by turbulence.

ASI, ALTIMETER, VSI USE

STATIC PRESSURE.


Pitot/Static SystemPitot/Static System


AltimeterAltimeter Measures the pressure in the atmosphere,

which is the weight of the air above you at any given altitude. This weight will change as the aircraft climbs or descends causing the altimeter to register a change.


AltimeterAltimeter Made up of a stack of aneroid

capsules each set at standard sea level. As the altitude changes these capsules expand and contract moving gears and thus the hands on the altimeter change.


Altimeter ErrorsAltimeter Errors Pressure:

– the atmospheric pressure changes when flying from place to place. If not corrected the altimeter will be inaccurate.

Temperature:– the altimeter is constructed to work on the values of the

ICAO standard atmosphere (15C), the temp is not always at this value.


Altimeter ErrorsAltimeter Errors Mountain Effect:

– when flying near mountains, winds can be gusty and cause a drop in local pressure. Consequently, the altimeter will not give an accurate altitude indication.


Airspeed IndicatorAirspeed Indicator Tells the pilot how fast they are traveling

through the air and not over the ground and is measured in knots and miles per hour. Indicates the difference between pressures in the pitot and static tubes.


Airspeed IndicatorAirspeed Indicator The reading on the airspeed

indicator is referred to as the Indicated Airspeed (IAS). True airspeed (TAS) is the calibrated airspeed corrected for airspeed indicator error due to density and temperature.


Airspeed IndicatorAirspeed Indicator The instrument is made up of an aneroid capsule

which measures the pitot pressure. The interior of the case is sealed and the static pressure is measured there. The changes in dynamic pressure (pitot) cause the aneroid capsule to expand and contract and this is registered and connected to a linkage that moves the hand on the ASI.


Calibrated AirspeedCalibrated Airspeed Is indicated airspeed corrected for

instrument errors and installation errors in the pitot static system


Equivalent AirspeedEquivalent Airspeed Calibrated airspeed corrected for

compressibility factor.


Airspeed MarkingsAirspeed Markings

GreenNormal (Vsl)

YellowCaution (Vno)

RedVelocity never exceed (Vne)

WhiteFlaps (Vfe)


Airspeed ErrorsAirspeed Errors Density:

– atmospheric density varies and as a result this will change the accuracy of the ASI.

Position:– Eddies that form as air passes over the wing are responsible for

error.

Lag:– the slowness of the working parts are responsible for this

error.


Airspeed ErrorsAirspeed Errors Icing:

– ice formation blocking either the pitot or static tube could give inaccurate readings.

Water:– water could block the tubes causing inaccurate

readings.


NOTE: You must use the buttons in the Confirmation Stage


A

B

C

D

Altimeter

Airspeed indicator

Static indicator

Let's try a few review questions on Theory of Flight:

Question #1 - Which instrument is used to indicate height above sea level?

Pitot indicator

Theory of FlightTheory of FlightAircraft InstrumentsAircraft Instruments

I’m afraid that answer is incorrect

Let's try again...

Flying Scholarship Program


Let's try again...



Let's try again...



That answer is correct.

Let's move on...


AltimeterAltimeter Measures the pressure in the atmosphere,

which is the weight of the air above youat any given altitude. This weight willchange as the aircraft climbs or descendscausing the altimeter to register a change.


A

B

C

D Calibrated airspeed

Indicated airspeed

True airspeed


Question #2 - What is indicated airspeed corrected for instrument errors and installation errors in the pitot static system.

Equivalent airspeed



Let's try again...



Let's try again...



Let's try again...




Let's move on...


Calibrated AirspeedCalibrated Airspeed Is indicated airspeed corrected for

instrument errors and installation errors inthe pitot static system


Vertical Speed IndicatorVertical Speed Indicator Indicates the

rate of climb and descent and is measured in feet per minute.


Vertical Speed IndicatorVertical Speed Indicator Measures the change in pressure between the

capsule (atmospheric pressure) and the case of the instrument. The capsule will expand and contract which is then transmitted by linkage to the dial of the instrument.

The instrument tends to lag and will only show an accurate rate after 6-9 seconds.


VariometerVariometer A very sensitive rate of climb indicator

that is used to find thermals. Works on the same principle as the altimeter: the higher the altitude the less the static pressure.


Magnetic CompassMagnetic Compass Consists of two north seeking magnets which are attached

to a float which is also attached to a compass card. This complete magnet system is mounted on a pivot and is free to rotate. The whole assembly is mounted within the compass bowl which is filled with alcohol to reduce the weight of the compass card and the magnets. The lubber line indicates the direction the aircraft is heading and is in line with or parallel to the longitudinal axis of the aircraft.


GyroscopeGyroscope It is a rotor, or spinning wheel, rotating at high

speed in a universal mounting, called a gimbal, so its axle can be pointed in any direction.

Gyroscopic Inertia:– the tendency of a rotating body to maintain its plane of

motion.


GyroscopeGyroscope Precession:

– the tendency of a rotating body, when a force is applied perpendicular to its plane of rotation, to turn in the direction of its rotation 90 to its axis and take up a new plane of rotation parallel to the force applied.


GyroscopeGyroscope


The Heading IndicatorThe Heading Indicator The heading indicator or

directional gyro is an instrument designed to indicated the heading of the airplane and because it is steady and accurate, to enable the pilot to steer that heading with the least effort.

Gyro InstrumentsGyro Instruments


The Artificial HorizonThe Artificial Horizon The artificial horizon or attitude indicator

provides the pilot with an artificial horizon as a means of reference when the natural horizon cannot be seen because of cloud, fog, rain or other obstructions to visibility. It shows the pilot the relationship between the wings and nose of the airplane and the horizon at the earth.



Turn and Slip IndicatorTurn and Slip Indicator Needle indicates the direction and rate of turn.

Ball indicates slipping or skidding

If the ball is opposite to the needle in a turn you are skidding. With the ball and needle on the same side the turn is slipping.



Turn and Slip IndicatorTurn and Slip Indicator

Straight and Level Coordinated left Turn

Slipping Left TurnSkidding Left Turn



NOTE: You must use the buttons in the Confirmation Stage


A

B

C

D

Variometer

Magnetic compass

Vertical speed indicator


Question #3 - A rotor, or spinning wheel, rotating at high speed in a universal mounting, called a gimbal, so its axle can be pointed in any direction is known as .

Gyroscope



Let's try again...



Let's try again...



Let's try again...




Let's move on...


GyroscopeGyroscope It is a rotor, or spinning wheel, rotating at

high speed in a universal mounting, calleda gimbal, so its axle can be pointed in anydirection.

Gyroscopic Inertia:– the tendency of a rotating body to maintain its

plane of motion.



Question #4 - What instruments work on a gyroscope?

Theory of FlightTheory of FlightAircraft instrumentsAircraft instruments

A

B

C

D

Variometer

Magnetic compass

Vertical speed indicator

Artificial Horizon


Let's try again...



Let's try again...



Let's try again...




Let's move on...


The Artificial HorizonThe Artificial Horizon The artificial horizon or attitude indicator

provides the pilot with an artificial horizon asa means of reference when the naturalhorizon cannot be seen because of cloud,fog, rain or other obstructions to visibility. Itshows the pilot the relationship between thewings and nose of the airplane and thehorizon at the earth.




Congratulations!!

You have now completed the Aircraft Instruments lesson and the Theory of Flight Module. Of course, this lesson and module is always available to you for future reference if required.

You are now ready to move along to the next module you have not completed. You can advance to the Self Test Module if you feel ready to challenge the final exam.

Good Luck!

Regional Gliding School Pitot/Static System l Pitot Tube –measures dynamic and static pressures and is positioned to be clear of the slipstream and.

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