Flight Instruments Part 2/3 Flashcards
Errors almost always indicate what
Blockage of the pitot tube, static ports, or both
Blockage of the pitot tube or static ports can be caused by:
Moisture (ice)
Dirt
Insects
Blockage of the static port affects:
ASI
Altimeter
VSI
Blockage of pitot tube affects
ASI
If pitot tube becomes blocked and drain hole remains clear:
Remaining pressure of ASI drops to ambient outside air pressure. ASI decreases to zero because ASI senses no differences between ram and static air pressure
If both pitot tube opening and drain hole become clogged simultaneously
Pressure in pitot tube is trapped. No change is noted on the ASI, should the airspeed increase or decrease.
If static port is unblocked and aircraft changes altitude, ASI will
ASI will change, but change is not related to a change in airspeed but a change in static pressure because ASI relies on dynamic and static pressure.
If static system becomes blocked but the pitot tube remains clear. If aircraft descends, the static pressure increases on the pitot side showing an (increase or decrease?) on the ASI
increase on the ASI
If an aircraft begins to climb after a static becomes blocked, the ASI begins to
decrease as the aircraft continues to climb
Trapped static pressure causes
The altimeter to freeze at the altitude where the blockage occurs.
A blocked static system causes VSI to
produce a continuous zero indication
What is an EFD?
Electronic Flight Display?
What is an Air Data Computer (ADC)
Pitot static inputs are translated for the EFD using an ADC
What is a trend vector on an EFD?
Magenta lines that move up and down on the ASI and Altimeter. ADC computes the rate of change and displays the 6 second projection of where the aircraft will be.
What instruments utilize gyroscopes?
Turn coordinator
Heading indicator
Attitude indicator
Name two important design characteristics of an instrument gyro.
Great weight for its size (or high density) & rotation at high speed with low friction bearings.
Name two fundamental properties of gyroscopic action.
Rigidity in space: gyroscope remains in a fixed position in the plane that it is spinning (more stable and less maneuverable at high speeds)
Precession: tilting and turning of gyro in response to a deflective force
Describe an airplane’s vacuum system with respect to it’s gyro
The vacuum system or pressure system spins the gyro by drawing a stream of air against the rotor veins to spin the rotor at high speeds
What indicators may become inaccurate if vacuum suction pressure is low?
Attitude & heading indicators
Name two types of turn indicators used in aircrafts.
Turn & slip indicator
Turn coordinator
Both of these indicate turn direction and quality (coordination)
On the turn coordinator indicator, what does is the little ball called?
Inclinometer, a liquid filled curved tube
What is a turn coordinator used for?
Used to establish maintain a standard rate turn by aligning the wing with the turn index
What are the marks on the outside of a turn coordinator?
First set of marks indicates an aircrafts level zero rate of turn
Second set of marks indicates a standard rate turn
What is a standard rate turn defined as?
A turn rate of 3degrees per second
What does a turn coordinator indicate?
Rate & direction of turn. It does not display any specific angle of bank
What does the inclinometer of the turn coordinator depict?
aircraft yaw (side to side movement of aircrafts nose)
Describe a slip
The rate of turn is too slow for the angle of bank. Ball moves to inside of the turn (same direction of the turn direction)
Describe a skid
Rate of turn is too great for the angle of bank and ball moves to the outside of the turn
Preflight for inclinometer:
Make sure it is full of fluid with no air bubbles, ball should be resting at its lowest point
How is the gyro mounted in the turn indicator?
on vertical plane
How is the gyro mounted in the attitude indicator?
on horizontal plane
