Flight Instruments Flashcards
What does the airspeed indicator (ASI) measure?
Difference between ram air pressure in pitot tube and ambient pressure in static port.
How does the altimeter function?
Uses an ____________ ____________ to compare air pressure in the _____________ port to a known local pressure set by the ____________.
Uses an aneroid barometer to compare air pressure in the static port to a known local pressure set by the pilot.
Above what altitude is the altimeter set to standard 29.92” Hg?
Above 18,000 feet.
What principle causes the altimeter to indicate higher than true altitude when flying from high to low pressure or temperature?
“High to low, look out below!”
How does the vertical speed indicator (VSI) show rate of climb?
Using a calibrated leak within the unit’s pressure chambers.
What is the primary cause of pitot-static system errors?
Blockages in the pitot tube or static port.
What happens if the front of the pitot tube is blocked and the static port is clear?
ASI reads zero.
What happens if both the front and drain holes of the pitot tube are blocked and the static port is clear?
ASI freezes in place.
What happens if the pitot tube is clear but the static port is blocked?
ASI reads inaccurately (reads lower at higher altitudes, higher at lower altitudes).
What are the two main principles of gyroscopic instruments?
Rigidity in space and precession.
What does the attitude indicator (AI) show?
Bank and pitch.
What error might the attitude indicator display during acceleration or deceleration?
May show a pitch up during acceleration and a pitch down during deceleration.
What must be periodically done to the directional gyro (DG) due to precession?
Recalibrate it to the correct magnetic heading.
What does the turn coordinator (TC) show?
Rate of turn and rate of roll.
What is the standard rate turn indicated by the turn coordinator?
A full circle in 2 minutes (90° turn in 30 seconds).
What error occurs in a magnetic compass due to electrical fields in the cockpit?
Deviation.
How is magnetic variation corrected?
Subtract east variation from true heading to get magnetic heading; add west variation.
What is the magnetic compass error when turning from a northern heading in the Northern Hemisphere?
Shows a lag (undershoot north, overshoot south - UNOS).
What is the magnetic compass error during acceleration or deceleration?
Acceleration shows a turn to the north, deceleration shows a turn to the south (ANDS).
What is the primary pitch instrument in straight and level flight?
Altimeter.
What is the supporting pitch instrument in straight and level flight?
Attitude Indicator (AI), Vertical Speed Indicator (VSI).
What is the primary bank instrument in straight and level flight?
Directional Gyro (DG).
What is the supporting bank instrument in straight and level flight?
Attitude Indicator (AI), Turn Coordinator (TC).
What is the primary power instrument in straight and level flight?
Airspeed Indicator (ASI), Tachometer (TACH).
