Chapter 11 - Aircraft Instrument Systems - Oral Questions Flashcards
A static check may be performed on a manifold pressure gauge by using what piece of information?
Current atmospheric pressure
What aircraft instrument can be used to check a manifold pressure gauge for proper indication?
Altimeter
Name several of the indication errors that may be found in altimeters
Scale errors, hysteresis, friction, installation
Scale Error - The altimeter must indicate the same altitude shown on the master indicator or manometer within a specified allowable tolerance
Hysteresis - The reading taken with the altitude increasing must agree with the readings at the same pressure level when the altitude is decreasing. A specified tolerance is allowed for this test.
Friction - Two altitude readings are to be taken at each pressure level, one before and one after the instrument is vibrated. There should be no more than a specified difference between the two readings.
Case leak - When the pressure inside the altimeter case corresponds to an altitude of 18,000 feet, is should not leak down more than a specified amount in a specified period.
What is the signal source in an electrical resistance type temperature indicating system?
A temperature bulb or sensing element
What type of temperature sensing system is normally used to measure a turbine engine exhaust gas temperature?
A thermocouple type system
What operating parameter is indicated by a tachometer?
Engine RPM (crankshaft or turbine rotor speed)
What is the name of the effect that causes a gyro to respond to an applied force at a point 90 degrees further in the direction of rotation?
Gyroscopic precession
What aircraft instruments are connected to the pitot-static system?
The altimeter,
vertical speed indicator,
airspeed, and
mach meter in high performance jets
What are the three sources of power used to drive a gyroscopic turn indicator?
Air from a vacuum source, from a pressure source, or an electric motor
What are two items that should be considered during inspection of a magnetic compass?
- The fluid must be clear
- The housing must be full with no bubbles
- The card must be legible and the lubber line intact
- The compass should be properly calibrated
In what way do magnetic fields generated by electrical equipment and steel parts in the airplane affect a magnetic compass?
Stray magnetic fields deflect the compass from the correct alignment with the earth’s magnetic field
Describe the basic operating concept of a synchro-type remote indicating system
A remote transmitter electrically signals a receiver inside the instrument
Why should you avoid cleaning obstructions from the sensing holes in a pitot-static system with a tool?
The holes are aerodynamically critical
(there needed for the instruments to work properly)
After components in a pitot-static system have been replaced, what tests or inspections are required?
The static system leak test specified in FAR 91.411
What quantity is measured by a capacitance type fuel quantity indicating system?
Mass of the fuel
Who is authorized to apply the range markings to an instrument dial face?
The manufacturer or a certificated instrument repair station
What is the purpose of a slippage mark on an instrument glass?
To indicate if the glass has moved, which could cause incorrect range markings when they are painted on the glass
What references should be consulted to determine the proper range markings for aircraft instruments?
The aircraft maintenance manual,
flight manual,
TCDS, or
Aircraft specifications
What is the meaning of a yellow arc on an aircraft instrument?
A caution or limited flight operations range
What is the reason for swinging a compass and how is it accomplished?
To compensate for deviations caused by magnetic fields in the aircraft, by adjusting the compensating magnets
