Quiz 2 Flashcards
what does a vertical speed indicator measure
rate of change between case and diaphragm pressures using static
what does an altimeter measure
absolute pressure
what are the 6 errors common in an altimeter
scale error hysteresis after effect friction case leak barometric scale error
what is hysteresis
lagging of indication caused by deflections
which instrument uses differential pressure for readings
airspeed indicators
what is the difference between ISA and TAS
Indicated airspeed - derived from pressure difference between pitot and static
TAS - true airspeed - derived from difference between pitot and static and then corrected for air density based on altitude and temperature
how does a vertical speed indicator (VSI) get its readings
static pressure rate of change
what is the purpose of an air data computer
replaces pneumatic instruments with fully electronic devices
can provide multiple outputs to various systems
how is a Pitot test carried out
close pressure control valve pressurize tank close crossbleed valve close pressure vent slowly open pressure control valve close pressure control valve wait 1 min. observe airspeed change release pressure and return to 0
how is a static test carried out
close vacuum control valve fill vacuum tank open crossbleed valve close pressure and vacuum vents slowly open vacuum control valve close vacuum control valve wait 1 min. observe altitude change open pressure vent - return to field
what instrument is used to indicate speed relative to the speed of sound
mach meter
what is used to indicate airspeed
comparison between dynamic pressure and static pressure
does a VSI have an accelerometer to improve the response to pressure changes
no, an IVSI (instant vertical speed indicator) uses an accelerometer
what instruments use static pressure for readings
altimeter
airspeed
VSI
where does dynamic pressure connect to an airspeed indicator in relation to static
dynamic pressure is fed into the case while static is fed into the diaphragm.
what is a radio altimeter and how does it measure altitude
it is used as a navigational aid. uses radio waves
what is pressure altitude
the altimeter reading when the barometer is 29.92 InHg
when is pressure altitude used
above 18,000ft the altimeter barometric setting is adjusted to 29.92 InHg
what barometric settings does a blind encoder use
always referenced to 29.92 InHg
is moisture in the pitot static system used to keep the system clean
no, moisture is removed from the system completely
what is the procedure to flush a pitot static system
disconnect lines from the instruments and blow towards the ports
how would altitude be lowered below field altitude
slowly open the pressure control valve
for a pressurized aircraft, what is the maximum leak rate of the static system
100 ft/min or 2% of max cabin differential. whichever is higher
what is the crossbleed valve in a pitot static test used for
balance pressure in airspeed indicator during a static pressure check
