Pitot static systems Flashcards
What is atmospheric pressure?
The force exerted by the weight of a column of air
What is standard sea level pressure in inches of mercury
29.92
What is standard sea level temperature in decrees Celsius?
15 C
What is the standard temperature lapse rate with altitude?
2 degrees C pr 1000’
A change in 1 inch of mercury pressure is equal to approximately ________ feet of altitude.
1000’
Define impact pressure
Static pressure plus dynamic pressure
Define static pressure
Ambient pressure
Which instruments depend on static pressure only?
VSI, Altimeter
Which instrument depend on both impact and static pressure?
Airspeed indicator
What pressures affect the pitot static system?
Dynamic and static
Name and define the three types of airspeed
a. Indicated: read from the dial on the face of the instrument
b. Calibrated: IAS corrected for instrument and position error
c. True: CAS corrected for density error
Name and explain the three errors in the airspeed indicator
a. Installation error: Misalignment of the pitot tube with the relative wind and position of the static vents
b. Density error - caused by pressure and temperature changes, air less dense as altitude changes.
c. Instrument error - caused by friction in the instrument
Is the vertical speed indicator (VSI) a pressure differential measuring instrument?
yes
What does the setting knob on the altimeter change when it is turned?
Kollsman setting and position of the needles
A change of .15 inch of mercury pressure is equal to _______ feet.
150
Define indicated altitude
Altimeter indication
Define True altitude
Altitude above MSL
Define Pressure altitude
Altitude above the Standard Datum Plane (29.92” Hg)
Define Absolute altitude
Altitude above ground
Define Altimeter setting
Station pressure corrected to MSL
Why is an altimeter setting necessary?
To correct for pressure changes
What is the maximum allowable error in the altimeter?
75’ +/- but operators manual should be checked to confirm accurate limit for their aircraft.
When flying into an area with lower pressure without resetting the altimeter, would your true altitude be higher or lower than your indicated altitude?
Lower
When flying into an area of higher pressure without resetting the altimeter, would your altimeter indicate higher or lower than your true altitude?
Lower
If you depart a base with an altimeter setting of 29.82 and an hour later receive a new altimeter setting of 30.22, how much higher or lower than true altitude would the altimeter indicate prior to adjusting the altimeter to a new setting?
400’ lower than true altitude
At the last reporting point you corrected the altimeter by setting 29.80. what is your true altitude in relation to indicated altitude (before you reset the altimeter)?
120 lower than indicated altitude
When flying into an area of colder than standard temperature, would the indicated altitude be more or less than true altitude?
More
What causes density error?
Nonstandard pressure and temperature
Define true airspeed
Calibrated airspeed corrected for density error.
