Flight Instruments Flashcards
What are the three instruments connected to the pitot-static system?
Altimeter, vertical speed, airspeed
What is the only instrument the pitot tube is connected to?
Airspeed
What is the static port connected to?
What does it do?
Altimeter, vertical speed, airspeed
Allows air pressure in the instruments to equalize with the outside ambient pressure
What will happen to each of the ALT, VSI, and ASI if the static port becomes blocked?
Altimeter will stop moving
Vertical speed indicator will reduce to zero if climbing or descending, or remain at zero
Airspeed indicator will under-read more as you climb, over-read more as you descend.
What will happen to each of the ALT, VSI, and ASI when the pitot tube becomes blocked?
Pitot tube affects airspeed ONLY
A blocked pitot will cause the airspeed indicator to act like an altimeter, increase with climb, decrease with descent.
What happens when a pitot tube is partially blocked?
Partial blockage with drain hole still open well slow dynamic pressure to slowly leak out. The ASI will decrease to zero, not instantly but QUICKLY.
What happens if the static line becomes disconnected in flight?
It would indicate cabin pressure, which is much lower than actual altitude
The VSI shows the rate of ascent or descent in?
Feet per minute
Typically due to the VSI lag, it takes about _____ to _____ seconds for the pressure differential to indicate a climb or descent.
6-8 seconds
What can large and abrupt pitch changes and turbulence do to the VSI?
can extend the lag period and cause erratic and unstable rate indications.
What is the reversal error on a VSI?
With sudden or abrupt pitch changes it will temporarily show the opposite of what the aircraft is doing.
What are 4 weather events that can lead to errors in the altimeter indication?
Low pressure systems
Temperature variations
Mountain effect and waves
Abnormally high pressure
After putting in the altimeter setting, verify that the altitude displayed is within _____ feet of the field elevation.
If not the altimeter needs recalibration.
50 feet
If an altimeter setting is set too high, the altimeter will display a reading that is ______
Too high
Flying from high pressure to low pressure and altimeter has not been adjusted, the altimeter will indicate a reading that is
Too high (you are lower than the altimeter indicates)
When an aircraft is flying from an area of low pressure into an area of high pressure, and the correct altimeter setting has not been obtained, the altimeter will read
Too low (you are higher than the altimeter indicates)
In the Northern hemisphere, a drift to the ____ indicates that an aircraft is flying into an area of low pressure.
Right
The highest setting we can have on most altimeters is
31.00 in. Hg
What is mountain effect?
Winds that deflect around mountains or valleys increase in speed, causing a drop in local pressure. A pressure altimeter in these conditions would give a reading that is too high
Pressure within mountain waves can _____ significantly.
Downdrafts are most severe at _____ _____
And may reach an intensity of ____ feet per minute
The drop in pressure in a mountain wave can cause the altimeter to over-read by as much as ____ feet
Decrease
Summit height
5,000 fpm
3,000 feet
Because mountain wave downdrafts can be quite smooth, a pilot may not notice that the aircraft is in a downdraft.
> Although the aircraft is going down in the wave the altimeter ________ because of the decrease in pressure.
> The altimeter will not register the descent.
Stays the same.
What is pressure altitude?
Altitude indicated when the altimeter is set to 29.92 in Hg. It is based on standard atmosphere
What is density altitude?
Pressure altitude corrected for temperature (the altitude that the aircraft performs like it is flying)
Hot days with low pressures and high humidity lead to (low/high) density altitude.
> That is, the ALTITUDE appears to be HIGH, although the actual density of the air is LOW.
High
