11.5.1 Instument Systems/ Avionic Systems Flashcards
Where are the most important basic flight instruments located
The Basic T
What is not a part of the basic T but located bottom right to it
Vertical Speed Indicator (VSI)
Hat is top right of the basic T
Altimeter - Indicates altitude of aircraft above sea level
What is top left of the basic T
Airspeed indicator - Shows speed which is a reference for all aerodynamic parameters influencing aircraft lift, drag and manoeuvrability
What is top middle of the Basic T
Artificial horizon - or attitude indication is integrated in the Attitude director indicator (ADI)
Shows pitch and roll altitude in relation to the horizon
What is bottom middle of the basic T
Compass or heading indication - Integrated in the Horizontal Situation Indicator (HSI)
Shows the direction of the aircraft on the longitudinal axis in relation to magnetic north
Apart from those in the basic T what additional flight instruments are there
- Vertical Speed Indicator (VSI)
- Mach meter
- Temperature indicators
What instruments (air data instruments) use air pressure from outside the aircraft
Altimeter and air speed indicator
What two pointers do most altimeters have as a minimum
100ft and 1000ft. Larger aircraft which fly at higher altitudes also have one for 10,000ft
How does a normal altimeter calculate altitude
They measure the static pressure of the atmosphere and indicate it in feet or meters
Hat happens to pressure if altitude increases
Pressure decreases
A pneumatic altimeter is usually found in small aircraft and as a standby in large aircraft. It has a sensitive pressure gauge, what is it called
Aneroid bellows
How does a pneumatic altimeter work
- Static pressure applied around the sealed case surrounds the bellows and compresses them
- The bellows deflection moves the instrument mechanism and turns the altitude pointer which shows the altitude on a scale calibrated in ft or meters
- The altimeter indication is calibrated to the standard atmosphere shown in a graph
Altimeters accuracy decreases with altitude so what is used on large aircraft to help rectify this
Large aircraft have bellows driven by the Air Data Computer (ADC) and use only electrical components such as motors, amplifiers or digital computers
To what conditions are altimeters calibrated to
Conditions of the standard atmosphere
What is the baro setting called
QNH
What is the actual pressure of the airport called (field elevation)
QFE
What is the transition altitude
The standard setting of 1013hpa must be selected during climb at a certain altitude called transition altitude
What is done with the altimeter setting when coming in for landing
It is set to either QNH or QFE of the destination to get the correct altitude indications for landing
What variable can be an issue with altimeter settings
Temperature. When it is cold clearance over mountains must be carefully monitored as the temperature can shift pressure levels giving the altitude a slightly different reading
On an airspeed indicator what line is connected to the bellows and what line is connected to the indicator case so it surrounds the bellows
Total pressure line is connected to the inside of the bellows and the static pressure is distributed to the indicator case so that it surrounds the bellows
Airspeed indicator
Low airspeed - ?
Medium speed - ?
High speed - ?
Low speed - the total pressure is low and the bellows are compressed
Medium speed - All mechanical parts are in the present position
High speed - the total pressure is high and the bellows expand
On small aircraft what are speed limits shown as on the airspeed indicator scale
They are marked with coloured ranges and lines
What is the green band on the digital airspeed indicator
Shows the normal operating range