11.5 Flashcards
What are the 4 classes of instruments
Flight
Engine
Navigation
Other
What are the 4 flight instruments
Altitude
Attitude
Airspeed
Direction of flight
What are the 4 parts of the basic T
Left - ASI
Middle - ADI
right - altimeter
Bottom - HSI
What is absolutel pressure
Compares atmospheric against zero
What is gauge pressure
It is the most common and the difference between atmospherics pressure and pressure measured
What is differential pressure
Comparison between two different pressures
What is a bellow
Multiple diaphragm changes connected
What material is the bourdon tube made of
Copper , brass or bronze
What is a aneroid capsule
Membrane or pressure sensitive capsules used
What happens in a aneroid capsule as atmospheric pressure changes
Higher atmospheric pressure will cause it to move more and vice versa
What are the two parts of a pressure transducer and what are the advantages
Made of indicator and transmitter unit
Advantage as it can measure hazardous fluids and it’s measured at source
What does a aneroid capsule transducer do
The capsules monitor two pressures
What happens in an aneroid capsule transducer when p1 px is more than p2
The iron core makes s1 the predominant coil
Two types of strain gauges
Foil and silicon
What does a strain gauge do
Convert mechanical strains into electrical output
What part measures total pressure
Pitot probe
What part measures static pressure
Static ports
What’s instruments use static pressure
Altimeter
ASI
VSI
Where are static ports located
Foward aircraft fuselage or pitot tube
What is static source error
Difference between measured and real static pressure
Where are pitot tubes located
Forward part of fuselage
What’s the function of a baffle in a pitot probe
Prevents water and foreign objects from entering the pitot pressure line
What is qnh
Atmospheric pressure at sea level
Altimeter will read airfield height above sea level
What is qfe
Atmospheric pressure at airfield level
Altimeter will read zero on take off or landing
What is qne
Height
What would qnh be set at below a transition altitude
3000ft outside air lanes
4000-6000 ft in air lanes
What are 3 point altimeter functions
Long - one turn per 1000ft
Short - one turn per 10000ft
Triangular - one per 100000 ft
What does radio altimeter do
Measure the distance from aircraft above the ground rather then sea level
What happens to pressure as altitude increases
Decreases
When does a evacuated capsule expand
When static pressure decreases with a increase in altitude
How can you combat hysteresis error
Replacing mechanical linkage between capsules and pointer with an electrical servo mechanism
What does the vsi show
Rate of ascent or decent
What extra part does a instantaneous vertical speed indicator have
Extra opening to compensate for internet low operating force in standard vsi
What does altimeter measure
Barometric height
Two names temperature defined as
Static air
Outside air temp
Number11
Stair air temp
12
Ram rise
Where are static ports
Foward fuselage
Area of smooth airflow
Sse dependent on what 3 things
Shape of fuselage
Airspeed
Angle of attack
What condition influences measured static
Side slip
How do you compensate for side slip
Cross porting
What must be fittted on ground
Cover on probe
What tells the pilots the orientation relative to the earths rotation
Attitude indicator
What does a vertical gyro provide
Attitude indication for ADI
What does directional gyro do
Provides heading refrence signal for the hsi and radio magnetic indicators
What does gyro stability depend on
Mass
Rotational speed
Radius (distance between axis and centre of mass)
What dictates the degrees of freedom
The amount of gimbles
2 gimbles give how much degrees of freedom
2
What type of gyro do we need
Tied and earth
How many degrees of freedom does a rate gyro have and what does it
1 degree of freedom and it’s used for turn co-ordination where axis is horizontal
What is rigidity
Ability to maintain its axis while pointing in a fixed in a fixed direction in space
What is gyro precession
Putting a force on one axis will be felt on the other axis
What the two properties that a rotor relies on for angular momentum
Rigidity and precession
What’s spinning
Gyro on x axis (own)
What’s tilting
Gyro on y axis (Horizontal)
What’s veering
Gyro on z axis (vertical)
What are levelling switches
Electrolytic switches
Vertical gyro is used when we have what
Artificial horizon
Gyro spin speed
2200 rpm
When does a gyro wonder
Mechanical imbalances inside
When a gyro is tied down how often is it checked
Every hour to make sure it’s 15 degrees
With gyro precession what was will the gyro spin
The direction of rotation
How does a laser gyro work
2 light sources going round in opposite directions
Advantage of laser gyro
No moving parts
Less maintenance
How many laser ring gyros
1 on each axis
How many accelerometers
3
Max gyro handing
20 minutes
Directional gyro also know as what
horizontal axis gyro
What’s on a hsi
Warning flags
What will be shown on ehsi
Weather radar
Turn and bank coordinators are powered by what
DC electrical system
Rate gyro degrees of freedom and how is it limited
1degrees & limited by a spring
True north vs magnetic north
Variation
Compass vs magnetic heading
Deviation
Hard iron magnetism
Caused by iron or parts in aircraft structure
Hard to demagnetise , easy to magnetise
Soft iron magnetism
Only magnetised when the field is around it , once it’s gone it’s no longer magnetised
Expansion unit is used for what
Compensated for fluid expansion caused by temp change
Why do u need to use the correct type of lamp for a replacement
If you don’t could lead to compass deviation when you switch on the lights
Where is the flux valve located
Far away from the magnetic fields of the aircraft
(wing tips , wing leading edge , vertical fin)
What does a flux valve do
Electrically transmits information to an aircraft’s compass system
How should stall warnings operate
5kts or 5% above stall speed
Where is the reed switch located
Behind the opening in the leading edge of the wing
How does the alpha vane prevent ice formation
Using an internal electrical heater
If no change happens after the stick shaker goes off what happens
The stick pusher is activated
