11.5 Flashcards
If an aircraft is (IFR) rated what must it have?
More than one source for each instrument (alternate source)
ECAM meaning?
Electronic centralised aircraft monitoring
Where is the PFD located?
The outboard side in the cockpit with one for pilot one for co pilot
EHSI meaning?
Electronic horizontal situational indicator
EADI meaning?
Electronic altitude directional indicator
How many screen are there on a typical EFIS system (electronic flight instrument system)
6
What is contained in the basic T?
Right = Altimeter
Left = airspeed indicator
Top middle = artificial horizon
Bottom middle = compass or heading indicator
What are the additional important flight instruments?
-vertical speed indicator
-Mach meter
-temperature indicators
Where are altitude based instruments on the basic T?
Right hand side
Qualitive and quantitive meaning?
Qualitive = colour or visual indication
Quantitive= purely informational or numerative
What is pressure displayed in?
Inches of mercury or hectopascals
Which instruments work off of pressure?
-Altimeter
-Air speed indicator
-Vertical speed indicator
What is the standard temperature at sea level?
15 degrees C
How much does temperature decrease with altitude?
2 degrees C per 1000 feet
What pressure type does an Altimeter measure from?
Static pressure
What is the pressure as a percentage of sea level at
-18,000 feet
-36,000 feet
-54,000 feet
18,000 = 50% of sea level
36,000 = 25% of sea level
54,000 = 12.5% of sea level
What happens to the altimeter at low level and what is done to negate this?
The altimeter is less accurate a radio altimeter is used instead below 2500 feet
How does an altimeter function?
As pressure decreases in the casing a bellow will expand this is measured, on larger aircraft this information is processed by the air data computer
Why is the aneroid capsule diaphragm corregated?
The higher surface are makes it more sensitive and therefore accurate
What is the meaning of the terms QNE, QNH and QFE?
QNE = used in cruise set to the standard pressure 1013.25 hPa
QNH = measured height above standard sea level
QFE = measured height above field elevation in terms of the closest airport
What pressure does the airspeed indicator read from?
Static and dynamic or total air pressure
What ports are connected to the airspeed indicator?
-Pitot and static
-pitot being connected to the bellows
-static is connected to the casing
What are the stall speed limits?
VFO = stall speed in landing configuration
VS1= stall speed in clean flight at maximum weight
VSE = maximum allowable speed with the flaps extended
VNO = maximum airspeed at cruise
VNE = maximum airspeed that cannot be exceeded
On an airspeed indicator what do green, white and yellow indicate?
Green = normal operation range
White = full flap operating range
Yellow = caution range
What does the vertical speed indicator show?
Rate of climb or descent in feet per minute
On a vertical speed indicator what is measured and what is used in this measurement?
A calibrated metering unit
Static pressure enters the casing this measures differential pressure
What is a disadvantage of the vertical speed indicator?
There is a lag
What does a Mach metre measure?
Ratio of actual speed to the local speed of sound
What are the two temperature readings?
Static air temperature
Total air temperature
What is static air temperature?
The temperature of the air unaffected by disturbed air from the air frame
What is total air temperature?
Disturbed air temperature usually effected by ram rise
When will static air temperature and total air temperature be the same?
On ground
Where is air temperature displayed?
EFIS or ECAM display
What is connected to the pitot static system?
-Altimeter
-Airspeed indicator
-vertical speed indicator
Where are static ports located?
In smooth undisturbed airflow
What causes static source error and how is it overcome?
Fuselage shape, angle of attack, airspeed and the positions of flaps and slats etc.
The air data computer accounts for it
When must a static port be blanked?
When the aircraft is parked or cleaned
What is an IRU and an ADIRU
Inertial reference unit
Air data inertial reference unit
What can affect static pressure measurements and how is it accounted for?
A side slip manoeuvre, there is one set on each side and they are connected
Where are pitot pressure tubes found?
On the nose into the airflow
What is the purpose of a baffle in a pitot pressure tube?
To prevent water or contaminant ingress
Where is the pitot drainage port?
At the lowest point
What is the purpose of heating pitot pressure tubes?
Prevent ice build up
What is the purpose of the alternate static selector?
If the pilot system fails it allows for both pilot and co pilot to read from the same system
Will small aircraft have an alternate static selector?
Only if it is certified for fly by instrument
Where are all of the instrument readings directed to for processing?
The air data computer
What is ARINC 429 and what is its speed?
-A method of transferring data
-32 BIT speed
- anything sent to ECAM or EFIC
How many air data computers are there?
3 for redundancy
What is hot standby?
When a system is activated and ready to go in a fault situation
What is ADM and where is it located?
Air data module - it converts pitot static probe into electrical signal to be sent to the ADIRU it is located in the pitot static tube
What is the function of the display management computer?
It takes the information from the ADC and puts it into the navigation display and PFD
When would a leak test be performed on the pitot static system?
When the system has been disturbed
When is QNE used?
In transition periods take off and landing
How does an encoding altimeter differ from a normal altimeter?
It gives altitude information as a numerical value as well as sending a digital code to the ATC transponder
When is a radio altimeter used?
Below 2500 feet
What is the basic principle of a radio altimeter?
The E&I bar principle
What differs with an instantaneous VSI?
It gives readings immediately as it has an extra operating force
How fast does a gyroscope spin and how long does it take to run down?
22,000 RPM
20 minutes
What gyroscope is used for an artificial horizon?
Vertical gyroscope
What does a vertical gyroscope give information on?
Pitch and roll
What is another name for a horizontal gyroscope and what does it give information on?
Directional gyroscope
Heading
What is a rate gyroscope used for?
Rate of turn indication
What type of gyroscope is a lazering gyroscope?
Rate gyroscope
How many lazering gyroscopes are needed?
3
What is in a standby gyroscope and how is it powered?
Battery
Vertical gyroscope
What will effect a gyroscopes rigidity?
-it’s mass
-rotational speed
-distance in radius
What is the main way to keep a gyroscope rigid in an aircraft?
Rotational speed
How is a gyroscope kept in its axis?
Through a gimble
How are gyroscopes classified?
-degrees of freedom
-spin axis of orientation
-by their use
What are degrees of freedom dictated by?
Number of gimballs
If a gyroscope has one gimbal how many degrees of freedom does it have
One
When is classification by spin axis important?
When it is maintained horizontally or vertically
What gyroscope type is needed on aircraft?
Earth tied
How many degrees of freedom does a rate gyroscope have if it’s constrained by springs?
1.5
What is gyroscope procession?
Input on x axis will influence the y axis
What is gyroscopic wander?
When the gyroscope stops pointing in a single direction and ‘drifts’
What is real wander?
(Random wander) caused by engineering defects
What is apparent topple?
The change in orientation relative to the earth due to change in location
How does an electrical artificial horizon work?
An induction motor constructed so the rotor is the cage spinning on a vertical axis, the case is hermatically sealed with an inert gas
What is the purpose of levelling switches?
To tie the gyroscope to its vertical axis, they are mounted at right angles and control the torque motors
What are the two types of levelling switches?
Mercury and electrolyte
What are the disadvantages of pneumatic gyroscopes?
-altitude increase slows the motor
-the pipelines are heavy
What effect do lazering gyroscopes work off of?
The Sagnac effect
Where are lazering gyroscopes fitted?
To the airframe with the strap-down system
What is a directional gyroscope?
High precision remote gyroscopes with two degrees of freedom
What are the functions of the horizontal situation indicator?
-heading indicator
-where the aircraft is relative to its course or radial
What does the turn and slip (bank) indicator provide?
-Rate of turn in degrees per second
-whether the bank angles is correct for the turn
What mechanism does a turn and bank indicator rely on?
-gyroscopically controlled pointer mechanism for the detection and indication of the rate at which the aircraft turns
What is the turn indicator mechanism?
A rate gyroscope on a horizontal axis with a low rate of spin (9000rpm) which operates on procession
What do rate gyroscopes have and what do they measure?
One gimbal with a freedom of 1.5 due to the springs, when a turn occurs it causes procession which moves against the spring
What is the rate of turn indication supplemented by?
Inclinometer = a ball which movement is dampened by a liquid, the ball being centred means the turn is perfectly coordinated
Where is a turn coordinater used?
In small aircraft
What must be installed at each pitot static?
A direction indicator (a directionally stabilised magnet or non magnetic)
What is CDMVT?
(Compass deviation magnetic variation true heading)
The true north differs from magnetic north
What is inclination?
Compasses measuring horizontal magnetic fields close to the poles have effected accuracy
What are the regulations conscerning magnetic instruments?
-Each compass or magnetic indicator must be installed so that is not heavily effected by interference or vibration
-No more than 10 degrees variation after compensation
-direction indicators must be safe
What must be done to deviation on magnetic compasses when they cannot be accounted for with correcting?
Recorded on a compass card
Hard iron magnetisation characteristics?
Hard to demagnetise easy to magnetise
Soft iron magnetisation characteristics?
It’s Temporary
What is the function of a direct leading compass and its design?
(Standby compass)
Must be kept away from instruments
No electrical parts (can function in total electrical loss)
A lobber line shows the centre of
How do you operate a direct reading compass?
-Must be kept horizontal
-it only works perfectly in level flight at a constant airspeed
-it can be effected by inclination
What is the purpose of a compass deviation card?
Gives information on heading in flight
What is important about compass lighting?
-brass case
-two contra wound filaments
