Pressure & Gyro Instruments Flashcards
Gyroscopic Rigidity depends on what properties: (select all of the correct answers)
Mass
Colour
Altitude
Rotor RPM
Mass distance from axis or rotation (moment)
Static Pressure
OAT
Mass, Rotor RPM and Mass Distance from Axis of Rotation (moment)
An increase in rotor mass (decreases, increases) rate of precession
What is the correct answer?
Decreases
Position Error is typically caused due to disturbences between registered static _____ and freestream ____ pressure
registered static pressure and freestream static pressure
State three in-flight ASI serviceability checks that could be performed
**1. Check ASI starts to register speed increase on the runway
- ASI indication should be as expected for a given power/aircraft configuration
- As a last resort you could conduct a stall and note the airspeed it stalls at against the correct stall speed**
Position Error mainly effects Pitot or Static vents?
Primarly the Static Vents (but can also effect the Pitot system)
If the static vent is blocked during flight, the Altimeter will (over-read, under-read, read zero, remain static/no change),
What is the correct answer?
Remain Static/No Change
The AI/AH requires how much suction for normal operation?
About 4”Hg
Increasing the distance of mass concentration from the axis of rotation (increases,decreases) gyroscopic Rigidity.
What is the correct answer?
Increases
What gyro type is the following statement describing;
Has freedom of movement in only two planes, the plane of rotation and one other, measurement about the third plane is measured by prescession of the gyro
Rate Gyro
You could check the HI/DI is serviceable while taxiing on the ground, when you turn left the number card must (increase/decrease)
What is the correct answer?
Decrease
The Attitude Indicator AI/AH uses what type of gyro?
Earth Gyro
The pictured Turn Coordinator shows the aircraft making a (left,right) turn that is (balanced,slipping,skidding).
What combination is the correct answer?
Right turn, slipping
Name the four main Gyro Types
Space, Tied, Earth, Rate
State the main precaution when using Pitot Heat on the ground
It must be used only very briefly to avoid damage caused by overheating on the ground
The Altimeter is considered serviceable if it reads +__ft and -__ft of the correct altitude on the ground
+30ft and -45ft
For the DI/HI to be deemed serviceable it must not precess (real drift) more than ___º per 15min or ___º per hour
more than 4º per 15min or 16º per hour
Serviceability of the Turn Coordinator can be checked during flight by timing and conducting a Rate 1 turn, It should take ___ min(s) to complete 180º and ___ min(s) to complete 360º
It should take 1 min(s) to complete 180º and **2 **min(s) to complete 360º
The red line at the end of the yellow arc on the ASI indicates?
VNE, Never Exceed Speed
You notice the static vent(s) are blocked and select the alternative static vent that uses cabin pressure, What effect will this have on the ASI?
Will cause a slight over read as cabin pressure is slighlty less
List three ASI pre-flight serviceability checks that should be performed
**1. Check for blocks, contamination, remove Pitot cover
- Check Pitot heater operation
- Check instrument indicates zero**
CAS is ___ corrected for _____ and _____
IAS corrected for Instrument and Position
The HI or DI uses which type of gyro?
Tied Gyro
Under what conditions should Pitot Heat be turned on?
Should be used in visible moisture where OAT is +10ºc or colder, or when OAT is 0ºc or less in all conditions
Compressibility correction factor is always a (deduction, addition) to CAS?
Always a deduction, CAS correct for compressibility = EAS
TAS is ___ corrected for ____
EAS corrected for Density
The pictured is a typical pitot head (pitot-static) system.
What indicated at Label B?
Pitot (pitot tube) drain hole
The VSI uses a metering unit which places a restriction on flow in or out of the (instrument case, aneroid capsule) which is the correct answer?
Instrument Case
The pictured Turn Coordinator shows the aircraft making a (left,right, no turn) turn that is (balanced,slipping,skidding).
What combination is the correct answer?
**no turn (straight), skidding.
(too much left rudder being used and right wing slightly down, but no rate of turn)**
The VSI measures?
Rate of static pressure change
Define Gyroscopic Precession
Is the 90º displacement of an applied force into a tiliting force applied 90º further in the plane of rotation
The HI/DI requires between ___“Hg and ___“Hg for normal operation
between 3.5”Hg and 4.5”Hg for normal operation
Define Static Pressure
The prevailing pressure at any point in the atmosphere
The pictured Turn Coordinator shows the aircraft making a (left,right) turn that is (balanced,slipping,skidding).
What combination is the correct answer?
Left turn, Skidding
The Rate gyro is typically used in what instrument
Turn Coordinator/Indicator
The Altimeter is designed/calibrated to indicate ____ above a set pressure level
indicate Height above a set pressure level
A typical Turn Indicator requires how much suction to operate normally?
2.5”Hg
Electrically driven AI/AH typically have freedom limits of ___º in pitch and ___º in roll.
85º in pitch and 360º in roll
When flying from high temp to an area of low temp, the Altimeter will read ____
will read high
The pictured Turn Coordinator shows the aircraft making a (left,right) turn that is (balanced,slipping,skidding).
What combination is the correct answer?
Left turn, Balanced
How can the VSI be checked for serviceability in-flight?
By timing a climb or descent. eg at 500ft/pm it should take 2min to climb or descend 1000ft.
VS0 marking on an ASI indicates?
Stall Speed ‘dirty’ - flaps down, landing gear down, power off
When QNH is set, the Altimeter will indicate
Height above mean sea level, called Altitude
The torque motors and levelling switch used in Electric AI/AH’s are used to minimise, what errors?
Acceleration and Turning Errors
On a typical ASI, The beginning of the white arc also indicates what?
VS0 - Stall speed ‘dirty’ - flaps down, landing gear down, power off
What common conditions can cause Position Error?
Turbulence, slip, skid, high AoA or when the undercarriage and flaps are lowered
When QNE is set on the Altimter, the Altimeter indicates ____ _____
Pressure Alititude
What is the key difference between a Pitot Probe/Tube and a Pitot Head/Pressure Head?
Pitot Probe/Tube measures only Total Pressure.
Pitot Head/Pressure Head is a combined pitot-static probe measuring Total Pressure and Static Pressure (individually)
You could check the HI/DI is serviceable while taxiing on the ground, when you turn right the number card must (increase/decrease)
What is the correct answer?
Increase
Total or Pitot pressure is _____ + _____
Dynamic + Static
Pictured is a typical ASI, The pressure entering the capsule at Label A is (dynamic, total, static, freestream).
What is the correct answer?
Total (Dynamic + Static)
The higher the RPM, the ____ the rate of Precession
Lower
The basic operating principle of the ASI (Air Speed Indicator) is?
ASI works on the principle of subtracting Static Pressure from Total Pressure to make use of Dynamic Pressure
If the static port becomes blocked, the VSI will read ____
will read **zero. **No rate of change.
VYSE speed on a typical light twin ASI indicates what and how is it shown on the ASI?
Indicates Best single engine rate of climb speed, indicated by a blue line or blue sector
Dynamic Pressure can be measured using what formula?
½pV2
Air driven AI/AH typically have freedom limits of ___º in pitch and ___º in roll. If exceeded the gyro will topple.
55º in pitch and 90º in roll
briefly describe Dynamic Pressure
The increase in air pressure above the prevailing atmospheric pressure (static)
A Tied gyro has freedom in ____plane(s) but is controlled in ____ plane
A Tied gyro has freedom in **all three **plane(s) but is controlled in one plane
(by an outside force to keep it pointing in one direction)
Which gyro type uses a gyro that ‘lies flat’ so its spin axis remains pointed to the centre of earth?
Earth gyro
Pictured is a typical Pitot Head (Pitot-Static system).
What is indicated by Label A?
Static Ports
Does the Turn Coordinator indicate roll?
Yes, but it does not give a direct indication of bank angle.
On a typical light twin ASI, VMCA indicates?
Minimum control speed with critical engine failed. (indicated by a red line in the lower speed range)
The ASI measures?
Dynamic Pressure
Static Pressure is used solely for what pressure instruments?
Vertical Speed Indicator (VSI) & Altimeter
If the Pitot Tube was suddenly blocked by Ice in level flight, The ASI will (under read, over read, read correctly) in a climb
What is the correct answer?
It will over read in a climb
Position Error will effect what Instruments?
Pressure Instruments, The ASI, Altimeter and VSI
VFE indicates what on the ASI?
The white arc, the flaps extended range
Which of the following errors apply to the typical air driven Attitude Indicator AI/AH?
Turning Error
False Vertical/Erection Error
Pendulosity Error
Acceleration Error
All of them
QNE is what hPa setting on the Altimeter?
1013hPa
Precession caused by frictional forces due to rotor bearings and gimbal systems is called?
Real Drift/Wander
When flying from an area of low temp to an area of high temp, the Altimeter will read ____
will read low
A Pitot leak would cause an ____ read on the ASI
under read on the ASI
When in a left turn, the rotor of the turn indicator tilts to the ____ and the minature aircraft on the instrument tilts ____
When in a left turn, the gyro rotor of the turn indicator tilts to the Right and the minature aircraft on the instrument tilts Left
Max structural cruise speed is denoted by what acronym and indicated by what colour on the ASI?
VNO, End of the green arc/start of the yellow arc
A drift nut or latitude rider is used to compensate for what gyroscopic ‘error’
Apparent Drift/Wander
Which air driven instrument commonly uses a pendulous unit?
The air driven AI/AH
CAS corrected for compressibility error is known as?
EAS - Equivilant Air Speed
If the static port becomes blocked and no alternative port is fitted to the aircraft, In an emergency what instrument could you break the glass on to allow the Altimeter to operate again?
Crack the glass of the VSI (it will result in a slight over read due to lower cabin pressure)
If the static vent(s) become blocked during level flight, It will cause the ASI to ____ read in a climb and ____ read in a descent
under read in a climb and over read in a descent
The white arc on the ASI is the ____ range
VFE - Flaps extended range, flaps cannot be used outside the white arc
VS1 on the ASI indicates?
Stall Speed ‘clean’ - flaps up, landing gear up, power off
The altimter setting that indicates height above landing area or highest point on an airfield manoeuvring area or runway threshold is known as?
QFE
