CHAPTER 3 How Do Those Instruments Work? Flashcards
What are the Compass Errors?
UNOS and ANDS
Turning Errors: U - Undershoot, N - North, O - Overshoot, S - South; Dip Errors: A - Accelerate, N - North, D - Decelerate, S - South
What is Variation in navigation?
The difference between true and magnetic directions
Isogonic lines identify the number of degrees of variation in that area
What is Deviation in navigation?
Compass error caused by aircraft magnetic fields
A compass card will correct for this error
What is Oscillation in relation to the compass?
Combination of all compass errors resulting in fluctuation of the compass card
Use the average indication between swings to set the aircraft heading indicator
How do you ensure that the altimeter is functioning properly?
Set it to the current altimeter setting
The altimeter must read within 75 feet of field elevation to be used
What is Indicated Altitude?
The value read directly from the altimeter when set to the current altimeter setting
What is Pressure Altitude?
Altitude read if the altimeter is tuned to the standard pressure value of 29.92” Hg
Used for flights at 18,000 feet MSL and above
What is True Altitude?
The height flown by the aircraft above sea level (MSL)
What is Density Altitude?
Pressure altitude corrected for non-standard temperature
High density altitude indicates low air density, affecting aircraft performance
What is Absolute Altitude?
Actual height above ground level (AGL)
True altitude minus the elevation of the terrain below the aircraft
What are some limitations of the heading indicator?
Precession or drift affecting proper heading
Standard practice to compare with the magnetic compass every 15 minutes
What is the difference between skidding and slipping?
Skidding: turning too much for the bank; Slipping: insufficient turn rate for the bank
Skidding indicates too much bank, while slipping indicates too little
How should a pilot prepare the heading indicator for IFR flight?
Set the heading indicator to the aircraft’s magnetic heading five minutes after engine start
How do you check for errors in the attitude indicator?
Check the horizon bar five minutes after engine start
The horizon bar should be up and stable, not tilting more than 5 degrees while taxiing
What errors occur in an attitude indicator?
Precession errors during turns and acceleration/deceleration errors
During acceleration, it shows a climb; during deceleration, it shows a descent
What happens if the pitot tube and drain hole are blocked?
Airspeed indicator acts as an altimeter, showing static pressure only
What happens if only the pitot tube is blocked?
The airspeed indicator shows zero airspeed
What happens if only the static port becomes blocked?
Airspeed indicator continues to operate but is inaccurate
Above blockage altitude shows lower airspeed; below shows higher airspeed
What does the Distance Measuring Equipment (DME) do?
Gives slant range distance in nautical miles from the aircraft to the station
Prone to errors when flying directly over a VOR
When is DME most accurate?
Smallest error at low altitude and/or long ranges
Should be at least a mile from the facility for every 1,000 feet of altitude
Where can pilots find information on VOR receiver ground checkpoints?
From the Chart Supplement
How do you check for VOR error over FAA-designated airborne checkpoints?
Center the CDI needle before flying over the checkpoint
What is the maximum allowable error for VOR receivers on the ground?
+/- 4°
+/- 6° over designated airborne checkpoints
How often must a VOR operational check be performed?
Once every 30 days
Must record checks in the aircraft log
What does a full scale deflection of the VOR CDI indicate?
A 10-degree or greater deviation from the course centerline
What happens when VORs are undergoing maintenance?
Facility may radiate a T-ES-T code or remove the VOR identification code
How do you know that you have just passed over a VOR station?
The TO/FROM indication will reverse
What is the range of a H-class VORTAC facility from 1,000 to 14,500 feet AGL?
40 nautical miles
What does a one ‘dot’ deflection indicate on the CDI?
2 degrees of displacement
When can a pilot use a GPS system for IFR navigation?
When it is FAA approved and certified
When can you use VFR-only GPS systems in IFR?
NEVER!
Only as an aid to situational awareness
If the Air Data Computer fails, what instruments will be lost?
Altitude, airspeed, and air temperature instruments
What does the Attitude and Heading Reference System (AHRS) supply data to?
Heading indicator, attitude indicator, and turn indicator
Describe an HSI.
A combination of VOR/ILS and heading indicator
Powered by a magnetometer, does not need resetting
What happens if the transponder fails during flight?
Flight may continue to destination; pilot may request deviation from flight plan
What is a Standard Rate of turn?
3 degrees per second
How is a Standard Rate turn indicated?
Needle of the turn-and-slip indicator points at the doghouse mark
What are the indications of a nose low unusual attitude?
Negative vertical speed, increasing airspeed, decreasing altitude
How do you recover from a nose low unusual attitude?
Reduce power, level the wings, raise the nose until level attitude is achieved
What are the indications of a nose high unusual attitude?
Positive vertical speed, increasing altitude, airplane above the horizon on the attitude indicator
What is the recovery process from a nose high unusual attitude?
Reduce power, lower the nose, level the wings
What are the steps to recover from a nose high unusual attitude?
• Increase power
• Lower the nose
• Level the wings
• Return to the prior altitude and heading
What are the indications of a nose high unusual attitude?
• Positive vertical speed indication
• Increasing altitude
• The airplane appears to be above the horizon on the attitude indicator
What are the indications of a nose low unusual attitude?
• Negative vertical speed indication
• Increasing airspeed
• Decreasing altitude
• The airplane is below the horizon on the attitude indicator
What are the steps to recover from a nose low unusual attitude?
• Reduce power
• Level the wings using rudder and aileron movements
• Raise the nose until level attitude is achieved
What are the three fundamental skills required for attitude instrument flying?
• Instrument cross check
• Instrument interpretation
• Airplane control
What does instrument interpretation require?
Understanding the construction of each instrument, their operating principles and how they relate to the overall performance of the aircraft
What is an Instrument Cross Check?
The information interpreted from each instrument is compared to verify they are all showing the same aircraft performance
What are the three elements of airplane control?
• Pitch
• Bank
• Power control
What are the three categories of flight instruments?
• Pitch instruments
• Bank instruments
• Power instruments
What are the four pitch instruments?
• Attitude Indicator
• Altimeter
• Airspeed indicator
• Vertical speed indicator
What are the four bank instruments?
• Attitude Indicator
• Heading indicator
• Turn coordinator/turn-and-slip coordinator
• Magnetic compass
What are the three power instruments?
• Manifold pressure gauge (if applicable)
• Airspeed indicator
• Tachometer
Define primary and secondary instruments.
Primary instruments show the most relevant information for certain flight conditions; secondary instruments support the information given by primary instruments.
What are the primary instruments that show straight and level flight?
• Altimeter
• Heading indicator
• Airspeed indicator
What are the primary instruments to check for airspeed changes in straight and level flight?
• Airspeed indicator (pitch)
• Heading indicator (bank)
• Tachometer or manifold pressure gauge (power)
What are the primary instruments used for establishing a level standard rate turn?
• Turn rate indicator
• Attitude indicator (control instrument)
What are the primary instruments used to detect airspeed changes in level turn?
• Airspeed indicator
• Altimeter and attitude indicator (secondary)
What are the primary instruments used when transitioning from straight and level flight to a constant airspeed climb?
• Attitude indicator
• Airspeed indicator
• Altimeter and tachometer (or manifold pressure gauge as secondary)
What are the primary instruments to refer to when maintaining straight constant airspeed climb?
• Airspeed indicator
• Heading indicator
• Manifold pressure gauge or tachometer
What primary instruments are used after increasing power to maintain a straight, constant rate climb?
• Vertical speed indicator (primary)
• Attitude indicator, heading indicator, and tachometer or manifold pressure gauge (secondary)
What primary instruments are referred to in order to maintain a straight, constant rate and stabilized climb?
• Vertical airspeed indicator
• Heading indicator
• Airspeed indicator
Which pitch instrument is used to correct altitude deviations?
Attitude indicator
What is the Pitch/Power/Performance concept of aircraft control?
Specific power and attitude combinations will result in specific performance
