Flight Instruments

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Flight Instruments
Which ways up?
Written for the Notre Dame Pilot Initiative By
the Pilots of the University of Notre Dame
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Dedication

• In memory of
• 01/30/2006
• Michael Waugh
• We'd never know how high we are,till we are
  called to riseand then, if we are true to
  plan,our statures touch the sky
• Emily Dickenson

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Roadmap

• Pitot-Static System
• Vacuum System
• Magnetic Compass

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Flight Instruments

• Pitot-Static System and Instruments
• Airspeed Indicator (ASI)
• Vertical Speed Indicator (VSI)
• Altimeter
• Vacuum System and Instruments
• Attitude Indicator
• Heading Indicator
• Turn Coordinator
• Suction Gage
• Magnetic
• Magnetic Compass

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• Pitot-Static

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Atmospheric Conditions

• International Standard Atmosphere (ISA)
• Pressure 29.92 inches Hg at sea level
• Temperature 15?C (59?F)
• Standard Lapse Rates
• Temperature lapses at 2?C per 1,000 feet
• Pressure lapses at 1.00 inch Hg per 1,000 feet

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Airspeed Indicator (ASI)

• V-speeds
• VA maneuvering
• VFE flap extend
• VLE landing gear extended
• VLO landing gear operating
• VNO max structural cruising speed
• VNE never exceed speed
• VR rotation
• VX best angle
• VY best rate
• VS stall clean configuration
• VSO stall landing configuration
• not on ASI (contained in POH)

• Arcs
• White
• Bottom VSO
• Top VFE
• Green
• Bottom VS
• Top VNO
• Yellow
• Bottom VNO
• Top VNE
• Red Line VNE

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Types of Airspeed

• Indicated Airspeed (IAS)
• Speed indicated on ASI
• Calibrated Airspeed (CAS)
• IAS corrected for calibration error
• Equivalent Airspeed (EAS)
• CAS corrected for compressibility error
• True Airspeed (TAS)
• EAS corrected for density error
• Altitude
• Nonstandard temperature
• Groundspeed (GS)
• Speed over the ground
• TAS adjusted for wind

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• At greater altitudes, the same volume of air
  contains fewer molecules of the gases that make
  it up. This means that the density of air
  decreases with increasing altitude.

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Density Altitude
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Altimeter
10,000s
1,000s
Kollsman Window
100s
Adjusting Knob
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Altimeter Types of Altitude

• Indicated Altitude
• Altitude indicated on altimeter
• Pressure Altitude
• Height above standard datum plane
• Altitude indicated when set to 29.92 inches Hg
• Density Altitude
• Pressure altitude corrected for nonstandard
  temperature
• airplane performance decreases with high density
  altitude
• True Altitude
• Actual height above mean sea level (MSL)
• Absolute Altitude
• Actual height above ground level (AGL)

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Altimeter Errors

• Flying from high pressure to low pressure without
  changing altimeter setting (instrument thinks
  youre higher
• indicated altitude will be higher than actual
  altitude
• one inch change in altimeter setting 1,000 ft
  indicated altitude in same direction
• Temperature Impact on True Altitude
• Warm days
• Actual altitude is higher than indicated
• Cold days
• Actual altitude is lower than indicated

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Vertical Speed Indicator (VSI)

• Rate Information shows stabilized rate of climb
  or descent
• Rate appropriate for student pilots is
• 500 feet per minute (FPM) rate of descent or
  climb
• Several second lag

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Blockages in Pitot-Static System

• Blocked Pitot System
• Affects Airspeed Indicator (ASI) only
• clogged pitot tube with clear drain hole shows
  zero airspeed
• clogged pitot tube with clogged drain hole shows
  airspeed varying with altitude
• Blocked Static System
• Affects all pitot-static instruments
• ASI inaccurate airspeed indications
• VSI constant zero indication
• ALT frozen at altitude where blockage
• occurred

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Blockages in Pitot-Static System
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• Vacuum-System

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Vacuum System Instruments
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Turn Coordinator

• Miniature Airplane
• Level Index
• level flight
• Turn Index
• standard rate turn (3 deg/sec)
• Shows roll and yaw of airplane
• Ball shows whether the angle of bank is
  coordinated with the rate of turn

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Attitude Indicator (AI)

• Artificial Horizon
• blue side up
• Miniature Airplane
• Pointer
• Bank Scale
• 10? bank
• 20? bank
• 30? bank
• 60? bank
• Adjustment Knob

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Attitude Indicator Examples
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Heading Indicator (Directional Gyro)

• Typically free gyros
• no built-in north-seeking capabilities
• Periodically align with compass error due to
  gyroscopic precession
• Use 360? azimuth
• right-most zero omitted
• 340? is shown as 34
• 60? is shown as 6
• Adjustment Knob

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Magnetic Compass

• Variation - angular difference between Magnetic
  North and True North. Shown on sectionals and
  will be taught in navigation lessons
• Deviation - compass error due to disturbance from
  metals and electrical accessories within the
  airplane. Correction card shows adjustments to
  magnetic heading
• Accurate only when flying in smooth air, in
  straight level, unaccelerated flight
• When on easterly or westerly heading, use the
  mnemonic acronym ANDS, Accelerate North,
  Decelerate South
• Turning Error
• Compass lags when turning from north.
• Compass leads when turning from south.
• Use acronym, NOSE, North Opposite, South Exceeds

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Questions?