Transcript calculates imc

Flight Instruments
Flight Instruments Overview
• Understanding will increase ability to safely utilize the instruments
• Three Categories:
• Pitot-Static
• Gyroscopic
• Magnetic
© 2015 Coast Flight Training. All Rights Reserved.
Pitot-Static System
• Consists of Three Instruments
and Related Components:
• Air Speed Indicator
• Altimeter
• Vertical Speed Indicator
• All about pressures
© 2015 Coast Flight Training. All Rights Reserved.
Instrument Locations
© 2015 Coast Flight Training. All Rights Reserved.
Pitot-Static System
• Uses pitot tube to sense total air pressure (dynamic + static)
• Static port to sense the static pressure within the dynamic flow
© 2015 Coast Flight Training. All Rights Reserved.
Altimeter
• Only instrument to show altitude
• Most vital
• Uses an aneroid wafer to hold ISA pressure
• Senses the difference between the outside static pressure and the
pressure in the aneroid wafer
• Difference is transmitted through gears to indicate altitude above ISA
© 2015 Coast Flight Training. All Rights Reserved.
© 2015 Coast Flight Training. All Rights Reserved.
Types of Altitudes
• Indicated: Read off the altimeter
• Pressure: Altitude above the Standard Datum Plane (ISA)
• Density: Pressure altitude corrected for variations in temperature
• True: Altitude above sea level (MSL)
• Absolute: Altitude above ground (AGL)
© 2015 Coast Flight Training. All Rights Reserved.
Pressure Altitude
• Indicated Altitude when Kollsman Window set to 29.92
© 2015 Coast Flight Training. All Rights Reserved.
Calculating Pressure Altitude
• To calculate pressure altitude:
• PA = field elevation + (29.92 – altimeter setting) x 1000
Note: Elevation refers to physical height above sea level;
it can be an altitude in flight
© 2015 Coast Flight Training. All Rights Reserved.
Density Altitude
• Density of a medium is affected by the temperature
• Think of molasses: is it harder or easier when it is warm?
• Density of Air has a direct effect on:
• Lift
• Prop Efficiency
• Engine Power Output
• The 3 H’s:
• High
• Hot
• Humid
© 2015 Coast Flight Training. All Rights Reserved.
Density Altitude
• Density of a medium is affected by the temperature
• Think of molasses: is it harder or easier when it is warm?
• Density of Air has a direct effect on:
• Lift
• Prop Efficiency
• Engine Power Output
• The 3 H’s:
• High
• Hot
• Humid
© 2015 Coast Flight Training. All Rights Reserved.
Calculating Density Altitude
• To calculate Density Altitude:
• DA = PA + (120 x (OAT °C– ISA temperature °C))
Note: ISA refers to the temperature it should be at the local altitude
under standard temperature conditions. Example, sea level = 15°C,
6000 feet = 3°C. (use the temperature lapse rate of 2°C per 1000’
increase in altitude)
© 2015 Coast Flight Training. All Rights Reserved.
Hazards of Pressure
• High to low, look out below
• Go from High to Low pressure
• Difference between static and reference pressure in the wafer
becomes larger and causes an increase in altitude
• The pilot will view this disturbance and descend which places him at a
lower true altitude and consequently, a lower absolute altitude
© 2015 Coast Flight Training. All Rights Reserved.
Hazards of Pressure
© 2015 Coast Flight Training. All Rights Reserved.
Hazards of Temperature
• Hot to cold, look out below
• Go from Hot area to Cold area
• Same pressure sensed by the altimeter will occur at a lower true
altitude
• Places the airplane at a lower absolute altitude
• The atmosphere compresses (contracts) when cold
© 2015 Coast Flight Training. All Rights Reserved.
Hazards of Temperature
© 2015 Coast Flight Training. All Rights Reserved.
Hazard Remedies
• Update altimeter settings frequently as practical through nearest
weather or controller
• Don’t forget: 1” Hg variation = 1000 feet difference.
• Not easily noticeable in flight because the pilot steadily
decreases/increases true altitude while the altimeter is held constant
• Check altimeter prior to flight: 75 feet
© 2015 Coast Flight Training. All Rights Reserved.
Vertical Speed Indicator
• Shows a climb or descent rate
• Instrument Relies upon static pressure and is used to sense a change
in pressure
• Compares instantaneous reference of static pressure within a
diaphragm to a delayed reference of static pressure within the case
• Trend information: Initial indication can be used to make minor
corrections during flight
• Rate Information: Shows a stabilized rate of change in altitude
© 2015 Coast Flight Training. All Rights Reserved.
Vertical Speed Indicator
• The case contains a
diaphragm connected
directly to the static
line
• The case is connected
to the static line
through a calibrated
leak
© 2015 Coast Flight Training. All Rights Reserved.
VSI Instrument Check
• Should indicate 0 before flight
• Stuck on different indication? No problem!
• Use new indication as the baseline
© 2015 Coast Flight Training. All Rights Reserved.
Airspeed Indicator
• Utilizes both the pitot tube and the static port
• Supplies two pressures: Ram and Static
• References the two against each other to show difference
• Difference is read in Knots
• Most susceptible to blocks, consider a pitot tube cover
© 2015 Coast Flight Training. All Rights Reserved.
Airspeed Indicator
• The case contains a
diaphragm connected to the
pitot (ram air) line
• The case is connected to the
static line
© 2015 Coast Flight Training. All Rights Reserved.
Types of Airspeed
• Indicated: Direct from instrument. No compensation for errors (KIAS)
• Calibrated: KIAS corrected for instrument installation error (KCAS)
• Equivalent: KCAS corrected for compressibility effects (EAS)
• True Airspeed: EAS corrected for temperature and altitude (TAS)
• Groundspeed: Speed above the ground (GS)
• Boat Analogy
© 2015 Coast Flight Training. All Rights Reserved.
Airspeed Indicator Markings
• White Arc: Flap Operating Range
• Green Arc: Normal Operating
Range
• Yellow Arc: Cautionary Range
(Smooth air only)
• Red Line: Never Exceed Speed
© 2015 Coast Flight Training. All Rights Reserved.
Airspeed Limitations
• VSO – Stall Speed (Flaps Extended)
• VS1 – Stall Speed (Normal Condition)
• VX – Best Angle of Climb
• VY – Best Rate of Climb
• VFE – Flap Extension Speed
• VA – Maneuvering Speed
• VNO – Normal Operating Limit
• VNE – Maximum Structural Cruising Speed
© 2015 Coast Flight Training. All Rights Reserved.
Socrative Short Answer
• VSO – 45
• VS1 – 50
• VX – 64
• VY – 76
• VFE – 102
• VA – 89 - 113
• VNO – 125
• VNE – 154
Archer 3 Airspeed Indicator
© 2015 Coast Flight Training. All Rights Reserved.
Airspeed Instrument Check
• Should read 0 or slightly moving in a strong headwind
• Checked for function on the takeoff roll
• Abort takeoff if no indication on takeoff roll
© 2015 Coast Flight Training. All Rights Reserved.
Pitot Static Errors
• If instruments don’t agree, assume error
• Two fail-safes:
• Alternate Static Source
• Pitot Heat
© 2015 Coast Flight Training. All Rights Reserved.
Blocked Static System
• Altimeter Stays Frozen
• VSI remains zero as it cannot sense a differential
• Airspeed Indicator will give inaccurate readings
• Will act as an altimeter
• Why is this dangerous?
• Think too fast on approach, inducing a stall
© 2015 Coast Flight Training. All Rights Reserved.
Blocked Pitot Tube
• Airspeed Indicator reads 0
• Land as soon as practical
• Proper Pitch and Power Produces a Predictable Performance
© 2015 Coast Flight Training. All Rights Reserved.
Blocked Pitot Tube Drain Hole
• Not applicable to Piper, but possible in Cessna
• Increases airspeed in climb, decreases airspeed in descent
© 2015 Coast Flight Training. All Rights Reserved.
The Pitot Static Mast
• Incorporates the Pitot Tube and
Static Ports all-in-one
• One Pitot Hole
• Two Static Holes for Varying
Angles of Attack
© 2015 Coast Flight Training. All Rights Reserved.
Gyroscopic Principles
• Rigidity in Space
• Newton’s First: Object at rest stays at rest
• Allows a basketball player to spin a ball on the tip of his finger
• Spin up a gyro, use it as a reference to identify deviations from the original
rotational plane
• Precession
• Turning/Tilting characteristic
• Force applied, realized 90 degrees in the direction gyro is spinning
• Friction/External Forces can cause a gyro to wander from original location
© 2015 Coast Flight Training. All Rights Reserved.
Gyroscopic Power
• Powered by electrical system
• Driven by air pressure from a vacuum pump
© 2015 Coast Flight Training. All Rights Reserved.
Vacuum System
• Consists of Two Instruments and
Related Components:
• Attitude Indicator
• Heading Indicator
(Directional Gyro)
• All about spinning wheels
© 2015 Coast Flight Training. All Rights Reserved.
Instrument Locations
© 2015 Coast Flight Training. All Rights Reserved.
Attitude Indicator
• Provides Pitch and Bank information
• Gyro spins on a horizontal plane
• Gyro moves in the roll / pitch axes and attached to a card that faces
the pilot
• Card has horizon, pitch and bank information on it
• Plane is really moving around the gyro
© 2015 Coast Flight Training. All Rights Reserved.
© 2015 Coast Flight Training. All Rights Reserved.
Attitude Indicator Check
• Should be aligned within 5 minutes
• Adjust the miniature airplane to the horizon from your POV
• 5 degrees of difference
• A note about pendulous vanes
© 2015 Coast Flight Training. All Rights Reserved.
Heading Indicator
• Heading information without the nuisance of compass errors
• Gyro stays in a vertical plane
• Is subject to errors cause by friction at about 15 degrees per hour
© 2015 Coast Flight Training. All Rights Reserved.
© 2015 Coast Flight Training. All Rights Reserved.
Heading Indicator Check
• Align to magnetic heading every 15 minutes and at beginning of flight
• Should indicate known headings during taxi
• Match the magnetic compass during straight and level, unaccelerated
flight
© 2015 Coast Flight Training. All Rights Reserved.
Electrical Gyroscopic Instruments
• One Instruments is powered by Electricity supplied by the Battery:
• Turn Coordinator
• Still operates on the same principles as vacuum system
© 2015 Coast Flight Training. All Rights Reserved.
Instrument Locations
© 2015 Coast Flight Training. All Rights Reserved.
Turn Coordinator / Slip-Skid Indicator
• Instrument relies on controlled precession in order to indicate rate of
turn
• Mounting of the gyro allows to sense both roll rate and turn rate
• Reacts to movement about horizontal plane as aft pressure increases
• Powered by an electric motor
• Slip and Skid indicator indicates Yaw
• Maintain coordinated flight (perpendicular to relative wind)
© 2015 Coast Flight Training. All Rights Reserved.
How does the TC Work?
• Uses principle of precession
• Yaw from turn causes force on
side of gyro
• Force is translated 90 deg in
direction of spin, which rolls the
gyro and mini airplane or needle
© 2015 Coast Flight Training. All Rights Reserved.
Skidding vs. Slipping
• Skidding Turn
• Nose is yawed in the direction of the turn
• Slipping Turn
• Nose is yawed away from the direction of the turn
© 2015 Coast Flight Training. All Rights Reserved.
Turn Coordinator Check
• Checked while taxiing
• Airplane indicate a turn in the direction the plane is moving
• Ball should move outside of the turn
© 2015 Coast Flight Training. All Rights Reserved.
Magnetic Instruments
• One magnetic compass
• Affected by the earth’s magnetic fields
© 2015 Coast Flight Training. All Rights Reserved.
© 2015 Coast Flight Training. All Rights Reserved.
Magnetism
• Magnet is a piece of metal containing iron that has a north and south
pole which attracts magnetic flux
• The earth acts as a giant magnet, so a magnet can be aligned with the
earths flux fields
• Magnet floats in kerosene fluid and is always trying to stay with
magnetic north
• Airplane pivots around the compass
• Pilot sees headings as etched into the card
© 2015 Coast Flight Training. All Rights Reserved.
Compass Errors - Variation
• The difference between true and
magnetic north
• Aeronautical charts referenced to true
• Runways aligned with magnetic
• Variation needs to be taken into
consideration
© 2015 Coast Flight Training. All Rights Reserved.
Compass Errors - Deviation
• Any error caused by a magnetic field other than the earths
• This could be a battery, magneto, alternator, or other electromagnetic
disturbance
• When a mechanic aligns the aircraft with known magnetic headings,
he can denote deviation
• Compass Deviation Card
© 2015 Coast Flight Training. All Rights Reserved.
Magnetic Dip
• Occurs when lines of flux dip into the earth over the poles
• Compass has a dip compensating weight
• Weight is the cause of northerly turning errors
• Also the cause of acceleration errors
© 2015 Coast Flight Training. All Rights Reserved.
Northerly Turning Error
• Undershoot North
• Overshoot South
• UNOS
© 2015 Coast Flight Training. All Rights Reserved.
Acceleration Error
• On an East or West Heading
• Acceleration indicates a turn to the North
• Deceleration (or negative acceleration) indicates a turn to the south
• ANDS
© 2015 Coast Flight Training. All Rights Reserved.
Oscillation Error
• Combination of all the errors results in small movements, or swings in
the compass indications
• Why we use the heading indicator in IMC
© 2015 Coast Flight Training. All Rights Reserved.
Digital Flight Instruments
• Newer Aircraft include a PFD and MFD
• Primary Flight Display and Multi-Function Display
• Both integrate all of the engine parameter and flight instruments into
two large, panel mounted screens
© 2015 Coast Flight Training. All Rights Reserved.
PFD
Turn
Coordinator
VSI
Airspeed
Altitude
Heading
© 2015 Coast Flight Training. All Rights Reserved.
MFD
© 2015 Coast Flight Training. All Rights Reserved.
Required Instruments for Flight – 91.205
• Changes for day and night
• ATOMATOFLAMES Acronym – day
• FLAPS - Night
• Read and Highlight the Regulation
• MEMORIZE!
© 2015 Coast Flight Training. All Rights Reserved.
ELT Requirements – 91.207
• Batteries to be replaced:
• 1 hour of cumulative use
• 50% of useful life
• Does not apply:
• Aircraft engaged in training if within 50 miles
• Agricultural
• Not carrying more than one person
© 2015 Coast Flight Training. All Rights Reserved.
Inoperative Instruments – 91.213
• Does an MEL Exist?
• May be without MEL if:
• Non-turbine
• Not part of ATOMATOFLAMES or FLAPS
• Option 1: Remove from the Aircraft, adjust maintenance records
• Option 2: Deactivate and placard inoperative
• Both options require that PIC make safety determination
• Final Option: Special Flight Permit
© 2015 Coast Flight Training. All Rights Reserved.
References
• Pilot’s Handbook of Aeronautical Knowledge
• Federal Aviation Regulations
© 2015 Coast Flight Training. All Rights Reserved.