Flight Instruments

Flight Instruments Overview © 2015 Coast Flight Training. All Rights Reserved. Understanding will increase ability to safely utilize the instruments Three Categories: Pitot-Static Gyroscopic Magnetic

Pitot-Static System © 2015 Coast Flight Training. All Rights Reserved. Consists of Three Instruments and Related Components: Air Speed Indicator Altimeter Vertical Speed Indicator All about pressures

Instrument Locations © 2015 Coast Flight Training. All Rights Reserved.

Pitot-Static System © 2015 Coast Flight Training. All Rights Reserved. Uses pitot tube to sense total air pressure (dynamic + static) Static port to sense the static pressure within the dynamic flow

Altimeter © 2015 Coast Flight Training. All Rights Reserved. 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.

Types of Altitudes © 2015 Coast Flight Training. All Rights Reserved. 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)

Pressure Altitude © 2015 Coast Flight Training. All Rights Reserved. Indicated Altitude when Kollsman Window set to 29.92

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 © 2015 Coast Flight Training. All Rights Reserved. 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

Density Altitude © 2015 Coast Flight Training. All Rights Reserved. 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

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 © 2015 Coast Flight Training. All Rights Reserved. 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

Hazards of Pressure © 2015 Coast Flight Training. All Rights Reserved.

Hazards of Temperature © 2015 Coast Flight Training. All Rights Reserved. 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

Hazards of Temperature © 2015 Coast Flight Training. All Rights Reserved.

Hazard Remedies © 2015 Coast Flight Training. All Rights Reserved. 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

Vertical Speed Indicator © 2015 Coast Flight Training. All Rights Reserved. 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

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 © 2015 Coast Flight Training. All Rights Reserved. Should indicate 0 before flight Stuck on different indication? No problem! Use new indication as the baseline

Airspeed Indicator © 2015 Coast Flight Training. All Rights Reserved. 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

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 © 2015 Coast Flight Training. All Rights Reserved. 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

Airspeed Indicator Markings © 2015 Coast Flight Training. All Rights Reserved. White Arc: Flap Operating Range Green Arc: Normal Operating Range Yellow Arc: Cautionary Range (Smooth air only) Red Line: Never Exceed Speed

Airspeed Limitations © 2015 Coast Flight Training. All Rights Reserved. V SO – Stall Speed (Flaps Extended) V S1 – Stall Speed (Normal Condition) V X – Best Angle of Climb V Y – Best Rate of Climb V FE – Flap Extension Speed V A – Maneuvering Speed V NO – Normal Operating Limit V NE – Maximum Structural Cruising Speed

Socrative Short Answer © 2015 Coast Flight Training. All Rights Reserved. V SO – V S1 – V X – V Y – V FE – V A – V NO – V NE – Archer 3 Airspeed Indicator

Airspeed Instrument Check © 2015 Coast Flight Training. All Rights Reserved. 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

Pitot Static Errors © 2015 Coast Flight Training. All Rights Reserved. If instruments don’t agree, assume error Two fail-safes: Alternate Static Source Pitot Heat

Blocked Static System © 2015 Coast Flight Training. All Rights Reserved. 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

Blocked Pitot Tube © 2015 Coast Flight Training. All Rights Reserved. Airspeed Indicator reads 0 Land as soon as practical Proper Pitch and Power Produces a Predictable Performance

Blocked Pitot Tube Drain Hole © 2015 Coast Flight Training. All Rights Reserved. Not applicable to Piper, but possible in Cessna Increases airspeed in climb, decreases airspeed in descent

The Pitot Static Mast © 2015 Coast Flight Training. All Rights Reserved. Incorporates the Pitot Tube and Static Ports all-in-one One Pitot Hole Two Static Holes for Varying Angles of Attack

Gyroscopic Principles © 2015 Coast Flight Training. All Rights Reserved. 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

Gyroscopic Power © 2015 Coast Flight Training. All Rights Reserved. Powered by electrical system Driven by air pressure from a vacuum pump

Vacuum System © 2015 Coast Flight Training. All Rights Reserved. Consists of Two Instruments and Related Components: Attitude Indicator Heading Indicator (Directional Gyro) All about spinning wheels

Instrument Locations © 2015 Coast Flight Training. All Rights Reserved.

Attitude Indicator © 2015 Coast Flight Training. All Rights Reserved. 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.

Attitude Indicator Check © 2015 Coast Flight Training. All Rights Reserved. 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

Heading Indicator © 2015 Coast Flight Training. All Rights Reserved. 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.

Heading Indicator Check © 2015 Coast Flight Training. All Rights Reserved. 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

Electrical Gyroscopic Instruments © 2015 Coast Flight Training. All Rights Reserved. One Instruments is powered by Electricity supplied by the Battery: Turn Coordinator Still operates on the same principles as vacuum system

Instrument Locations © 2015 Coast Flight Training. All Rights Reserved.

Turn Coordinator / Slip-Skid Indicator © 2015 Coast Flight Training. All Rights Reserved. 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)

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 © 2015 Coast Flight Training. All Rights Reserved. Skidding Turn Nose is yawed in the direction of the turn Slipping Turn Nose is yawed away from the direction of the turn

Turn Coordinator Check © 2015 Coast Flight Training. All Rights Reserved. Checked while taxiing Airplane indicate a turn in the direction the plane is moving Ball should move outside of the turn

Magnetic Instruments © 2015 Coast Flight Training. All Rights Reserved. One magnetic compass Affected by the earth’s magnetic fields

© 2015 Coast Flight Training. All Rights Reserved.

Magnetism © 2015 Coast Flight Training. All Rights Reserved. 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

Compass Errors - Variation © 2015 Coast Flight Training. All Rights Reserved. The difference between true and magnetic north Aeronautical charts referenced to true Runways aligned with magnetic Variation needs to be taken into consideration

Compass Errors - Deviation © 2015 Coast Flight Training. All Rights Reserved. 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

Magnetic Dip © 2015 Coast Flight Training. All Rights Reserved. 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

Northerly Turning Error © 2015 Coast Flight Training. All Rights Reserved. Undershoot North Overshoot South UNOS

Acceleration Error © 2015 Coast Flight Training. All Rights Reserved. On an East or West Heading Acceleration indicates a turn to the North Deceleration (or negative acceleration) indicates a turn to the south ANDS

Oscillation Error © 2015 Coast Flight Training. All Rights Reserved. Combination of all the errors results in small movements, or swings in the compass indications Why we use the heading indicator in IMC

Digital Flight Instruments © 2015 Coast Flight Training. All Rights Reserved. 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

PFD © 2015 Coast Flight Training. All Rights Reserved. Airspeed Altitude VSI Heading Turn Coordinator

MFD © 2015 Coast Flight Training. All Rights Reserved.

Required Instruments for Flight – © 2015 Coast Flight Training. All Rights Reserved. Changes for day and night ATOMATOFLAMES Acronym – day FLAPS - Night Read and Highlight the Regulation MEMORIZE!

ELT Requirements – © 2015 Coast Flight Training. All Rights Reserved. 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

Inoperative Instruments – © 2015 Coast Flight Training. All Rights Reserved. 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

References © 2015 Coast Flight Training. All Rights Reserved. Pilot’s Handbook of Aeronautical Knowledge Federal Aviation Regulations