M03 Flight Instruments 1

Required VFR flight instruments under 14 CFR 91.205

Magnetic compass, airspeed indicator, and altimeter

Required IFR instruments mnemonic

GRAA B C A R D D

G in GRAB CARD D

Generator

R in GRAB CARD D

Radios

A in GRAB CARD D

Attitude indicator

B in GRAB CARD D

Ball or slip-skid indicator

C in GRAB CARD D

Clock showing hours, minutes, and seconds

A in GRAB CARD D

Altimeter

R in GRAB CARD D

Rate of turn indicator

D in GRAB CARD D

Directional gyro

DME requirement under the IFR instrument mnemonic

DME if using the VOR above 24,000 feet

Pitot-static instruments

Airspeed indicator, altimeter, and vertical speed indicator

ADC

Air Data Computer

ADC information

OAT, airspeed, altitude, and vertical speed

AHRS

Attitude Heading and Reference System

AHRS information

Attitude, heading, rate of turn, and slip-skid

Airspeed indicator

Measures differential pressure

Airspeed indicator static pressure

Static pressure enters through the static port and goes directly into the sealed case

Airspeed indicator ram air pressure

Ram air pressure enters through the pitot tube and goes into the diaphragm

ICE-T

Indicated, calibrated, equivalent, and true airspeed

Indicated Airspeed (IAS)

Airspeed read directly from the airspeed indicator

Calibrated Airspeed (CAS)

IAS corrected for installation and position error

Equivalent Airspeed (EAS)

CAS corrected for compressibility at high airspeeds and altitudes

True Airspeed (TAS)

CAS corrected for altitude and non-standard temperature; the speed the aircraft moves through the air

Vne

Never Exceed speed; exceeding it can cause structural damage

Vne indication

Top of the yellow arc and red line

Vno

Normal Operating speed; maximum structural cruising speed or maximum speed for normal operations

Vno indication

Top of the green arc

Vfe

Maximum Flaps Extended speed; maximum speed with flaps down

Vfe indication

Top of the white arc

Altimeter source

Static port only

Altimeter aneroid wafer

Sealed inside the sealed altimeter case

Altimeter standard reference

The aneroid wafer is at a constant 29.92 inches Hg

Types of altitude mnemonic

TAPID

True altitude

Altitude above mean sea level

Absolute altitude

Altitude above ground level

Pressure altitude

Height above or below the standard datum plane

Indicated altitude

Altitude indicated on the altimeter

Density altitude

Pressure altitude corrected for non-standard temperature

High pressure to low pressure altimeter error

If flying from high pressure to low pressure without resetting the altimeter, the altimeter reads higher than the aircraft's actual altitude

High to low pressure mnemonic

HIGH TO LOW, LOOK OUT BELOW

High temperature to low temperature altimeter error

If flying from high temperature to low temperature without resetting the altimeter, the altimeter reads higher than the aircraft's actual altitude

High to low temperature mnemonic

HOT TO COLD, LOOK OUT BELOW

VSI

Vertical Speed Indicator

VSI operation

Similar to an altimeter but uses a calibrated leak

VSI function

Shows the rate of climb or descent

VSI units

Typically feet per minute

Pitot-static system failure in IMC

The pilot should consider whether it is an emergency, what action to take, where to go, how to get there, and how to determine aircraft attitude

Pitot tube blocked with drain hole open

Airspeed indicates zero

Pitot tube blocked with drain hole open reason

There is no differential pressure because pressure in the diaphragm becomes the same as outside air pressure

Entire pitot tube blocked

Airspeed acts like an altimeter

Entire pitot tube blocked indication during climb

Airspeed increases as altitude increases

Entire pitot tube blocked reason

The diaphragm becomes sealed and operates like an aneroid wafer

Static port blocked

Altimeter freezes, VSI reads zero, and airspeed becomes inaccurate

Static port blocked airspeed above blockage altitude

Airspeed indicates lower than actual

Static port blocked airspeed below blockage altitude

Airspeed indicates higher than actual

Alternate static source

Provides static pressure from inside the cabin

Alternate static source pressure

Cabin pressure is lower than outside pressure

Alternate static source altimeter indication

Indicates slightly higher than actual altitude

Alternate static source airspeed indication

Indicates higher than actual airspeed

Alternate static source VSI indication

Indicates a momentary climb and then stabilizes

Magnetic compass purpose

Uses Earth's magnetic field to indicate direction

Earth's magnetic field

Produced by the spinning iron and nickel core of the Earth

Lines of flux

The magnetic field lines created by Earth's spinning iron and nickel core

Magnetic compass alignment

A free-rotating magnet aligns with Earth's magnetic lines of flux

Magnetic compass construction

Uses two magnets mounted on a float

Magnetic compass fluid

The chamber is filled with white kerosene

White kerosene purpose

It will not freeze and dampens float oscillations

Air bubbles in magnetic compass

Are undesirable

Lubber line

Indicates the aircraft's magnetic heading

Magnetic compass errors

Variation, deviation, magnetic dip/turning errors, acceleration errors, and oscillation errors

Variation

The difference between true and magnetic directions

True north and magnetic north separation

Approximately 1,300 nautical miles

Variation geographic dependence

Varies by geographic location

Magnetic north movement

Magnetic north is continuously moving

Deviation

Local magnetic fields in the aircraft conflict with Earth's magnetic field

Sources of deviation

Electrical current in the aircraft structure, nearby wiring, or magnetized parts of the structure

Deviation by heading

Deviation is different on each heading

Compass card

Compass card is specific to the aircraft

Magnetic dip

The tendency of the magnetic compass to be pulled toward the magnetic equator

Magnetic dip cause

The Earth's magnetic field runs parallel to the surface only at the magnetic equator

Magnetic dip with latitude

Dip angle increases as you move closer to the magnetic poles

Magnetic equator

The point halfway between the magnetic north and south poles where Earth's magnetic field runs parallel to the surface

ANDS

Accelerate North, Decelerate South

NOSS

North Opposite, South Same

UNOS

Undershoot North, Overshoot South

Acceleration error

An error that occurs when accelerating or decelerating on an east or west heading

Acceleration error during acceleration on E/W

Compass initially indicates a turn toward north

Acceleration error during deceleration on E/W

Compass initially indicates a turn toward south

Acceleration error cause

The compass magnet tilts toward the north pole and the counterweight creates greater inertia on one side

NOSS error headings

NOSS errors occur when turning from an east or west heading

NOSS when turning north

Compass lags behind; initially indicates no turn or a turn in the opposite direction

NOSS when turning south

Compass leads ahead; indicates a faster turn than is actually occurring

UNOS error

If on an east or west heading and turning toward north or south, magnetic dip causes an undershoot or overshoot error

UNOS north turn

Undershoot north

UNOS south turn

Overshoot south

UNOS correction amount

Amount of undershoot or overshoot depends on latitude

UNOS example 270° to 180°

Turn until the compass indicates approximately 150°

UNOS example 090° to 030°

Turn until the compass indicates approximately 050°

UNOS example conditions

Approximate values shown are for a 30° latitude locality and bank angles between 15° and 18°