AC Instruments Prelims

Jimmy Doolittle

An aviation pioneer who made a flight without outside visual references, proving that blind flight was possible.

Consolidated NY-2 Aircraft

The aircraft used by Jimmy Doolittle for his historic blind flight.

Artificial Horizon

An instrument that indicates the aircraft's pitch and roll.

Altimeter

An instrument that measures altitude based on air pressure.

Radio Direction Finder

A device used to determine the aircraft's position relative to the landing area.

Visual Flight Rules (VFR)

Regulations that require pilots to operate in weather conditions that allow visual navigation.

Instrument Flight Rules (IFR)

Regulations that require pilots to fly by reference to instruments in the cockpit.

Instrument Meteorological Conditions (IMC)

Weather conditions that require the use of instruments for navigation.

Direct Sensing Instrument System

An instrument system that senses the situation directly.

Remote-Sensing Instrument System

An instrument system that requires information to be captured and sent to a separate display unit.

Flight Instrument

Instruments used to provide information about the aircraft's flight status.

Engine Instrument

Instruments that measure operating parameters of the aircraft engine.

Navigation Instrument

Instruments used to determine the aircraft's direction and distance.

Altimeter Indicator

An instrument that indicates altitude based on barometric pressure.

Airspeed Indicator

An instrument that measures the speed of the aircraft through the air.

Attitude Indicator

Also known as the artificial horizon, it shows the aircraft's orientation in relation to the horizon.

Heading Indicator

Also known as the directional gyro, it indicates the aircraft's heading with respect to magnetic north.

Vertical Speed Indicator

An instrument that indicates the rate of climb or descent of the aircraft.

Turn Coordinator

An instrument that indicates the rate of turn and coordination of the aircraft.

Very High Frequency Omni-Directional Range (VOR)

A standard radio navigation system for cross-country flying in the US.

-         VHHF range: 108-177.95 MHz

Automatic Direction Finder (ADF)

A navigation instrument used since the 1930s.

Non-Directional Beacons (NDB)

Radio beacons used for navigation, especially at smaller airports.

190-1,800 kHz range

Engine Oil Pressure Gauge

An important instrument that indicates the oil pressure in the engine.

Tachometer

An instrument that measures the rotation speed of the engine's shaft or disk.

Exhaust Gas Temperature Indicator (EGT)

An instrument that monitors the exhaust gas temperature of an internal combustion engine.

Manifold Pressure Gauge

An instrument used in piston aircraft engines to measure pressure inside the induction system.

Fuel Pressure Gauge

An instrument that measures the pressure of fuel in the system.

Because of the Oil Pump

Engine Oil Pressure Gauge Importance

3 BASIC KINDS OF INSTRUMENT

Flight instrument
Engine strument
Navigation instrument

Electricity

Used by way of wires that carry sensor information into the cockpit

Coventional, Analog, Traditional cockpit

Relies numerous mechanical gauges (steam guages)

Glass cockpit

features electronic (digital) Large Lcd screens

Term

synonym or called for cockpit instrument as a whole

Calibrated Airspeed (CAS

corrected for altitude related atmospheric

Indicated Airspeed (lAS)

corrected for installation error and instrument error

True Airspeed (TAS)

used for flight planning calculations

Groundspeed (GS)

speed over the ground

Turn and Slip Coordinator

Indicate rotation about the longitudinal axis

Inclinometer

to indicate iif the aircraft is in coordinated flight or in a SLIP or SKID

Skid

centrifugal force higher than centripetal force

Slip

centripetal force higher than centrifugal force

Lubrication

to reduce friction and prevents heating of the engine.

Cooling

oil absorbs heat

Cleaning

because of abrasion

3 most common reasons for low oil pressure

LOW OIL LEVEL

WORN-OUT

OIL OVERHEATING

non-electrical instrument

Most materials expand when subjected to an increase in temperature and contract when the tem­perature decreases.

Liquid Expansion

Measuring instrument is a common household or medical thermometer

Solid Expansion

-         Bimetallic strip thermometer

          - utilizes a sandwich of two metals with different expansion coefficients

          - to measure the outside air temperature

          - include brass and iron

Gas Expansion

Principle of Expanding Gas

Electrical Instrument

Use of electricity in Measuring temperature is very common in aviation

Temperature can be determined electrically either by measuring resistance or voltage and using the result to move an electrical temperature indicator

Resistance Instrument

Resistance change-type temperature instruments use a fine nickel-wire coil placed into the end of temperature-sensing bulb

THERMOCOUPLE INSTRUMENT

Used to measure relatively high temperatures.

mechanical movement instruments

Accelerometers, synchroscopes, tachometers

ACCELEROMETER

-         Operates on the principle of inertia

-         Instrument that measures acceleration

-         Used to monitor the forces acting upon an airframe

SYNCHROSCOPES

An instrument that indicates whether two or more rotating devices, such as engines, are synchronized

Tachometer

-         Or tach

-         An instrument that indicates the speed of the crankshaft of a reciprocating engine

-         It can be a direct or remote-indicating instrument

-         Helicopters use this to indicate main rotor shaft rpm

Dial

is calibrated to indicate revolutions per minutes (rpm)

Reciprocating engine

uses tachometer to monitor engine power and to ensure the engine is operated within certified limits. Calibrated in rpm

Gas turbine

uses tachometer to monitor the speed(s) of the engine

turbine engine tachometer

calibrated in percentage of rpm

helicopter tachometer

with engine rpm, rotor rpm, and slippage indications

Mechanical Tachometer and electrical tachometer

Two types of tachometer system

mechanical tachometer

-         Indicator connected to the engine by a flexible drive shaft

-         small, single-engine light aircraft

-         The simplified mechanism of a flyweight type mechanical tachometer

electrical tachometer

-         Connected via wires

-         Greater accuracy with lower maintenance

-         A simplified magnetic drag cup tachometer indicating device

●       2 cyclic pitch control

●       2 collective pitch control

●       2 Pairs of Antitorque Pedals

• Right torque pedal

• Left torque pedal

●       An Overhead control panel

●       Instrument panel

●       Inter-seat control panel

 

Typical Helicopter Cockpit contains

torque indicator

indicates twisting force or rotating force of a helicopter rotors such as main rotor and tail rotor

2 cyclic pitch control

movement/ direction

2 collective pitch control

• lift

• Some old model helicopters only contain one Collective Pitch Control

2 Pairs of Antitorque Pedals

●       rotation for twisting force

-         Right torque pedal - tail rotor/ fast

-         Left torque pedal - slow

An Overhead control panel

-         Located above the pilots

-         usually contains electrical panel, light panel, hydraulic panel, fire system

instrument panel

usually contains basic flight and navigation instruments, engine parameters, transmission parameters

Inter-seat control panel

usually contains radio control panels, autopilot panel, navigation panel, fuel

RPM indicator

-         indicates the amount of main rotor Revolutions Per Minute (RPM).

-         indicate the exact number or percentage (%) of turns per minute.

-         In HELICOPTER - short needle marked with letter R and inner circle indicates main rotor RPM; the long needle marked with T and external circle indicates engine turbine RPM.