Aircraft Instruments

Aerospace Technology I

Facilitator-Mr. Lee

Adapted from- Aerospace: The Journey of Flight

Objectives • Classify the three major groups of aircraft

instruments by their principles of operation.

• Classify the two major groups of aircraft instruments by their uses.

Early Aircraft Instruments • The first aviators relied on their senses

because there were no instruments.

o Airspeed was first judged by the force of the wind on the pilot’s face and the whine of wind through the rigging

o The attitude of the aircraft was determined by tying a piece of heavy string to the aircraft

If the string was flying straight back, the pilot was doing fine

Early Aircraft Instruments… • Early instruments were adequate for “low

and slow” aircraft.

• Early instruments were designed to give pilots specific information about the engine or the attitude of the aircraft.

Classification by Principle of Operation

• Instruments can be classified by their principle of Operation:

o Mechanical instruments

o Pressure instruments

o Electrical instruments

Mechanical Instruments • Mechanical instruments work by means of

direct mechanical linkage.

o One example is a float might rise and fall in a fuel cell and be linked to the fuel gauge by a cable.

o Another example would be gyroscopic stability, which means that a spinning flat weight tends to line up on one of its axes.

Pressure Instruments • Pressure instruments work on the idea that

a fluid, such as air, exerts pressure.

Electrical Instruments • Electrical instruments operate on the

principles of electricity, including magnetism.

Classification By Use • Aircraft instruments can be classification by

use:

o Performance:

Performance tells how the aircraft has responded to commands

o Control

Control tells the current state of some aircraft devices

Engine Instruments Examples • Tachometer – measures speed;

how fast the engine’s crankshaft is turning.

• Oil Pressure and Temperature Gauges provide constant readings on the pressure and temperature.

Flight Instruments • Purpose – allow for safe flight

and show pilot how well the airplane is performing.

• The Airspeed Indicator informs the pilot of the speed through the air.

• Aircraft Altimeters feet of altitude.

Flight Instruments • The Turn-and-Slip indicator

does two things:

o The needle, indicates the direction and rate of the turn.

o The ball in the glass tube, called the inclinometer, indicates the quality of the turn.

• The Vertical Velocity Indicator tells the pilot at what rate the airplane is climbing or descending.

o It is also known as the vertical speed indicator or the rate-of-climb indicator

Navigation Instruments • Navigation Instruments are used to help the

pilot find the way to the destination.

• The most important navigation instrument is a magnetic compass.

• Most planes have a heading indicator.

o It is a type of compass.

Flight Instruments

Review • Classify the three major groups of aircraft

instruments by their principles of operation.

o Mechanical instruments

o Pressure instruments

o Electrical instruments

• Classify the two major groups of aircraft instruments by their uses.

o Performance:

o Control

Learn Long Live Long