Grnd-48 Theory of Flight 4 Flight Instruments

Four basic flight instruments

Altimeter, airspeed indicator, attitude indicator, heading indicator

What makes up the pitot-static system?

Pitot-static head, static ports

What does the pitot-static system do?

Provides air pressure sensations directly to differential pressure instruments for the measure of IAS and altitude

What do air data systems allow for?

They allow for a greater number of air data outputs from more complex air data measurements. Includes addition of more sensors, transducers, and an air data computer.

Three common air data outputs

Pressure altitude, airspeed (i.e. TAS), density

Three types of altitude

Pressure altitude (ref. 29.92 altimeter), true altitude (ref. MSL), absolute altitude (AGL)

RadAlt

Wide beam FM signal radiated toward the ground and reflected back up (wide beam for greater averaging and not responding to small/rapid fluctuations). Measures absolute altitude.

Three uses for gyroscopes

Attitude and heading reference systems, determination of direction and rate of turn, stabilisation of equipment

Two basic properties of gyroscopes

Rigidity, precession

Rigidity

The axis of rotation of the gyro wheel tends to remain in a fixed direction in space if no force is applied to it

Precession

The axis of rotation has a tendency to turn at a right angle to the direction of an applied force

What is the effect that allows a laser gyroscope to work?

Sagnac effect

When are simple magnetic compasses used?

Generally used for emergencies or to cross check other systems

When are simple magnetic compasses reliable?

Only during straight and level unaccelerated flight

Gyrosyn Compass

Remotely located unit to detect earth’s magnetic field.

Incorporates a gyroscope for stability - accurate during turns and accelerations.

Requires electrical power.

Drives other cockpit indicators.

Two main components of heading indicators

Heading reference index, rotating compass card