Operation of Systems

Specific Study Areas

Study the following systems in your aircraft's POH:

Engine
Fuel system
Oil system
Electrical system
Flight controls

Wet Sump Oil System: PHAK 7-16

A wet-sump system stores all the engine oil in a pan at the bottom of the engine. The pump draws oil up, sends it through the engine to lubricate and cool it, and the oil returns to the sump to start over again.

Ignition System: PHAK 7-15

The starter turns the engine.

Turning the engine turns the magnetos.
A magneto with an impulse coupling makes a strong spark at low RPM.
Once the engine fires, the magnetos take over completely.
The airplane no longer needs the battery to keep running.

Flight Instruments: PHAK 8-3, 7, 8

Altimeter: The altimeter has sealed, flexible metal aneroid wafers inside that expand or contract based on outside air pressure. As you climb, outside pressure drops, and the wafers expand. As you descend, pressure increases, and they compress. This movement turns gears that move the needles to show your altitude.
Vertical Speed Indicator: The VSI compares fast and slow changes in air pressure. A diaphragm inside gets pressure right away, but the rest of the instrument fills more slowly. When pressure changes quickly (like during a climb or descent), the difference causes the needle to move up or down. It has a small delay due to the restricted orifice (calibrated leak).
Airspeed Indicator: The ASI measures how fast you’re moving through the air. It compares pressure from the pitot tube (facing forward into the wind) with static pressure. The difference moves a diaphragm connected to the needle. It shows speed in knots or miles per hour and is the only instrument that uses both pitot and static pressure.

Instrument Errors: PHAK 8-10

Compass Errors: PHAK 8-24

V.D.M.O.N.A.

Variation: the difference between true north and magnetic north.
Deviation: due to magnetic field of the aircraft.
Magnetic Dip: gets closer to the north pole.
Oscillation: due to turbulence or rough control.
Northerly Turning Errors: (UNOS) undershoot north, overshoot south.
Acceleration/Deceleration Errors: (ANDS) accelerate north, decelerate south.

*Note: compass errors do not apply to the Archer because it is not equipped with a magnetic direction indicator.

Vacuum and ADAHRS Systems: PHAK 8-(12-20)

Vacuum System

The vacuum system is a traditional method for powering certain flight instruments. It uses an engine-driven vacuum pump to create suction, which pulls air through hoses and over internal gyroscopes in instruments like the attitude indicator and heading indicator. As the air flows through the instruments, it causes the gyros to spin at high speeds. The stability of these spinning gyros allows the instruments to display the aircraft’s orientation and heading. The turn coordinator is typically electrically powered, not vacuum-driven, to ensure redundancy in case of vacuum failure. This setup is simple and effective but has been largely replaced in modern aircraft by electronic systems.

ADAHRS System

Your G1000-equipped Archer uses an ADAHRS, which stands for Air Data and Attitude Heading Reference System. This modern, digital system replaces the old gyroscopic and pitot-static instruments with solid-state sensors. The Air Data Computer (ADC) collects information from the pitot and static sources to calculate airspeed, altitude, and vertical speed. The AHRS (Attitude Heading Reference System) uses accelerometers, magnetometers, and rate sensors to determine attitude, heading, and rate of turn—all without spinning gyros. These digital systems drive your Primary Flight Display (PFD) and are more reliable, less prone to mechanical failure, and easier to maintain than vacuum-driven instruments.

Flux Gate: PHAK 8-20

A flux gate is a type of magnetic sensor used in aviation to measure the direction of the Earth’s magnetic field more accurately than a standard compass. It is typically mounted in a wing or tail section to avoid interference and is part of systems like the slaved heading indicator or HSI. The flux gate detects magnetic heading and sends an electrical signal to a slaving amplifier, which keeps the heading indicator automatically aligned with magnetic north. Its purpose is to provide stable and accurate heading information without the errors found in traditional magnetic compasses.

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