PPL Stage 1 Systems

How is a magneto started?

The starter turns the engine, which turns the magneto. The impulse coupling helps produce a strong, properly timed spark at the engine’s low starting RPM.

What is the purpose of the magnetos?

They create electrical energy for the spark plugs and ignite the fuel-air mixture.

Do the magnetos require the aircraft battery?

No. They are engine-driven and self-powered.

Why does each cylinder have two spark plugs?

For redundancy and more complete, efficient combustion.

What happens when a magneto is switched OFF?

The ignition switch grounds it through the P-lead.

What happens if one magneto fails in flight?

The engine continues running on the other magneto, but with reduced power and efficiency.

What does the impulse coupling do during engine start?

It delays the spark and makes the magneto spin faster to produce a stronger spark.

Which instruments use the pitot-static system?

Airspeed indicator, altimeter, and vertical speed indicator.

What pressure does the airspeed indicator use?

Pitot pressure and static pressure.

What pressure does the altimeter use?

Static pressure only

What pressure does the VSI use?

Static pressure, measured with a calibrated leak.

What happens if the pitot tube opening becomes blocked but the drain remains open?

The airspeed indication drops toward zero.

How does the airspeed indicator work?

It compares pitot pressure with static pressure using a diaphragm.

How does the altimeter work?

Aneroid wafers expand as pressure decreases and contract as pressure increases.

How does the VSI work?

It measures how quickly static pressure changes using a diaphragm/calibrated leak.

What happens if the pitot opening and drain are both blocked?

The airspeed indicator behaves somewhat like an altimeter.

What happens if the static source becomes blocked?

The altimeter freezes, VSI reads zero, and airspeed becomes inaccurate.

What is the alternate static source used for?

It supplies static pressure if the normal static source becomes blocked.

What are the four parts of an electrical system?

Generation, storage, distribution, and consumption.

What generates electrical power during normal operation?

The alternator.

What stores electrical energy?

The battery.

What protects electrical circuits?

Circuit breakers.

Will the engine stop if the master switch is turned off?

No. The magnetos operate independently of the electrical system.

What engine is installed in the DA40 XLT?

A Lycoming IO-360-M1A: four-cylinder, horizontally opposed, fuel-injected, air-cooled, normally aspirated engine.

What does “IO-360” mean?

Fuel-injected, horizontally opposed engine with approximately 360 cubic inches of displacement.

How is the engine cooled?

Air flows through openings in the cowling and around the cylinders.

What are the four strokes of the engine cycle?

Intake, compression, power, and exhaust.

What are the engine’s basic needs?

Fuel, air, compression, and ignition.