Systems and High-Altitude Operations practice questions

Answer: B) A governed RPM

• AIncorrect. That's fixed-pitch.
• BCorrect. Blade pitch adjusts automatically.
• CIncorrect. That's the mixture control.
• DIncorrect. That's the throttle.

Answer: C) At a low point in the fuel system

• AIncorrect. It's in the fuel system.
• BIncorrect. Contaminants sink to low points.
• CCorrect. It traps water and sediment.
• DIncorrect. It's at a low point near the engine.

Answer: A) Once, if the POH allows

• ACorrect. Repeated resets risk fire.
• BIncorrect. That risks fire.
• CIncorrect. One reset may be allowed.
• DIncorrect. Follow the POH.

Answer: A) Water and other contaminants in the fuel

Fuel is drained from the sumps and strainer before flight mainly to find and remove water and other contamination. The sample's color also helps confirm the correct fuel grade.

• ACorrect. Sumping catches water, which is heavier than avgas and settles at the low points, along with sediment and other contaminants. The sample's color also helps confirm the right fuel grade.
• BIncorrect. You can't judge a vapor lock tendency from a sump sample. The sample is checked for water, sediment and fuel grade.
• CIncorrect. Fuel quantity is checked visually in the tanks and on the gauges. A small sump sample says nothing about how much fuel is on board.
• DIncorrect. Vents are checked by inspecting the vent lines and openings. Draining a sample doesn't confirm that a vent is clear.

Answer: B) A circuit breaker or fuse in that circuit

Circuit breakers and fuses protect individual electrical circuits by opening them when current exceeds a safe level. Regulators, switches and meters don't do this job.

• AIncorrect. The voltage regulator controls the alternator's output voltage. It doesn't open individual circuits that draw too much current.
• BCorrect. A circuit breaker or fuse sits in series with the circuit and opens it when current exceeds its rating, protecting the wiring and equipment.
• CIncorrect. The master switch and battery contactor connect or disconnect the battery and the bus. They don't sense an overload in an individual circuit.
• DIncorrect. The ammeter or loadmeter only shows current flow. It gives no protection against an overload.

Answer: A) Turn it on before entering visible moisture when the temperature is at or near freezing

Pitot heat should be turned on before flying into visible moisture at or near freezing temperatures. Even a small amount of ice can block the pitot tube and cause airspeed indication errors.

• ACorrect. Even light ice can block the pitot tube's ram-air opening, so the heat should be on before entering visible moisture near freezing to prevent ice from forming.
• BIncorrect. Erratic readings mean the pitot tube may already be blocked. Pitot heat is meant to prevent ice, so waiting for symptoms defeats its purpose.
• CIncorrect. Structural and pitot icing are most common in visible moisture at temperatures near or a little below freezing. Waiting for much colder air misses the riskiest conditions.
• DIncorrect. Pitot heat is for preventing ice. Running it for long periods on the ground can overheat the probe because there is no cooling airflow.

Answer: B) Generally up to about FL280

• AIncorrect. That needs pressure-demand oxygen.
• BCorrect. Higher altitudes need demand or pressure systems.
• CIncorrect. Oxygen is used in flight.
• DIncorrect. They're common in unpressurized airplanes.

Answer: C) Evaporative icing in the induction system

Fuel injection reduces evaporative (carburetor-type) icing. Its drawbacks include hard hot starts, vapor lock on the ground on hot days, and restart problems after fuel starvation.

• AIncorrect. The PHAK lists vapor lock during ground operations on hot days as a drawback of fuel-injection systems, not an advantage.
• BIncorrect. Trouble starting a hot engine is a known drawback of fuel injection. Students moving from carbureted engines often need to learn a separate hot-start procedure.
• CCorrect. Fuel is injected near the intake ports, not vaporized in a carburetor venturi, so fuel injection reduces evaporative icing. Impact (induction) icing can still block the air intake.
• DIncorrect. The PHAK lists problems restarting an engine that quit from fuel starvation as a drawback of fuel-injection systems.

Answer: C) To keep the right fuel-air ratio in thinner air

• AIncorrect. Leaning can raise temperatures.
• BIncorrect. The mixture doesn't control oil pressure.
• CCorrect. It improves efficiency and smoothness.
• DIncorrect. It's an operating procedure.

Answer: A) The next higher grade of avgas approved by the engine manufacturer

The specified fuel grade is the minimum. If it isn't available, use the next higher grade the manufacturer approves, never a lower grade or an unapproved fuel.

• ACorrect. The specified grade is the minimum. A higher grade may be used when the manufacturer's recommendations allow it.
• BIncorrect. A lower grade than specified can cause detonation and possible preignition, which can damage the engine. Enriching the mixture doesn't make it acceptable.
• CIncorrect. Automotive gasoline may be used only when it is specifically approved for the airplane and engine, for example by a supplemental type certificate.
• DIncorrect. Jet fuel in a reciprocating engine lowers its resistance to knock and can cause severe detonation and engine failure.