17. Propeller - Q&A

On a modern single lever turboprop, the power lever controls:

• only the engine fuel flow with no effect on propeller blade angle, which is controlled by a separate propeller control lever
• only the propeller blade angle with no effect on engine fuel flow, which is controlled by a separate throttle lever in cockpit
• both the engine fuel flow and the propeller blade angle through a coordinated control system managed by the FADEC or similar

Propeller control during engine start:

• is not active during engine start, as the propeller blades remain in whatever position they were in when the engine was shut down
• positions the blades at maximum coarse pitch to provide the highest possible thrust immediately when the engine starts running
• positions the blades at a low pitch angle to minimise the load on the starter motor and allow the engine to accelerate to idle

The limits for a tracking check are

• 1/4 inch maximum difference between adjacent blades.
• 1/8 inch maximum difference between opposite blades.
• 1/8 inch maximum difference between all blades.

If the TAS of an aircraft increases, the CSU will

• increase the blade angle to provide constant RPM.
• decrease the blade angle to provide constant RPM.
• change the blade angle to provide constant RPM.

When storing wooden propellers

• store in a dry well ventilated and illuminated location.
• store in a horizontal position.
• wrap in greaseproof paper.

When a propeller is removed, the securing parts are kept with

• all separately in cases.
• the propeller.
• the engine.

Minor surface damage located in a repairable area, but not on the leading or trailing edges of aluminium blades, may be repaired by first

• filing with a half round or flat file.
• sanding and applying a proper filler.
• filing with a riffle file.

With a multi-engined aircraft the torque pressure would be

• There is only one gauge for all engines.
• same on all engines.
• similar on all engines.

Auto feathering is disarmed

• during landing.
• during take off.
• in the cruise.

If governor weight spring pressure is reduced

• governor weights will pivot inwards raising the governor valve allowing the blades to move to a coarser pitch.
• governor weights will spring outwards raising the governor valve allowing the blades to move to a finer pitch.
• governor weights will spring outwards raising the governor valve allowing the blades to move to a coarser pitch.

Thrust and camber faces of a propeller should be blended out to

• 5 times the depth of damage.
• 10 times to the depth of damage.
• 30 times to the depth of damage.

Operation with the engine at maximum boost should be limited to

• prop at fine to prevent overstressing the engine.
• prop at coarse to prevent overstressing the engine.
• prop at windmill to prevent overstressing the engine.

A rotating propeller imparts rearwards motion to a

• small mass of air at high velocity.
• large mass of air at low velocity.
• small mass of air at low velocity.

When in reverse pitch, CTM will tend to move the propeller blades towards

• a positive pitch.
• a position depending on rpm.
• a negative pitch.

If the speeder spring pressure of a CSU is increased the blade will

• coarsen off.
• fine off.
• will not move.

In a two position propeller

• ATM turns the prop to fine.
• oil pushes the prop to fine.
• oil pushes the prop to coarse.

In what position is the constant-speed propeller control placed to check the magnetos?

• Full decrease, low propeller blade pitch angle.
• Full increase, low propeller blade pitch angle.
• Full increase, high propeller blade pitch angle.

The purpose of using reverse pitch propellers is to

• provide aerodynamic breaking.
• allow aircraft to taxi backwards.
• reverse the direction of rotation of the propeller.

The function of a propeller pitch lock is to prevent the propeller from

• coarsening.
• reducing below flight fine pitch.
• fining off in the event of pitch lock mechanism failure.

The function of a propeller pitch lock is to prevent the propeller from

• coarsening.
• reducing below flight fine pitch.
• fining off in the event of pitch lock mechanism failure.

When the compressive force on a speeder spring is reduced, the propeller blades will

• remain fixed.
• fine off.
• coarsen.

When governor spring load is less than governor weights, the CSU is in

• overspeed.
• underspeed.
• normal.

The purpose of the pitch change cams is to

• convert rotary motion to linear motion.
• prevent windmilling.
• convert linear motion to rotary motion.

How is the efficiency of a turbo prop engine assessed?

• By correcting propeller RPM for ambient Air temperature and barometric pressure.
• By comparing compressor and propeller RPM against a reference figure.
• By comparing torque meter pressure against a reference figure.

On a Hartzell prop with counterweights, full oil supply would indicate

• on-speed condition.
• overspeed condition.
• underspeed condition.