Powerplant Test Question Bank

Please Note:

Subject matter codes appear above each item.

A.8.0.0.1.A.1 A01

Which statement is true regarding bearings used in high powered reciprocating aircraft engines?

A. Crankshaft bearings are generally of the ball-type due to their ability to withstand extreme loads without overheating.

B. There is less rolling friction when ball bearings are used than when roller bearings are employed.

C. The outer race of a single row, self aligning ball bearing will always have a radius equal to the radius of the balls.

A.8.0.0.2.B.1 A01

A condition that can occur in radial engines but is unlikely to occur in horizontally opposed engines is

A. valve overlap.

B. zero valve clearance.

C. hydraulic lock.

A.8.0.0.3.A.1 A01

Which condition would be the least likely to be caused by failed or failing engine bearings?

A. High oil temperatures.

B. Low oil temperatures.

C. Excessive oil consumption.

A.8.0.0.4.A.1 A01

What is the principal advantage of using propeller reduction gears?

A. To enable the engine RPM to be increased with an accompanying increase in power and allow the propeller to remain at a lower, more efficient RPM.

B. To enable the engine RPM to be increased with an accompanying increase in propeller RPM.

C. To enable the propeller RPM to be increased without an accompanying increase in engine RPM.

A.8.0.0.5.A.1 A01

Which of the following will decrease volumetric efficiency in a reciprocating engine?

1. Full throttle operation.

2. Low cylinder head temperatures.

3. Improper valve timing.

4. Sharp bends in the induction system.

5. High carburetor air temperatures.

A. 1, 2, 3, and 4.

B. 3, 4, and 5.

C. 2, 4, and 5.

A.8.0.0.6.A.1 A01

Which of the following is a characteristic of a thrust bearing used in most radial engines?

A. Tapered roller.

B. Double row ball.

C. Deep groove ball.

A.8.0.0.7.A.1 A01

Which bearing is least likely to be a roller or ball bearing?

A. Master rod bearing (radial engine).

B. Rocker arm bearing (overhead valve engine).

C. Crankshaft main bearing (radial engine).

A.8.0.0.8.A.1 A01

The operating temperature valve clearance of a radial engine as compared to cold valve clearance is

A. less.

B. greater.

C. the same.

A.8.0.0.9.A.1 A01

A nine cylinder engine with a bore of 5.5 inches and a stroke of 6 inches will have a total piston displacement of

A. 1,425 cubic inches.

B. 1,283 cubic inches.

C. 740 cubic inches.

A.8.0.1.0.A.1 A01

The five events of a four stroke cycle engine in the order of their occurrence are

A. intake, power, compression, ignition, exhaust.

B. intake, ignition, compression, power, exhaust.

C. intake, compression, ignition, power, exhaust.

A.8.0.1.1.A.1 A02

The primary concern in establishing the firing order for an opposed engine is to

A. keep power impulses on adjacent cylinders as far apart as possible in order to obtain the greatest mechanical efficiency.

B. keep the power impulses on adjacent cylinders as close as possible in order to obtain the greatest mechanical efficiency.

C. provide for balance and eliminate vibration to the greatest extent possible.

A.8.0.1.2.A.1 A02

If fuel/air ratio is proper and ignition timing is correct, the combustion process should be completed

A. when the exhaust valve opens at the end of the power stroke.

B. 20 to 30° before top center at the end of the compression stroke.

C. just after top center at the beginning of the power stroke.

A.8.0.1.3.A.1 A02

Grinding the valves of a reciprocating engine to a feather edge is likely to result in

A. normal operation and long life.

B. excessive valve clearance.

C. preignition and burned valves.

A.8.0.1.4.B.1 A02

Which statement is correct regarding engine crankshafts?

A. Moveable counterweights serve to reduce the dynamic vibrations in an aircraft reciprocating engine.

B. Moveable counterweights serve to reduce the torsional vibrations in an aircraft reciprocating engine.

C. Moveable counterweights are designed to resonate at the natural frequency of the crankshaft.

A.8.0.1.5.B.1 A02

On which strokes are both valves on a four-stroke cycle reciprocating aircraft engine open?

A. Intake and compression.

B. Power and exhaust.

C. Exhaust and intake.

A.8.0.1.6.A.1 A02

Master rod bearings are generally what type?

A. Ball.

B. Roller.

C. Plain.

A.8.0.1.7.A.1 A02

The actual power delivered to the propeller of an aircraft engine is called

A. brake horsepower.

B. indicated horsepower.

C. friction horsepower.

A.8.0.1.8.A.1 A02

Cam ground pistons are installed in some aircraft engines to

A. act as a compensating feature so that a compensated magneto is not required.

B. provide a better fit at operating temperatures.

C. equalize the wear on all pistons.

A.8.0.1.9.A.1 A02

Using the following information, determine how many degrees the crankshaft will rotate with both the intake and exhaust valves seated.

Intake opens 15° BTDC.

Exhaust opens 70° BBDC.

Intake closes 45° ABDC.

Exhaust closes 10° ATDC.

A. 25°.

B. 290°.

C. 245°.

A.8.0.2.0.A.1 A02

Some aircraft engine manufacturers equip their product with choked or taper-ground cylinders in order to

A. increase the compression pressure for starting purposes.

B. flex the rings slightly during operation and reduce the possibility of the rings sticking in the grooves.

C. provide a straight cylinder bore at operating temperatures.

A.8.0.2.1.A.1 A02

An aircraft reciprocating engine using hydraulic valve lifters is observed to have no clearance in its valve-operating mechanism after the minimum inlet oil and cylinder head temperatures for takeoff have been reached. When can this condition be expected?

A. As a result of carbon and sludge becoming trapped in the lifter and restricting its motion.

B. When the lifters become deflated.

C. During normal operation.

A.8.0.2.2.A.1 A02

What tool is generally used to measure the crankshaft rotation in degrees?

A. Timing disk.

B. Prop Protractor.

C. Dial indicator.

A.8.0.2.3.A.1 A02

If an engine with a stroke of 6 inches is operated at 2,000 RPM, the piston movement within the cylinder will be

A. at maximum velocity around TDC.

B. constant during the entire 360° of crankshaft travel.

C. at maximum velocity 90° after TDC.

A.8.0.2.4.A.1 A02

If the intake valve is opened too early in the cycle of operation of a four-stroke cycle engine, it may result in

A. engine kickback.

B. improper scavenging of exhaust gases.

C. backfiring into the induction system.

A.8.0.2.5.A.1 A02

Some cylinder barrels are hardened by

A. tempering.

B. shot peening.

C. nitriding.

A.8.0.2.6.A.1 A02

Which statement is correct regarding a four stroke cycle aircraft engine?

A. The exhaust valve opens on the exhaust stroke.

B. The intake valve closes on the intake stroke.

C. The intake valve closes on the compression stroke.

A.8.0.2.7.A.1 A02

On which part of the cylinder walls of a normally operating engine will the greatest amount of wear occur?

A. Near the center of the cylinder where piston velocity is greatest.

B. Wear is normally evenly distributed.

C. Near the top of the cylinder.

A.8.0.2.8.B.1 A02

During overhaul, reciprocating engine exhaust valves are checked for stretch

A. with a contour or radius gauge.

B. by placing the valve on a surface plate and measuring its length with a vernier height gauge.

C. with a suitable inside spring caliper.

A.8.0.2.9.A.1 A02

When is the fuel/air mixture ignited in a conventional reciprocating engine?

A. When the piston has reached top dead center of the intake stroke.

B. When the piston reaches top dead center on the compression stroke.

C. Shortly before the piston reaches the top of the compression stroke.

A.8.0.3.0.A.1 A02

Ignition occurs at 28° BTDC on a certain four-stroke cycle engine, and the intake valve opens at 15° BTDC. How many degrees of crankshaft travel after ignition does the intake valve open? (Consider one cylinder only.)

A. 347°.

B. 707°.

C. 373°.

A.8.0.3.1.A.1 A02

What is the purpose of the safety circlet installed on some valve stems?

A. To prevent valves from falling into the combustion chamber.

B. To hold the valve spring retaining washer in position.

C. To hold the valve guide in position.

A.8.0.3.2.A.1 A02

Valve overlap is defined as the number of degrees of crankshaft travel

A. during which both valves are off their seats.

B. between the closing of the intake valve and the opening of the exhaust valve.

C. during which both valves are on their seats.

A.8.0.3.3.B.1 A02

The valve clearance of an engine using hydraulic lifters, when the lifters are completely flat, or empty, should not exceed

A. 0.00 inch.

B. a specified amount below zero.

C. a specified amount above zero.

A.8.0.3.4.A.1 A02

If the exhaust valve of a four stroke cycle engine is closed and the intake valve is just closed, the piston is on the

A. power stroke.

B. intake stroke.

C. compression stroke.

A.8.0.3.5.A.1 A02

How many of the following are factors in establishing the maximum compression ratio limitations of an aircraft engine?

1. Detonation characteristics of the fuel used.

2. Design limitations of the engine.

3. Degree of supercharging.

4. Spark plug reach.

A. Two.

B. Three.

C. Four.

A.8.0.3.6.A.1 A02

Full floating piston pins are those which allow motion between the pin and

A. the piston.

B. both the piston and the large end of the connecting rod.

C. both the piston and the small end of the connecting rod.

A.8.0.3.7.A.1 A02

The primary purpose in setting proper valve timing and overlap is to

A. permit the best possible charge of fuel/air mixture into the cylinders.

B. gain more thorough exhaust gas scavenging.

C. obtain the best volumetric efficiency and lower cylinder operating temperatures.

A.8.0.3.8.A.1 A02

If the hot clearance is used to set the valves when the engine is cold, what will occur during operation of the engine?

A. The valves will open late and close early.

B. The valves will open early and close early.

C. The valves will open early and close late.

A.8.0.3.9.A.1 A02

The purpose of two or more valve springs in aircraft engines is to

A. eliminate valve spring surge.

B. equalize side pressure on the valve stems.

C. equalize valve face loading.

A.8.0.4.0.A.1 A02

During overhaul, the disassembled parts of an engine are usually degreased with some form of mineral spirits solvent rather than water mixed degreasers primarily because

A. solvent degreasers are much more effective.

B. water mixed degreaser residues may cause engine oil contamination in the overhauled engine.

C. water-mixed degreasers cause corrosion.

A.8.0.4.1.A.1 A02

Why does the smoothness of operation of an engine increase with a greater number of cylinders?

A. The engine has larger counterbalance weights.

B. The power impulses are spaced closer together.

C. The power impulses are spaced farther apart.

A.8.0.4.2.A.1 A02

Compression ratio is the ratio between the

A. piston travel on the compression stroke and on the intake stroke.

B. combustion chamber pressure on the combustion stroke and on the exhaust stroke.

C. cylinder volume with piston at bottom dead center and at top dead center.

A.8.0.4.3.A.1 A02

If the crankshaft runout readings on the dial indicator are plus .002 inch and minus .003 inch, the runout is

A. plus .001 inch.

B. .005 inch.

C. minus .001 inch.

A.8.0.4.4.A.1 A02

(1) Cast iron piston rings may be used in chrome plated cylinders.

(2) Chrome plated rings may be used in plain steel cylinders.

Regarding the above statements,

A. both No. 1 and No. 2 are true.

B. neither No. 1 nor No. 2 is true.

C. only No. 1 is true.

A.8.0.4.5.A.1 A02

How is proper end-gap clearance on new piston rings assured during the overhaul of an engine?

A. By using rings specified by the engine manufacturer.

B. By accurately measuring and matching the outside diameter of the rings with the inside diameter of the cylinders.

C. By placing the rings in the cylinder and measuring the end-gap with a feeler gauge.

A.8.0.4.6.A.1 A02

The volume of a cylinder equals 70 cubic inches when the piston is at bottom center. When the piston is at the top of the cylinder, the volume equals 10 cubic inches. What is the compression ratio?

A. 7:10.

B. 7:1.

C. 1:7.

A.8.0.4.7.A.1 A02

When cleaning aluminum and magnesium engine parts, it is inadvisable to soak them in solutions containing soap because

A. some of the soap will become impregnated in the surface of the material and subsequently cause engine oil contamination and foaming.

B. the soap can chemically alter the metals causing them to become more susceptible to corrosion.

C. the parts can be destroyed by dissimilar metal electrolytic action if they are placed together in the solution for more than a few minutes.

A.8.0.4.8.A.1 A03

What is the purpose of a power check on a reciprocating engine?

A. To determine if the fuel/air mixture is adequate.

B. To check magneto drop.

C. To determine satisfactory performance.

A.8.0.4.9.A.1 A03

What will be the likely result if the piston ring gaps happen to be aligned when performing a differential pressure compression check on a cylinder?

A. A worn or defective ring(s) indication.

B. The rings will not be seated.

C. Little or no effect.

A.8.0.5.0.A.1 A03

Which of the following will be caused by excessive valve clearance of a cylinder on a reciprocating aircraft engine?

A. A power increase by shortening the exhaust event.

B. Intake and exhaust valves will open early and close late.

C. Reduced valve overlap period.

A.8.0.5.1.A.1 A03

The floating control thermostat, used on some reciprocating engine installations, helps regulate oil temperature by

A. controlling oil flow through the oil cooler.

B. controlling air flow through the oil cooler.

C. recirculating hot oil back through the sump.

A.8.0.5.2.A.1 A03

Which of the following would indicate a general weak engine condition when operated with a fixed pitch propeller or test club?

A. Manifold pressure lower at idle RPM than at static RPM.

B. Lower than normal static RPM, full throttle operation.

C. Lower than normal manifold pressure for any given RPM.

A.8.0.5.3.A.1 A03

What is required by 14 CFR Part 43 Appendix D when performing an annual/ 100-hour inspection on a reciprocating engine aircraft?

A. Magneto timing check.

B. Valve clearance check.

C. Cylinder compression check.

A.8.0.5.4.A.1 A03

After spark plugs from an opposed engine have been serviced, in what position should they be reinstalled?

A. Swapped bottom to top.

B. Next in firing order to the one from which they were removed.

C. Next in firing order to the one from which they were removed and swapped bottom to top.

A.8.0.5.5.A.1 A03

As the pressure is applied during a reciprocating engine compression check using a differential pressure tester, what would a movement of the propeller in the direction of engine rotation indicate?

A. The piston was on exhaust stroke.

B. The piston was positioned past top dead center.

C. The piston was on compression stroke.

A.8.0.5.6.A.1 A03

Excessive valve clearance results in the valves opening

A. late and closing late.

B. early and closing late.

C. late and closing early.

A.8.0.5.7.A.1 A03

During routine inspection of a reciprocating engine, a deposit of small, bright, metallic particles which do not cling to the magnetic drain plug is discovered in the oil sump and on the surface of the oil filter. This condition

A. is probably a result of ring and cylinder wall wear and is cause for engine removal and/or overhaul.

B. may be a result of abnormal plain type bearing wear and is cause for further investigation.

C. is normal in engines utilizing plain type bearings and aluminum pistons and is not cause for alarm.

A.8.0.5.8.A.1 A03

A characteristic of dyna focal engine mounts as applied to aircraft reciprocating engines is that the

A. engine attaches to the shock mounts at the engine's center of gravity.

B. shock mounts eliminate the torsional flexing of the powerplant.

C. shock mounts point toward the engine's center of gravity.

A.8.0.5.9.A.1 A03

If metallic particles are found in the oil filter during an inspection,

A. the cause should be identified and corrected before the aircraft is released for flight.

B. it is an indication of normal engine wear unless the particles are nonferrous.

C. it is an indication of normal engine wear unless the deposit exceeds a specified amount.

A.8.0.6.0.A.1 A03

If the oil pressure gauge fluctuates over a wide range from zero to normal operating pressure, the most likely cause is

A. low oil supply.

B. air lock in the scavenge pump intake.

C. broken or weak pressure relief valve spring.

A.8.0.6.1.A.1 A03

What special procedure must be followed when adjusting the valves of an engine equipped with a floating cam ring?

A. Eliminate cam bearing clearance when making valve adjustment.

B. Adjust valves when the engine is hot.

C. Adjust all exhaust valves before intake valves.

A.8.0.6.2.B.1 A03

Which of the following is most likely to occur if an overhead valve engine is operated with inadequate valve clearances?

A. The valves will remain closed for longer periods than specified by the engine manufacturer.

B. The further decrease in valve clearance that occurs as engine temperatures increase will cause damage to the valve-operating mechanism.

C. The valves will not seat positively during start and engine warmup.

A.8.0.6.3.A.1 A03

Excessive valve clearances will cause the duration of valve opening to

A. decrease for intake valves and increase for exhaust valves.

B. increase for both intake and exhaust valves.

C. decrease for both intake and exhaust valves.

A.8.0.6.4.A.1 A03

What does valve overlap promote?

A. Better scavenging and cooling characteristics.

B. A backflow of gases across the cylinder.

C. Lower intake manifold pressure and temperatures.

A.8.0.6.5.A.1 A03

At what speed must a crankshaft turn if each cylinder of a four stroke cycle engine is to be fired 200 times a minute?

A. 1,600 RPM.

B. 400 RPM.

C. 800 RPM.

A.8.0.6.6.A.1 A03

Engine crankshaft runout is usually checked

1. during engine overhaul.

2. during annual inspection.

3. after a "prop strike" or sudden engine stoppage.

4. during 100-hour inspection.

A. 1 and 3.

B. 1, 3, and 4.

C. 1, 2 and 3.

A.8.0.6.7.B.1 A03

Before attempting to start a radial engine that has been shut down for more than 30 minutes,

A. turn the ignition switch on before energizing the starter.

B. turn the propeller by hand three or four revolutions in the opposite direction of normal rotation to check for liquid lock.

C. turn the propeller by hand three to four revolutions in the normal direction of rotation to check for liquid lock.

A.8.0.6.8.A.1 A03

An engine misses in both the right and left positions of the magneto switch. The quickest method for locating the trouble is to

A. check for one or more cold cylinders.

B. perform a compression check.

C. check each spark plug.

A.8.0.6.9.A.1 A03

A hissing sound from the exhaust stacks when the propeller is being pulled through manually indicates

A. exhaust valve blow by.

B. a cracked exhaust stack.

C. worn piston rings.

A.8.0.7.0.A.1 A03

If the oil pressure of a cold engine is higher than at normal operating temperatures, the

A. oil system relief valve should be readjusted.

B. oil dilution system should be turned on immediately.

C. engine's lubrication system is probably operating normally.

A.8.0.7.1.A.1 A03

If an engine operates with a low oil pressure and a high oil temperature, the problem may be caused by a

A. clogged oil cooler annular jacket.

B. sheared oil pump shaft.

C. leaking oil dilution valve.

A.8.0.7.2.A.1 A03

Which fuel/air mixture will result in the highest engine temperature (all other factors remaining constant)?

A. A mixture richer than a full rich mixture of .087.

B. A mixture leaner than a manual lean mixture of .060.

C. A mixture leaner than a rich best power mixture of .085.

A.8.0.7.3.A.1 A03

If an engine cylinder is to be removed, at what position in the cylinder should the piston be?

A. Bottom dead center.

B. Top dead center.

C. Halfway between top and bottom dead center.

A.8.0.7.4.A.1 A03

The horsepower developed in the cylinders of a reciprocating engine is known as the

A. shaft horsepower.

B. brake horsepower.

C. indicated horsepower.

A.8.0.7.5.A.1 A03

Engine operating flexibility is the ability of the engine to

A. deliver maximum horsepower at a specific altitude.

B. run smoothly and give the desired performance at all speeds.

C. meet exacting requirements of efficiency and low weight per horsepower ratio.

A.8.0.7.6.A.1 A03

Standard aircraft cylinder oversizes usually range from 0.010 inch to 0.030 inch. Oversize on automobile engine cylinders may range up to 0.100 inch. This is because aircraft engine cylinders

A. have more limited cooling capacity.

B. operate at high temperatures.

C. have relatively thin walls and may be nitrided.

A.8.0.7.7.A.1 A03

If the ignition switch is moved from BOTH to either LEFT or RIGHT during an engine ground check, normal operation is usually indicated by a

A. slight drop in RPM.

B. momentary interruption of both ignition systems.

C. large drop in RPM.

A.8.0.7.8.A.1 A03

During ground check an engine is found to be rough running, the magneto drop is normal, and the manifold pressure is higher than normal for any given RPM. The trouble may be caused by

A. several spark plugs fouled on different cylinders.

B. a dead cylinder.

C. a leak in the intake manifold.

A.8.0.7.9.A.1 A03

What is the best indication of worn valve guides?

A. Low oil pressure.

B. Low compression.

C. High oil consumption.

A.8.0.8.0.A.1 A03