1 Powerplant Written Review

Comprehensive practice questions covering engine inspections, fire protection, electrical systems, fuel metering, and induction based on lecture notes.

publication contains mandatory replacement time for turbine engine parts

Engine manufacturer's service instructions 

When inspecting an engine, document used to determine if proper magnetos are installed 

Aircraft Engine Specifications or TCDS 

document contains a table that lists specific engines which a propeller is adaptable 

Propeller TCDS

A Cessna 180 aircraft has a McCauley propeller damaged in a ground accident. If the exact model is not available for replacement, what is used to find an approved alternative replacement 

Aircraft Specifications or TCDS

Where are airworthiness standards found for issuance of type certificates for small airplanes with nine or less passenger seats in normal, utility, and acrobatic categories 

Part 23

When must a SB be complied with 

Only when it is referred to/mandated in an AD (or specifically required by operations specifications/regulations) 

Determine portion of AD applicable for a Model O-690 series engine, serial No. 5863-40 with 283 hours time in service. 

Line (B)(1). serial number falls between 5265-40 and 6129-40, and engine has more than 275 hours time in service, compliance is required within 25 hours after effective date and every 100 hours after 

AD applicability statement reading "Applies to all IVO-355 engines, serial Nos. T8000-T8300, having less than 2,400 hours total time"

apply to an IVO-355 engine, serial No. T8164, with 2,100 hours total time and 300 hours since rebuild

reciprocating engine using a shrouded exhaust muffler as a source for cabin heat, exhaust system must be 

Visually inspected for cracks or operational carbon monoxide detection test 

Indentations on bearing races caused by high static loads are 

Brinelling 

How is the flow range of fuel discharge nozzles in a fuel-injected engine indicated?

By a letter stamped on the hex of the nozzle body.

How is flow range of fuel discharge nozzles in a fuel-injected engine indicated 

By letter stamped on hex of nozzle body 

Serviceability limits for turbine blades are more stringent than turbine nozzle vanes

A limited number of small nicks and dents can be permitted in any area of a turbine blade

True. False

fire extinguisher container pressure limits when temp is 50°F 

$$475\text{--}625\text{ psig}$$

fire extinguisher container pressure limits when temp is 75°F 

$338\text{ psig}$ minimum and $424\text{ psig}$ maximum.

fuel or oil fire is 

Class B

fire involving energized electrical equipment is 

Class C

common type of portable fire extinguisher on the ramp for fires on the exterior of aircraft extinguishing agent 

Carbon dioxide

operating principle of a spot detector sensor in fire detection 

bimetallic thermoswitch closes a circuit when heated to a specific high temp 

continuous-loop fire detector is what type of detection 

Overheat detection

fire detection operates on rate-of-temperature-rise 

Thermocouple

fire detection use heat to test sensing element during cockpit test 

Thermocouple, Lindberg

fire detection detects fire even when sensing element is inoperative, will not test when cockpit test circuit is energized 

Kidde, Fenwal

how a Systron-Donner fire detector responds after fire is extinguished or overheat condition removed 

automatically resets

Fenwal physical construction 

single wire surrounded by continuous string of ceramic beads inside a tube 

Fenwal sometimes use spot detectors in parallel between two separate circuits 

to allow a single fault to occur without triggering a false alarm 

Kidde physical construction 

Two wires embedded in thermistor/ceramic core inside a tube 

Lindberg operating principle 

operates on buildup of gas pressure inside a sealed tube proportional to temp 

device used to convert AC induced into loops of the rotating armature of a DC generator to DC 

Commutator

If generator voltage will not build up when field is flashed, and solder is found on brush cover plate indicates 

open armature

As generator load increases (within rated capacity), voltage and amp output reaction 

Voltage- constant, amp- increases 

what output frequency of an AC generator (alternator) depends on 

speed of rotation, number of field poles 

Why do some engine-driven generators use constant-speed drive 

To control the speed of the alternator so it regulates to constant frequency (Hertz) output 

speed an eight-pole AC generator turns to produce 400 Hertz AC 

$$6,000\text{ RPM}$$

smallest terminal stud size allowed for aircraft electrical power 

No. 10

maximum number of electrical terminals connected to any single terminal stud 

Four

regarding wire terminals: 

Electrical wires larger than 10 gauge use uninsulated terminals.

Electrical wires smaller than 10 gauge use uninsulated terminals.

True. False

basic types of circuit breaker count used in powerplant electrical 

Three (Trip-free, Non-trip-free, Automatic reset) 

FAR requires aircraft using fuses as circuit protective devices carry "one spare set, or three spares of each kind" 

Part 91

When air passes through a carburetor venturi, three physical changes occur 

Velocity increases, temp and pressure decrease 

volume of air passing through a carburetor venturi is reduced, pressure at venturi throat 

increases 

three changes occur when a back-suction mixture control operates 

varies pressure on fuel in the float chamber to adjust fuel flow 

components control ratio and volume of the fuel-air mix delivered to cylinders 

Ratio: Mixture control. Volume: Throttle 

Where throttle valve is located on a float carburetor 

After main discharge nozzle and venturi (between venturi and engine) 

correct concerning idle system of a float carburetor 

low pressure between edges of the throttle valve and throttle body pulls fuel from the idle passage 

primary function of idling air bleed in a float carburetor 

aids emulsifying and vaporizing fuel at idle 

Float carburetors with economizers are configured to operate so 

They are set for leanest practical mix delivery at cruise and enriched by economizer at higher power 

function of metering orifice in main air bleed at a given altitude 

provides better fuel vaporization, controls fuel discharge at low engine speeds 

an engine with a float carburetor runs excessively rich at full throttle, likely cause is clogged 

Main air bleed 

an engine with a float carburetor backfires or misses when throttle is rapidly advanced, likely cause 

Accelerating pump not operating properly 

What is the primary difference between Teledyne-Continental and RSA continuous fuel injection systems?

Teledyne-Continental uses fuel pressure as the metering force.

precaution taken when applying thread lubricant to tapered pipe plug in a carburetor float bowl 

Engage first thread of plug bare, put small amount of lubricant on second thread, screw plug in 

an engine with a pressure carburetor, fuel supply is ensured when operating in idle range 

By a spring in the unmetered fuel chamber to supplement normal metering forces 

characteristic of metered fuel pressure (Chamber C) in an injection carburetor 

held constant through entire engine operating range 

engine with a pressure carburetor is normally started 

with primer while mix control is at idle cutoff 

if vapor vent float in a pressure carburetor loses buoyancy and sinks 

amount of fuel returning to fuel tank from the carburetor increases 

primary difference between Teledyne-Continental and RSA continuous injection 

Teledyne-Continental uses fuel pressure as metering force 

system abnormality is least likely to occur during operation of engine with direct cylinder fuel injection 

Backfire 

function of altitude compensating (aneroid) valve used with Teledyne-Continental injection on turbocharged engines 

Prevents an overly rich mix during sudden acceleration 

regarding mix richness in air-cooled reciprocating engines: 

mix at rated power is richer than mix through normal cruise

mixture at idle is richer than mix at rated power

True. True

Maximum power is considered to be developed in a reciprocating engine with air-fuel mixture ratio of 

12:1

type of mix change is caused by using less-than-normal throttle opening during engine start 

rich mix 

would cause a chronically lean mix and high cylinder head temp operating at sea level or low altitude 

automatic mixture control stuck in extended position 

condition an engine runs lean even though there is a normal volume of fuel in the carburetor 

Incomplete fuel vaporization 

Excessively rich or lean idle mix result in 

Incomplete combustion 

indication shows optimum idle mix obtained during engine check 

with mix control moved slowly to IDLE CUTOFF, manifold pressure decreases slightly, RPM increases momentarily before engine ceases 

If an engine will not idle, likely fuel system cause 

economizer valve not operating correctly 

Detonation occurs when air-fuel mix 

Burns too fast 

density of air is critical for correct fuel metering. air sample weighs the most 

100 parts dry air 

describes basic function of altitude mix control 

regulates richness of fuel-air charge entering engine to compensate for decreased air density at altitude 

fuel systems of aircraft certificated in standard classification must include a mechanical feature 

positive means of shutting off fuel to all engines 

FAR requirement for fuel flow rate capability of a gravity-feed fuel system 

must be capable of 150% of takeoff fuel consumption 

Where main fuel strainer or filter is located in the fuel system 

Between fuel tank outlet and fuel metering device 

common large aircraft reciprocating engines engine-driven fuel pump 

rotary vane (requires pressure relief valve) 

When an electric primer is used to start an engine, how is required fuel pressure built up 

By electric booster (auxiliary) pump 

Fuel pump relief valves designed to compensate for atmospheric pressure variations are 

Balanced relief valves 

location a fuel pump relief valve directs excess bypassed fuel 

Back to inlet side of fuel pump 

pilot reports fuel pressure fluctuates wildly and exceeds upper design limits when throttle is advanced. likely cause 

sticking fuel pump relief valve 

period an engine-driven fuel pump internal bypass valve opens and remains open 

When boost pump pressure is greater than engine-driven fuel pump discharge pressure (during engine start or engine pump failure) 

purpose of engine-driven fuel pump bypass valve 

prevents damaged or inoperative pump blocking fuel flow of another auxiliary pump in series 

statement with centrifugal fuel boost pump in a fuel tank is NOT true 

centrifugal pump is classified as positive displacement 

purpose of fuel transfer ejectors in a fuel tank 

To assist in continuous transfer of fuel from main tank cavity into boost pump sump 

Why kerosene is preferred over avgas as turbine engine fuel 

contains more heat energy per gallon and lubricates internal fuel system components 

it is necessary to control acceleration and deceleration rates via fuel control unit on turbine engines 

To prevent compressor blowout or combustion die-out 

When trimming a turbine engine fuel control, parameters to adjust 

idle RPM, maximum speed, Engine Pressure Ratio 

atmospheric condition must be verified prior to performing turbine engine trimming 

Obtain true ambient temp reading comparable to air entering engine inlet 

functional operational difference between an Electronic Engine Control and a Full-Authority Digital Engine Control 

Standard EEC: Receives operational data and electronically adjusts a hydromechanical fuel control unit. 

FADEC: Receives all operational data, develops commands to actuators to control engine parameters 

As engine manifold pressure increases, what happens to air in the cylinder 

density of air in cylinder increases 

On small reciprocating engines, fuel vaporization is artificially increased within induction 

By circulating fuel-air mix through intake passages routed through warm engine oil sump 

reciprocating engine induction when de-icing alcohol is injected with a fluid system 

Into airstream directly ahead of carburetor 

common maintenance factor in failure of an engine to develop full rated power during takeoff 

Improper adjustment or rigging of carburetor heat valve control linkage 

in a turbocharge system when waste gate is completely closed 

All exhaust gas is directed through the turbine wheel 

purpose of intercooler in conjunction with super or turbocharger 

To cool compressed air entering carburetor or fuel metering device from turbocharger discharge 

three primary regulating control components of a sea-level boosted turbocharge system 

exhaust bypass valve (waste gate), density controller, differential pressure controller 

function of Density Controller in a turbocharge system 

limits maximum manifold pressure produced by turbocharger at full throttle 

function of Rate-of-Change Controller in a turbocharge system 

controls rate the turbocharger discharge pressure is allowed to increase 

function of Differential Pressure Controller in a turbocharge system 

reduces tendency for "bootstrapping" during part-throttle, controls all positions of waste gate except when fully open 

percentage of total heat energy generated by combustion is carried out of reciprocating engine with exhaust gas 

greatest portion of heat generated by combustion is carried out with the exhaust 

specific part of air-cooled engine cylinder features greatest cooling fin area per square inch 

exhaust valve port 

How reciprocating engines in helicopters are supplied with cooling airflow 

By continuous cooling fan mounted directly to and driven by the engine