Book Questions Flashcards
which statement is true regarding bearings used in high powered reciprocating aircraft engines?
There is less rolling friction when ball bearings are used than when roller bearings are employed.
a condition that can occur in Radial engines but is less likely to occur in horizontally opposed engines is…?
hydraulic lock
which condition would be least likely caused by failed or failed engine bearings?
Low oil temps
what is the principal advange of using propeller reduction gears?
to enable the engine RPM to be INCREASED with an accompanying INCREASE in power and allow the propeller to remain at a LOWER RPM
which will decrease volumetric efficiency in a reciprocating engine?
improper valve timing, sharp bends in the induction system and high carb air temps
which is a charastic of a thrust bearing used in most radial engines?
Deep-Groove Ball
which bearing is least likely to be a roller or ball bearing?
Master Rod Bearing (radial engine)
the operating temp valve clearance of a radial engine as compared to a cold valve clearance is?
Greater
a 9 cylinder engine with a bore of 5.5” and a stroke of 6” will have a total piston displacement of?
1,283 cubic inches
the distance that is known as one half of the diameter is ?
radius
there are 5 events in a 4 stroke cycle enginem the order of their occurrance is?
intake, compression, ignition, power, exhaust
the primary concern in establishing the firing order for an opposed engine is to?
provide for balance and eliminate vibration to the greatest extent possible
If fuel/air ratio is proper and ignition timing is correct, the combustion process should be completed?
Just after top (dead) centre at the beginning of the power stroke
Grinding the valves of a reciprocating engine to a feather edge is likely to result in?
Pre ignition and burnt valves
Which statement is correct regarding engine crankshafts?
Movable counterweights serve to reduce the torsion of vibrations in an aircraft Reciprocating engine
On which strokes are both valves on a four stroke cycle reciprocating aircraft engine open?
Exhaust and intake
Which type of roller bearings are generally used for connecting rods and camshafts?
plain
What is the actual power delivered to the propeller of an aircraft engine called?
brake horsepower
Turbo prop engines measure power produced with a torque meter, and it is proportional to what type of piston engine horsepower?
Brake horsepower
Cam-ground pistons are installed in some aircraft engines to?
Provide a better fit at operating temperatures
Some aircraft engine manufacturers equipped their product with choked or taper-ground cylinders in order to?
Provide a straight cylinder bore at operating temperatures
What tool is generally used to measure the crankshaft rotation in degrees?
timing disk
If an engine with a stroke of 6” inches operated at 2000 RPM, the piston movement within the cylinder will be?
At maximum velocity, 90 degrees after tdc
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?
During normal operation
Using the following information, determine how many degrees the crankshaft will rotate with both the intake and exhaust evolves seated(CLOSED)…
Intake valve opens at 15’ BTDC
Exhaust opens 70’ BBDC
Intake closes 45’ ABDC
Exhaust closes 10’ ATDC
245 degrees
If the intake valve is opened too early in the cycle of operation of a 4 stroke cycle engine, it may result in?
Backfiring into the induction system
Some cylinder barrels are hardened by?
Nitriding
Which statement is correct regarding a four stroke cycle aircraft engine?
The intake valve closes on the compression stroke
On which part of the cylinder walls of a normally operating engine with the greatest amount of wear occur?
Near the top of the cylinder
During overhaul reciprocating engine exhaust valves are checked for stretch with?
With a contour or radius gauge
When is the fuel/air mixture ignited in a conventional reciprocating engine?
Shortly before the piston reaches the top of the compression stroke
What is the purpose of a safety circlet (circlip) installed on some valve stems?
To prevent valves from falling into the combustion chamber
Valve overlap is defined as the number of degrees of crankshaft travel during?
During which both valves are off their seats
ingition occurs at 28’ BTDC on a certain 4 stroke cycle engine, and the intake valve opens at 15’ degrees BTDC. How many degrees of crankshaft travel after ignition does the intake valve open? Consider one cylinder only)
373 degrees
The valve clearance of an engine using hydraulic lifters when the lifters are completely flat, or empty, should not exceed?
A specified amount above 0
If the exhaust valve of a 4 stroke cycle engine is closed and the intake valve is just closing, the piston is on the?
Compression stroke
Which of the following are factors in establishing the maximum compression ratio limitations of an aircraft engine?
Detonation characteristics of the fuel, design limitations of the engine, and the degree of supercharging
Full floating piston pins are those which allow motion between the pin and what?
Both the piston and the small end of the connecting rod
The primary purpose in setting proper valve timing and overlap is to?
Obtain the best volumetric efficiency and lower cylinder operating temperatures
If the hot clearance is used to set the valves when the engine is cold, what will occur during operation of the engine?
The valves will open late and close early
What is the purpose of installing two or more springs on each valve in an aircraft engine?
To eliminate valve spring vibration or surging
During overhaul, the disassembled parts of an engine are usually degreased with some form of a mineral spirit solvent rather than water-mixed degreasers primarily because?
Water-mixed degreaser residues may cause engine oil contamination in the overhauled engine
Why does the smoothness of operation of an engine increase with the greater number of cylinders?
The power impulses are spaced closer together
Compression ratio is the ratio between?
Cylinder volume with piston at bottom dead centre and at top dead center
If the crankshaft runout readings on the dial indicator are plus 0.002 inch and minus 0.003 inch the runout is?
0.005 inch
(1) Cast iron piston rings may be used in chrome plated cylinders.
(2) Chrome plated rings may be used in plain steel cylinders.
Both 1 and 2 are true
How is proper edge clearance on new pistons ring assured during the overhaul of an engine?
By placing the rings in the cylinder and measuring the end gap with a feeler gauge
When cleaning aluminium and magnesium engine parts, it is inadvisable to soak them in solutions containing soap because?
Some of the soap will become impregnated in the surface of the material, and subsequently cause engine oil contamination and foaming
What is the purpose of a power check on a reciprocating engine?
To determine satisfactory performance
What will be the likely result if the piston ring gaps happen to be aligned when forming a differential pressure compression check on a cylinder?
a worn or defective ring(s) indication
The volume of a cylinder equals 70 cubic inches when the piston is at bottom dead centre. When the piston is at top of the cylinder, the volume equals 10 cubic inches.
What is the compression ratio?
7:1
Which of the following will be caused by excessive valve clearance of a cylinder on a reciprocating aircraft engine?
Reduced valve overlap period
The floating control thermostat used on some reciprocating engine installations helps regulate oil temperature by?
Control the air flow through the oil cooler
Which of the following would indicate a general weak engine condition when operated with a fixed-pitch propeller or test club.
Lower the normal static RPM, full throttle operation
What is required by 14 CFR (FAR) Part 43 Appendix D when performing an annual 100 hour inspection on a reciprocating engine?
cylinder compression check
During a 100 hour inspection, what must be checked/performed?
Oil screen check
During a 100 hour inspection of a starter generator, what is NOT an inspection item?
Shaft bearing condition
During a 100 hour inspection for starter generators, what are two inspection requirements?
1. Oil leakage
2. Shaft bearing condition
3. Commutator wear and pitting
- Oil leakage
& - Commutator wear and pitting
After spark plugs from an opposing engine have been serviced, in what position should they be reinstalled?
Next in firing order to the one from which they were removed and swapped bottom to top.
as the pressure is applied during a reciprocating engine compresson check using a differential pressure tester, what would the movement of the propeller in the direction of engine rotation indicate?
The pistion was positioned past top dead center.
excessive valve clearance results in the valves opening?
late and closing early
during routine inspection of a reciprocating engine, a deposit of small, bright metallic particles which do not cling to the magnetic drain plus is discovered in the oil sump and on the surface of the oil filter. this condition….
may be a result of abnormal plain type bearing wear and is cause for further investigation.
a characteristic of dyna-focal engine mounts as applied to an aircraft reciprocating engines is that the…?
the shock mounts point towards the engines center of gravity
if metallic particals are found in the oil filter during inspection…?
the cause should be identified and corrected before the aircraft is released for flight.
if the oil pressure gauge fluctuated over a wide range from zero to normal operating pressure, the most likely cause is….?
low oil supply
what special procedure must be followed when adjusting the valves of an engine equipped with a floating cam ring?
eliminate cam bearing clearance when making a valve adjustment
which of the following is most likely to occur if an overhead valve engine is operated with inadequate valve clearances?
the valves will not seat positively during start and engine warm up
excessive valve clearances will cause the duration of the valve opening to…?
decrease for both intake and exhaust valves
what does valve overlap promote?
better scavenging and cooling characteristics
what speed must a crankshaft turn if each cylinder of a 4 stroke cycle engine is to be fire 200 time a minute?
400RPM
engine crankshaft runout is usually checked…?
during engine overhaul and after a ‘prop strike’ or sudden engine stoppage
before attempting to start a radial engine, that has been stut down for 30 mins…?
turn the propeller by hand 3 - 4 revolutions in the normal direction of rotation to check for fluid lock.
an engine misses in both right and left positions of the magneto switch. the quickest method for locating the trouble is to…?
check for one or more cold cylinders
a hissing from the exhaust stacks when the propleer is being pulled through manually indicates?
Exhaust valve blow-by
if the oil pressure of a cold engine is higher than at normal operating temps, the…?
engines lubrication is probably not operating normally
if an engine operates with low oil pressure and high oil temps, the problem meay be caused by a…?
leaking oil dilution valve
which fuel/air mixture will result in the highest engine temp (all other factors constant)?
a mixture leaner than a manual mixture of 0.060
If an engine cylinder is to be removed, at what position in the cylinder should the piston be?
Top Dead Center TDC
the horsepower developed in the cylinders of a reciprocating engine is known as ?
indicated horsepower
the theoretical horsepower a reciprocating engine develops is?
IHP indicated horsepower
engine operating flexability is the ability of the engine to..?
run smoothly and give the desired performance at all speeds
Standard aircraft cylinder oversizes usually range from 0.010” to 0.030”. oversizes on automobile engine cylinders may range up to 0.100”. this is because the aircraft engine cylinders …?
have relatively thin walls and may be nitrided
if the ingition switch is moved from BOTH to either LEFT or RIGHT during an engine ground check, normal operation is usually indicated by a slight…?
drop in torque meter pressure indication
during ground check an engine is found to be running rough, the magneto drop is normal, and the manifulf pressure is higher than normal for any given RPM. The trouble may be caused by…?
a dead cylinder
what is the best indication of worn valve guides?
high oil consumption
by use of a differencial pressure tester, it is determined that cylinder 3 of a 9 cylinder radial engine will not hold pressure after the crankshaft has been rotated by 260 degrees from top dead center compression stroke cylinder 1. how can this indication usually be interpreted?
by a normal indication
when does valve overlap occur in the operation of an aircraft reciprocating engine?
at the end of the exhaust stroke and at the beginning of the intake stroke
what is the advantage of metalic-sodium filled exhaust valves in aircraft reciprocating engines
reduce valve operating temps
valve clearance changes on opposed type engines using hydraulic lifters are accomplished by?
push rod replacement
what is likely to occur if a reciprocting engine is operated at high power settings before it is properly warmed up?
Oil starvation of bearings and other parts
An INCREASE of manifold pressure with a constant RPM will cause the bearing load in an engine to…?
INCREASE
direct mechanical push pull carb heat control linkages should normally be adjusted so that the stop located on the diverter valve will be contacted…?
before the stop at the control lever is reached in both HOT and COLD positions
reduced air density at high altitude has a decided effect on carburetion, resulting in a reduction of engine power by?
excessively enriching the fuel/air mixture
increased water vapor (higher relative humidity) in the incoming air to a reciprocating engine will normally result in which of the following…?
decreased engine power at a constant RPM and manifold pressure
which of the following engine servicing comditions generally requires engine pre-oilling prior to starting the engine?
engine installion
during the inspection of the engine control system in which push-pull control rods are used, the threaded rod ends should…?
be checked for the amount of thread engagement by means of inspection holes
which of the following conditions would most likely lead to detonation?
use of fuel with too LOW octane rating
an unsupercharged aircraft reciprocating engine, operated at full throttle from sea level, to 10,000ft, provided the RPM is unchanged, will…?
lose power due to reduced density of the air drawn into the cylinders
which of the following would most likely cause a reciprocating engine to backfire through the induction system at low RPM operation?
lean mixture
how may it be determined that a reciprocating engine with a dry sump is pre-oiled sufficiently?
oil will flow from the engine return line or indicator port
what is the basic operating sequence for reducing the power output of an engine equipped with a constant speed propeller?
reduce the manifold pressure then the RPM
(1) preignition is caused by improper ignition timing
(2) detonation occurs when an area of a combustion chamber becomes incandescent and ignites the fuel/air mixture in advance of normal times ignition
NEITHER 1 Nor 2 is true
which statement pertaining to fuel/air ratios is true?
the mixture ratio which gives the best power is richer than the mixture ratio which gives max economy
what is meant by 1:15 air/fuel ratio?
too rich to fly
a reciprocating engine with a fuel/air ratio at more than 15 parts air to 1 part fuel by weight is…?
too lean to fly
what is the best fuel/air ratio for creating power?
1:15
backfiring through the carb generally results from the use of…?
an excessively lean mixture
which of these conditions will cause an engine to have an increased tendency to detonate?
High manifold pressure or high intake air temps
OR
Engine overheated
when will small induction air leaks have the most noticable effect on engine operation?
at low RPM
one of the best indicators of a reciprocating engine combustion chamber problem is…?
spark plug condition
to reduce the power output of an engine equipped with a constant speed propeller and operating near maximum BMEP, the…?
Manifold pressure is reduced with the throttle control before the RPM is reduced with the propeller control.
what would cause excessive pressure build up in the crankcase in a reciprocating engine?
Plugged crankcase breather
excessive valve clearance in a piston engine …?
decreases valve overlap
to what alitiude will a turbo charged engine maintain sea level pressure…?
critical altitude
if air is heard coming from the crankcase breather or oil filler during a differencial pressure check, what is this an indication of?
pistion ring leakage
one cause of afterfiring in an aircraft engine is?
an excessively rich mixture
afterfiring in aircraft engine may be caused by…
1. overly rich fuel mixture.
2. faulty spark plugs.
3.
4. defective fuel-injection nozzels
5. incorrect valve clearance
1, 2, 4, 5
On a reciprocating engine aircraft using a shrouded exhaust muffler system as a source for cabin heat, the exhaust system should be?
Visually inspected for any indication of cracks or an operational carbon monoxide detection test should be done
What is the result of an exhaust muffler internal failure in a small reciprocating engine?
Partial or total blockage of flow of exhaust gases resulting in engine failure.
- Airworthiness directives are federal aviation regulations and must be complied with unless specific exemption is granted.
- Airworthiness directives of an emergency nature may require Immediate compliance upon reciept.
BOTH 1 and 2 are true
Which of the following contains a minimum checklist for 100-hour inspection of engines?
14 CFR (FAR) Part43 Appendix D
When must an airworthiness directive (AD) be completed after it becomes effective?
As specified in the AD
Which of the following contains a table that lists the engines to which a given propeller is adaptable?
Propeller type certificate data sheet
Which of the following component inspections is to be accomplished on a 100 hour inspection?
Check Cylinder Compression
You are performing a 100 hour inspection on a R985-22 aircraft engine. What does ‘985’ indicate?
Total piston displacement of the engine
Straightening nitrided crankshafts is?
NOT recommended
The breaking loose of small pieces of metal from coated surfaces, usually caused by defective plating or excessive loads, is called?
Flaking
Each powerplant installed on an airplane with a standard airworthiness certificate must have been?
Type Certificated
A Severe condition of chafing or fretting in which a transfer of metal from one part to another occurs is called… what?
Galling
Indentations on bearing races caused by high static loads are known as
Brinelling
Where would you find type design information for an R1830-92 engine certificated under the Civil Air Regulation (CAR) and installed on a DC-3?
The Aircraft Engine Specifications
When inspecting an aircraft reciprocating engine what document is used to determine if the proper magnetos are installed?
Aircraft engine specifications or type certificate data sheet
Which of the following can inspect and approve an engine MAJOR repair for its return to service?
Certified mechanic with inspection authorisation
What publication is used for guidance to determine whether a powerplant repair is major or minor?
14 CFR Part 43
During a 100 hour inspection on a wooden propeller, you find it is necessary to replace the laminate, this is a…?
Minor maintenance
The airworthiness standards for the issue of type certificates for small airplanes with nine or less passenger seats in the normal, utility, and acrobatic categories may be found in the?
14 CFR Part 23
Which of the following contains approved data for performing major repair to an aircraft engine?
The manufacturer’s maintenance instructions when FAA approved
What maintenance records are required following a major repair of an aircraft engine?
Entries in the engine maintenance record and FAA Form 337
A ground incident that results in propeller sudden stoppage would require a crankshaft runout inspection. What publication would be used to obtain crankshaft runout tolerance?
Current manufacture maintenance instructions
Sudden stoppage occurs when one or more of the propeller blades strike an object in such a way that the revolutions per minute RPM?
Drops to zero in less than one revolution
The fuel flow meter used with the continuous fuel injection system installed on an aircraft horizontally opposed reciprocating engine measures the fuel pressure drop across the??
fuel nozzles
Which unit most accurately indicates fuel consumption of a reciprocating engine?
Fuel Flow Meter
Turboprop engines indicate power produced using measurement by a?
Torque Meter
Which of the following conditions is usually not acceptable to any extent in turbine blades?
Cracks
How is the flow range of the fuel discharge nozzles installed in a fuel injected reciprocating engine indicated
By a letter stamped on the hex of the nozzle body
What section in the Instructions for Continued Airworthiness (ICA) is faa approved?
Airworthiness limitation section
What publication contains the mandatory replacement time for parts of a turbine engine?
Engine manufacture service instructions
Select the airworthiness directive applicability statement which applies to an IVO 355 engine serial number T8164 with 2100 hours total time, and 300 hours since rebuilding?
Applies to all IVO 355 engines, Serial numbers T8000 through T8300, having less than 2400 hours total time.
- Serviceability limits for turbine blades are much more stringent than those for turbine nozzle vanes. ✔️
- A limited number of small nicks and dents can usually be permitted in any area of the turbine. ❌️
ONLY 1 is true
The principal fault in the pressure type. Fuel flow metre indicating system installed on a horizontally opposed continuous flow fuel injected aircraft reciprocate engine, is that a plugged fuel injection nozzle will cause a??
Higher-than-normal fuel flow indication
Motor-driven impeller and turbine fuel flow transmitters are designed to transmit data…using?
Using aircraft electrical system power
The fuel flow indicator rotor and needle for a motor-impeller and turbine indicating system is driven by?
An electrical system
On a twin-engine, aircraft with fuel injected reciprocating engines, one fuel flow indicator reads considerably higher than the other in all engine operating configurations. What is the probable cause of this indication?
One or more fuel nozzles are clogged
The fuel flow indication system used with many fuel injected opposed engine airplanes utilizes a measure of?
Fuel pressure
The fuel flow indication and data sent from motor driven impeller and turbine, and motor less type fuel flow transmitter is a measure of?
Fuel mass flow
In addition to fuel quantity, a computerised fuel system (CFS) with a totalizer-indicator provides indication of how many of the following…?
1. Fuel Flow Rate
2. Fuel since reset or inital startup
3. Fuel time remaining at current power setting
4.
3
If an aircraft equipped with a pressure drop type fuel flow indicating system, if one of the injector nozzles becomes restricted, this would cause a decrease in fuel flow with?
An increased fuel flow indication on the gauge
A manifold pressure gauge is designed to?
Indicate absolute pressure in the intake manifold
The purpose of an exhaust guess analyzer is to indicate?
fuel/air ratio being burnt in the cylinders
Which of the following types of electric motors are commonly used in electric tachometers?
Synchronous motors
Where are the hot and cold junctions located in an engine cylinder temperature indicating system?
The hot junction is located at the cylinder and the cold junction is located at the instrument
Basically, the indicator of a tachometer system is responsive to change in what?
Frequency
Which statement is correct concerning a thermocouple-type temperature indicating instrument system?
It requires no external power source
Which statement is true regarding a thermocouple-type cylinder head temperature measuring system?
The voltage output of thermocouple system is determined by the temperature different between the two ends of the termocouple
The basic meter used to indicate cylinder head temperature in most aircraft is?
Galvanometer
Which of the following is a primary engine instrument?
Tachometer
A complete break in the line between the manifold pressure gauge and the induction system will be indicated by the gauge registering what?
Prevailing atmospheric pressure
Engine oil temperature gauge indicates the temperature of the oil?
Entering the engine
Why do helicopters require a minimum of two synchronous tachometer systems?
One indicated engine RPM and the other main rotor RPM
If thermocouple leads were inadvertently crossed at installation, what would the temperature gauge pointer indicate?
Moves off-scale on the zero side of the meter
A common type of electrically operated oil temperature gauge utilizes?
Either a wheat stone bridge or ratiometer circuit
The indication on a thermocouple type cylinder head temp indicator is produced by?
A current generated by the temperature difference between dissimilar metal hot and cold junctions
- How can an instrument range market show whether the current state of powerplant operation is normal, acceptable for a limited time, or unauthorised?
- Powerplant instrument range markings are based on the installed engine operating limits, which may not exceed (but I’ll not necessarily equal to) those limits shown on the engine types certificate data sheet.
BOTH 1 and 2 are true
Thermocouple leads?
Are designed for a specific installation and may not be altered
Thermocouple leads are used to measure cylinder temperatures on an aircraft reciprocating engine and are?
Connected to the electrical wiring on one end and cylinder on the other
- Engine pressure ratio EPR is a ratio of the exhaust gas pressure to the engine in the air pressure and indicates thrust produced? ✔️
- Engine pressure ratio EPR is a ratio of the exhaust pressure to the inlet air pressure and indicates volumetric efficiency?❌️
ONLY 1 is true
What unit in a tachomater system sends information to the indicator?
The three phase AC motor
Engine pressure ratio is determined by ?
Dividing turbine outlet pressure by engine total inlet pressure
Turbine engine EGT thermocouples are constructed of?
Chromel and alumel
Which of the following instrument discrepancies require replacement of the istrument?
Glass Cracked, Will not Zero out, Pointer loose on shaft, Fogged
- Generally, when a turbine engine indicates high EGT for particular EPR (when there is no significant damage), it means that the engine is out of trim. ✔️
- Some turbine powered aircraft use RPM as the primary indicator of thrust produced, others use EPR as a primary indicator. ✔️
BOTH 1 and 2 are true
Bourdon tube instrument may be used to indicate?
Pressure and temp
An indication of unregulated power changes that result in continual drift of manifold pressure indication on a turbo supercharged engine is known as what?
Bootstrapping
Which of the following instrument conditions is acceptable and does not require immediate action?
Case paint chipped
A change in engine manifold pressure has a direct effect on the?
Mean effective cylinder pressure
The EGT gauge used with a reciprocating engine is primarily used to furnish temperature readings in order to?
Obtain the best mixture for setting fuel efficiency
A red triangle dot or diamond mark on an engine instrument face or glass indicates?
The maximum limit for high transients such as starting
Which of the following fire detection systems are commonly used in an engine nacelle?
Kiddle continious-loop
What is the function of a fire detection system?
To activate a warning device in the event of a powerplant fire
How does carbon dioxide extinguish and aircraft engine fire?
Contact with the air converts the liquid into snow and gas that smothers the flame
What retains the nitrogen charge and fire extinguishing agent in a high rate discharge HRD container?
Breakable and fusable disks.
A continuous loop fire detector is what type of detector?
Overheat detector
(Refer to figure 2) Determine the fire extinguisher container pressure limits when the temperature is 75F?
338 minimum and 424 maximum
What is the operating principle of the spot detector sensor in a fire detection system?
A bimetalic thermoswitch that closes when heated to a high temperature
How is the fire-extinguishing agest distributed in an engine section?
Spray nozzles and perforated tubing
Which of the following is the SAFEST fire-extinguishing agent to use from a stand point if toxicity and corrosion hazards?
Bromochlorofifluoromethane (Halon 1301)
Which of the following fire extinguishing agests is best for preventing reflash?
Bromochlorodifluoromethane (Halon 1211)
Which of the following is NOT used to detect fires in reciprocating engine nacelles?
Smoke detectors
What is the principle of operation of the continuous loop fire detection system sensor?
Core resistant materials which prevents current flow at normal temps
The most satisfactory fire extinguishing agent for a tailpipe or intake fire is?
Carbon Dioxide
The explosive cartridge in a discharge valve of a fire extinguisher container is?
a life dated unit
Why does one type of fenwal fire detection system used spot detectors wired in parallel between 2 separate circuits?
So that a single fault may exist in the system without sounding a false alarm
Which of the following fire protection systems measures temperature rise compared to a reference temperature?
Thermocouple
The pulling out or down of an illuminated fire handle in a typical large jet aircraft fire protection system commonly accomplishes what events?
Closes fuel shut off, closes hydraulic shut off, disconnect the generator field, and arms the fire extinguishing system.
A fire detection system operates on the principle of a build up of gas pressure within a tube proportional to temperature. Which of the following systems does this statement define?
Lindberg continious element system
The fire detection system that uses a single wire surrounded by a continuous string of ceramic beads in a tube is the?
Fenwal system
The fire detection system that uses TWO wires embedded in a ceramic core within a tube is the?
Kidde System
A fuel or oil fire is defined as a?
Class B fire
A fire detection system that operates on the rate of temp rise is a?
Thermocouple system
a fire involving an energised electrical equipment is defined as a?
Class C fire
Two continuous loop fire detection systems that will not test due to a broken detector element are the?
Kidde and Fenwal system
Which statement best describes the blowout type indicator disc on a fixed fire extinguishing system?
When the yellow indicator disk is missing, it indicates the fire extinguishing system has been normally discharged.
The most satisfactory extinguishing agent for en electrical fire is?
Carbon dioxide
Which of the following fire detection systems will detect a fire when an element is inoperative but will not test when the test circuit is energized?
The Kidde and Fenwal System
Which of the following fire detection systems uses heat in the normal testing of the system?
Thermocouple and Lindberg system
After a fire is extinguished or overheat condition removed in an aircraft equipped with a systron-donor fire detector, the detection system…?
will automatically reset
The use of water on class D fires will…?
Will cause the fire to burn more violently and can cause explosions
For fire detection and extinguishing purposes, aircraft power plant areas are divided into fire zones based on?
The volume and smoothness of the air flow through engine compartments
(Refer to Fig 3) What are the fire extinguisher container pressure limits when the temperature is 50F?
475 - 625 PSIG
What device is used to convert alternating current, which has been induced into the loops of the rotating armature of a dc generator, to direct current?
A Commutator
A certain direct current series motor mounted within an aircraft draws more amperes during startup than when running under its rated load. The most logical conclusion that may be drawn is?
The condition is normal for this type of motor.
The statonary field strength in a direct current generator is varied according to?
According to the load requirements
what type of electric motor is generally used with a direct-cranking engine starter?
Direct current, series-wound motor
upon what does the output frequency of an AC generator (altenator) depend?
The speed of rotation and the number of field poles
A high surge of current is required when a d c electric motor is first started. As the speed of the motor increases?
The counter EMF builds up and opposes the applied EMF, thus reducing the current flow through the armature
Alternators (AC generators) that are driven by a constant speed drive CSD mechanism are used to regulate the alternator to a constant?
Hertz output
What is used to polish commutators or slip rings?
Double-zero sandpaper
If a generator is malfunctioning, its voltage can be reduced to residual or by actuating the?
Generator master switch
If the points in a vibrator-type voltage regulator stick in the closed position while the generator is operating, what will be the probable result?
Generator voltage output will increase
Why is a constant speed drive used to control the speed of some aircraft engine driven generators?
So the frequency of the alternating current output will remain constant
According to the electron theory of the flow of electricity, when a properly functioning DC alternator and voltage regulating system is charging an aircrafts battery, the direction of the current flow through the battery is?
is into the negative terminal and out of the positive terminal
Aircraft that operate more than one generator connected to a common electrical system must be provided with?
Individual generator switches that can be operated from the cockpit during flight
The most effective method of regulating aircraft direct current generator output is to vary, according to load requirements , the?
Strength of the stationary field
electric motors are often classified according to the method of connecting the field coils and armature. Aircraft engine starter motors are generally of which type?
Series
As the generator load is increased (within its rated capacity) the voltage will?
Remain constant and the amperage output will increase
As the flux density in the field of a DC generator increases and the current flow to the system increases?
The force required to turn the generator increases
What is the purpose of a reverse-current cutout relay?
It opens the main generator circuit whenever the generator voltage drops below the battery voltage/
Generating voltage will not build up when the field is flashed and soldier is found on the brush cover plate. these are most likely indications of?
an open armature
Why is it unnecessary to flash to field of the exciter on a brushless alternator?
Permenant magnets are installed in the main field poles
How are rotor windings on an aircraft alternator usually excited?
By variable direct current
What precaution is usually taken to prevent electrolyte from frozen in lead acid batteries?
Keep the battery fully charged
What is the amphour rating of a storage battery that is designed to deliver 45 amps for 2.5 hours?
112.5 ampere hour
How many hours will a 140 ampere-hour battery deliver 15 amps?
9.33 hours
How many hours can a 130 ampere-hour battery deliver 12 amps?
10.83 hours
What is a basic advantage of using AC for electrical power for a large aircraft?
AC systems operate at a higher voltage than DC systems and therefore use LESS CURRENT and can use smaller and lighter weight wiring
The wiring OEM colour code on civilian aircraft will have what result with a military technician?
Can cause problems (colour code are different)
What are the two types of AC motors that are used to produce a relatively high torque?
Three phase induction and Capacitor start
- Alternators are rated in volt amps, which is a measure of the apparent power being produced by the generator. ✔️
- Alternating current has the advantage over direct current in that its voltage and current can easily be stepped up or down. ✔️
BOTH 1 and 2 are true
What is the frequency of most aircraft alternating current?
400 hertz
The reason for flashing the field in a generator is to?
Restore residual magetism to the field frame
The part of a DC alternating power system that prevents reverse flow of current from the battery to the alternator is the?
Rectifier (Diode)
The part of a DC alternating power system that prevents reverse flow of current from the battery to the alternator is the?
DIODE (Rectifier)
The generating system of an aircraft charges the battery by using?
Constant voltage and varying current
The constant current method for charging a nickel-cadmium battery is the?
is the Most effective method in maintaining cell balance
Which of the following aircraft circuits does NOT contain a fuse/circuit breaker?
Starter circuit… does NOT contain a fuse /circuit breaker
The max number of terminals that may be connected to any one terminal stud in an aircraft electrical system in ?
FOUR …. 4
What is the max number of bonding jumper wires that may be attached to one terminal grounded to a flat surface is ?
FOUR …. 4
Starter brushes should be replaced when they are worn down to?
One-half on the original length
When installing an electrical switch, under which of the following conditions should the switch be derated from its nominal current rating?
Direct current motor circuits
The resistance of the current path through the aircraft is always considered negligible, provided the?
The structure is adequately bonded
In order to reduce the possibility of ground shorting the circuits when the connectors are separated for maintenance, the AN and MS electrical connectors should be installed with the?
Pin section on the ground side of the electrical circuit
When does current flow through the coil of a solenoid operated electrical switch?
Continually, as long as the control circuit is complete
When a 28 volt, 75 ampere generator is installed on an aircraft, an electrical load analysis ground check is performed, and it is determined that the battery is furnishing 57 amperes to the system, with all electrical equipment operating. This indicates?
The load will be within the generator load limits
What type of lubricant may be used to aid in pulling electrical wires or cables through conduits?
Soapstone Talc
Which of the following is regulated in a generator to control its voltage output?
The strength of the field
Bonding jumpers should be designed and installed in such a manor that they?
They provide low electrial resiatance in the ground circuit
Arcing at the brushes and burning of the commutator of a motor may be caused by?
Weak bush springs
The max allowable voltage drop between the generator and the bus bar is?
2% of the regulated voltage
ON-OF two position engine electrical switches should be installed..?
so the ON postion is reached by a forward or upward motion
When selecting an electrical switch for installation in an aircraft circuit utlizing a direct current motor?
A derating factor should be applied
When installing electrical wiring parallel to a fuel line, the wiring should be…?
Above the fuel line.
What speed must an Eight-pole AC generator turn to produce 400 hertz?
6000 RPM
How many basic types of circuit breakers are used in powerplant installation electrical system?
3 …. THREE
Which federal aviation regulation specifies that each resetable circuit protective device requires a manual operation to restore service after the device has interrupted the circuit?
14 CFR Part 23
The time/current capacities of a circuit breaker of fuse must be … below?
Below those of the associated conductor
- Most modern aircraft use circuit breakers rather than fuses to protect their electrical circuits. ✔️
- Part 23 requires that all electrical circuits incorporate some form of circuit protective device. ❌️
ONLY 1 is True
Electrical switches are rated according to the?
Voltage and current they can control
Electrical circuit protection devices are installed primarily to protect the?
Wiring
What type of electrical circuit protection is used for powerplant electrical systems?
Circuit breakers
- Electrical circuit protection devices are rated based on the amount current that can be carried without overheating the wiring insulation.
- A “trip free” circuit breaker makes it impossible to manually hold the circuit closed when excessive current is flowing
BOTH 1 and 2 are true.
Which of the following Federal Aviation Regulations require that all aircraft using fuses as the circuit protective devices carry “one spare set of fuses, or three spare fuses of each kind required”?
14 CFR (FAR) Part 91.
Which of the following Federal Aviation Regulations states “No person may describe in any required maintenance entry or form an aircraft, airframe, aircraft engine, propeller, appliance, or component part as being overhauled unless…?
14 CFR (FAR) 43.2
Which of the following Federal Aviation Regulations lists the procedural requirements for the issuance of
an STC (Supplemental Type Certificate)?
14 CFR (FAR) Part 21
What is the smallest terminal stud allowed for aircraft electrical power systems?
No. 10
A typical barrier type aircraft terminal strip is made from?
Paper based phenolic compound
A term commonly used when 2 or more electrical terminals are installed on a single lug of a terminal strip is called…?
Stacking
Aircraft electrical wire is manafacture in sizes according to a standard known as…?
American wire gauge AWG
Aircraft wire size is determined using a…?
Wire gauge
Airfraft copper coated electrical wire is coated with tin, silver, or nickel in order to…?
Prevent Oxidization
What will be the result of operating an engine in extremely high temperatures using a lubricant recommented by the manafacture for a much lower temperature?
The oil pressure will be lower than normal
- Electrial wires LARGER than 10 gauge are uninsulated terminals. ✔️
- Electrial wires smaller than 10 gauge are uninsulated terminals. ❌️
ONLY 1 is True
- Gas turbine and reciprocating engine oils can be mixed or used interchangeably ❌️
- Most Gas turbine engine oils are synthetic ✔️
ONLY 2 is True
The advantage of using synthetic oils over petroleum based oils are…?
1. Low Volatlilty
2. Low Pour Point
3. High Viscosity Index
4. Good Lube Qualities
5. Low Coke and Lacquer Formation
6. Low Foaming
1, 2, 3, 4, 5, and 6 are all advantages
An oil seperator is generally associated with which of the following?
Engine driven vacuum pump
The time in seconds required for exactly 60 cubic centimetres of oil to flow through an accurately calibrated orifice at a specific temperature is recorded as a measurement of the oils, what?
Viscosity
Upon what quality or characteristic of a lubricating oil is its viscosity index based?
Its rate of change in viscosity with temperature change
Lubricating oil was with high viscosity index ratings, are oils in which?
In which the viscosity does not vary much with temperature change
Compared to reciprocating engine oils, the types of oils used in turbine engines?
Have less tendancy to produce coke and lacquer
The oil used in reciprocating engines has a relatively high viscosity due to?
Large clearances and high operating temps
If all other requirements can be met, what type of oil should be used to achieve theoretically perfect engine lubrication?
The thinnest oil that will stay in place and maintain a reasonable film strength?
In addition to lubricating, engine oil performs what function?
1. Cools
2. Seals
3. Cleans
4. Prevents Corrosion
5. Cushions Impact Loads (Shock)
1, 2, 3, 4, 5.
Specific gravity is a comparison of the weight of a substance to the weight of an equal volume of what?
Distilled water at a specific temperature
Which of the following has the greatest effect on the viscosity of lubricating oil?
Temperature
What advantage do mineral base lubricants have over vegetable oil based lubricants when used in aircraft engines?
Chemical Stability
The recommended aircraft engine lubricants are?
Mineral or synthetic based
High tooth pressures and high rubbing velocity, such as a curve of spare type gears, require the use of … what?
an EP lubricant
Manufacturers normally require turbine engine oil servicing within a short time after engine shutdown primarily to?
Prevent overservicing
What type of oil do most engine manufacturers recommend for NEW reciprocating engine break in?
Straight mineral oil
What type of oil do most engine manufacturers recommend AFTER new reciprocating engine break in?
Ashless Dispersant oil
As a general rule, the mixture setting on a reciprocating engine operating at or near take of power that provides the best cooling is?
FULL RICH
The engine oil temperature regulator is usually located between which of the following on a dry sump reciprocating engine?
The scavenger pump outlet and the oil storage tank
What will happen to the oil if the line between the scavenger pump and the oil cooler separates?
The return oil will be pumped overboard
At cruise RPM, some oil will flow through the relief valve of a gear type engine oil pump. This is normal as the relief valve is set at a pressure which is?
Lower than the pressure pump capabilities
In a reciprocating engine oil system, the temperature bulb senses oil temperature at the?
At the point after the oil has passed through the oil cooler
The oil dampened main bearing utilized in some aircraft turbine engines is used to?
Provide an oil film between the outer race and the bearing housing in order to reduce vibration tendencies in the rotor system and to allow for slight missalignment
What is the purpose of the last chance oil filters?
To filter the oil immediately before it enters the main bearings
In a jet engine which uses a fuel oil heat exchanger, the oil temperature is controlled by a thermostatic valve that regulates the flow of the?
Oil through the heat exchanger
What prevents pressure within the lubricating oil tank from rising above or falling below ambient pressure?
Oil tank vent
Oil tank filler on reciprocating engines are marked with word…?
OIL in accordance with 14 CFR PArt 25
What is the primary purpose of the fuel/oil heat exchanger?
Cool the oil
What unit in the aircraft engine lubrication system is adjusted to maintain the desired system pressure?
Oil pressure relief valve
Low oil pressure can be detrimental to the internal engine components. However, high oil pressure should…?.
Should be limited to the engine manufacturers recommendations
Some larger reciprocating engines use a compensating oil pressure relief valve to?
Provide a high engine oil pressure when the oil is cold and automatically lower the oil pressure when the oil warms up
What is the source of most of the heat that is absorbed by the lubricating oil in a reciprocating engine?
Piston and cylinder walls
How are teeth of the gears in the accessory section of the engine normally lubricated?
By splashed or sprayed oil
In order to maintain a constant oil pressure, as the clearances between the moving parts of an engine increased through normal, wear the supply pump output?
Remains relatively constant (at a given RPM) with less oil being returned to the pump inlet by the relief valve
The valve assemblies of opposed reciprocating engines are lubricated by a means of a?
Pressure system
What will result if an oil filter becomes completely blocked?
Oil will flow at the normal rate through the system
How are the piston pins of most aircraft engines lubricated?
By oil which is sprayed or thrown by the master or connecting rods
The ventline connecting the oil tank supply and the engine in some dry sump engine installations permits?
The oil tank to be vented through the normal engine vent
An engine lubrication system pressure relief valve is usually located between the pump?
The pump and the internal oil system
Where is the oil of a dry sump reciprocating engine exposed to temperature control valve sensing unit?
Oil cooler inlet
Which of the following conditions is the oil cooler flow control valve open on a reciprocating engine?
When the temperature of the oil returning from the engine is too low
In reciprocating engines, oil is directed from the pressure relief valve to the inlet side of the…? pressure pump.
Pressure pump
If the oil in the oil cooler and annual jacket becomes congealed, what unit prevents damage to the cooler?
surge protection valve
A primary source of oil contamination in a normally operating reciprocating engine is?
Combustion deposits due to combustion chamber blow by and oil migration on the cylinder walls
A drop in oil pressure may be caused by?
Foreign material under the relief valve
The main oil filters strain the oil at which point in the oil system?
Just as it leaves the pressure pump
An oil tank having a capacity of 5 gallons must have an expansion space of?
2 quarts
Why is expansion space required in an engine oil supply tank?
For oil enlargement and collection of foam
The magnetic circuit of a magneto consists of a permanent multi-pole rotating magnet. The core is made of?
Soft Iron
What is the difference between a low tension and high tension engine ignition system?
A low tension system uses a TRANSFORMER COIL near the spark plugs to boost voltage, while the high tension system voltage is constant from the magneto to the spark plugs.C
What test instrument could be used to test an ignition harness for suspected leakage?
A high tension lead tester
In a low tension ignition system, each spark plug requires an individual?
Secondary Coil
What will be the effect if the spark plugs are gapped to wide?
Hard Starting
What would be the effect if the spark plugs are gapped too wide and the engine is operating at a high altitude airport?
Engine fails to idle properly
When removing a shielded spark plug, which of the following is most likely to be damaged?
Core insulator
What likely effect would a cracked distributor rotor have on a magneto?
Ground the secondary circuit through the crack
A certain 9 cylinder radial engine used on non-compensated single unit, dual type Magneto with a 4 pole rotating magnet and separately mounted distributors. Which of the following will have the lowest RPM at any given speed?
Distributors
Which of the following breaker point characteristics are associated with a faulty capacitor?
coarse grained
How are most radio engine spark plug wires connected to the distributor block?
By use of cable piercing screws
Thermocouples are usually inserted or installed on the??
Hottest cylinder of the engine
Capacitance afterfiring of a spark plug is caused by?
The stored energy in the ignition shielded lead unloading after a normal timed ignition
It is found that a shielded Ignition system does not adequately reduce Ignition noise. It may be necessary to install?
A filter between the mangeto and the Magneto switch
