Download AMT-P POWERPLANT/ BAKER'S SCHOOL LIST OF FAA ORAL QUESTIONS|450Qs&As|ALREADY GRADED A+ and more Exams Aviation in PDF only on Docsity!
AMT-P POWERPLANT/ BAKER'S SCHOOL LIST OF
FAA ORAL QUESTIONS|450Qs&As|ALREADY GRADED
A+
What is the main advantage of a horizontally opposed engine over a radial engine for powering modern aircraft? ANS:->> The horizontally opposed engine has a much smaller frontal area & is easier to streamline than a radial engine. How many throws are there in the crankshaft of a six-cylinder horizontally opposed engine
- ANS:->> Six. What kind of connecting rod arrangement is used in a radial engine - ANS:->> A master rod connects the single throw of the crankshaft with the piston. All of the other pistons are connected to the master rod with link rods. Of what material are most piston rings made - ANS:->> Gray cast iron. What is the reason for using hydraulic valve lifters in an aircraft engine - ANS:->> Hydraulic valve lifters keep all of the clearance out of the valve operating mechanism. This decreases the wear of the valve train components. At what speed does the camshaft turn, relative to the crankshaft speed in a horizontally opposed engine - ANS:->> The camshaft turns at one half of the crankshaft speed.
What kind of main bearings are used in a horizontally opposed engine – ANS:->> Steel-backed, lead-alloy bearing inserts. On what stroke is the piston of a reciprocating engine when the intake valve begins to open
- ANS:->> On the exhaust stroke. On what stroke is the piston of a reciprocating engine when the exhaust valve begins to open - ANS:->> On the power stroke. Why are both the hot & cold valve clearances given for most radial engines
- ANS:->> The hot clearance is given for valve timing purposes. The timing is adjusted with the valves in cylinder number one, set with the hot clearance. When the timing is set, all of the valves are adjusted to their cold clearance. What is meant by a cam-ground piston - ANS:->> A piston that is not perfectly round. Its dimension parallel with the wrist pin is several thousandths of an inch less than its dimension perpendicular to the wrist pin. When the piston reaches operating temperature, the metal in the piston pin boss expands enough that the piston becomes perfectly round. Where is the piston in a reciprocating engine when the ignition spark occurs - ANS:->> About 30 degrees of crankshaft rotation before the piston reaches top center of the compression stroke. What is meant by a full-floating wrist pin
- ANS:->> A wrist pin that is not clamped in either the piston or the
conditions, the mixture explodes rather than burns. This explosion is called detonation. Why is a compression check important for determining the condition of an aircraft reciprocating engine
- ANS:->> A compression check can determine the condition of the seal between the piston rings & the cylinder walls, & the seal between the intake & exhaust valves & their seats. What is meant by the compression ratio of a reciprocating engine
- ANS:->> The ratio of the volume of the cylinder with the piston at the bottom of its stroke to the volume with the piston at the top of its stroke. In what position should the crankshaft be when a magneto is being timed to the engine – ANS:->> The piston in cylinder no. 1 should be in the correct position for ignition to occur. This is normally about 30° before top center on the compression stroke. What is the purpose of a cold cylinder check
- ANS:->> A cold cylinder check determines which cylinder is not firing. Run the engine for a few minutes at the speed, and on the magneto, at which it runs roughest. Shut it down and feel the exhaust stack near the cylinder head. The cylinder with the stack that is not as hot as the others is the cylinder that has not been firing. What is checked on engine runup to determine the operational condition of the engine – ANS:->> Idling RPM and manifold pressure, engine acceleration, maximum static RPM and manifold pressure, magneto drop, ignition switch safety check, propeller pitch change, propeller feathering, oil pressure, fuel pressure, & fuel
flow. How can you determine the firing order of an 18-cylinder radial engine - ANS:->> Begin with cylinder 1, add 11, and subtract 7, whichever will keep the numbers between 1 and 18. 1 - 12 - 5 - 16 - 9 - 2 - 13 - 6 - 17 - 10 - 3 - 14 - 7 - 18 - 11 - 4 - 15 - 8. What are two main causes of a cylinder having low compression
- ANS:->> Piston rings not seating or broken, and valves not seating or burned. What is a hydraulic lock in an aircraft engine – ANS:->> Oil has drained past the piston rings and filled the combustion chamber of cylinders that are below the center line of the engine. If the crankshaft is turned over with this oil in the cylinder it will lock, and there is a probability that the piston, cylinder, or connecting rod will be damaged. How is a hydraulic lock removed from an aircraft engine
- ANS:->> Remove a spark plug from the locked cylinder and drain all of the oil out. Clean the spark plug and replace it. What is a low-tension ignition system – ANS:->> It is an ignition system using a magneto with a brush-type distributor and a coil that has no secondary wiring. Low voltage is directed from the magneto to a transformer mounted on the cylinder head. Here the low voltage is boosted to a high voltage and is directed through a very short high-tension lead to a spark plug. There is one transformer for each spark plug. What is a floating cam ring on a large radial engine
- ANS:->> It is a cam ring that rides on a shelf-type bearing with a large amount of clearance between the bearing and the ring. When adjusting the valves on an aircraft engine with a floating cam ring, the pressure of the
ANS:->>In the aircraft maintenance manual. What must normally be done to a nose-wheel airplane before removing an engine
- ANS:->>The tail of the airplane must be supported. What should be done to the cylinders to protect them from rust and corrosion when preparing the engine for long-time storage - ANS:->>Spray a preservative oil inside the cylinders and replace the spark plugs with desiccant plugs. What should be used to cover the ends of fuel and oil lines that have been disconnected from the engine - ANS:->>The correct plugs or caps. Never cover the end of a line with tape. What is meant by a QEC engine assembly - ANS:->>An engine that has been prepared for a quick
engine change. The engine is on its mount and all of the accessories are installed. A minimum of time is required to change engines. All that is needed is for the controls, wiring, and fluid lines to be connected to the firewall. What is meant by rigging the engine controls so they have some "cushion" - ANS:->>The control on the engine component must contact its stop before the control handle in the cockpit reaches its stop. This causes the control handle to spring back a slight amount when it is moved to the extent of its travel. What are two ways of pre-oiling an engine - ANS:->>a. Before the spark plugs are installed and after the oil tank or sump is fitted, turn the engine over with the starter until oil runs out of the fitting to which the oil pressure gage connects. b. Use a pre-oiler tank. Air pressure forces oil through all of the passages until some of it flows from the oil pressure gage fitting. What are the two basic sections of a turbine engine - ANS:->>The hot section & the cold section. What are the two basic types of compressors that are used in aircraft turbine engines - ANS:->>Axial-flow & centrifugal. What is the purpose of stators in an axial-flow compressor - ANS:->>The stators convert some velocity energy into pressure energy & change the direction of the air so it is proper for the next stage of rotors. What are three types of combustors used on aircraft turbine engines - ANS:->>Can-type, annular-type, & can-annular-type. How many igniters are there normally in an aircraft turbine engine - ANS:-
Two.
What is meant by a hung start in a turbine engine - ANS:->>A start in which ignition occurs, but the engine does not accelerate to a self-sustaining speed. What is meant by a hot start in a turbine engine - ANS:->>A start in which ignition occurs, but the internal temperatures go high enough that they can damage the engine. What is meant by creep of the turbine blades - ANS:->>A condition of permanent elongation of the turbine blades. Creep is caused by the high temperatures & the high centrifugal loading imposed on the blades. How is the compressor of a turbine engine cleaned - ANS:->>An emulsion-type cleaner is sprayed through the engine while it is being motored by the starter or operated at a low speed. The wash is followed by a clean water rinse. More vigorous cleaning is done by injecting a mild abrasive, such as ground-up apricot pits or walnut shells, into the engine while it is operating at low speed. Where is water injected into a turbine engine for cooling purposes - ANS:-
Into the compressor inlet & into the engine diffuser case. At what point in a turbine engine is the temperature the highest - ANS:- At the inlet to the high-pressure turbine. What is the function of the interconnect tubes between the cans of a turbine engine that uses can-type combustors - ANS:->>These tubes allow the flame to travel from the cans that contain the igniters to all of the other cans when the engine is being started.
What are two types of thrust reversers that are used on turbojet engines - ANS:-
The mechanical blockage-type & the aerodynamic blockage-type. What is meant by trimming a turbojet engine - ANS:->>Adjusting the fuel control to get the correct idling & maximum-thrust RPM. What is meant by a hot-section inspection - ANS:->>An inspection of the hot section of a turbine engine. The hot section includes the combustors, the turbine, and the exhaust system. What is meant by on-condition maintenance of a turbine engine - ANS:->>The monitoring of the engine performance at regular intervals and determining when maintenance is required based on certain operating parameters specified by the engine manufacturer. What checks of a turbine engine are necessary to verify preflight condition - ANS:- Inspection of the cowling and all air inlet areas and attachment of the engine to the airframe, inspection of the inlet guide vanes and the first stage of the compressor or fan blades, check for unusual noise when the compressor is rotated, inspection of the rear turbine and exhaust system, check the quantity of the lubricating oil for the engine and the constant-speed drive unit, check the ignition system for operation by listening for the sparks. What type of equipment should be used to determine that a turbine engine is performing up to the standards specified by the engine manufacturer - ANS:->>A JetCal Analyzer/Trimmer has all of the instrumentation and cables to determine the EGT, EPR, and the other parameters specified by the engine manufacturer. What determines whether or not a 100-hour inspection is required for an aircraft - ANS:->> 100 - hour inspections are required only on aircraft that carry persons for hire or are used to give flight instruction for hire.
Where can you find the model of magneto that is approved for an engine specified by the examiner - ANS:->>In the Type Certificate Data Sheet for the engine. What is a Supplemental Type Certificate - ANS:->>An approval issued by the FAA for a modification to a type-certificated airframe, engine, or component. What paperwork is necessary for the installation of a magneto that was not approved for an engine when it was certificated, but is approved for the engine when installed according to an STC - ANS:->>A form FAA 337 must be completed stating that the installation was done in accordance with the specific STC. Does the tachometer of a geared reciprocating engine indicate the speed of the crank shaft or of the propeller shaft - ANS:->>The speed of the crankshaft. What is indicated if the needle of a ratiometer-type oil temperature indicator pegs to the high side of the dial as soon as the aircraft master switch is turned on - ANS:->>There is an open in the bulb circuit that causes the instrument to see an infinite resistance. The higher the resistance in the bulb circuit, the higher the temperature indication. What type of indicating system is used to measure the exhaust gas temperature of a turbine engine - ANS:->>A set of thermocouples arranged in an averaging circuit. These thermocouples are installed in the tail pipe of the engine.
In what units is the tachometer for a reciprocating engine calibrated - ANS:->>In hundreds of RPM. What two pressures are measured to get the Engine Pressure Ratio of a turbojet engine - ANS:->>The turbine discharge total pressure and the compressor inlet total pressure. What is used to measure the fuel flow of a horizontally opposed, fuel- injected reciprocating engine - ANS:->>A pressure gauge that measures the pressure drop across injector nozzles. What is measured by the tachometers used on a two-spool gas turbine engine - ANS:->>The N1 tachometer shows the RPM of the low-pressure compressor, and the N2 tachometer shows the RPM of the high-pressure compressor. In what units is the tachometer for a turbine engine calibrated - ANS:->>In percent of the engine's rated takeoff RPM. What kind of mechanism is normally used to measure oil pressure in a reciprocating engine - ANS:->>A bourdon tube mechanism. Why do most engine oil pressure gauges have a restrictor in the line between the engine and the instrument - ANS:->>The restrictor damps out pressure pulsations in the oil to keep the needle from oscillating How does a torquemeter actually measure the torque produced by an engine - ANS:->>A torquemeter is actually an oil pressure gauge. The pressure it measures is produced in a torque sensor and is proportional to the amount of strain in the torsional shaft that drives the reduction gears of the turboprop
ANS:->>If there are instrument abnormalities, there are possibly damaged turbine components. Who is authorized to repair a fuel flow indicating system - ANS:->>The components can be repaired only by an FAA approved repair station certificated for the particular instruments. Where can you find the electrical power requirements for a fuel flow indicating system - ANS:->>In the aircraft maintenance manual. Where in the fuel system is the fuel flow transmitter located - ANS:->>Between the fuel control and the fuel nozzles. What kind of indicating system is used to measure oil temperature in a small, single-engine, general aviation airplane - ANS:->>A sealed system in which a bulb, partially filled with a highly volatile liquid, is installed inside the oil strainer. The bulb is connected to a pressure gage by a copper tube. The pressure of the gas above the liquid is proportional to the temperature of the oil that surrounds the bulb, and the pressure gage is calibrated in terms of temperature. What type of instrument system is used for measuring cylinder-head temperature and exhaust gas temperature - ANS:->>A thermocouple system. What kind of electrical instrument system is used for measuring oil temperature - ANS:->>A ratiometer-type system. What should a thermocouple cylinder-head temperature indicator read when the engine is cold - ANS:->>The same as the outside air temperature gage. What is critical in the installation of the thermocouple leads for a cylinder-head
temperature indicator, the length of the leads or their resistance - ANS:->>The resistance is critical, it must have the resistance specified on the indicator. This is usually 2 or 8 ohms. What should a ratiometer temperature indicator read when the electrical power is off - ANS:->>The pointer should be off scale on the low side. What kind of tachometer is used on most small single-engine airplanes - ANS:-
A magnetic drag tachometer that is similar to an automobile speedometer. What would likely cause the pointer of a magnetic drag tachometer to oscillate
- ANS:->>Either a dry cable connecting the indicator to the engine, or a kink in the cable housing. Is it permissible for a mechanic with an airframe and powerplant rating to replace the tachometer cable for a magnetic drag tachometer - ANS:->>Yes, this does not constitute a repair to an instrument. What kind of tachometer is used on most large multi-engine airplanes - ANS:-
A three-phase AC electric tachometer. What is measured to indicate the engine RPM with a three-phase AC electric tachometer - ANS:->>The frequency of the AC the tachometer generator produces. What kind of indicator mechanism is used to measure manifold pressure - ANS:->>A differential bellows. What should a manifold pressure gage read when the engine is not operating - ANS:->>The existing barometric pressure as indicated on the altimeter
cannot indicate a general overheat condition. How is a thermocouple-type fire detection system checked for operation - ANS:-
Press the test switch. This heats the test thermocouple enough for it to close the sensitive relay, which in turn closes the slave relay and activates the fire warning light and bell. Does a break in a continuous-loop fire detection system keep the system from detecting a fire - ANS:->>No, the unit will show a fault when it is tested, but it will still warn of a fire. Does the pressure-type continuous-element fire detector system detect a general overheat condition, as well as a fire - ANS:->>Yes, a high temperature on a small portion of the sensor or a lower temperature over the entire sensor will cause it to release enough gas to close the diaphragm switch & warn of a fire. What are the two most commonly used fire extinguishing agents used for engine fires - ANS:->>Halogenated hydrocarbon, such as Halon 1301, & carbon dioxide. What extinguishing agent is used in the high-rate-discharge fire extinguishing systems installed in most turbojet engine installations - ANS:->>Halon 1301. What happens when the pilot pulls the fire-pull T-handle in the cockpit of a jet transport airplane
- ANS:->>The bottle discharge switch is uncovered & armed, the generator field relay is tripped, fuel is shut off to the engine, hydraulic fluid is shut off to the pump, the engine bleed air is shut off, &
the hydraulic pump low-pressure lights are deactivated. How can a mechanic determine the state of charge of the HRD bottles of fire extinguishing agent - ANS:->>A pressure gage on the bottle shows the pressure of the contents of the bottle. What method is used to discharge an HRD bottle in a turbine engine installation - ANS:->>An electrically ignited powder charge blows a knife through the seal on the bottle & discharges the contents. Which type of fire detection system operates on the rate of temperature rise - ANS:->>The thermocouple system. What is indicated if the yellow blow-out plug of the fire extinguisher system on the side of the engine nacelle is blown out - ANS:->>The built-in fire extinguishing system has been discharged by normal operation. What is indicated if the red blow-out of the fire extinguisher system on the side of the engine nacelle is blown out - ANS:->>The built-in fire extinguishing system has been discharged by a high temperature condition. How is a pressure-type continuous-element fire detector systems checked for operation - ANS:->>Low-voltage alternating current is sent through the sheath of the detector element. This heats the element, & it releases enough gas to close the diaphragm switch. What are four types of engine fire detection systems - ANS:->>Thermoswitch system, thermocouple system, thermistor-type continuous-loop system, pneumatic-type continuous-loop system.
