RJs ARF Codes Flashcards
How many watts of power are consumed by a 1/3 horsepower, 28 volt DC motor that is 75% efficient?
Power consumed is the same as Power in. Therefore, 1 hp = 746 watts. Power In = Power Out = 0.33 hp × 746 W/hp = 246.18 W. Efficiency = Power Out / Power In.
How high should the electrolyte level be in a properly serviced lead-acid battery?
It should be at the recommended level specified by the manufacturer.
Why is a hydrometer not used to measure the state of charge of a nickel-cadmium battery?
The electrolyte of a nickel-cadmium battery does not undergo the same chemical changes that occur when the battery is charged or discharged.
What is a result of cell imbalance in a nickel-cadmium battery?
The low internal resistance allows current to flow between the unbalanced cells and generate heat.
What is thermal runaway?
A large current flow allowed in the low internal resistance causes the cells to produce more heat than they can dissipate. The heat further lowers the internal resistance, allowing more current to flow, which continues until the battery destroys itself.
How may THERMAL runaway be prevented?
monitoring the temperature at the cells and controlling the charging current
How is it possible to know when a nickel-cadmium battery is fully charged?
Completely discharge the battery and apply a constant current charge to 140% of its ample hour capacity
What is the function of a current limiter?
heavy-duty fuse (30 amps) They are used to protect a section of a circuit, like a large electrical bus.
What is used to neutralize spilled electrolyte from a nickel-cadmium battery?
boric acid.
How many views can there be on an orthographic projection?
Six.
How many views are used to show most objects in an aircraft drawing?
Three.
What information is given in the title block of an aircraft drawing?
-name and address part maker
-name of the part
-scale of the drawing
-name of the draftsman
-name of the engineer approving the part
-number of the part
Where is the title block normally located on an aircraft drawing?
In the lower right-hand corner.
Where would an aviation mechanic find aircraft electrical schematics?
In the aircraft maintenance manual or the aircraft circuit diagram manual.
How are the ends of two control cables normally connected together?
swaged, threaded terminals on the ends connected with a turnbuckle
How much is a fairlead allowed to deflect a control cable?
No more than 3°.
Why are the control cables of large airplanes normally equipped with automatic tension regulators?
aluminum in the aircraft structure contracts as temperature drops. control cables could become loose. Auto tension regulators keep cable tension constant
What is a sintered metal hydraulic filter?
A surface filter, the element is made of powdered metal fused under heat and pressure.
What is the purpose of the differential PRESSURE INDICATOR on a hydraulic filter?
It indicates when the filter is clogged and fluid is bypassing the filter element.
What is a Cuno filter?
An edge filter made of a stack of thin metal discs separated by thin scraper blades. Contaminants collect on the edge of the discs, scraped out by rotating the discs. contaminants collect in the bottom of the filter case for removal
What type of direction-finding compass has NO MOVING PARTS and integrates with digital systems?
Solid state magnetometers.
How does a flux gate compass operate?
An alternating electric current is passed through coils, driving the core
through an alternating cycle of magnetic saturation.
Which frequency band is used for long range communications from an aircraft?
High frequency band (2 to 25 megahertz).
What are the two methods of modulating camera waves for transmitting information?
Amplitude modulation (AM) and frequency modulation (FM).
What is the preferred location for a VOR antenna on an airplane?
On top of the aircraft, along the septum pipe of the fuselage.
Which component of the Instrument Landing System shares the antenna with VOR?
The ILS localizer.
What must be done before a fuel selector valve can be removed from an aircraft?
The tank to which the valve is connected must be drained or otherwise isolated.
What must be done after a fuel valve is replaced?
The fuel system must be checked for leaks.
Where can you find the correct part number for the fuel quantity sensor to be installed in an aircraft fuel tank?
In the Illustrated Parts Catalog for the aircraft.
Where are fuel system strainers located?
-the outlet to the tank,
-inbetween the outlet of the fuel tank and the inlet to the fuel metering device.
Why do the fuel strainers used on some turbine-engine aircraft have a warning device?
Strainers clog because ice forms on the filter element. The flight crew can route the fuel through a fuel heater to melt the ice.
How does water appear in the fuel drained from the tank sumps?
Water appears as a clear globule in the bottom of the container used to collect the fuel drained from the sumps.
Why must an aircraft fuel valve have a detent in its operating mechanism?
The detent gives the pilot a positive indication by feel when the selector valve is in the full ON and full OFF position.
What must be done after a fuel system strainer has been cleaned or replaced?
The system must be tested for leaks by pressurizing the system with the boost pump, if one is used.
What must be done if the sump drains sample shows traces of jet fuel?
The fuel system must be drained and flushed out with the proper grade of aviation gasoline.
What is a starter-generator?
A starter-generator is a generator and a starter combined into a single unit.
How many sets of field windings are contained in a STARTER GENERATOR?
There are two sets of field windings. One is used to start the engine and one is used for the generation of electrical power.
What is the function of an ice detector when ice is detected?
To illuminate an annunciator light in the flight deck and, in some aircraft, to automatically turn on anti-icing systems.
What is a sight line?
A line drawn on a flat pattern layout within the bend allowance that is one bend radius from the bend tangent line.
What is the main function of throatless shears in an aircraft sheet metal shop?
used to cut mild carbon steel up to 16-gauge, and stainless steel up to 12 gauge.
can be used to cut irregular curves in metal.
What kind of metal forming is done by a sub roll former?
Simple curves with a large radius.
What kind of metal forming is done by bumping
Compound curves in sheet metal.
When forming a curved angle, what must be done to the flanges?
The flanges must be stretched for a convex curve and shrunk for a concave curve.
When hand-forming a piece of sheet metal that has a concave curve, should the forming be started in the center of the curve, or at its edges?
Start at the edges and work toward the center.
What is meant by a joggle in a piece of sheet metal?
A joggle is a small offset near the edge of a piece of sheet metal that allows the overlap of another piece of metal.
For maximum strength of a formed sheet metal, should the bend be made along or across the grain of the metal?
Across the grain.
What determines the minimum bend radius that can be used when forming a sheet metal structural fitting?
The alloy, thickness, and its hardness.
What is meant by the neutral axis in a sheet of metal?
A plane within the metal that neither stretches nor shrinks when the metal is being bent.
What is a mold line in the development of a flat pattern for a formed metal part?
An extension of the flat sides beyond the radius.
What is the bend tangent line?
A line in a flat pattern layout at which the bend starts.
What is meant by setback?
The distance the jaws of a brake must be set back from the mold line to form a bend.
What is meant by bend allowance?
actual amount of metal in a bend. It’s distance between bend tangent lines
What must be done to an aircraft fuel tank before it can be repaired by welding?
The gasoline fumes must all be purged from the tank by running live steam through it for at least 30 minutes, by soaking it in hot water or by filling it with nitrogen or carbon dioxide.
What precaution should be taken when drilling out rivets on an airplane or drilling holes for a repair?
Do not allow the drill to enter into the space behind the structure, as the drill may cause damage.
What are two advantages of laminated construction over riveted sheet metal?
Light weight and rigidity.
What are two popular types of core material used in laminated structure?
Foam and honeycomb.
What are two popular types of matrix material used in laminated structure?
Polyester and epoxy resins.
What are the two parts of a polyester matrix material?
Resin and catalyst.
What are the two parts of an epoxy matrix material?
Resin and hardener.
What are three materials that may be used to reinforce the matrix material for aircraft structure?
Fiberglass, Kevlar®, and graphite.
What is meant by a unidirectional fabric?
A fabric in which all of the major fibers run in the same direction.
What is meant by the ribbon direction of a honeycomb material?
direction of a piece of honeycomb that is parallel to the strips that make up the core.
What are the three basic BRAKE actuating systems?
a. An independent system not part of the aircraft main hydraulic system.
b. A booster system that uses the aircraft hydraulic system intermittently.
c. A power brake system that only uses the aircraft main hydraulic system as a source of pressure.
What is the purpose of the shuttle valve in the brake system of an aircraft using hydraulic power brakes?
The shuttle valve is an automatic canister valve that allows the brakes to be operated by hydraulic system pressure under all normal conditions; if this pressure is lost, it allows the brakes to be operated by the emergency backup system.
How does an anti-skid brake system keep the wheels of an aircraft from skidding on a wet runway?
The anti-skid system monitors the rate of deceleration of the wheels. If any wheel slows down faster than it should, the pressure on the brake in that wheel is released until the wheel stops decelerating, then the pressure is reapplied.
What abnormal event warrants a special brake inspection?
If the aircraft experiences an aborted takeoff or an emergency braking event. These events cause excessive heating of brakes, wheels, and tires.
What is the likely cause of spongy brakes?
There are air bubbles in the brake lines.
What are the two methods of bleeding brake systems?
Gravity and pressure bleeding.
What condition exists when a brake locks on a water-covered runway?
Hydroplaning.
What is the likely cause of a dragging brake?
A warped disc.
Where can you find a list of BRAKE FLUIDS approved for the aircraft?
In the aircraft service manual.
What is used to flush brake lines and cylinders if the system uses vegetable base fluid?
Alcohol
What is used to flush brake lines and cylinders if the system uses mineral-base fluid?
Naphtha, Varsal, or Stoddard solvent.
How do you measure the amount of brake lining wear on single disc brakes?
Measure the clearance between the disc and the inboard side of the brake housing with the brakes applied.
What is the purpose of the debooster in a hydraulic power brake system?
The debooster DECREASES THE PRESSURE AND INCREASES THE VOLUME of fluid going to the brakes. This gives the pilot better control of the brakes.
What should be done to hydraulic brakes when the pedal has a spongy feel?
The spongy feel is caused by air in the brake. The brakes should be bled of this air.
What is the purpose of the compensator port in the master cylinder of aircraft brakes?
opens the brake reservoir to the wheel cylinders when the brakes are off.
What are the two basic types of hydraulic fluid used in modern aircraft?
Mineral base fluid and phosphate ester base fluid.
Does the main hydraulic pump take its fluid from the bottom of the reservoir or from a standpipe?
The main pump normally takes its fluid from a standpipe, while the emergency pump takes its fluid from the bottom of the reservoir.
Why are some hydraulic reservoirs pressurized?
ensures that fluid will be supplied to the inlet of the pumps at high altitude
What are two ways aircraft hydraulic reservoirs may be pressurized?
By an aspirator in the fluid return line or by bleed air from one of the engine compressors.
What is used to flush a hydraulic system that uses Skydrol hydraulic fluid?
Trichlorethylene or the solvent recommended by the aircraft manufacturer.
What is used to flush a hydraulic system that uses mineral base hydraulic fluid?
Naphtha, Varsal, or Stoddard solvent.
Where can you find the type of hydraulic fluid required for a particular aircraft?
In the maintenance manual for the aircraft. This information is also on a placard on the system reservoir.
What type of pump is a gear pump considered?
A gear pump is a constant displacement high pressure pump.
What type of pump is a piston pump with a VARIABLE cam plate considered?
A piston pump with a variable cam changes the effective (not actual) length of each piston stroke, making it a variable displacement with constant pressure.
What kind of filter is a filter element?
A filter with a special paper element.
What is a double-action pump?
A pump that delivers fluid with the movement of the pump handle in both directions.
Why do most engine driven hydraulic pumps have a shear section in their drive couplings?
If the pump should seize, the shear section will break, disconnecting the pump from the engine and preventing further damage.
How is the air charge of an accumulator checked for proper servicing?
All hydraulic pressure must be bled from the system and the pressure is checked on a gauge.
What is the function of the cabin outflow valve on a pressurized aircraft?
The cabin outflow valve, controlled by the pressure controller, maintains the correct amount of pressure inside the cabin.
What is the function of the cabin pressure safety valve on a pressurized aircraft?
The cabin pressure safety valve prevents cabin pressure from exceeding the maximum allowable differential pressure.
Why must pressurized aircraft have a negative pressure relief valve?
The structure of an aircraft cabin is not designed to tolerate the inside pressure being lower than the outside pressure.
What keeps the cabin of a pressurized aircraft from being pressurized when the aircraft is on the GROUND?
A squat switch on the landing gear holds the safety valve open when the aircraft is on the ground.
What are three ways supplemental oxygen can be carried in an aircraft?
As a high pressure gas, in its liquid form, and as a solid in the form of a chemical candle.
What is a continuous-flow oxygen system?
An oxygen system that continuously allows a metered amount of oxygen into the mask.
What is a pressure demand oxygen system?
An oxygen system that flows oxygen to the mask only when the wearer of the mask inhales. Above a specified altitude, the regulator meters oxygen under pressure into the mask when the wearer inhales.
How is cabin pressure controlled in a pressurized aircraft?
More pressure than is needed is pumped into the aircraft cabin, and the pressure controller modulates the outflow valve to maintain the correct pressure in the cabin.
What type of system is used to indicate the position of the wing flaps?
Usually a resistance type remote indicating system such as the DC Selsyn system.
What information is shown by the wing flap position indicator?
The number of degrees the flaps are lowered.
Who is authorized to perform the altimeter tests to determine the accuracy of the altimeter?
The manufacturer of the aircraft on which the tests are conducted, or a certificated repair station properly equipped and authorized to perform the test.
Where are the requirements for the altimeter system tests found?
14 CFR Part 43, Appendix E.
How often should an altimeter be checked if it is installed in an aircraft for IFR flight?
Every 24 calendar months.
How much difference is allowed between the altitude indication on the automatic pressure altitude reporting equipment and that on the altimeter?
125 feet
To what altitude must altimeters be tested?
To the highest altitude the aircraft will be flown on IFR flight.
What record must be made of a test of an altimeter?
-The aircraft permanent maintenance record
-must show the date
-maximum altitude to which the altimeter was tested,
-name of the person approving the aircraft for return to service
To what avionic equipment is the output from an encoding altimeter connected?
The ATC transponder.
What is the allowable difference between the surveyed elevation of the airport and the indication on the altimeter when it is set to the local altimeter setting?
75 feet.
What instruments in an aircraft are connected to the static system?(indicators)
The airspeed indicator, vertical speed indicator, and altimeter.
What are the differences between absolute, gauge, and differential pressure instrument systems?
An absolute pressure instrument measures actual pressure. Gauge pressure instruments measure the difference between existing barometric pressure and pressure inside a sealed container. Differential pressure instruments display the difference between two pressures.
Example: Pitot pressure and static pressure used to display airspeed.
What does an angle of attack (AOA) indicator provide for the pilot?
The AOA offers a visual indication of the amount of lift the wing is producing at a given airspeed or angle of bank.
What is the purpose of a stick shaker used on some aircraft?
It provides an artificial stall warning to the pilot.
Why is it important for a stall warning system to be adjusted correctly?
A stall warning system is adjusted to allow sufficient margin and warning prior to an actual stall.
What systems does a takeoff warning system monitor?
-when the power lever is advanced and checks for proper position of flaps and trim systems
-A warning horn/ light will be activated if the takeoff configuration is incorrect.
What CONDITIONS are indicated by a landing gear warning system?
A red light will illuminate if any of the gear is in an unsafe condition. A green light shows when all landing gear are down and locked. An aural warning will sound a horn if the landing gear are not down when the throttles are retarded for landing.
Which frequency band is used for long-range communications from an aircraft?
The high frequency band (2 to 25 megahertz).
What are the two methods of modulating carrier waves for transmitting information?
Amplitude modulation (AM) and frequency modulation (FM).
On what two frequencies does the emergency locator transmitter operate?
121.5 and 243.0 megahertz.
Where is the ELT transmitter normally located on an aircraft?
In the tail of the aircraft or as far aft as possible, so it will be least likely to be damaged in a crash.
How often should ELT batteries be replaced or recharged?
-When the transmitter has been in use for more than 1 cumulative hour, -when the battery expiration date has been reached
-when 50% of their useful life or charge has expired.
How can you know WHEN (TIME) an ELT battery must be replaced or recharged?
By the date marked on the outside of the transmitter.
How often must ELTs be inspected for proper installation, battery corrosion, operation of the controls and sensor, and the presence of the radiated signal?
Every 12 calendar months.
What causes an ELT to activate/ turn on
An inertia switch that detects an impact parallel to the longitudinal axis of the aircraft as would occur in a crash.
How is an ELT tested to determine that it is working?
Actuate the test switch and listen on 121.5 or 243.0 MHz. Make the test during the first five minutes of the hour and do not allow the ELT to operate for more than 3 sweeps. If the ELT is operated outside of this time frame, you should contact the control tower before conducting the test.
What is the basic purpose of an autopilot?
It frees the human pilot from continuously having to fly the aircraft, and flies with a degree of precision. It also couples with various electronic navigational aids.
What are the basic subsystems of an automatic flight control system? (Auto pilot)
Command, error sensing, correction, and follow-up.
What type of device is normally used in the error sensing subsystem?
Gyros.
What are three types of servos that are used in the correction subsystem?
Hydraulic, pneumatic, and electric.
What is the purpose of the follow-up subsystem in an autopilot? (Corrections)
It stops the control movement when the surface has deflected the proper amount for the signal sent by the error sensor.
Where can you find the correct part number for the fuel quantity sensor to be installed in an aircraft fuel tank?
In the Illustrated Parts Catalog for the aircraft.
Where are fuel system strainers located?
One strainer is located in the outlet to the tank, and the main strainer is located in the fuel line between the outlet of the fuel tank and the inlet to the fuel metering device.
Why do the fuel strainers used on some turbine engine aircraft have a warning device that signals the flight crew when the strainer is beginning to clog up?
Strainers clog because ice forms on the filter element. The flight crew can route fuel through a fuel heater to melt the ice.
Why are fuel tanks divided into compartments or have baffles installed in them?
The compartments or baffles keep the fuel from surging back and forth as the aircraft changes its attitude in flight.
How is a fuel leak indicated on a reciprocating engine powered aircraft?
The dye in the gasoline stains the area around the leak.
What is the function of the sump in a fuel tank?
The sump, or lowest point, in a fuel tank is located below the fuel outlet. It collects water and contaminants and will have a drain to remove them.
What are the three different types of luel tanks?
Built-up tanks, integral tanks, and bladder tanks.
What problem can occur in a bladder tank with a blocked vent?
As internal tank pressure decreases, the pressure differential between the atmosphere and the tank can cause the tank restraints to fail and the tank can collapse and block the fuel outlet.
How do you prepare an aluminum fuel tank for welding?
Remove all fuel and thoroughly wash the tank, inside and out, with hot water and detergent. The tank should be purged with live steam for at least 30 minutes to remove all residual fuel and vapors.
After welding an aluminum fuel tank, to what pressure should the tank be tested?
3.5 psi.
What size generator must be used in an aircraft electrical system if the connected electrical load is 30 amps, and there is no way of monitoring the generator output?
When monitoring is not practical, the total continuously connected electrical load must be no more than 80% of the rated generator output. This would require a generator with a rating of 37.5 amps. Practically, a 40 amp generator would be installed.
What is meant by ‘flashing’ the field of a generator?
Restoring the residual magnetism to the frame of the generator. This is done by passing battery current through the field coils in the direction it normally flows when the generator is operating.
What is meant by paralleling the generators in a multi-engine aircraft?
Adjusting the voltage regulators so all the generators share the electrical load equally.
What are three types of voltage regulators used with aircraft generators?(rose toy)
Vibrator type, carbon-pile type, and solid state-type.
How does a constant speed drive (CSD) unit maintain a constant output frequency of the AC generator?
By maintaining a constant speed of the generator as the engine speed varies.
What is an integrated drive generator (IDG)?
When a constant speed drive (CSD) is combined within the alternator housing, the assembly is known as an IDG.
What is meant by a trip-free circuit breaker?
A circuit breaker that cannot be closed while a fault exists, regardless of the position of the operating handle.
What is meant by a slow blow fuse?
A fuse that will allow more current than its rating to flow for a short period of time, but will open the circuit if more than its rated current continues to flow.
What is the function of a fuse or circuit breaker in an aircraft electrical circuit?
It protects the wiring from an excess of current. It will open the circuit if enough current flows to heat the wire.
What are two principles upon which circuit breakers operate?
-Magnetic circuit breakers open a circuit when the current creates a strong enough magnetic field.
-Thermal circuit breakers open a circuit when the current causes enough heat.
What circuit in an aircraft electrical system is not required to have a circuit protective device?
The main circuit for starter motors, used during starting only.
Is an automatic-reset circuit breaker approved for aircraft electrical circuits?
No, a manual operation is needed to restore service after the circuit breaker has tripped.
How does a vibrator-type voltage regulator maintain a constant voltage?
When the voltage rises above the desired value, an electromagnetic relay opens and inserts a resistor in the generator field circuit, decreasing the field current and lowering the generator output voltage.
What two components are normally housed with a vibrator voltage regulator in a single-unit generator control?
A current limiter and a reverse current cutout relay.
What are the two types of inverters found in aircraft?
Rotary inverters and Static inverters.
What is the purpose of an inverter?
To convert DC electricity to AC electricity.
How does a rotary inverter create AC voltage?
By using a DC motor to spin an AC generator.
Where could you find the part number of a switch (electrical) in an aircraft electrical system?
In the equipment table or bill of materials on the electrical circuit diagram for the aircraft.
What is the main disadvantage of aluminum wire over copper wire for use in an aircraft electrical system?
Aluminum wire is more brittle than copper; it is more subject to breakage when it is nicked or when it is subjected to vibration.
What size aluminum wire would be proper to replace a piece of four gauge copper wire?
Two-gauge. When you substitute aluminum wire for copper wire, use a wire that is two gauge numbers larger.
What is the smallest size aluminum wire that is approved for use in aircraft electrical systems?
Six gauge.
Can you substitute aluminum wire for copper wire?
Yes. However, you must use aluminum wire two wire gauge sizes larger to carry the same current. Aluminum wire should never be used in runs of three feet or less, or in communication and navigation systems.
Can wire in free air carry the same current as wire in a bundle?
Yes/No, Wire in free air may be used to a higher current level than the same size wire in a bundle.
Always refer to an electrical wire size selection chart.
What are common causes of wire failure in a crimped connector?
The wire was not inserted far enough into the connector and/or the connector was excessively crimped.
What is one of the first things to check if an electrical component does not operate?
Always start with simple solutions and move to more complex. Is the component turned on? Is power available?
For example, if a light doesn’t function is the system turned on, is the aircraft electrical system energized, or is the bulb burnt out?
What may be provided by the manufacturer to assist in troubleshooting?
Manufacturers often provide a troubleshooting logic chart.
What are the four basic steps of troubleshooting?
- Know how the system should operate.
- Observe the way the system is operating.
- Divide the system into smaller segments to isolate trouble.
- Look for the obvious problem first.
When routing a fluid line parallel to an electrical wire bundle, which should be on top?
The electrical wire bundle should be on top.
What is an SPDT switch?
A single pole, double-throw switch.
If no specific instructions are available, which way should the operating handle of an electrical switch move to turn a component on?
Forward or upward.
What color insulator on a preinsulated solderless connector indicates that the connector is proper for a 10-gauge wire?
Yellow.
How many splices are allowed in a single wire run?
One.
