Orals Flashcards
What is the function of a vortex generator?
It is designed to delay or prevent separation of the boundary layer.
What are the three axes of an airplane?
Longitudinal, Lateral, and Vertical
What are the 3 primary flight controls of an aircraft?
Ailerons, Elevator, and rudder
Name several secondary flight controls and describe their general purpose.
Secondary flight controls consist of various types of trim tabs such as balance tabs, anti-servo and servo tabs, and spring tabs. Their function is to assist the pilot in moving the controls and trim the aircraft to fly hands off
Name several types of auxiliary flight controls and describe their general purpose.
The auxiliary flight controls consist of the various high-lift devices used during low-speed flight such as leading and trailing edge flaps, slats, slots, speed brakes, etc.
What is a servo trim tab?
It is an auxiliary control, positioned by the movement of a cockpit control and designed to create aerodynamic forces to assist in moving a control surface.
What is a spring tab?
It is an auxiliary control designed to aid the movement of a primary control at high speeds when control forces become too high
What is a balance trim tab?
It is an auxiliary control designed to create aerodynamic forces to assist in moving a control surface. The tab is positioned by a control rod connected to the fixed surface on the same side as the horn on the tab.
What are four most common types of high lift devices?
Leading and trailing edge flaps, slats, and slots.
Describe some of the tools used to check control surface travel.
A universal propeller protractor, or special control surface protractor.
Name three mechanical methods by which flight control systems may be actuated.
Cables, push pull rods, and torque tubes
What is a fairlead?
It is a device to prevent a cable from rubbing on the aircraft structure.
What are the most likely places for a control cable to wear or break?
Where the cables pass over pulleys or through fairleads.
What information is required before a cable rigging chart can be used?
The ambient temperature and the cable size.
What is the function of a cable tension regulator?
It automatically adjusts the cable tension to compensate for expansion and contraction in the aircraft structure.
Describe the function of a rotorcraft collective pitch control.
The collective control causes each rotor blade to change its pitch angle by the same amount, thus increasing or decreasing the lift produced by the rotor.
Describe the function of a rotorcraft cyclic pitch control.
The cyclic control tilts the main rotor disc by changing the pitch angle of each rotor blade during the cycle of its rotation, which causes the helicopter to move in the direction the rotor tilts
What mechanism is most commonly used to compensate for the torque produced by the main rotor of a helicopter?
The tail rotor
How is the amount of thrust produced by the tail rotor controlled?
By moving the foot pedals.
Why should control surfaces be locked when an aircraft is parked?
To prevent damage from the wind.
What is the major type of damage to aluminum structures that s caused by exposure to the weather?
Corrosion.
Name several methods for forming sheet metal.
Bending or folding, stretching, shrinking, bumping, and crimping.
What are the dimensions of a properly formed rivet head?
The head should be 1 1/2 times the shank diameter in width and 1/2 the shank diameter in height.
Describe the markings found on the heads of A, B, D, AD, and DD rivets.
A rivets are plain, B rivets have a cross, D rivets have a raised dot, AD rivets have a dimple, and DD rivets have double dash.
What happens to the stem of a self-plugging rivet when the rivet is installed?
The stem is pulled until it snaps off and the remaining projecting part is trimmed flush with the head.
Name at least 3 types of self-plugging mechanical lock rivets.
CherryMAX, CherryLOCK, OLYMPIC-LOK and Hucklok rivets
What is the difference between the tools required to pull a CherryLOCK rivet and a CherryMAX rivet?
CherryLOCK rivets require a tool for each different size and head shape, while one pulling tool will set any size CherryMAX rivet.
Which of the five stresses is the most common cause of rivet failure?
Shear.
If a 2024 rivet must e replaced with a 2117 rivet, how do you determine the size to be used?
For 5/32 or smaller diameter, use the next larger size 2117 rivet, assuming that the edge distance and spacing meet the minimum requirements
Describe the process for determining the total length of a solid rivet for a particular installation.
Add the grip length plus 1 1/2 times the rivet diameter.
What minimum edge distance and spacing should be used for a single row of protruding head rivets?
Not less tan 2 rivet diameters from the edge and not less than 3 rivet diameters apart
How can a mechanic determine whether the countersink for a flush rivet should be dimpled or drilled?
By the thickness of the top sheet; thin sheets are dimpled while thick sheets may be countersunk.
What action is taken to prevent cracks from forming while dimpling magnesium or some hard sheet metals?
Hot dimpling equipment is used to preheat and soften the metal before the dimple is formed.
What type of damage can occur when using a rivet set that does not properly fir the rivet?
If the radius of the set is too small, the rivet head may be damaged, whereas a set with an oversized radius may cause damage to the sheet metal.
Why is it important to use the proper size and weight bucking bar when performing sheet metal riveting?
If a bucking bar is too large or heavy it may be difficult to control and may cause damage to the surrounding structure, whereas a buking bar that is too light will not properly upset the rivet before work hardening occurs.
What procedures should be followed to properly remove a solid shank rivet?
Center punch the rivet and then drill just to the base of the rivet head with the same size or one size smaller drill. Once drilled, use a in punch to tip off the rivet head and drive the remaining shank out of the hole while supporting the surrounding metal
What are the two special calculations that must be made when bending sheet metal?
Bend allowance and setback.
What factors must be considered in order to determine setback?
The thickness of the metal and the bend radius.
What is done to a corner where two bends intersect to prevent cracking?
Relief holes are drilled in the corner
What are the 2 reasons for installing a lightening hole in a sheet metal wing rib?
Lightening holes reduce weight and increase stiffness.
When repairing an all metal aircraft, how do you determine what metals should be used?
Always use metal of the same type and thickness as the original structure.
What are the three forms of wood commonly used in aircraft construction?
Solid, laminated, and plywood.
What type of wood should be used when splicing or reinforcing plywood webs?
The same type of plywood as originally used
Name at least four different types of defects found in wood.
Knots, checks, splits, pitch pockets, cross grain, curly grain, decay, dry rot, etc.
Can a section of wood containing a hard knot be used?
Yes, within specified limits.
What type of glue may have been used in older wooden aircraft construction that requires careful inspection to detect deterioration?
Casein glue.
What are the 3 types of glues used in modern aircraft construction and repair?
Resorcinol glue, Phenol-formaldehyde glue, and epoxy resin glue.
Is compression wood acceptable for structural repairs?
No.
Why should the various pieces of wood being joined be kept in the same room for at least 24 hours prior to joining?
To allow the moisture content to equalize, thereby minimizing dimensional changes in the wood.
Why is it important to consider the open-assembly time when gluing wooden structures?
If the maximum open assembly time is exceeded, the joint may fail since he glue may begin setting up before the joint is assembled.
Why is it important to apply the proper clamping pressure to a glue joint?
Clamping forces air out of the joint, brings the wood surfaces together evenly and is, in part, responsible for the strength of the glue line.
Describe a joggle and explain its function.
A joggle is an offset formed at an intersection of two or more sheets of metal to allow the multiple sheets to be stacked flat against each other
Describe some methods used to apply pressure to glue joints.
Clamps, nailing strips, power presses, brads, nails, and small screws.
What minimum curing temperature should be observed when joining wood with various adhesives?
70 Fahrenheit or as specified by the glue manufacturer.
When inspecting wood structures, why might it be important to consider stains and discolored areas?
Stains and discoloration usually accompany decay and/or rot.
Describe the acceptable methods used to repair elongated bolt holes found in a wooden wing spar?
Remove the section containing the elongated hole and splice in a new section or replace the entire spar.
What type of joint is used to splice a solid or rectangular wood spar?
A scarf joint
In what areas are splice to a wood spar prohibited?
Under an attachment fitting for the wing root, landing gear, engine mount, lift, or inter-plane strut.
What is the maximum number of splices allowed for any single spar?
2
Describe the characteristics of a scarf joint.
The pieces to be joined are tapered or beveled on a slope of 1 to 10 or 1 to 12
Why must the beveled cut be accurate on both pieces of wood being repaired with a scarfed joint?
The two pieces must match exactly to ensure a tight glue joint.
What are two primary uses for plywood in aircraft construction?
Gusset plates and aircraft skin.
Provide examples of at least 3 types of plywood skin repairs.
Splayed patches, surface patches, plug patches, and scarfed patches.
What type of patch should be used to repair small holes in thin plywood skin if the skin is less than 1/10th inch thick?
A splayed patch should be used if the hole can be cleared out to a diameter of less than 15 thickness of the skin.
What should be done to prevent a plywood patch and the pressure plate from sticking together if glue is extruded from the joint?
Place a piece of waxed paper or vinyl plastic between the patch and the pressure plate.
Why are lightweight steel bushings sometimes used in wooden structures?
Bushings prevent the wood from being crushed when the bolts are tightened.
What is the purpose of large surface area washers when used on wooden structures?
Large washers provide additional bearing area for hardware to help preclude damage to wood when the hardware is tightened.
Name several facings and core materials used in bonded honeycomb structures intended for special applications.
Stainless steel, titanium, magnesium, plywood, glass, nylon, and cotton cloth.
Describe the construction of a bonded honeycomb structure.
It is a laminated structure that has a solid facing bonded to either side of a core consisting of open, six sided cells.
What must be done with a damaged area in a bonded honeycomb structure prior to beginning repairs?
The area must first be inspected to determine the damaged area prior to completely removing the damaged material.
A drill bit used for drilling composites should operate at approximately what speed?
Use an air-driven tool capable of a free speed of up to 20,000 rpm
What are the most common causes for delamination of a composite structure?
Sonic vibration, expansion of internal moisture, liquid leakage, and a manufacturing error.
What type of defect in, or damage to, a bonded honeycomb structure can be repaired using the potted repair method?
Filling a hole.
Name some of the factors that cause crazing in transparent plastic windows and windshields?
Exposure to UV light, stress, solvents, and improper handling.
How should a hole be drilled in Plexiglass to avoid damage to the hole when the drill breaks through the underside?
Back up the plastic with a piece of wood and feed the drill slowly.
Name he three principle types of welding.
Gas welding, electric arc, electric resistance
What are some advantages of gas shielded arc welding?
The weld is stronger, more ductile, and more corrosion resistant
Which method of welding is less likely to cause buckling or warping of thin metal sheets?
Electric arc welding
What is the purpose of shielding an arc weld with an inert gas?
The gas prevents atmospheric oxygen and or nitrogen from contaminating the weld.
What is a common method of controlling expansion when welding a joint?
Place tack weld along the length of the joint
What is the effect of inadequate penetration on a weld?
The weld will be weak.
Wha is the purpose of the flux used wth brazing and silver soldering?
Th flux cleans the base metal by removing any oxide film
What type of flame is used when torch brazing or silver soldering?
A neutral flame
What must be done to a soldering iron tip to increase the amount of heat transferred from the tip to the work?
The tip must be clean of all contaminants and properly tinned.
What is the preferred method for welding aluminum?
TIG Welding
What is the preferred method of welding magnesium?
TIG welding
What precautions must be observed in order to weld titanium?
All traces of oxygen and nitrogen must be kept away from the weld area.
Describe one type of repair that could be made to a dented steel tube cluster joint.
A formed steel patch plate could be welded over the damaged area.
How can a soft flame be obtained without reducing the heat output of the torch?
Use a larger tip and adjust the gas pressure accordingly.
What factors determine the amount of heat delivered by a gas welding torch?
The size of the torch tip and the gas pressure.
When an oxyacetylene torch is extinguished, which valve is turned of first?
Turn off the acetylene valve first.
When a gas welding project is completed, what safety precautions should be accomplished?
All the valves are turned off and the gas pressures are relieved.
What should be done to a heat treated aluminum part after welded repairs are completed?
The part must be reheat treated
Welding magnesium can create a serious safety hazard. What is the nature of this hazard?
Magnesium burns with a very hot flame that is hard to extinguish.
What technique might be used to enable a tight-fitting inner sleeve to be inserted into a tubular repair?
The inner tube could be chilled with dry ice or in a freezer while the outer tube could be heated slightly with a torch.
Aircraft covering fabrics are made of materials from what two sources?
Organic materials and synthetic materials
How would you determine the strength requirements for fabric used to recover an aircraft?
The fabric must be of at least the quality and strength of the fabric used by the original manufacturer.
What two types of organic fibers are used for covering aircraft?
Cotton and linen
What is meant by warp, weft, and bias?
Warp is the direction along the length of the fabric, weft is the direction across the fabric at right angles to the warp, and bias is a direction 45 degrees to the warp and weft.
What is the purpose of the selvage edge on a roll of fabric?
It prevents it from unraveling.
What identification marking is found on the selvage edge, and in which direction is the warp applied?
The FAA-PMA stamp is found on the edge and the warp is applied parallel to the line of flight.
How are the fabric type and strength requirements determined for fabric covered aircraft?
The original manufacturer determines the fabric type, and the strength requirements are a function of the never exceed speed and wing loading.
What types of synthetic fibers are used for covering aircraft?
Fiberglass and heat shrinkable polyester fibers
Which of the several types of fabric is unaffected by moisture and mildew?
Fiberglass
What is the function or purpose of reinforcing tape?
Reinforcing tape is used between the fabric and the rib stitching to prevent the lacing cord from cutting through the fabric.
Where could you use surface tape?
Over rib stitching and sewed seams, over lapped edges, around corners, along leading and trailing edges.
How should the edges of drainage, inspection, and ventilation holes be reinforced?
With plastic, aluminum, or brass grommets.
What are the principle methods used to test the condition of fabric?
Punch testers such as Maule or Seybolt, and laboratory pull testing
Fabric is considered unairworthy when it has deteriorated to what percentage of its original strength?
Less than 70 precent
How should a structure that will be covered with doped fabric be prepared following inspection and prior to covering?
Treat it with a protective coating of paint or varnish as appropriate
What is the principle advantage of the envelope method for covering wings?
Almost all the seams are machine sewed by the envelope supplier
What is a tie-off knot?
A standard, modified seine knot used on all stitches except the starting stitch
Name three common types of machine sewed seams
Plain overlap, folded fell, and French fell
Where are anti tear strips used?
Under wing rib stitching when the never-exceed speed is greater than 250 mph
How would you determine the correct spacing for rib stitching if the original spacing was unknown?
Consult the chart in AC 43.13 1B
Why is butyrate dope safer to use than nitrate dope?
It is much less flammable
What are the two types of dope used for fabric finishes?
Cellulose Nitrate and Cellulose Acetate Butyrate
What is the appearance of a blushing paint finish?
Chalky or cloudy
What finishing defect is the result of a paint room temperature that is too warm?
Pinholes or blisters
What causes dope to blush?
High humidity, moisture in the spray system, or application over a damp surface.
What factors cause spray paint sags and runs?
Inadequate surface preparation or paint sprayed on too thick
What components or parts of the airframe must be protected from damage when using paint stripper?
Windshields and windows, plastics, composites, synthetic rubber, and fabrics.
What is the function of zinc-chromate or wash primers?
Primers serve to inhibit corrosion and provide a good bond between the metal and the topcoats.
Name several common types of paint used on aircraft
Zinc chromate and wash primers, synthetic enamels, acrylic lacquer, and polyurethane
What is the proper thinner to use with zinc-chromate primer?
Toluene
What health and safety precautions must be observed when using the toxic solvents and thinners that are part of modern finishing systems?
Respirators and or masks must be worn when spraying finishes.
If spray painting dust causes a surface to appear dry and rough, what are the most likely causes?
Too much air pressure or the spray gun is too far from the surface being painted.
What causes “orange peel”
Spray pressure too high, use of a thinner that dries too fast, cold temperatures, or a damp draft over the surface.
What regulation governs the application of the registration numbers to aircraft registered in the United States?
FAR Part 45
Other than appearance, what is another reason for touching up painted surfaces?
Reduction or elimination of general corrosion problems.
What references should used to determine if a control surface must be checked and or rebalanced after painting?
The manufacturer’s service manual.
What would be the effect if dope was used over paint or enamel?
The dope tends to dissolve those materials.
What are the three most commonly used methods of applying paint?
Dipping, brushing, and spraying
What is the effect on paint finishes if too much drier is added to the paint?
The paint film will be brittle and tend to crack and peel.
What paint systems may be used with epoxy topcoats?
Any paint system in good condition.
What could cause an AC electric motor to run too fast?
Excessive applied voltage or shorted field windings.
What tool is used to check a motor or generator armature for shorts and opens under load conditions?
A growler.
When using a growler, what indication will occur when a short exists between an armature segment?
When a metal blade is held over the armature and a short exists in a segment, the blade will begin to vibrate and chatter
How is the output voltage of an alternator controlled?
By varying the field current that excites the alternator.
What instruments are used to monitor electrical system loads?
Ammeters and voltmeters
How would you identify a specific wire in a wire bundle?
By the identification code marked on the wire.
What tool would you use the determine the size of an unmarked wire?
A wire gauge
What color are the navigation lights on the wingtips?
Left wingtip is red and right wingtip is Green
Name several types of electrical devices that would be considered intermittent loads on an electrical system.
Landing gear, cowl and wing flap motors, radio transmitters.
Why would if be necessary to analyze an electrical system before increasing the load on the system?
To determine that the generator capacity, wire size, and protective device capacity will not be exceeded.
What factors should be considered when determining the wire size for a particular application?
The system voltage, permissible voltage drop, current to be carried, wire length and whether the load is continuous or intermittent.
What is the relationship between the inside diameter of a conduit and the outside diameter of a wire bundle inside it?
The conduit must be 25% larger than the wire bundle.
What is the maximum number of terminal lugs that can be placed on a single terminal strip stud?
Four
What is the proper length for a bonding jumper?
As short as practical but long enough to allow free movement of the component
Under what conditions must a switch be derated from its nominal rating?
When used with inductive circuits, circuits with high in rush current, and with DC motors.
At what point do electric motors draw the most current?
When starting
Circuit breakers are designed to open before what condition occurs?
Before the wire emits smoke.
At what point in a circuit should the protective device be located?
As close to the power source as possible.
What type of circuit breaker may NOT be used in an aircraft?
An automatic resetting type
What part of an aircraft is identified by a white navigation light?
The tail
What could cause an AC electric motor to run too slowly
Lack of lubrication, defective wiring, or a low applied voltage.
What should be done when making a bonding or grounding connections between dissimilar materials?
Use a suitable washer so that any corrosion will occur on the washer
Prior to making a continuity check, what must be done to the electrical circuit?
The power must be turned off.
What materials form the bases of the three types of hydraulic fluids
vegetable, mineral, and phosphate-esters
What colors denote mineral based and phosphate ester based hydraulic fluids?
Mineral based are Red, phosphate ester are light purple
What are the results of exposing lacquers, oil based paint, plastic resins, and vinyl compounds to phosphate ester based hydraulic fluid?
The materials will be damaged and or softened, or the paint will peel.
Name several sources used to develop hydraulic pressure.
Hand pumps, Engine driven pumps, and electrically driven pumps
What would cause the bypass valve in a hydraulic filter to open and allow unfiltered fluid to circulate in the system?
A clogged filter element.
Describe several methods of pressurizing a hydraulic reservoir.
Engine bleed air, system pressure acting on a small piston in the reservoir, using variable displacement hydraulic pumps
What feature prevents engine damage if an engine driven hydraulic pump seizes or is overloaded?
A shear section in the pump driveshaft will break, disconnecting the pump from the engine.
Describe the purpose of a pressure relief valve.
Pressure relief valves limit the maximum pressure produced by the pump, thereby preventing failures of the system components
Engine driven pumps deliver the output fluid flow in what two forms?
As a constant volume or variable volume.
Describe the operation of a gear type pump.
Two meshed gears driven by a power source rotate in a housing. Inlet fluid is carried around the outside and delivered to the outlet side as the gears rotate
Describe the purpose of a pressure regulator
Pressure regulators manage the output of the pump to maintain system pressure. They allow the pump to be unloaded so it turns without significant resistance.
What is the device that is used in some systems to supplement the pump outlet during periods of high demand?
An accumulator
What are the three different types of accumulators?
Piston. Diaphragm. Bladder.
What safety precautions must be taken prior to disassembling an accumulator?
Release all of the air preload
When a hydraulic unit is replaced, what precautions should be taken to avoid contamination of the system?
All lines should be capped or plugged immediately after they are disconnected
What types of components or systems are pneumatically operated in some aircraft?
Landing gear, brakes, flaps, and other mechanical actuators
Name several sources for pneumatic power
Storage bottles, engine bleed air, engine driven compressors, or vane pumps
What happens to excess pressure in a pneumatic system?
A relief valve vents it overboard
What is the function of a restrictor in a pneumatic system?
To control the rate of flow of the airflow
What are the reasons for periodically purging a pneumatic system?
To remove moisture and contaminants.
What is the purpose of a torque link on an oleo strut?
To keep the wheel in alignment and prevent the piston from coming out of the cylinder.
A landing gear shock strut should be inflated with what gas?
Nitrogen or dry air
What conditions should a mechanic lock for during a regular inspection of the exposed piston section of a landing gear?
Cleanliness, evidence of damage, and proper extension.
What prevents air from leaking out between the two halves of a split wheel assembly?
An o ring
Why are fusible plugs installed on some aircraft wheels?
To release the pressure generated by heat buildup before a tire blows.
What safety precaution must be taken when removing a wheel from an axle or when disassembling a wheel?
Verify that the tire is completely deflated before removing a wheel from an axle or before wheel disassembly.
What are the visible signs of excessive heating on a wheel bearing?
The bearing surfaces show discoloration.
How are the pilot’s nose wheel steering commands transmitted to the steering control unit of a large aircraft?
Mechanically. Electrically. Hydraulically
How is the nose wheel steering mechanism usually actuated on a small aircraft?
By means of mechanical linkage connected to rudder pedals
What is the name of the unit that prevents a nose wheel from vibrating or oscillating?
A shimmy damper
What are the most common sources of power used to extend and retract landing gear?
Hydraulic pressure and electric motors
At what times should a gear retraction check be performed?
During annual or other inspections and following a hard landing.
What mechanisms ensure that a nose wheel is not turned as it retracts into its wheel well?
Internal centering cams in the strut or an external track
Name several types of brake actuating systems
Independent master cylinders. Boosted Brakes. Power Controlled Brakes.
What is the function of an antiskid system?
Anti skid systems allow large aircraft to achieve maximum braking effectiveness without allowing wheels to skid or lock
What is the purpose of a debooster?
To reduce hydraulic system pressure to a lower value for more satisfactory brake action
Describe two methods of bleeding brakes
A pressure pot can be attached to the bleeder valve and fluid forced back towards the master cylinder and or reservoir, or the master cylinder can be used for forcing fluid from the reservoir to the brakes.
Before a brake system can be inspected for leaks what action must be accomplished?
Pressure must be applied to the system.
What maintenance function has the greatest impact on tire service life?
Ensuring the tires are properly inflated
What effects does under inflation have on aircraft tires?
Internal heat damage possibly leading to premature tire failure, and more tread wear on the shoulders than in the center.
What unit in an antiskid system generates the antiskid warning signal?
The control unit
How is a pilot alerted that an antiskid system has automatically returned to a manual brake system?
By a warning light
What is the significance of an antiskid warning?
The system is off or has failed.
By what usual means does the stall warning system in a small aircraft alert the pilot of an impending stall?
An audible alert and or warning light
What devices are used to provide warnings for a retractable landing gear system?
A horn or other aural device and a red warning light or lights
How can a pilot determine that the landing gear is down and locked?
A green light or lights and or another type of visual indicator.
Name at least two conditions that would activate a takeoff configuration warning system in a jet transport aircraft.
Incorrect leading or trailing edge flap position, stabilizer position, or speed brake not stowed. The manufacturer may establish other conditions.
What landing gear positions must be indicated by regulations
Down and locked. Up and locked
Under what conditions will a landing gear aural warning sound?
When the throttle is retarded and the landing gear is not down and locked
How does a takeoff configuration warning differ from a landing gear warning?
Takeoff warnings are usually an intermittent horns while landing gear warnings are steady
What is the function of a Mach airspeed warning system?
To alert the pilot that the never-exceed speed limit has been reached or exceeded
What systems are commonly used to activate the landing gear warning system?
The throttles and the wing flaps
Why do airplanes with bleed air anti icing of the wing leading edge have anti ice overheat lights?
To indicate an over temperature condition, usually as the result of a break in the bleed air ducts
What warning system may be required when a nickel cadmium battery is installed in an aircraft?
A battery temperature monitoring system
At what time would a check of a landing gear warning system normally be made?
During landing gear retraction test
What is the purpose of an annunciator system?
To show by means of a warning light that some parameter requires attention by the flight crew.
If an aircraft with retractable landing gear has only one green light to indicate the gear is down and locked, how will the switches be connected?
In series
Were would you locate the procedures for checking and adjusting the landing gear switches?
In the aircraft maintenance manual
What is the usual means for alerting the crew of a jet transport that the cabin doors are not properly closed?
A warning light
Why are transport category aircraft equipped with a master caution and a warning system?
To alert crew that a malfunction has occurred and corrective action may be required.
A static check may be performed on a manifold pressure gauge by using what piece of information?
Current atmospheric pressure
What aircraft instrument can be used to check a manifold pressure gauge for proper indication?
The sensitive altimeter
Name several of the indication errors that may be found in altimeters.
Scale errors, hysteresis, friction, installation
What is the signal source in an electrical resistance type temperature indicating system?
A temperature bulb or sensing element
What type of temperature sensing system is normally used to measure a turbine engine exhaust gas temperature?
Thermocouple system
What operating parameter is indicated by a tachometer?
Engine RPM
What is the name of the effect that causes a gyro to respond to an applied force at a point 90 degrees further in the direction of rotation?
Gyroscopic Precession
What are the three sources of power used to drive a gyroscopic turn indicator?
Air from a vacuum or pressure source, or an electric motor.
What are two items that should be considered during inspection of a magnetic compass?
The fluid must be clear. The housing must be full with no bubbles. The compass should be properly calibrated. etc.
In what way do magnetic fields generated by electrical equipment and steel parts in an airplane affect a magnetic compass?
Stray magnetic fields deflect the compass from correct alignment with the Earth’s magnetic field.
Describe the basic operating concept of a synchro type remote indicating system.
A remote transmitter electrically signals a receiver inside the instrument.
What aircraft instruments are connected to the pitot static system?
The altimeter. Vertical Speed Ind. airspeed and Mach meter in high performance jets
Why should you avoid cleaning obstructions from the sensing holes in a pitot static system?
The holes are aerodynamically critical.
After components in a pitot static system have been replaced, what tests or inspections are required?
The static system leak test specified by FAR 91.411
What quantity is accurately measured by a capacitance type fuel quantity indicating system?
The mass of the fuel
Who is authorized to apply the range markings to an instrument dial face?
The manufacturer or a certified instrument repair station.
What is the purpose of a slippage mark on the instrument glass?
To indicate if the glass has moved which could cause incorrect range markings on an instrument
What references should be consulted to determine the proper range markings for aircraft instruments?
The AMM, Flight manual, TCDS or Aircraft Specifications
What is the meaning of a yellow arc on an aircraft instrument?
A caution or limited flight operations range.
What is the reason for swinging a compass and how is it accomplished?
To compensate for deviations, caused by magnetic fields in the aircraft, by adjusting the compensating magnets
What are the basic components of a radio communication system?
A microphone, transmitter, antennas, receiver and speaker or headphones
What frequency range is used by most modern voice communications systems?
VHF 118-136 MHz
What does the term ADF stand for?
Airborne direction finding
What is the function of VOR equipment?
Navigation
Name the components of a typical airborne VOR navigation system
A receiver. Antennas. Frequency selector and a visual display indicator.
What does DME stand for?
Distance Measuring Equipment
At what interval must an ATC transponder be certified?
Every 24 calendar months
Why are two antennas usually required for an ILS system?
The localizer and glideslope signals are transmitted on different frequencies
What information does the glideslope beam provide?
Vertical guidance to enable the aircraft to maintain the correct descent angle
What is the power source for an ELT
An internal battery
Describe one method of monitoring the signal output during an ELT test
Tune a communications receiver to 121.5 MHz
How would you determine if the batteries in an ELT are due for recharge or replacement?
By looking for an expiration date for recharge or replacement on the battery and or in the aircraft maintenance records
At what time is a test of an installed ELT permitted?
During the first 5 minutes after the hour and for no more than 3 sweeps
Where on the aircraft would you expect to find a DME antenna?
On the bottom of the fuselage in a location that isn’t blocked by the wing during turns.
Describe the shape and location of a transponder antenna?
Either a short blade or a short wire with a ball end located on the bottom of the fuselage
Name the basic components of an autopilot system.
Gyros. Servos A controller. Amplifier or computer.
What are the sensing elements of an autopilot system?
Attitude. Directional. Turning Gyros. Altitude Sensor
What is the function of the servos in an autopilot system?
The servos actuate the flight controls
What is the purpose of a bonding jumper from a radio shock mount to the airframe?
To provide a low impedance ground return.
Describe the procedure used to route coaxial cable from an antenna to a receiver
The cable should be supported every 2 feet, bends should be 10 times the cable diameter, and it should be routed separately from other wires.
What controls the temperature in a thermal anti icing system?
Hot and cold air are mixed.
What are the sources of heat for thermal anti icing systems?
Bleed air from the compressor section of a turbine engine, engine exhaust heat exchangers and combustion heaters.
What prevents overheating of the leading edges of a thermal anti icing system operated b engine bleed air
Overheat sensors signal the anti icing valves to close and shut off the hot air
What happens to the hot air used by a thermal anti ice system after it has heated the surface?
The air is dumped overboard
Why is it necessary to provide overheat protection for anti icing systems that use turbine engine bleed air?
The air is hot enough to cause damage to he aircraft structure
What are the effects of arcing on an electrically heated windshield?
Localized overheating and damage to the windshield
Can the operation of an electrically heated pitot tube be checked with the aircraft’s ammeter and if so how?
Yes, turn the pitot heater on and observe the deflection of the ammeter needle.
Describe several potential problems associated with electrically heated windshields
Arcing, delamination, scratches, and discoloration
Why do some pneumatic deicer boot systems have an electrically operated timer?
To automatically cycle the boots, provide the proper rest time, and the recycle the boots
What are the two common methods of inflating pneumatic deicer boots?
Bleed air from a turbine engine or the exhaust from an engine driven vacuum pump
What procedure is used to hold deicer boots flat with the airfoil surface during flight?
Suction is applied to the boots
Why do some deicer boot systems incorporate an oil separator
If a wet pump is used, oil must be removed before it reaches the boots because oil damages the rubber
What methods are used to attach a deicer boot to the leading edges of the wing and tail surfaces?
Adhesives, fairing strips and screws, or a combo of both
What important step should be taken prior to making a cold patch repair to a deicer boot?
Consult the manufacturers service manual and follow the repair instructions explicitly
Describe the methods commonly used to remove rain from a windshield
Windshield wipers, a blast of air, or chemical rain repellant
What power sources are used to operate windshield wipers?
Electricity or hydraulic pressure.
Name two problems associated with in flight operation of aircraft windshield wipers
Insufficient blade pressure caused by aerodynamic forces and failure to oscillate fast enough
Describe the operation of a pneumatic rain removal system
A high velocity air blast prevents the rain from reaching the surface of the windshield
What are the effects of spraying rain repellant on a dry windshield?
It smears and streaks which reduces visibility and is hard to remove when dry
Where would you find information on the acceptable limits of windshield delamination?
In reference material provided by the manufacturer
Is there any specific requirement as to the type of oxygen used in an aircraft system, and if so, what is it?
Only aviators breathing oxygen should be used
Describe the operating principle of a continuous flow oxygen system
High pressure oxygen flows from the storage cylinder to a pressure regulator where its pressure s reduced and then to the mask outlets whenever the system is turned on
Describe the operating principle of a pressure demand oxygen system
Demand systems allow oxygen to flow from the cylinder to the regulator and then to the mask only when the user inhales. Pressure demand systems provide oxygen to the mask at higher than atmospheric pressure when used at extremely high altitudes, forcing oxygen into the users lungs
What should be used to purge an oxygen system of moisture?
Oxygen, dry air, or nitrogen
What action must be taken when an oxygen system has been open to the atmosphere?
the system must be purged of any moisture
Describe the safety precautions that should be observed when servicing oxygen systems
Avoid all contact with petroleum based oil or grease, don’t smoke, keep everything clean, service systems outdoors if at all possible and keep the caps on the bottles to protect the valves
What is a roots blower?
A type of engine driven compressor
Name two different types of independent cabin air compressors
Positive displacement and centrifugal
What is the source of pressurization air in most jet aircraft?
Engine bleed air
What device provides the principle means of controlling cabin pressure?
Outflow valve
What unit regulates the position of the outflow valve?
Cabin pressure controller
Name several methods used on recip engine aircraft for providing heated cabin air
Exhaust shroud heat exchangers, combustion heaters, electric heaters
What is the function of the ventilating air in a combustion heater?
Ventilating air transports the heat from the heater into the cabin and prevents combustion gases from entering the cabin if the combustion chamber develops a crack.
What are the sources of ventilating air in a combustion heater?
Ram air in flight, a blower on the ground, or possibly a compressor if the airplane is pressurized
Name the basic components of an air cycle cooling system
Compressor, expansion turbine, heat exchangers, various valves
Describe the basic operating principles that allow an air cycle system to produce cool air
Hot engine bleed air is cooled in the primary heat exchanger, compressed, then cooled again in the secondary heat exchanger. This air is expanded across the turbine where energy is extracted and the pressure is reduced. This produces a large temperature drop
Describe the basic operating principles of a water separator
Cool, moist air is swirled so that water droplets are separated by a centrifugal force, captured by a sock, and drained
Name the principle components of a vapor cycle system
Compressor, condenser, expansion valve, and evaporator
In what significant way is a vapor cycle cooling system different form an air cycle system?
Vapor cycle uses a refrigerant
Why is oil added to the refrigerant in a vapor cycle cooling system?
To lubricate the compressor
Why do some aircraft have fuel jettison systems?
To allow the crew to reduce the weight of the aircraft down to or below the maximum allowable landing weight
Is there any reason why a fuel jettison system might be required on a small aircraft?
Yes, if the maximum takeoff weight exceeds the maximum allowable landing weight a jettison system should be required
What are some other names for a single point fueling system?
An underwing or pressure refueling system
Why do multi engine airplanes have fuel crossfeed systems?
To allow any engine to draw fuel from any tank
The fuel selector valve for a multi engine aircraft must have at least 3 positions. What are they?
On, OFF, Crossfeed
Why do some fuel tanks have internal baffles?
To resist fuel surging or sloshing caused by changes in the attitude of the aircraft
What are the two types of fuel cells?
Integral or wet wing fuel cells and bladder type fuel cells
What does the term wet wing mean?
It means that sealed portions of the aircraft wing structure form the fuel tanks
How is the weight of the fuel supported when bladder type fuel cells are used?
The bladder is supported by the aircraft structure which contains it
Why do turbine engine aircraft have fuel temperature indicating systems?
To allow the crew to determine if the fuel is cold enough to produce a danger of the formation of ice crystals
Name four types of fuel quantity gauging systems currently in use
Sight gauges, mechanical, electric, and electronic
Why are electronic fuel quantity indicating systems more accurate than other types?
They measure the mass of the fuel instead of the volume
What are drip gauges and sight gauges?
Underwing, bayonet type fuel gauges
What is the purpose of an in transit light associated with an electrically operated fuel tank shutoff valve?
To provide indication that the valve is in motion between one position and another
For what reason is a fuel jettison system usually divided into two separate, independent systems, one for each wing?
To help maintain lateral stability by jettisoning fuel from a heavy wing if necessary
What procedures should be followed regarding gaskets and seals when replacing fuel system components?
All old gaskets and seals should be replaced with new ones
Is it possible for a fuel system to develop a leak that has no visible evidence such as a stain or a spot, if so, how?
An internal component such as a valve could develop a leak
How is a fuel tank checked for leaks following a patch or welded repair?
The tanks is slightly pressurized with air and the repaired area is leak checked with a soap and water solution
Name some advantages of a single point fueling system
It reduces fueling time, reduces chances for contamination and fire, and eliminates damage to the aircraft skin
Why should you wait for a period of time after fueling an aircraft before checking the fuel sumps?
To allow time for water and contaminants to settle to the drain point
Briefly describe the components of a thermal switch fire detection system
Temperature sensitive switches that complete a circuit at a specific temperature and trigger a warning
Are thermal switches wired in series or in parallel with each other?
Parallel
How are the detector units in a double loop Fenwal system wired?
In parallel between two complete loops of wiring
In what way is a thermocouple fire warning system different from a thermal switch system?
Thermocouple systems are sensitive to the rate of temperature change, whereas thermal switch systems respond to a specific temperature value
Breifly describe the components of a Kidde continuous loop fire detection system
A Kidde system has Inconel loop whose resistance changes with temperature
Briefly describe the components and operation of a Lindberg fire detection system
A stainless steel tube contains an inert gas and a discrete material that absorbs some of the gas. When the tube heats up, some gas is released, raising the pressure in the tube, which activates a pressure switch
Describe the process or mechanism by which photoelectric smoke detectors generate a warning of a possible fire
Smoke particles refract light in the detector unit causing the photoelectric cell to conduct electricity and trigger the alarm
How can the operation of a photoelectric smoke detector be tested?
By actuating a test switch
Name two types of smoke detection systems used in aircraft
Light refraction and ionization types
What are the usual locations where a carbon monoxide detector would be installed?
In an aircraft cockpit or cabin
How does a carbon monoxide detector indicate the presence of this deadly gas?
The tan spot on the detector turns gray or black
What are the possible effects of kinks and sharp bends in the sensing elements of a fire warning system?
False fire warnings caused by short circuits
How is a Freon container checked for proper pressure?
A chart must be used to determine the maximum nd minimum gauge pressure readings based on the ambient temperature.
Name the two basic types of fire extinguishing systems.
The conventional system and the high rate discharge system
Name the extinguishing agent most commonly used by a conventional fire extinguishing systems
Carbone Dioxide
Name the extinguishing agent most commonly used by high rate discharge fire extinguishing systems
Halon, also known as freon
How are Freon bottles protected from excessively high temperatures and how can you tell that this has occurred?
A thermal fuse will release the agent if the bottle temperature exceeds a certain limit. This blows out a red indicator disk
What condition is indicated if the yellow disk is missing in a fire extinguishing system?
The system has been discharged normally
Describe the mechanism by which Freon bottle is discharged
An electrical signal fires an explosive squib, which ruptures a frangible disk
How is the service life of a discharge cartridge calculated?
From the date stamped on the cartridge by the manufacturer
Where do you find the regulation that specifies the operating conditions that make 100 hour inspections mandatory?
FAR Part 91
A certified Airframe and Powerplant mechanic may sign off and approve for return to service following what type of inspection?
100 hour inspection
Under what conditions may a mechanic perform an annual inspection and return the aircraft to service
The mechanic must hold an Inspectors Authorization
May an aircraft that is overdue for an annual inspection be flown to a place where the inspection can be performed?
Yes, provided a ferry flight permit is obtained
In order for an individual person to conduct a 100 hour inspection and approve the return to service, that person must have what type of certificate?
Both A and P ratings
An aircraft is required by FAR 91.409 to have a 100 Hour inspection. Is it legal to fly that airplane beyond the inspection requirement and if so for how long?
Yes the aircraft can be operated for up to 10 hours if required to reach a place where the inspection can be accomplished
An airplane is flown 4 hours over the 100 hour inspection limit to reach your maintenance facility. How do you account for those 4 hours?
The 4 hours are included in the next 100 hours time in service period
What types of operation require that aircraft operating under part 91 must undergo 100 hour inspections?
Aircraft operated for compensation or hire, or used for flight instruction when provided by the flight instructor
An aircraft under a progressive inspection program is operated for compensation or hire. Does it need a 100 hour inspection
No, progressive inspections replace 100 hour inspections
Who is authorized to supervise a progressive inspection?
Certified A and P mechanic who hold an IA, certified repair stations, or the aircraft manufacturer
When a progressive inspection program is discontinued, at what time is the next 100 hour inspection due?
100 hours after the last complete inspection of the progressive program
An owner desires to use a progressive inspection program. To whom does the owner apply for authorization?
To the FAA Flight Standard District Office having jurisdiction over the area where the owner is located.
Is an engine run up required as part of a 100 hour inspection?
Yes
Where would you locate the required items that must be recorded in the aircraft maintenance records following completion of a 100 hour inspection?
FAR Part 43
Where might you locate a sample of the recommended statement for recording the approval for return to service of an aircraft following completion of a 100 hour inspection?
FAR Part 43
Where would you look to find approved information for wok on an aircraft electrical system?
In the manufacturers maintenance manual or other instructions for continued airworthiness
What are the limitations placed on mechanics with regard to propellers?
Mechanics may not perform major repairs to or alterations of propellers
After equipment is installed in accordance with an STC, who must approve the return to service?
An A and P with an IA
