General Custom Study Sesh
(1) In nondestructive testing, a discontinuity may be defined as an interruption in the normal physical structure or configuration of a part. (2) A discontinuity may or may not affect the usefulness of a part. Regarding the above statements,
(1) In nondestructive testing, a discontinuity may be defined as an interruption in the normal physical structure or configuration of a part. (2) A discontinuity may or may not affect the usefulness of a part. Statement (1) is true. In nondestructive testing, a discontinuity may be defined as an interruption in the normal physical structure or configuration of a part. Statement (2) is also true. A discontinuity may or may not affect the usefulness of a part.
The Air Transport Association of America (ATA) Specification No. 100 (1) establishes a standard for the presentation of technical data in maintenance manuals. (2) divides the aircraft into numbered systems and subsystems in order to simplify locating maintenance instructions. Regarding the above statements,
(1) establishes a standard for the presentation of technical data in maintenance manuals. (2) divides the aircraft into numbered systems and subsystems in order to simplify locating maintenance instructions Statement (1) is true. The ATA Specification 100 is a standard for arranging and presenting technical data in maintenance manuals. Statement (2) is also true. The ATA Specification 100 divides the aircraft into numbered systems and subsystems to simplify locating maintenance instructions.
(1) Propellers are NOT included in the Airworthiness Directive system (2) A certificated powerplant mechanic may make a minor repair on an aluminum propeller and approve for return to service. Regarding the above statements,
(2) A certificated powerplant mechanic may make a minor repair on an aluminum propeller and approve for return to service.
(1) In the corrosion process, it is the cathodic area or dissimilar cathodic material that corrodes. (2) In the Galvanic or Electro-Chemical Series for metals, the most anodic metals are those that will give up electrons most easily. Regarding the above statements,
(2) In the Galvanic or Electro-Chemical Series for metals, the most anodic metals are those that will give up electrons most easily. Statement (1) is false. It is the anodic, not the cathodic, material that is destroyed in the corrosion process. Statement (2) is true. Corrosion occurs in an anodic material when it gives up electrons to a cathodic material. The more easily a material gives up electrons, the more anodic, or corrosive, it is.
(1) According to 14 CFR Part 91, repairs to an aircraft skin should have a detailed dimensional sketch included in the permanent records. (2) On occasion, a mechanic may need to make a simple sketch of a proposed repair to an aircraft, a new design, or a modification. Regarding the above statements,
(2) On occasion, a mechanic may need to make a simple sketch of a proposed repair to an aircraft, a new design, or a modification. Statement (1) is not true. 14 CFR Part 91 requires that maintenance records contain 'a description (or reference to data acceptable to the Administrator) of the work performed...' There is no requirement in 14 CFR Part 91 that a detailed dimensional sketch of a repair become a part of the aircraft's permanent records. Statement (2) is true. A simple sketch is often needed to help a mechanic make a repair, a new design, or a modification.
(1) Schematic diagrams indicate the location of individual components in the aircraft. (2) Schematic diagrams indicate the location of components with respect to each other within the system. Regarding the above statements,
(2) Schematic diagrams indicate the location of components with respect to each other within the system. Statement (1) is not true. Schematic diagrams do not indicate the location of individual components in the aircraft. Statement (2) is true. Schematic diagrams do show the location of the components with respect to each other within the system.
A certain aircraft bolt has an overall length of 1-1/2 inches, with a shank length of 1-3/16 inches, and a threaded portion length of 5/8 inch. What is the grip length?
.5625 inch. The grip length of a bolt is the length of the unthreaded portion of the shank. If the shank is 1-3/16 (1.1875) inches long, and the threaded portion is 5/8 (0.625) inch, the grip length is 1.1875 - 0.625 = 0.5625 inch.
What force is exerted on the piston in a hydraulic cylinder if the area of the piston is 1.2 square inches and the fluid pressure is 850 PSI?
1,020 pounds. The force exerted on a piston by hydraulic fluid is found by multiplying the area of the piston by the amount of pressure acting on each square inch of the piston. In this problem the area is 1.2 square inches and a pressure of 850 pounds acts on each square inch. The force is 1,020 pounds.
Which of the following statements is/are correct in reference to flare fittings? 1. AN fittings have an identifying shoulder between the end of the threads and the flare cone. 2. AC and AN fittings are considered identical except for material composition and identifying colors. 3. AN fittings are generally interchangeable with AC fittings of compatible material composition.
1. AN fittings have an identifying shoulder between the end of the threads and the flare cone. AN flare fittings have a shoulder between the end of the threads and the flare cone. In AC fittings the threads go all the way to the cone. AN fittings are dyed blue or black and AC fittings are gray or yellow. The threads on an AN fitting are courser than those on an AC fitting. AN and AC fittings are not interchangeable.
Which of the following statements is/are generally true regarding the charging of several aircraft batteries together? 1. Batteries of different voltages (but similar capacities) can be connected in series with each other across the charger, and charged using the constant current method. 2. Batteries of different ampere-hour capacity and same voltage can be connected in parallel with each other across the charger, and charged using the constant voltage method. 3. Batteries of the same voltage and same ampere-hour capacity must be connected in series with each other across the charger, and charged using the constant current method.
1. Batteries of different voltages (but similar capacities) can be connected in series with each other across the charger, and charged using the constant current method. 2. Batteries of different ampere-hour capacity and same voltage can be connected in parallel with each other across the charger, and charged using the constant voltage method. Batteries having different voltages, but similar capacity can be connected in series and charged by the constant-current method. Batteries having the same voltage but different ampere-hour capacity can be connected in parallel and charged at the same time, if they are charged by the constant-voltage method.
Scratches or nicks on the straight portion of aluminum alloy tubing may be repaired if they are no deeper than what?
10 percent of the wall thickness. Scratches or nicks are allowed in a piece of aluminum alloy tubing provided it is no deeper than 10 percent of the wall thickness of the tube, and it is not in the heel of a bend. Scratches and nicks should be burnished out of the tube, to prevent stress concentrations.
A complete detailed inspection and adjustment of the valve mechanism will be made at the first 25 hours after the engine has been placed in service. Subsequent inspections of the valve mechanism will be made each second 50-hour period.From the above statement, at what intervals will valve mechanism inspections be performed?
100 hours. Since the valve mechanism is required to be inspected only every second 50-hour period, the engine can operate for 100 hours between valve mechanism inspections.
The issuance of an Airworthiness Certificate is governed by
14 CFR Part 21. 14 CFR Part 21 entitled 'Certification Procedures for Products and Parts' governs the issuance of an Airworthiness Certificate.
Which regulation provides information regarding instrument range markings for an airplane certificated in the normal category?
14 CFR Part 23. Information regarding instrument range markings that must be used on aircraft certificated in the normal category is found in 14 CFR Part 23, 'Airworthiness Standards: Normal, Utility, Acrobatic and Commuter Category Airplanes.'
What is the speed of a spur gear with 42 teeth driven by a pinion gear with 14 teeth turning 420 RPM?
140 RPM. The speed ratio is the reciprocal of gear ratio. The spur gear with 42 teeth is driven by a pinion gear with 14 teeth. This is a gear ratio of 3:1. The spur gear will turn at 1/3 the speed of the pinion gear. If the pinion gear turns at a speed of 420 RPM, the spur gear will turn at a speed of 420 ÷ 3 = 140 RPM.
What is the speed ratio of an input gear with 36 teeth meshed to a gear with 20 teeth?
1:1.8. The speed ratio is the reciprocal of the gear ratio. The large gear has 36 teeth and the small gear has 20 teeth. This is a gear ratio of 1.8:1, or a speed ratio of 1:1.8.
Which of the following are acceptable to use when utilizing chemical cleaning agents on aircraft? 1. Synthetic fiber wiping cloths when using a flammable agent. 2. Cotton fiber wiping cloths when using a flammable agent. 3. Atomizing spray equipment.
2. Cotton fiber wiping cloths when using a flammable agent. 3. Atomizing spray equipment. When cleaning and/or depainting an aircraft surface with a flammable agent, use only a cotton wiping cloth or a natural bristle brush. Synthetic fibers tend to create unsafe charges of static electricity that could ignite the flammable agent. Emulsion-type cleaning agents may be applied to the surface with atomizing spray equipment. After the agent has penetrated the dirt or exhaust residue, it is scrubbed with a natural bristle brush and washed from the surface.
Liquid penetrant inspection methods may be used on which of the following? 1. porous plastics. 2. ferrous metals. 3. nonferrous metals. 4. smooth primer-sealed wood. 5. nonporous plastics.
2. ferrous metals. 3. nonferrous metals. 5. nonporous plastics. Liquid penetrant inspection methods may be used to detect faults that extend to the surface on both ferrous and nonferrous metals and nonporous plastics
Which of the bolthead code markings shown identifies an AN corrosion resistant steel bolt?
3 The cross on the head of a bolt identifies it as a standard AN bolt made of nickel alloy steel. The cross inside a triangle identifies the bolt as an NAS close-tolerance bolt. The single dash on the head of a bolt identifies it as a standard bolt made of corrosion-resistant steel.
(Refer to Figure 62, 62A, & 62B as necessary.) How many parts will need to be fabricated by the mechanic in the construction and installation of one doubler?
3. The mechanic must fabricate three parts to install the doubler. For the -100 installation, one doubler -101 and two clips -103 are needed. For the -200 installation, one doubler -102 and two clips -103 are needed.
How long does the holder of a certificate issued under 14 CFR part 65 have to notify the FAA after any change in permanent mailing address?
30 days 14 CFR 65.21 states that within 30 days after any change in his permanent mailing address, the holder of a certificate issued under this part shall notify the Department of Transportation, Federal Aviation Administration, Airman Certification Branch, Post Office Box 25082, Oklahoma City, OK 73125 in writing, of his new address.
How much power must a 24-volt generator furnish to a system which contains the following loads? UNIT RATING One motor (75 percent efficient) 1/5 hp Three position lights 20 watts each One heating element 5 amp One anticollision light 3 amp(Note: 1 horsepower = 746 watts)
450 watts. The motor is 1/5 hp, therefore 746 watts (1hp) / 5 = 149 watts. This is the output of the engine. It takes more energy to produce 149 watts -- find this with the efficiency rating, 149/X = 75/100; X = 199. Therefore, the 1/5-horsepower motor that is 75 percent efficient requires 199 watts. The three position lights require a total of 60 watts. The heating element requires 120 watts. The anticollision light requires 72 watts. The total power the generator must produce is 451 watts.
If a double-acting actuating cylinder in a 3,000 psi system has a piston with a surface area of three square inches on the extension side, and a rod with a cross-section area of one square inch attached to the piston on the other side, approximately how much force will the actuator be able to produce when retracting?
6,000 pounds. The force a hydraulic actuator can exert is determined by the area of the piston and the pressure of the fluid acting on the piston. The effective area on the retracting side of the piston is two square inches. 2 sq. in. x 3,000 psi = 6,000 pounds of force
Which of these publications contains standards for protrusion of bolts, studs, and screws through self-locking nuts?
AC 43.13-1B. AC 43.13-1B, on page 7-11 states that 'After the nut has been tightened, make sure that the bolt or stud has at least one thread showing past the nut.'
Technical information about older aircraft models, of which no more than 50 remain in service, can be found in the
Aircraft listing The certification specifications for aircraft of which there are fewer than 50 currently in service, or of which there were fewer than 50 certificated, are found in the Aircraft Listing.
When, or under what condition(s) are adverse loading checks conducted?
Anytime a repair or alteration causes EWCG to fall outside the CG range. When a repair or alteration of an aircraft has been made that causes the empty weight-center of gravity to fall outside the EWCG range, an adverse-loaded CG check should be conducted to determine whether or not it is possible to load the aircraft in such a way that its operational CG will fall outside of its allowable limits.
Which heat-treating process of metal produces a hard, wear-resistant surface over a strong, tough core?
Case hardening. Case hardening is a heat treatment process for steel in which the surface is hardened to make it wear resistant, but the inside of the metal remains strong and tough. Annealing is a heat treatment process for either ferrous or nonferrous metal that makes the metal softer. Tempering is a method of heat treatment in which some of the hardness is removed from a hardened metal. Removing some of the hardness makes the metal less brittle.
Aircraft bolts are usually manufactured with a
Class 3 fit for the threads. A class-1 fit is a loose fit. This is used for coarse-thread stove bolts and square nuts. A class-2 fit is a free fit. It is used on some machine screws. A class-3 fit is a medium fit. It is used on almost all standard aircraft bolts.
The following words are an example of what kind of statement in an AD? 'Required within the next 25 hours time-in-service after the effective date of this AD, unless already accomplished.
Compliance.
The following words are an example of what kind of statement in an AD? 'Required within the next 25 hours time-in-service after the effective date of this AD, unless already accomplished.
Compliance. 'Within the next 25 hours time-in-service after the effective date of this AD,' is a statement of compliance time or date.
What method of magnetic particle inspection is used most often to inspect aircraft parts for invisible cracks and other defects?
Continuous. The continuous method of magnetic particle inspection is used for most aircraft parts because it provides the strongest magnetic field to attract the oxide from the fluid. In the continuous method of magnetic particle inspection, the part is either placed between the heads of the magnetizing machine or held inside the solenoid (coil). Magnetizing current flows while the fluid is pumped over the part. In the residual method of magnetic particle inspection, used for some smaller parts, the parts are magnetized and the magnetizing current is shut off. Only residual magnetism is left in the part to attract the oxide.
Which tubings have the characteristics (high strength, abrasion resistance) necessary for use in a high-pressure (3,000 PSI) hydraulic system for operation of landing gear and flaps?
Corrosion-resistant steel annealed or 1/4H. Rigid tubing made of corrosion-resistant steel, either annealed or 1/4 hard, is used in high-pressure hydraulic or pneumatic systems where high strength and abrasion resistance are important.
How is a flooded engine, equipped with a float-type carburetor, cleared of excessive fuel?
Crank the engine with the starter or by hand, with the mixture control in cutoff, ignition switch off, and the throttle fully open, until the fuel charge has been cleared. A flooded reciprocating engine can be cleared of excessive fuel by placing the mixture control in the CUTOFF position to shut off all flow of fuel to the cylinders. Turn the ignition off, open the throttle and crank the engine with the starter or by hand until the fuel charge in the cylinders has been cleared.
Which tool can be used to measure the alignment of a rotor shaft or the plane of rotation of a disk?
Dial indicator. A dial indicator is used to measure the alignment of a rotor shaft. The dial indicator is clamped to the structure, the contact finger is placed against the surface of the shaft, and the indicator is zeroed. The shaft is rotated and the dial indicator measures the amount the shaft is out of alignment. The plane of rotation of a disk may also be measured with a dial indicator.
Which of the following is NOT considered a method of heat transfer?
Diffusion. Heat can be transferred from a body having a high level of heat energy to a body having a lower level of heat energy by three methods: conduction (actual physical contact), convection (transfer through vertical currents), and radiation (transfer by electromagnetic waves). Diffusion is not a method of heat transfer.
Where should you find this entry? 'Removed right wing from aircraft and removed skin from outer 6 feet. Repaired buckled spar 49 inches from tip in accordance with figure 8 in the manufacturer's structural repair manual No. 28-1.'
FAA Form 337. The description of the repair, as is shown here, would be made on FAA Form 337 (Major Repair and Alteration Form). This form must be completed when an airframe, engine, propeller, or appliance has been subjected to a major repair or major alteration.
Which condition is an indication of improperly torqued cell link connections of a nickel-cadmium battery?
Heat or burn marks on the hardware. Nickel-cadmium batteries are made differently from lead-acid batteries in that the individual cells are removable and are connected together with metal straps secured to the tops of the cells with nuts. If the cell-link connections are not properly torqued, they will cause a high-resistance path for the current. They will become overheated and will show burn marks.
Why should an aircraft maintenance technician be familiar with weld nomenclature?
In order to gain familiarity with the welding technique, filler material, and temperature range used. It is extremely important to make a weld repair equal to the original weld. Identifying the kind of metal to be welded, identifying the kind of welding process used in building the part originally, and determining the best way to make welded repairs are of utmost importance.
What is the opposition to the flow of AC produced by a magnetic field with generated back voltage (EMF) called
Inductive reactance. Alternating current is in a constant state of change; the effects of the magnetic fields are a continuously inducted voltage opposition to the current in the circuit. This opposition is called inductive reactance, symbolized by XL, and is measured in ohms just as resistance is measured. Inductance is the property of a circuit to oppose any change in current and it is measured in henries. Inductive reactance is a measure of how much the countering EMF in the circuit will oppose current variations.
Which of the following may not be detectable even by careful visual inspection of the surface of aluminum alloy parts or structures?
Intergranular corrosion. Intergranular corrosion is an attack along the grain boundaries of an alloy and commonly results from a lack of uniformity in the alloy structure. Intergranular corrosion is difficult to detect in its early stage, and ultrasonic and eddy current inspection methods must be used.
Most modern aircraft are designed so that if all seats are occupied, full baggage weight is carried, and all fuel tanks are full, what will be the weight condition of the aircraft?
It will be in excess of maximum takeoff weight. Most modern aircraft are designed so that if all seats are occupied, full baggage weight is carried, and all fuel tanks are full, the aircraft will be grossly overloaded. It will be in excess of maximum takeoff weight.
What tool is generally used to set a divider to an exact dimension?
Machinist scale. Dividers are not considered to be a precision measuring tool. They are set with a machinist's scale. One of the points of the dividers is placed at the one-inch mark on the scale. The other point is moved out until it touches the mark for the distance you want between the points.
What type of line is normally used in a mechanical drawing or blueprint that indicates invisible edges or contours?
Medium weight short dashes, evenly spaced. A medium-weight dashed line is called a hidden line and is used to show an edge or object not visible to the viewer. A medium solid line is used as a visible outline or object line. Alternate short and long light dashes are used to show a center line.
(Refer to Figure 18.) When the landing gears are up and the throttles are retarded, the warning horn will not sound if an open occurs in wire
No. 4. Wire No. 4 is in the landing gear warning horn ground circuit. If it is open, the warning horn cannot sound when the landing gears are up and the throttles are retarded. Wire No. 2 is in the red warning-light circuit and not in the warning horn circuit. Wire No. 9 is in the green light circuit.
When an aircraft is positioned for weighing on scales located under each landing gear wheel, which of the following may cause erroneous scale readings?
Parking brakes set. When positioning an aircraft on platform type scales for weighing, the parking brakes must be released so there will be no side load applied to the scale platform. Any side load will cause an erroneous scale reading.
In a sectional view drawing, what sections illustrate particular parts of an object?
Removed. A removed section illustrates particular parts of an object. It is similar to revolved sections, except it is placed at one side and, to bring out pertinent details, often drawn to a larger scale than the main view on which it is indicated.
One way a part may be demagnetized after magnetic particle inspection is by
Slowly moving the part out of an ac magnetic field of sufficient strength. A steel part is magnetized by holding it in a strong, steady magnetic field that aligns all of the magnetic domains in the material. It is demagnetized by placing it in an AC magnetic field that continually reverses its polarity. This causes the domains to continually reverse their direction. As the domains are reversing, the part is slowly moved from the field so the domains remain in a disoriented state when the demagnetizing force is removed.
A Technical Standard Order (TSO) is issued by whom?
The Administrator (FAA) TSOs are issued by the Administrator under 14 CFR Part 21
When a Teflon hose has been in service for a time, what condition may have occurred and/or what precaution should be taken when it is temporarily removed from the aircraft?
The hose may have developed a set, or have been manufactured with a pre-set shape, and must be supported to maintain its shape. Teflon hoses develops a permanent set after having been in use for an extended period of time or may have been manufactured with a permanent set for the particular function, thus is should be supported to maintain its shape and prevent inadvertent straightening.
Which statement regarding the hydrometer reading of a lead-acid storage battery electrolyte is true?
The hydrometer reading does not require a temperature correction if the electrolyte temperature is 80°F. When testing the specific gravity of the electrolyte of a lead-acid battery, the temperature must be taken into consideration. No correction is necessary when the electrolyte temperature is between 70°F and 90°F. A correction of 0.4 should be added to the specific gravity reading for each 10° above 80°F, and 0.4 should be subtracted from the specific gravity reading for each 10° below 80°F.
A person installing a product, part, or appliance on a type certificated product must make certain that the item's records document what type of statement?
The product, part, or material meets FAA airworthiness standards.
Which maintenance action is an airframe major repair?
The repair of portions of skin sheets by making additional seams. According to the list of major alterations, major repairs and preventive maintenance listed in 14 CFR Part 43, Appendix A, the repair of portions of skin sheets by making additional seams is considered to be an airframe major repair. Neither of the other alternatives listed here is an airframe major repair.
Which statement is applicable when using a sketch for making a part?
The sketch must show all information to manufacture the part. A sketch is a simple, rough drawing made rapidly and without much detail. A sketch is frequently drawn for use in manufacturing a replacement part. Such a sketch must provide all necessary information to those persons who must manufacture the part.
Which is classified as a major repair?
The splicing of skin sheets. 14 CFR Part 43, Appendix A (b)(1)(xxiv) lists the splicing of skin sheets as an airframe major repair.
What effect, if any, will aviation gasoline mixed with jet fuel have on a turbine engine?
The tetraethyl lead in the gasoline forms deposits on the turbine blades. Many aviation gas turbine engine manufacturers allow the use of some aviation gasoline as a fuel when turbine fuel is not available. The manufacturer limits the amount of time aviation gasoline can be used for two reasons: (1) The tetraethyl lead in the aviation gasoline causes deposits to form on the turbine blades. (2) Aviation gasoline does not have the lubricating properties of kerosine. Using too much gasoline can cause excessive wear on the fuel control.
What is the purpose of adding Tetraethyl lead to aviation gasoline?
To improve the gasoline's performance in the engine. Tetraethyl lead is added to aviation gasoline to increase its critical pressure and temperature. The higher critical pressure and temperature allow the engine to operate with higher cylinder pressures without the fuel-air mixture detonating.
Why is it considered good practice to normalize a part after welding?
To relieve internal stresses developed within the base metal. When a part is welded, it has expanded and been fused to another part. When it cools, stresses inside it try to deform it. After a part has been welded, it should be normalized by heating it to a temperature above its critical temperature and allowed to cool in still air. This heating relieves the stresses in the metal, and the part is not so likely to crack in service.
In order to reconstruct lost or destroyed aircraft maintenance records, what is it necessary to establish?
Total time-in-service of the airframe. Advisory Circular AC 43-9C 12. states that in order to reconstruct lost or destroyed maintenance records, it is necessary to establish the total time-in-service of the airframe.
How long is a mechanic certificate with airframe and/or powerplant ratings valid?
Until surrendered, suspended, or revoked. 14 CFR 65.15 states that a mechanic certificate with airframe and/or powerplant rating is effective until it is surrendered, suspended, or revoked.
How may magnesium engine parts be cleaned?
Wash with a commercial solvent, decarbonize, and scrape or grit blast. Magnesium engine parts are cleaned by washing them with a commercial solvent such as naphtha or Stoddard solvent, then soaking them in a decarbonizer that has been proven safe for magnesium. Any hard deposits that are not removed by this treatment can be removed with a scraper or with a grit blast.
Which maintenance record entry best describes the action taken for a control cable showing approximately 20 percent wear on several of the individual outer wires at a fairlead?
Wear within acceptable limits, repair not necessary. Flexible and extra-flexible control cable should be replaced when the individual wires in each strand appear to blend together (outer wires worn 40 to 50 percent). Since these wires are only worn 20 percent, the wear is within acceptable limits and repair is not necessary.
Fretting corrosion is most likely to occur
When two surfaces fit loosely together and can move relative to one another. Fretting corrosion is a form of corrosion that forms between closely fitting assembled parts that have a slight amount of relative motion. When sheets of aluminum alloy are riveted together, there should be no relative motion between the sheets or between the sheets and the rivets. But if there is a slight bit of movement, the protective oxide coating will be rubbed off of the metal and a new oxide coating will form. The material that has been rubbed off acts as an abrasive and accelerates the wear.
When approving for return to service after maintenance or alteration, the approving person must enter in the maintenance record of the aircraft
a description (or reference to acceptable data) of work performed, date of completion, the name of the person performing the work (if someone else), signature, certificate number, and kind of certificate held. A maintenance record entry that is made after maintenance or alteration must contain the following: 1. A description (or reference to data acceptable to the Administrator) of the work performed; 2. The date of completion of the work performed; 3. The name of the person performing the work if other than the person approving the work for return to service; and 4. The signature, certificate number, and kind of certificate held by the person approving the work for return to service.
A wing with a very high aspect ratio (in comparison with a low aspect ratio wing) will have
a low stall speed. Wings with a high aspect ratio have low drag at high angles of attack, low stalling speed, and good control at low airspeeds. Sailplanes have very high aspect ratios and fly slowly.
When determining the empty weight of an aircraft, certificated under current airworthiness standards (14 CFR Part 23), the oil contained in the supply tank is considered
a part of the empty weight The empty weight of an aircraft certificated under 14 CFR Part 23 includes a full supply tank of engine oil
If the reference datum line is placed at the nose of an airplane rather than at the firewall or some other location aft of the nose,
all measurement arms will be in positive numbers. The reference datum used for weight and balance purposes can be located anywhere the aircraft manufacturer chooses. Current practice is to locate it on or near the nose or out ahead of the aircraft. The reason for this is that all of the arms will be positive (they will all be behind the datum). If all of the arms are positive, the moment of all added weight will be positive, and the moment of all removed weight will be negative. This will simplify weight and balance computations and will give less chance for error.
A drawing in which the subassemblies or parts are shown as brought together on the aircraft is called
an installation drawing An installation drawing is one in which all of the parts and subassemblies are brought together.
The Society of Automotive Engineers (SAE) and the American Iron and Steel Institute use a numerical index system to identify the composition of various steels. In the number '4130' designating chromium molybdenum steel, the first digit indicates the
basic alloying element. In the SAE four-digit numbering system for identifying the composition of steel, the first two digits identify the basic alloy, and the second two digits show the percentage of carbon in hundredths of a percent.
Nickel-cadmium battery cases and drain surfaces which have been affected by electrolyte should be neutralized with a solution of
boric acid. An area that has been affected by the electrolyte from a nickel-cadmium battery should be washed and neutralized with ammonia or a boric acid solution, allowed to dry thoroughly, then painted with an alkali-resisting varnish.
Intergranular corrosion in aluminum alloy parts
cannot always be detected by surface indications. Intergranular corrosion forms along the grain boundaries within an aluminum alloy. Since this type of corrosion does not necessarily extend all the way to the surface of the metal in its early stages, it is quite possible for intergranular corrosion to reach an advanced state before it shows up on the surface.
Spilled mercury on aluminum
causes rapid and severe corrosion that is very difficult to control. Mercury spilled in an aircraft requires immediate action for its isolation and recovery to prevent it from causing corrosion damage and embrittlement of the aluminum structural components. Mercury is highly toxic and spreads very easily from one surface to another.
The speed of sound in the atmosphere
changes with a change in temperature.
One way of obtaining increased resistance to stress corrosion cracking is by
creating compressive stresses (via shot peening) on the metal surface. Stress-corrosion cracking is an intergranular cracking of the metal which is caused by a combination of stress and corrosion. Shot peening a metal surface increases its resistance to stress corrosion cracking by creating compressive stresses on the surface. Any applied tensile stress must first overcome the surface compression before the tensile stress is felt.
The useful load of an aircraft consists of the
crew, usable fuel, passengers, and cargo The useful load of an aircraft is the difference between its empty weight and the maximum allowable gross weight. It does not include any of the fixed or required equipment as these are part of the empty weight.
Working drawings may be divided into three classes. They are:
detail drawings, assembly drawings, and installation drawings.
Fayed surfaces cause concern in chemical cleaning because of the danger of
entrapping corrosive materials. Fayed surfaces are the parts of a structure that are covered in a lap joint. It is important when a structure is chemically cleaned that the fayed surfaces be protected so that corrosive materials do not seep between the sheets in the lap joints. This would cause corrosion to form in an area where it is hard to detect.
Generally speaking, bolt grip lengths should be what?
equal to the thickness of the material which is fastened together.
When a discrepancy list is provided to an aircraft owner or operator after an inspection, it says in effect that
except for these discrepancies, the item inspected is airworthy. Advisory Circular AC43-9C 10. b. states that when a discrepancy list is provided to an owner or operator, it says, in effect, except for these discrepancies, the item inspected is airworthy.
Magnetic particle inspection is used primarily to detect
flaws on or near the surface. Magnetic particle inspection is used to detect flaws in ferromagnetic material on or near the surface. These flaws form north and south magnetic poles when the part is magnetized. Iron oxide suspended in a fluid pumped over the part is attracted to and held by the magnetism and it outlines the flaw.
The core material of Alclad 2024-T4 is
heat-treated aluminum alloy, and the surface material is commercially pure aluminum. Alclad 2024-T4 is a type of sheet metal that has a core of 2024-T4 solution-heat-treated aluminum alloy. Commercially pure aluminum is rolled onto the surfaces of the sheet for corrosion protection. The name Alclad is a registered trade name
A line used to show an edge which is not visible is a
hidden line. A phantom line is a light line made up of an alternate long dash and two short dashes. A phantom line shows the location of a part that is used as a reference. A hidden line is a medium-weight, dashed line that shows a surface or a part that is not visible from the view in which it appears. A break line is a wavy or a zigzag line used to show that a part has been broken off and only part of it is shown.
The testing medium that is generally used in magnetic particle inspection utilizes a ferromagnetic material that has
high permeability and low retentivity. The testing medium used to indicate the presence of a fault in magnetic particle inspection is a finely ground iron oxide that has a high permeability and low retentivity, and is nontoxic. It is usually suspended in a light oil such as kerosine.
The term that describes the combined resistive forces in an ac circuit is what?
impedance.
Maximum zero fuel weight is the
maximum permissible weight of a loaded aircraft (passengers, crew, and cargo) without fuel. The zero fuel weight of an aircraft is the maximum allowable weight of the loaded aircraft without fuel. The weight of the cargo, passengers, and crew are included in the zero fuel weight.
(1) Private aircraft are required by regulations to be weighed periodically. (2) Private aircraft are required to be weighed after making any alteration. Regarding the above statements,
neither No. 1 nor No. 2 is true. Statement (1) is not true. No Federal Aviation Regulation requires that private aircraft be weighed periodically. Statement (2) is not true. When a private aircraft is altered, the weight and balance records must be updated to show any change that has been made in the weight or in the empty-weight CG location. These changes are normally found mathematically rather than by actually weighing the aircraft.
Metal tubing fluid lines are sized by wall thickness and
outside diameter in 1/16 inch increments. Metal tubing used in aircraft fluid power installations is sized by its outside diameter, which is measured fractionally in sixteenths of an inch.
When stopping a nosewheel-type airplane after taxiing (or towing), the nosewheel should be left
pointed straight ahead. When stopping an airplane that is equipped with a nosewheel, the nosewheel should be left straight ahead to relieve any strain on the nose gear and to make it easier to start moving straight ahead.
An airplane wing is designed to produce lift resulting from
positive air pressure below the wing's surface and negative air pressure above the wing's surface along with the downward deflection of air. Aerodynamic lift is produced on an airfoil by the pressure difference across the airfoil along with the downward deflection of air. The pressure below the wing surface is greater than that above the wing. The pressure below the wing may be considered positive and that above the wing negative.
The control valve switch must be placed in the neutral position when the landing gears are down to
prevent the warning horn from sounding when the throttles are closed. If the control-valve switch were not in the neutral position, as shown here, the landing gear warning horn would sound when either throttle is closed and both landing gears are down. The ground for the horn would be supplied through wire 6, the closed throttle switch, wires 5 and 10, the control valve switch, wire 11, the right gear switch, wire 3, the left gear switch, and wire 14 to ground.
Excessive stress on fluid or pneumatic metal tubing caused by expansion and contraction due to temperature changes can best be avoided by
providing bends in the tubing. Never select a path for a rigid fluid line that does not require bends in the tubing. Bends are necessary to permit the tubing to expand and contract under temperature changes and to absorb vibration.
A certificated mechanic shall not exercise the privileges of the certificate and rating unless, within the preceding 24 months, the Administrator has found that the certificate holder is able to do the work or the certificate holder has
served as a mechanic under the certificate and rating for at least 6 months. A certificated mechanic shall not exercise the privileges of the certificate and rating unless, within the preceding 24 months, the Administrator has found that the certificate holder is able to do the work or the certificate holder has served as a mechanic of the certificate and rating for at least six months.
The empty weight of an airplane is determined by
subtracting the tare weight from the scale reading and adding the weight of each weighing point. When an aircraft is to be weighed, it is placed on the scales and chocked to prevent its rolling. The weight of the chocks is called tare weight. The empty weight of the aircraft is found by subtracting the tare weight from the scale readings, to get the net weight. The net weight from each weighing point is added to get the total net weight which is the total empty weight of the aircraft.
In a metal tubing installation,
tension is undesirable because pressurization will cause it to expand and shift When making an installation of rigid metal tubing, each run of the tubing must have at least one bend in it to allow for the shifting of the line as it is pressurized. There must be no tension on the line (the flare in both ends of the tube should rest squarely on the flare cones of the fittings and not have to be pulled into place with the nut).
The voltage drop in a circuit of known resistance is dependent on what?
the amperage of the circuit. The voltage drop across a circuit is determined by two things: the resistance of the conductor and the amount of current flowing through it (the amperage). In this question, the resistance of the circuit is fixed; therefore, the voltage drop is determined by the amperage in the circuit.
When computing weight and balance, an airplane is considered to be in balance when
the average moment arm of the loaded airplane falls within its CG range.
During discharge, nickel-cadmium batteries will show a lower liquid level than when at full charge because
the electrolyte becomes absorbed into the plates. If a nickel-cadmium battery is stored for a long period of time, some of the electrolyte in the cells will be absorbed into the plates, and the level will drop. The electrolyte level will rise when the battery is given a freshening charge before it is put into service.
Jet fuel number identifiers are
type numbers and have no relation to the fuel's performance in the aircraft engine. Jet engine fuel identification numbers (JP-4, JP-5, Jet A, Jet A1, and Jet B) are identification numbers only and do not relate in any way to the performance of the fuel in the engine.
A gas or fluid line marked with the letters PHDAN is
used to carry a hazardous substance. PHysically DANgerous The marking PHDAN on a fluid line indicates that the fluid carried in the line is physically hazardous and dangerous to personnel.
A fuel that vaporizes too readily may cause what?
vapor lock. If a fuel vaporizes too readily, it has a high vapor pressure. It requires a high pressure to keep the vapors in the fuel. Vapors that form in a fuel line can prevent liquid fuel flowing through the line and can stop the engine because of fuel exhaustion. This is a vapor lock.
Aspect ratio of a wing is defined as the ratio of the
wingspan to the mean chord. The aspect ratio of a wing is the ratio of the wing span to the mean, or average, chord. For a non-rectangular wing, aspect ratio is found by dividing the square of the wing span by the wing area.
