Jeppesen Generals

Give one advantage of pre-preg (pre-impregnated) materials, other than saving time in the construction or repair of composite components.

1. Pre-preg fabrics contain the corect amount of matrix. 2. The matrix material evenly and completely permeates the reinforcing fibers. 3. The matrix has the resin and hardener in the correct proportions.

What is indicated by the markings on the heads of solid rivets?

The material that they are made of, and indirectly, their strength.

How can you keep heat treated aluminum alloy rivets soft enough to install after the quenching process?

If the rivets are stored in a freezer they will remain soft for several days.

What is the grip length of a bolt?

The length of the unthreaded portion.

In what way are AN standard steel bolts identified?

By the code markings on the bolt heads.

What is the difference between a close tolerance bolt and a general putpose bolt?

Close tolerance bolts are machined to more accurate dimensions.

For what types of applications are self-locking nuts not allowed?

Self locking nuts may not be used either the bolt or the nut is subject to rotation.

If the maintenance procedures do not specify a torque value for a bolt or nut, how can you determine the proper values?

Consult a standard torque table such as found in AC 43.13-1B.

What is most commonly used type of aircraft control cable?

Extra flexible 7 x19 stainless steel cable.

What type of precision measuring instruments can be used to measure the outside dimensions of aircraft parts?

Outside micrometers and vernier calipers.

For what reasons should a micrometer be periodically calibrated?

If dropped, its accuracy may be affected, or if the spindle is over-tightened, the frame may be sprung, or continually sliding objects between the anvil and the spindle may wear the surfaces.

What are the two types of fluid lines commonly found in aircraft?

Rigid metal lines and flexible hoses.

Describe the method of classifying metal tube according to size.

Metal tubing is sized according to wall thickness and outside diameter. Outside diameter is measured in 1/16th inch increments.

When installing stainless steel tubing, what type of fitting should be used?

Stainless steel fittings.

What is the function of the sleeve on a flared-tube fitting?

The nut fits over the sleeve and draws the sleeve and the tubing flare tightly against the male fitting to form the seal.

Describe the two types of flares commonly used on aircraft tubing.

The single flare and the double flare.

How can you determine if a fitting is an AN type rather than an AC type?

AN fittings have a shoulder between the flare cone and the end of the threads, AC fittings do not.

What are the most significant differences between AN and AC fittings.

Sleeve length, thread pitch, and the shoulder between the threads and the flare cone on AN fittings.

What are the names of the parts of a flareless tube fitting?

The nut and the ferrule or sleeve.

How can you tell a flareless fitting from a flare-type fitting?

Flareless fittings don't have a flare cone and there is no space between the threads and the end of the fitting.

What is the effect of over-tightening a flare type fitting?

The sealing surface may be damaged or the flare cut off.

In addition to being securely clamped, what is an additional requirement for installing metal fuel, oil and hydraulic lines?

The lines must be electrically bonded to the structure.

What are some of the important advantages of Teflon tubing?

It is compatible with nearly every liquid, has a broad operating temperature range, low resistance to fluid flow and has a very long shelf and service life.

Describe the identification markings commonly found on flexible hoses.

A lay line, identification such as a Mil Spec number, the manufacturers name or symbol, the hose size and a date code.

How can you determne if a flexible hose has been correctly or incorrrectly installed?

The lay line will be straight if the hose is properly installed. A twisted lay line indicates an incorrect installation.

How are flexible hose sizes designated?

By the inside diameter, measured in 1/16th inch increments.

What precautions must be observed when deburrring the end of a tube after it is cut?

The wall thickness must not be reduced in size or fractured.

Describe the operation of quick disconnect couplings.

Each half has a valve that is held open when coupled and spring-loaded closed when disconnected.

If you fabricate a replacement for a flexible hose, what percent of the total length must be added to allow for movement under pressure?

5 to 8 percent.

What happens to the tube when a flareless fitting is overtightened?

The tube is weakened when the nut drives the cutting edge of the sleeve too deeply into the tube.

Why are quick disconnect fittings used?

To provide a quick means to connect or disconnect a fluid line without loss of fluid or entrance of air into the system.

Describe the steps involved in dye penetrant inspection.

The surface is cleaned, and then penetrant is applied to dwell for a specified time. The penetrant is then removed with an emulsifier or cleaner. Once removed, the part is dried and then developer is applied. The results are then inspected and interpreted.

Name some tools that are commonly used to assist in making visual inspections of welds.

A magnifying glass, flashlight, mirror and, possibly, a borescope.

What are some of the non-destructive testing methods that may be used on aluminum parts?

Visual, dye penetrant, eddy current, ultrasonic testing and radiography.

What process occurs during the preparation stage of a dye penetrant inspection when the penetrating liquid is applied, and then removed from a cracked part?

The penetrant enters the crack by capillary action and remains there until made visible by the developer.

A correctly made weld will have what bead width and how much penetration?

The bead width should be 3 to 5 times the thickness of the base metal and there must be 100%.

What tell tale characteristics are evidence of a cold weld?

A cold weld has rough, irregular edges that are not feathered into the base metal and has variation in penetration amounts.

The penetration of a fillet weld should be what percentage of the thickness of the base metal?

25 to 50 percent.

Describe the basic steps for conducting a magnetic particle inspection.

Magnetize the part, then coat the surface with ferromagnetic particles. If a defect or discontinuity is present, the particles align with the discontinuity forming a visible pattern.

Is there any requirements for cleaning an aircraft prior to an annual or 100 hour inspection?

It is not only good, common sense, but it is a legal requirement as specified in FAR Part 43, Appendix D.

Discuss the general precautions that should be observed when washing an airplane.

Avoid or protect areas, which may be damaged or contaminated, such as: Pitot and static ports, hinges, sealed areas, and bearings.

What are some of the more common light-duty cleaning agents?

Soap or detergents and water.

What materials are commonly used as heavy duty cleaners?

Solvents and emulsions.

What are the preferred cleaners for plastic surfaces such as windshields?

Mild soap and water or a manufacturer approved cleaner.

What type of cleaning agents should be used to remove grease, oil or fuel from aircraft tires?

Soap and water.

Give at least three examples of the factors that cause or influence corrosion.

1) The environmental conditions 2) The presence of dissimilar metals. 3) The type of metal. 4) The presence of electrolytes and/or contaminants. 5) The condition of protective coatings.

Name at least three forms of corrosion.

1) Surface. 2) Intergranular 3) Filliform 4) Dissimilar metal (or galvanic) 5) Oxidation. 6) Pitting 7) Stress. 8) Fretting

Name at least one cause of filliform corrosion.

1) Improper or incomplete curing of a wash primer prior to painting.

2) Failure to completely wash off acidic surface contamination.

What are the visible signs of filliform corrosion?

Blistered paint surfaces or worm or thread-like tracks or patterns under the paint.

What are two primary factors that may cause development of stress corrosion cracks?

A corrosive environment and sustained tensile stress.

What are the visible signs of fretting corrosion?

The corrosion residue has a dark, smoky appearance and often appears around and streaming back from rivet heads.

Why are piano-type hinges prime spots for corrosion?

The steel pin and aluminum hinge material are dissimilar metals and the hinge design tends to trap moisture and contaminants.

What is the best way to protect piano hinges from corrosion?

Keep them clean and properly lubricated.

Provide at least four examples of procedures used to prevent corrosion.

1) Cleaning 2) Lubrication 3) Treatment 4) Sealing 5) Inspection 6) Installing protective covers 7) Keeping drain holes free and clear.

Describe the tools that should be used to remove corrosion from anodized aluminum surfaces.

Nylon scrubber pads such as Scotch-Brite, bristle brushes, aluminum wool, or aluminum wire brushes.

Describe the effects of using steel brushes or steel wool to remove corrosion from aluminum surfaces.

Steel brushes or steel wool must not be used aluminum because steel particles can become embedded in the aluminum and cause corrosion.

What is the purpose of Alodine?

Alodine is a chemical process that deposits a protective film on aluminum alloys. This film improves corrosion resistance and paint adhesion.

For what reason should you avoid cleaning anodized aluminum surfaces with aluminum metal polish?

Aluminum metal polish should not be used on anodized aluminum surfaces because it will remove the oxide coat.

Why should aircraft fabrics and plastics be cleaned only with recommended cleaners?

Recommended cleaners cause the least amount of deterioration or damage.

List at least five examples of areas in an aircraft that are prone to corrosion.

1) Battery compartments 2) Exhaust trail areas 3) Bilge areas 4) Vent areas 5) Landing gear and wheel wells 6) Fuel tanks 7) Wing flap recesses 8) Around and below galleys and lavatories 9) Piano Hinges 10) Any area that can trap water

Name at least three possible hazards that may be encountered during typical ground operations, such as during engine run-up or taxiing?

The possibility or fire, especially during engine starting. Turning props, rotors, prop or jet blast and inlet areas. Other aircraft, vehicles, people and obstacles. Foreign objects such as rocks, gravel, rags, or loose hardware. High noise levels that might cause hearing damage. Hydraulic lock in radial engines. Weathervaning of tailwheel aircraft.

What is the most generally used knot for tying down small aircraft?

The bowline (although other anti-ship knots may be used).

Describe the precautions that should be taken to protect life and property while starting and running an aircraft engine.

Study the procedures in the airplane flight manual. Be sure propeller intet area is clear and check for loose stones, gravel etc. that could be sucked into the prop or engine. Also ensure that the prop or jet blast doesn't blow into hangars or other airplanes, and have a fire guard nearby.

If an engine induction fire occurs while starting a reciprocating engine, what procedure should be followed to extinguish the fire?

Continue cranking the engine to start it and suck the fire into the engine. If the engine doesn't start and the fire continues to burn, discontinue the start attempt and extinguish the fire with a suitable fire extinguisher.

What safety procedures must be observed when hand-propping a small aircraft engine?

Become thoroughly trained. Have a qualified person in the cockpit, check the brakes, call "SWITCH OFF" before moving the prop, and make sure you have solid footing. When ready to start, call "CONTACT" and listen for the reply. Swing the prop with the flat of your hand and move back from the prop arc.

What procedure should be followed prior to starting a large engine to detect and/or prevent a hydraulic lock in the cylinders?

Pull the propeller through by hand for three or four complete revolutions. Resistance to the prop turning indicates a possible hydraulic lock in at least one of the cylinders.

What is the cause of hydraulic lock in large radial engines?

Oil seeps by the piston rings and accumulates in the combustion chamber of lower cylinders. When a piston comes up on its compression stroke, the incompressible liquid seizes it.

What is meant by the term "Hot Start" when starting a jet engine?

Ignition occurs with an excessively rich mixture, leading to a rapid temperature rise that can exceed the exhaust gas temperature limit.

When towing an aircraft, should you use the tow vehicle or aircraft brakes to stop the aircraft?

The tow vehicle brakes should be used except in an emergency - then the aircraft brakes may be used.

Why should an aircraft technican become familiar with standard light signals?

Light signals may be used when taxiing an airplane without a radio or when a radio becomes inoperative on a tower controlled airport.

If a mixture of aviation gasoline and jet fuel is used in a reciprocating airplane engine, what are the possible results?

Avgas contaminated by jet fuel must not be used in piston engines - the engine may be damaged or destroyed.

What does the number 100 signify in 100LL aviation gasoline?

It refers to the lean mixture performance number (or octane rating) of the fuel.

Is it permissible to use avgas in a turbine engine?

Limited operation may be allowed by the manufacturer. Continued use may reduce efficiency due to lead deposits on the turbine blades.

What are some of the possible outcomes of using a lower grade of avgas than the specified grade?

An increased chance of engine damage due to detonation, loss of engine power, and an increased probability of overheating.

Part 23.973 of the FAA regulations specifies that certain markings must be placed adjacent to fuel filler openings. What markings are used for reciprocating engine-powered airplanes?

The filler openings must be marked with the fuel grade and word "AVGAS".

Describe the important precautions that should be observed when fueling an aircraft.

Be certain you are using the correct fuel, properly ground the aircraft and refueling unit, and protect the aircraft surfaces from hose and nozzle damage.

The marking requirements for oil tank filler openings are specified by FAR23.1157. What markings are required for a piston engine powered airplane?

The word "OIL" and the permissible grades and/or types or a reference to the appropriate Airplane Flight Manual for permissible grade and/or types.

Where can the standard aircraft taxi hand signals be found?

In the aeronautical information manual (AIM).

Under what conditions should a reciprocating engine be pre-oiled?

Prior to starting a new engine or one that has been preserved for storage. This ensures adequate lubrication on initial startup.

Under what conditions may automobile gasoline be used in an aircraft engine?

Only if approved by the FAA, usually by the issuance of a Supplemental Type Certificate (STC).

What are the indications of water in aircraft fuel after draining a sample from the fuel sumps?

The sample may have a cloudy or hazy appearance or a solid slug of water.

What federal aviation regulation prescribes the requirements for issuance of a type certificate?

FAR (14 CFR) Part 21.

What part of the FARs describes the airworthiness standards for Transport Category airplanes?

FAR part 25.

What part of the FARs describes the performance chatacteristics that a small aircraft must demonstrate in order to be airworthy?

FAR Part 23.

Who is responsible for ensuring that only the most current information is used when performing maintanance on an aircraft?

The person performing the maintenance.

Why are Airworthiness Directives issued?

To correct unsafe conditions found in aircraft, engines, propellers, or appliances.

How does the FAA notify aircraft owners of unsafe conditions that must be corrected?

By issuing Airworthiness Directives.

How do you determine the timeframe within which AD compiance is required?

The AD contains the compliance time or period for completing the corrective action.

If a mechanic wishes to develop a checklist for an annual or 100-hour inspection, what publication contains the guidelines for the required inspection items?

FAR Part 43, Appendix D contains the scope and detail of an inspection checklist.

How can you determine if the repair of damage is a major or minor repair?

FAR Part 43, Appendix A defines major and minor repairs as well as preventive maintenance.

What publication might you consult for guidance when maintaining an old aircraft for which no maintenance manual exists?

AC43.13-1B or its latest revision.

What are Advisory Circulars?

Non-regulatory information of interest to the aviation public.

What publication would you consult to determine an aircraft's (or engine's or propeller's) type design and its limitations?

The Type Certificate Data Sheeets and/or Aircraft Specifications.

In what FAA publication could you find a list of engines approved for use in a specific make and model of airplanes?

In the Type Certificate Data Sheets and/or Aircraft Specifications.

What reference material can be used to determine if an aircraft is certificated in more than one category?

In the Type Certificate Data Sheets and/or Aircraft Specifications.

What is the name of the manual that the manufacturer provides to technicians who normally performs work on the systems and components of an aircraft?

The aircraft maintenance manual.

Under what circumstances is compliance with a manufacturer's service bulletin mandatory?

When the service bulletin is incorporated into an AD (or other approved data).

What kinds of publications are used by aircraft manufacturers to notify owners of design defects and product improvements?

Service Bulletins, Service Letters and Service Instructions.

If you need to determine the serviceable dimensional limits for an engine part, what publication would you consult?

The current engine manufacturer's overhaul manual.

How often is the summary of AD's published?

Every two years.