General 2 Flashcards
Name the parts of a military standard flareless tube fitting
-body
-sleeve
-nut
What type fitting materials should be used with stainless steel tubing?
Stainless steel
What is the purpose of a sleeve on a flared tube connection?
The nut and sleeve together when tightened will draw the sleeve and tubing flare slightly against the male fitting to form a tight seal
What happens to a flareless tube fitting when it is over tightened?
The nut drives the cutting edge of the sleeve deeply into the tube, causing the tube to be weakened
What are the identification markings usually found on flexible rubber hose?
-Lay line
-hose size
- Date of manufacture
- Pressure and temperature limits
Name at least two synthetic material materials commonly used in the manufacture of flexible hose
- Buna-N
- Neoprene
- Butyl
- ethylene propylene diene monomer (EPDM)
- Teflon
When selecting a flexible hose for use in phosphate Ester based hydraulic fluid system, the hose should be made of which synthetic rubber compound?
Butyl
What is the maximum interval for repeating the required markings on a flexible hose?
No more than 9 inches along the length of the hose
What percentage of flattening is allowed when bending metal tubing?
No more than 75% of the original diameter
How can you determine if a fitting is an AN type rather than an AC type?
AN fittings have a shoulder
AC fittings do not have a shoulder
What are the most significant differences between AN and AC fittings?
- Sleeve length
- Thread pitch
- the shoulder between the threads and the flare cone on AN fittings
How do you tell a flareless fittings 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 grounding to the structure
What are some of the most important advantages of TEFLON tubing?
- compatible with most fluids
- Wide temperature range
- Low resistance to fluid flow
- Long shelf and service life
Describe the operation of quick disconnect couplings:
Each half has a valve that is held open when coupled and is spring loaded closed when disconnected
Why are quick disconnect fittings used?
Quick means to connect or disconnect a fluid line without loss of fluid and entrance of air into the system
When fabricating a flexible hose what percent of the total length must be allowed for freedom of movement under pressure?
5 to 8% of its total length
How can you tell that a flexible hose has been installed in a twisted position?
A twisted lay line
Name at least two considerations when installing flexible, hose assemblies
- Slack
- Flexing
- Twisting
- Bending
- Clearance
- clamping
Scratches and nicks may be repaired IF they are less than what percentage of the wall thickness?
10%
Flexible hoses should be clamped every how many inches at least?
24
What is the difference between flare angles for aviation and automotive flares?
45° flares are used on cars
35° to 37° are used in aviation
Which steel alloy is noted for its toughness and is most commonly used for aircraft structures, frame members, engine mounts, landing gear, parts, and other structural parts?
Chrome Molybdenum steel
What type of cable is commonly used in primary control systems?
Extra flexible 7 x 19 stainless steel cable
When performing a penetrant inspection what happens when the penetrant is applied and removed from a part that is cracked?
The penetrate liquid enters the crack and remains there in order to make the crack visible after the developer is applied
What is the procedure for performing a dye penetrant inspection?
- Clean the surface
- Apply a penetrant
- Remove the penetrate with an emulsifier or cleaner
- Dry the area
- Apply a developer
- Interpret the results
What NDT methods could be used for detecting surface cracks in aluminum fittings?
- dye penetrant
- x-ray
- ultrasonic
- Eddy current
- visual inspection
Which NDT method can be performed without removing the surface coatings, such as primer, paint and anodized films?
Eddy current
Thermoplastic and Thermosetting resin are commonly used in modern aircraft for what reasons?
Thermoplastic – windows and windshields
Thermosetting - matrix material in composite structures
Name, one material commonly used as the reinforcing component in structural composite laminates?
- aramid -Kevlar
- fiberglass
-Graphite
Name, one substance commonly used as the matrix material in structural composite laminates
-polyester resin
-Epoxy resin
Why is a tire cage recommended when inflating aircraft tires?
To prevent possible personal injury due to the tire or wheel failing
What are the starting safety procedures when hand propping a small engine?
Fuel on, switch off, throttle closed, and brakes on. “ contact” is called out in the switch is placed ON. Be sure the ground is firm and do not lean into the propeller arc.
What is the procedure for extinguishing reciprocating engine induction system fires that occur during starting?
Continue cranking to start the engine and blow out the fire. If engine does not start in the fire continues to burn discontinue starting and have fire guard extinguish the fire.
What is meant by the term “HOT START” when starting an aircraft turbine engine?
It means the engine operating temperature exceeded the specified limits during start
What are the physical and safety requirements for starting and running a powerplant?
- use that proper checklist
-Position the aircraft into the wind - check propeller and/or jet intake area
- secure external power cart
- Use a fire guard
Why should fingers not be curled over the prop when hand propping an engine?
Kickback from the engine may break them or draw your body into the blades propellers
When towing an aircraft with a tow vehicle, which breaks are used when the aircraft is to be stopped?
The tow vehicle breaks. The aircraft brake should only be used in emergency conditions.
Why should aviation mechanics know standard light signals?
They can be used for taxi control when taxing aircraft without a radio or when the radio becomes inoperative on a tower controlled airport
Where are aircraft hand signals published?
Aeronautical information manual (AIM)
What are some typical ground operation hazards to watch for or take precautions against?
- FOD
- Other aircraft
- Noise levels
- Hydraulic lock
- The possibility of fire
- Jet blast and jet intake areas
Under what conditions should a reciprocating engine be pre-oiled?
Prior to starting a new engine or one that has been preserved for storage
What is meant by a ratio and how is a ratio expressed?
A fraction that compares one number to another ex. 6:2
What is the base in the following expression? 10^3
10
How do you write 0.00000096 in scientific notation?
9.6×10^-7
What is the exponent in the following expression? 10^3
3
What is meant by scientific notation?
A method of writing very large or very small numbers, using powers of 10
How do you write 56, 000, 000 in scientific notation
Move the decimal to the left or right until there is one non-0 integer on its left. If you moved the decimal to the left, you’ll multiplied by 10 times the number you moved it to the left, so 56, 000, 000 would be 5.6×10^7
Where may a mechanic find an example of a 100 hour inspection maintenance record entry?
FAR part 43.11
