Airframe Flashcards
For maximum strength of a formed sheet metal fitting, should the bend be made along or across the grain of the metal?
Across the grain
What determines the minimum bend radius that can be used when forming a sheet metal structural fitting?
Alloy
Metal thickness
Hardness
What is meant by the neutral axis in a sheet of metal?
A plane within the metal that neither stretches nor shrinks when the metal is being bent
What is a mold line in the development of a flat pattern for a formed metal part?
An extension of the flat sides beyond the radius
What is the bend tangent line?
A line in a flat pattern layout at which the bend starts
What is meant by setback?
The distance the jaws of a brake must be set back from the mold line to form a bend
What is meant by bend allowance?
The actual amount of metal in a bend. it is the distance between the bend tangent lines in a flat pattern layout
What is a sight line?
A line drawn on a flat pattern layout within the bend allowance that is one bend radius from the bend tangent line. When the sight line is directly below the nose of the radius bar on the brake, the bend will start at the bend tangent line
What is the main function of throatless shears in an aircraft sheet metal shop?
Throatless shears are used to cut mild carbon steel up to 10-gauge, and stainless steel up to 12-gauge. They can be used to cut irregular curves in the metal.
What kind of metal forming is done by a slip roll former?
Simple curves with a large radius.
What kind of metal forming is done by bumping?
Compound curves in sheet metal.
When forming a curved angle, what must be done to the flanges?
The flanges must be stretched for a convex curve and shrunk for a concave curve
When hand-forming a piece of sheet metal that has a concave curve, should the forming be started in the center of the curve, or at its edges?
Start at the edges and work toward the center
What is meant by a joggle in a piece of sheet metal?
A joggle is a small offset near the edge of a piece of sheet metal that allows the sheet to overall another piece of metal
What is another name for GTA welding?
TIG welding
What is used as the electrode in GTA welding?
A small-diameter tungsten wire
What are three types of power that can be used for GTA welding?
DC-straight polarity
DC-reverse polarity
AC
Which type of power provides the greatest heat and deepest penetration in GTA welding?
DC-straight polarity
Which type of power is used for GTA welding aluminum and magnesium?
DC-reverse polarity
What effect does moisture have on a wood aircraft structure?
Moisture causes the wood to swell and crack as it dries out. It allows fungus to develop in the wood and cause it to decay.
What type of nondestructive inspection is suitable for detecting internal damage in honeycomb material?
Ultrasonic inspection
What is the simplest way to detect delamination in a composite structure?
Tap the surface with the edge of a coin. If the material is sound, the tapping will result in a clear ringing sound; but if it is delaminated, the sound will be a dull thud.
Of what class of resins are aircraft windows and windshields made?
Thermoplastic
What is meant by crazing of a transparent plastic material?
Tiny hair-like cracks that may not extend all of the way to the surface. Crazing is caused by stresses or chemical fumes.
If a mechanic gives a 100-hour inspection to an aircraft that proves to be unairworthy, what must the mechanic give the owner or operator of the aircraft?
A signed and dated list of all of the discrepancies that keep the aircraft from being airworthy
Where can you find the recommended statement to use for recording the approval or disapproval of an aircraft for return to service after a 100-hour inspection?
In 14 CFR 43.11
Under what conditions can an aircraft be operated with a 100-hour inspection overdue?
The aircraft can be operated for no more than 10 hours after an inspection is due for the purpose of flying it to a place where the inspection can be performed.
For how long can an aircraft be operated if a 100-hour inspection is overdue?
For no more than 10 hours. The time beyond the 100 hours must be subtracted from the time before the next inspection is due.
Under what conditions can an aircraft that is due for an annual inspection be operated?
It can only be flown when a special flight permit is issued
What certification is required for a mechanic to be able to approve an aircraft for return to service after a 100-hour inspection?
An aviation Mechanic certificate with Airframe and Powerplant ratings
What determines whether or not an aircraft must be given a 100-hour inspection?
Aircraft that carry persons for the hire and aircraft that are used for flight instruction for hire must be given 100-hour inspections
What is the difference between an annual inspection and a 100-hour inspection?
An annual inspection can be conducted only by an A&P mechanic who holds an inspection Authorization, while a 100-hour inspection can be performed by an A&P mechanic without an IA. (The inspections themselves are identical)
What certification is required for a mechanic to conduct an annual inspection and approve the aircraft for return to service after the inspection?
An aviation Mechanic certificate with Airframe and Powerplant ratings and an Inspection Authorization
What is progressive inspection?
An inspection of the same level as an annual inspection but approved by the FAA to be performed on a schedule that does not require the aircraft to be out of service for the time necessary to perform the entire inspection all at once
What certification is required for a mechanic to conduct a progressive inspection?
An Aviation Mechanic certificate with Airframe and Powerplant ratings and an Inspection Authorization
Where can you find the requirements for inspecting the altimeter and static systems of aircraft operated under instrument flight rules?
In 14 CFR Part 43, Appendix E
Where can you find the requirements for inspecting the ATC transponder that is installed in an aircraft?
In 14 CFR Part 43, Appendix F
What items must be inspected on a helicopter in accordance with the instructions for Continued Airworthiness?
The drive shafts or similar systmes
The main rotor transmission gear box
The main rotor and center section
The auxiliary rotor
Where may a list of the approved lubricants for greasing an aircraft retractable landing gear be found?
In the aircraft maintenance manual
Where can you find the specifications for the type of fluid used to service an aircraft landing gear shock strut?
On the nameplate on the strut
How much oil should be put into an oleo shock strut?
With the strut completely deflated, fill it to the level of the filler plug
What kind of filter is a micronic filter?
A filter with a special paper element
What is a double-action pump?
A pump that delivers fluid with the movement of the pump handle in both directions
Why do most engine-driven hydraulic pumps have a shear section in their drive couplings?
If the pump should seize, the shear section will break, disconnecting the pump from the engine and preventing further damage
What are the two basic types of hydraulic fluid used in modern aircraft?
Mineral base fluid and phosphate ester base fluid
Does the main hydraulic pump take its fluid from the bottom of the reservoir, or from a standpipe?
The main pump normally takes its fluid from a standpipe, while the emergency pump takes its fluid from the bottom of the reservoir. If a break in the system should allow the main pump to pump all of its fluid overboard, there will still be enough fluid in the reservoir to allow the emergency system to extend the landing gear and actuate the brakes.
Why are some hydraulic reservoirs pressurized?
Pressurization ensures that fluid will be supplied to the inlet of the pumps at high altitude where there is not enough atmospheric pressure to do this
What are two ways aircraft hydraulic reservoirs may be pressurized?
By an aspirator in the fluid return line or by bleed air from one of the engine compressors