Airframe Oral Questions

What kind of repair can be made to a small damage of the core material and one face sheet of a piece of aluminum alloy honeycomb structure?

A potted compound repair.

How do you grind the point of a twist drill that is to be used for drilling transparent acrylic material?

The cutting edge should be dubbed off to a zero rake angle, and the included angle of the tip should be ground to 140 degrees.

What is a warp clock in a structural repair manual?

An alignment indicator to show the orientation of the plies of a composite material. The ply direction is shown in relation to a reference direction.

What are two types of repair to a damaged honeycomb core composite material?

Room-temperature cure repair and hot-bonded repair.

What is the definition of a critical fatigue area of a control cable?

Any working length of a cable where the cable runs over, under, or around a pulley, sleeve, or through a fairlead; or any section where a cable is flexed, rubbed, or worked in any manner; or any point within 1 foot of a swaged-on fitting.

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?

A signed and dated list of all the discrepancies/unairworthy items that make the aircraft unairworthy.

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?

14 CFR Part 43.11

Under what conditions can an aircraft be operated with a 100-hour overdue?

No more than 10 hours exceeding. Time beyond 100 hours is subtracted from time before next inspection is due.

Under what conditions can an aircraft be operated with an annual overdue?

It can only be flown with a special flight permit (ferry permit).

What certification is required to approve an aircraft to return to service after a 100-hour?

Airframe and Powerplant.

What determines whether or not an aircraft must be given a 100-hour inspection?

Aircraft that are used for hire require 100-hour.

What is the difference between a 100-hour and annual?

Inspections are identical. Annual is only conducted by A&P with Inspection Authorization, 100-hour can be conducted with just A&P. 100-hour is required for aircraft for hire.

What certification is required to conduct an annual inspection and approve for return to service?

Airframe and Powerplant with Inspection Authorization.

What is a progressive inspection?

Same level as annual but approved by the FAA to be performed in chunks on a schedule, and does not require the aircraft to be out of service for extended periods of time.

What certification is required to conduct a progressive inspection?

Airframe and Powerplant with Inspection Authorization.

Where can you find the requirements for inspecting the altimeter and static systems of aircraft operated under instrument flight rules?

14 CFR Part 43, Appendix E

Where can you find the requirements for inspecting the ATC transponder that is installed in an aircraft?

14 CFR Part 43, Appendix F

What items must be inspected on helicopters in accordance with the instructions for continued airwothiness?

Drive shafts or similar systems, the main rotor transmission gear box, the main rotor and center section, and the auxiliary rotor.

Where would an aviation mechanic find required special inspections?

In the aircraft maintenance manual.

What are the three basic brake actuating systems?

a. An independent system not part of the aircraft main hydraulic system.

b. A booster system that uses the aircraft hydraulic system intermittently.

c. A power brake system that only uses the main hydraulic system as a source of pressure.

Is a chevron seal a one-way or two-way seal?

One-way seal.

To which side of a chevron seal should the pressure be applied?

To the open side.

Is an O-ring seal a one-way or two-way seal?

A two-way seal.

How can you be sure of getting an O-ring made of the correct material for a specific hydraulic component?

Correct part number and obtained from a reputable source.

On which side of an O-ring should the backup ring be placed?

On the side away from pressure.

What should be done to the sharp edges of threads and actuator pistons when installing O-rings?

The sharp edges should be covered with paper.

What are the two main gasses that make up our atmosphere?

Nitrogen and oxygen.

What is used to check an oxygen system for leaks?

A special leak-detector liquid that is a form of non-oily soap.

Why must fittings in an oxygen system not be tightened to stop a leak when there is pressure in the system?

When there is pressure, the tubing is expanded slightly; if the fitting is tightened when expanded, it will likely leak when the pressure is reduced.

What kind of gaseous oxygen system must be used to service an aircraft oxygen system?

Only Aviators Breathing Oxygen. Hospital oxygen contains too much moisture.

What identification must be stamped on an oxygen bottle carried in the aircraft?

DOT 3AA or DOT 3HT, date of manufacture, and the date of all the hydrostatic tests.

To what pressure and how often should DOT 3AA oxygen cylinders be hydrostatically tested?

They should be tested to 5/3 of their working pressure every three years.

To what pressure and how often should DOT 3HT oxygen cylinders be hydrostatically tested, and when should they be retired from service?

They should be tested to 3,083 psi every three years and retired after 15 years or 4,380 pressurizations, whichever occurs first.

What kind of lubricant can be used for installing fittings in an oxygen system component?

Teflon tape or a special water-based lubricant.

What cleaning solutions can be used to clean parts used in an oxygen system?

Anhydrous ethyl alcohol, isopropyl alcohol, or freon.

What can be used to dry components in an oxygen system after they have been cleaned?

Water-pumped dry nitrogen.

What may be used to purge the lines in an oxygen system after it has been opened for servicing?

Water-pumped dry nitrogen.

What must be done before any maintenance can be done on an oxygen system?

The oxygen supply must be turned off at the bottle valve.

How is cabin pressure controlled in a pressurized aircraft?

The pressure controller modulates the outflow valve to maintain correct cabin pressure.

What is the function of the cabin outflow valve on a pressurized aircraft?

It maintains the correct cabin pressure. Controlled by the pressure controller.

What is the function of the cabin pressure safety valve on a pressurized aircraft?

It prevents the cabin pressure from exceeding the maximum allowable differential pressure.

Why must pressurized aircraft have a negative pressure relief valve?

The structure is not designed for the inside pressure being less than the outside pressure.

What keeps the cabin of a pressurized aircraft from being pressurized when the aircraft is on the ground?

A squat switch on the landing gear holds the safety valve open when on the ground.

What size generator must be used in an aircraft electrical system if the connected electrical load is 30 amps, and there is no way of monitoring generator output?

When monitoring is not practical, the total continuous electrical load should not exceed 80% of the generator's output. This means the generator would have to be at least 37.5 amps.

What is meant by “flashing” the field of a generator?

Restoring residual magnetism to the frame of the generator. This is done by passing current through the field coils in the direction it normally flows when operating.

What is meant by paralleling the generators in a multi-engine aircraft?

Adjusting the voltage regulators so all the generators share the same electrical load equally.

What are the three types of voltage regulators used with aircraft generators?

Vibrator-type, carbon-pile type, and solid state-type.

What type of seals is used for MIL-H-5606 hydraulic fluid?

Either neoprene or Buna-N.

What type of seals are used for phosphate ester-based hydraulic fluids? (Skydrol)

Butyl rubber or ethylene-propylene elastomers.