Airframe - AM.II.G.K10 - Oxygen system maintenance and inspection procedures

Question 1

What are the two main gases which make up our atmosphere?

Answer 1

Nitrogen and oxygen

Question 2

What is used to check an oxygen system for leaks?

Answer 2

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

Question 3

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

Answer 3

• When the system is pressurised, the tubing is expanded slightly
• If the fitting is tightened when it is expanded, it will likely leak when the pressure is reduced

Question 4

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

Answer 4

• Only aviators breathing oxygen
• Hospital and welding oxygen both contain too much moisture to be used

Question 5

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

Answer 5

• The identification DOT 3AA or DOT 3HT
• Date of manufacture
• Date of all of the hydrostatic tests

Question 6

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

Answer 6

• 5/3 of their working pressure
• every three years

Question 7

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

Answer 7

• tested to 3083psi
• every 3 years
• retired from service after 15 years or 4380 cycles, whichever occurs first

Question 8

What kind of lubricant can be used for installing fittings in an oxygen system component? (2)

Answer 8

• Teflon tape
• special water based lubricant

Question 9

What is used to check for leaks after replacing a fitting in an oxygen system?

Answer 9

A special leak detector liquid which is a form of non oily soap

Question 10

What cleaning solutions can be used to clean parts used in an oxygen system? (3)

Answer 10

• Anhydrous ethyl alcohol
• isopropyl alcohol
• freon

Question 11

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

Answer 11

Water-pumped dry nitrogen

Question 12

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

Answer 12

Water pumped dry nitrogen

Question 13

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

Answer 13

The oxygen supply must be turned off at the bottle valve