ATA 35

Passenger Oxygen Masks
On February 19 our Service Center, Trimec, reported that during an operational inspection of the passenger oxygen drop down masks, there was one that would not let oxygen flow thru the connection between the larger line attached to the barbed fitting on the oxygen drop down box and the smaller line that goes to the mask. In this case the smaller line was squeezed shut and would not allow oxygen to flow to the mask. The part number in question is a 174080-31 Rev “K”. The, Batch was LC0526K. This lot had been shipped around July of 2005.
A thorough inspection of the masks that are installed in your aircraft is recommended. This inspection should include a functional test of the mask as well as the aircraft system.

Please refer to the IAI AMM 35-00-00 Oxygen system adjustment and test paragraph 1, Steps (1) thru (36).

This may be the time for you to accomplish your chapter 5 requirements: 6- 8 year factory overhaul or 20 life limit.

A follow up investigation of the event is underway and if any fleet action is required it will be communicated accordingly.