B737-300
Maintenance Powerplant; Maintenance Airframe
Maintenance Technician 30
Communication Breakdown; Situational Awareness
Aircraft Equipment Problem Critical; Deviation / Discrepancy - Procedural Published Material / Policy; Deviation / Discrepancy - Procedural FAR
General Maintenance Action
Procedure; Human Factors
Aircraft had a depressurization [event]. The aft Flight Attendant O2 mask door didn't drop. Upon opening the door; it was found that the O2 mask box was taped. If you do a mask drop on the hook you should still look inside each O2 mask door for any obstructions. Day Shift. Duty time eight hours.
Reporter stated he doesn't know what caused the depressurization event on the B737-300 aircraft when the aft Flight Attendant jumpseat; ceiling O2 oxygen mask panel door did not open. Further troubleshooting indicated the O2 door latch release solenoid had failed and would not release the door panel. That is when Maintenance also noticed masking tape had been holding the Flight Attendant's O2 masks inside; not allowing the masks to drop. He was informed that he had performed and signed-off a 'Full Drop' Check on the same aft O2 panel approximately 18 months earlier during a 'C' Check. He noted that he could not have satisfied the requirement of the 'Full Drop' Check if he had taped the mask up inside the mask unit. Reporter stated that he believes a Fuselage Upper Crown Inspection had been accomplished at some point after the 'C' Check he was involved with had been completed. The Crown Inspection requires removal of the Vertical Stab Dorsal Fin forward lower fairing. Bolts that secure the lower fairing have to be accessed by removing a ceiling panel above the aft Flight Attendant's jumpseat that also holds the Flight Attendant's O2 mask unit. When that panel is reinstalled; a 'Full Drop' Check and deployment of the O2 door and masks must also be accomplished. But; if the same ceiling panel was removed under a Maintenance write-up; than the requirement to do a Full Drop Check of the O2 masks may not have been accomplished. His Air Carrier is currently reviewing their maintenance records. He has thirty years experience in aircraft maintenance.
An Aircraft Maintenance Technician (AMT) was informed about a depressurization event on a B737-300 aircraft where the aft Flight Attendant jumpseat O2 oxygen masks ceiling door did not open. The O2 masks were also held inside with masking tape. Oxygen masks were not available to flight attendants.