Date: 201406
Local time of day: 1201-1800
Location: ZZZ.Airport, US
Light: Daylight
Aircraft: Regional Jet 200 ER/LR (CRJ200)
Operator: Air Carrier
Operating under: Part 121
Mission: Passenger
Flight phase: Parked
Aircraft component: Oxygen System/Pax
Component problem: Malfunctioning
Reporter organization: Air Carrier
Reporter function: Technician
Reporter qualification: Maintenance Airframe; Maintenance Powerplant
Human factors: Communication Breakdown; Troubleshooting
Anomaly: Aircraft Equipment Problem Critical; Deviation / Discrepancy - Procedural Published Material / Policy; Deviation / Discrepancy - Procedural Maintenance
Detector: Person Maintenance
When detected: Aircraft In Service At Gate
Result: General Flight Cancelled / Delayed; General Maintenance Action
Contributing factors: Company Policy; Environment - Non Weather Related; Procedure; Human Factors
Primary problem: Human Factors

Narrative: Another Technician and I were dispatched to a CRJ-200 aircraft to troubleshoot a Number 2 Integrated Drive Generator (IDG) Fault late afternoon June 2014. The aircraft was only on the ground for a short time. We determined we needed more time to rectify the IDG issue and proceeded to MEL it instead. We entered the passenger cabin where my colleague began the logbook entries for the MEL. I was seated in Row-1 (D/F) at this time. As I was seated; something on the Passenger Service Unit (PSU) above my head caught my eye. I noticed the Red Test Latch on the passenger oxygen PSU door was flipped and was sticking down in the Test position. This concerned me. This latch is used during the Operational Test of the Passenger Oxygen System. It prevents the PSU oxygen door from opening more than an inch or so. This allows the technician to verify the Latch Release System works while at the same time prevents a repack of all the passenger cabin oxygen masks. Upon seeing this latch deployed to the Test position; I did a check of the remainder of the oxygen PSU doors in the cabin. To my shock I found the test latch on the oxygen PSU door above Row-5 (A/C) also set to the Test position. As soon as my colleague finished the IDG MEL paperwork; I opened two discrepancies in the logbook documenting the position of the test latches at Rows 1 (D/F) and 5 (A/C). I then looked back in the logbook to see who may have been working on the Passenger Oxygen System. I discovered the aircraft was released from our Heavy Check [Maintenance] Provider in ZZZ1 approximately eight days earlier. I was told this aircraft had maintenance performed on the passenger oxygen system in Heavy Check. No other work was documented on the passenger oxygen system since heavy check. To the best of my knowledge; this aircraft flew over a week with no passenger oxygen available to passengers in Rows 1 (D/F) and Row 5 (A/C) should the need have arisen. I was unable to determine the serviceability of the passenger oxygen system at Rows 1 (D/F) and 5 (A/C); as the aircraft was already late for departure at this point. I elected to MEL the passenger oxygen system at seats 1 (D/F) and 5 (A/C). All four seats were considered 'Inoperative' as well under the provisions of the Oxygen MEL. The MELs were cleared the following day by another Technician who performed a satisfactory Operational Test of the passenger oxygen system. The MEL'd seats and oxygen PSUs were then returned to service. I found it quite disturbing that this aircraft was released from Heavy Check with two PSUs unable to provide passenger oxygen. Equally disturbing was the fact that this condition went over a week before being caught. As it was; I just happened to see it by pure happenstance. Quality Control appears to be seriously lacking at this Heavy Check Vendor. I find it troubling that a technician could perform a task only part way before signing off on it and releasing the system for service. I feel that lack of adequate training and lack of proper oversight may be factors in this incident. Also; I feel that flight attendants and/or flight deck crews should be made aware of the significance of these red test latches. When I explained why I was taking the four seats out of service; the Flight Attendant thanked me for showing her the red latch and explaining its significance. She said she never knew they existed and that she'd be looking for them during her Pre-flight Checks from now on. Perhaps this is something that crews should be made cognizant of in their Recurrent Training. Extra sets of eyes each day would have most likely caught this potentially dangerous situation much sooner.

Callback: Reporter stated he works for a Part 121 Air Carrier as a Line Aircraft Maintenance Technician (AMT). He was later questioned by certain Maintenance Management Representatives as to why he didn't just flip the Red Test Latches back up inside the Passenger PSU Units and sign-off the discrepancy; instead of deferring both rows of passenger seats. He was very frustrated with their lack of understanding of the Passenger Oxygen System and the potentially serious consequences with passengers not having access to oxygen masks in their seat row. He had no idea of the status of the PSU Units; unless he would be given enough time to perform a Passenger O2 Mask Door Drop Test; which Maintenance decided they did not want to do at that time; so he deferred both seat rows.Reporter stated the passenger O2 mask discrepancy was the result of improper maintenance at the same Heavy Check Repair Station that just one week earlier had not properly installed (secured) the forward hinge pin into structure for the Number 2 Engine Core cowl. The cowl later separated in flight.



Synopsis: A Line Aircraft Maintenance Technician (AMT) reports Red Test Latches were found extended from the overhead Passenger Service Units (PSU) oxygen masks doors at two passenger seat rows on a CRJ-200 aircraft. Oxygen would not have been available to those passengers. Aircraft had been flying for a week after release from a domestic Repair Station. Technician suggests flight attendants/flight crews be made aware of significance of extended Red Test Latches during Recurrent Training.