 |
37000 Feet | Browse and search NASA's Aviation Safety Reporting System |
|
A maintenance supervisor and a contract maintenance inspector report that a cessna CE680 flight crew at FL430 experienced a sudden stoppage of oxygen (O2) flow in mid-breath; even though the crew O2 bottle pressure was 1500 psi. Maintenance found the composite type crew oxygen bottle shut-off valve not fully opened.
| Attributes | |
| ACN | 1078891 |
| Time | |
| Date | 201303 |
| Local Time Of Day | 1801-2400 |
| Place | |
| Locale Reference | ZZZ.ARTCC |
| State Reference | US |
| Environment | |
| Light | Dusk |
| Aircraft 1 | |
| Make Model Name | Cessna Citation Sovereign (C680) |
| Operating Under FAR Part | Part 91 |
| Flight Phase | Cruise |
| Component | |
| Aircraft Component | Oxygen System/Crew |
| Person 1 | |
| Function | Other / Unknown |
| Qualification | Maintenance Airframe Maintenance Powerplant |
| Experience | Maintenance Technician 24 |
| Person 2 | |
| Function | Inspector |
| Qualification | Maintenance Powerplant Maintenance Airframe |
| Events | |
| Anomaly | Aircraft Equipment Problem Critical Deviation - Procedural Published Material / Policy Flight Deck / Cabin / Aircraft Event Other / Unknown |
Narrative:
Crew reported discrepancy - at FL430; while on oxygen (O2); the PIC's O2 flow suddenly stopped in mid breath. Bottle pressure was 1;500 psi at the time. Investigation revealed no switch positions out of place. First officer's mask proved to have the same issue. Descended aircraft to FL240 whereupon masks were frequently tested and both were found to deliver about one good breath after a several minute wait; after which no O2 could be obtained from the mask without another several minute wait. On ground; mask appears to function properly for several breaths. Bottle pressure on ground is at top of green arc. Discrepancy corrective action - upon inspection found O2 bottle regulator; shut-off valve not in the fully open position. Removed faulty safety wire and installed new safety wire securing valve in the correct position. O2 system operations check is good. Recommend maintenance personnel involved be familiarized with ensuring the regulator valve in seated fully in the 'on' position. Maintenance supervisor.
Original NASA ASRS Text
Title: A Maintenance Supervisor and a contract Maintenance Inspector report that a Cessna CE680 flight crew at FL430 experienced a sudden stoppage of oxygen (O2) flow in mid-breath; even though the crew O2 bottle pressure was 1500 PSI. Maintenance found the composite type Crew Oxygen Bottle shut-off valve not fully opened.
Narrative: CREW REPORTED DISCREPANCY - At FL430; while on oxygen (O2); the PIC's O2 flow suddenly stopped in mid breath. Bottle pressure was 1;500 PSI at the time. Investigation revealed no switch positions out of place. First Officer's mask proved to have the same issue. Descended aircraft to FL240 whereupon masks were frequently tested and both were found to deliver about one good breath after a several minute wait; after which no O2 could be obtained from the mask without another several minute wait. On ground; mask appears to function properly for several breaths. Bottle pressure on ground is at top of green arc. Discrepancy corrective action - upon inspection found O2 bottle regulator; Shut-Off valve not in the fully open position. Removed faulty safety wire and installed new safety wire securing valve in the correct position. O2 System operations check is good. Recommend Maintenance personnel involved be familiarized with ensuring the regulator valve in seated fully in the 'ON' position. Maintenance Supervisor.
Data retrieved from NASA's ASRS site as of July 2013 and automatically converted to unabbreviated mixed upper/lowercase text. This report is for informational purposes with no guarantee of accuracy. See NASA's ASRS site for official report.