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37000 Feet | Browse and search NASA's Aviation Safety Reporting System |
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Atx X unauthorized descent below assigned altitude due to aircraft equipment problem pressurization had less than standard separation from small aircraft Y.
| Attributes | |
| ACN | 250552 |
| Time | |
| Date | 199308 |
| Day | Sun |
| Local Time Of Day | 1801 To 2400 |
| Place | |
| Locale Reference | atc facility : rqz |
| State Reference | AL |
| Altitude | msl bound lower : 11000 msl bound upper : 11300 |
| Environment | |
| Flight Conditions | VMC |
| Light | Dusk |
| Aircraft 1 | |
| Operator | common carrier : air taxi |
| Make Model Name | Light Transport, Low Wing, 2 Turboprop Eng |
| Flight Phase | descent other |
| Route In Use | enroute : direct enroute airway : ztl |
| Flight Plan | IFR |
| Aircraft 2 | |
| Operator | general aviation : personal |
| Make Model Name | Small Aircraft, Low Wing, 1 Eng, Retractable Gear |
| Flight Phase | cruise other |
| Route In Use | enroute : direct |
| Flight Plan | IFR |
| Person 1 | |
| Affiliation | government : faa |
| Function | controller : radar |
| Qualification | controller : radar |
| Experience | controller non radar : 2 controller radar : 7 |
| ASRS Report | 250552 |
| Person 2 | |
| Affiliation | company : air taxi |
| Function | flight crew : first officer |
| Qualification | pilot : instrument pilot : commercial |
| Experience | flight time total : 3100 |
| ASRS Report | 250694 |
| Events | |
| Anomaly | aircraft equipment problem : less severe altitude deviation : overshoot conflict : airborne less severe non adherence : clearance non adherence : required legal separation |
| Independent Detector | other controllera |
| Resolutory Action | controller : issued new clearance flight crew : overcame equipment problem flight crew : declared emergency |
| Consequence | faa : investigated |
| Miss Distance | horizontal : 25200 vertical : 400 |
| Supplementary | |
| Primary Problem | Aircraft |
| Air Traffic Incident | Pilot Deviation |
Narrative:
Atx X lost cabin pressure and said he had to descend to 10000 ft. Atx X was only cleared to 12000 ft. Atx X descended to 11300 ft which was less than standard separation from small aircraft Y. Atx X didn't declare an emergency, which I feel he should have or I should have done it for him. He should not have started his descent on his own. Supplemental information from acn 250694: atx X was cruising at 16000 ft en route to bna from mgm via vuz to rqz, vols arrival. In between mgm and rgz a flow duct separated from an engine causing a cabin altitude light to come on due to rapidly rising cabin altitude. We took the action depicted by our quick reference handbook and contacted ZTL to descend to 10000 ft. We were cleared to 12000 ft and began our descent. I contacted ZTL again and told them we needed 10000 ft. He said he was unable due to traffic. I said we need a vector, we need 10000 ft. He said ok, and gave us a turn. At approximately 11500 ft we were able to stabilize our cabin altitude with the remaining flow.
Original NASA ASRS Text
Title: ATX X UNAUTH DSCNT BELOW ASSIGNED ALT DUE TO ACFT EQUIP PROB PRESSURIZATION HAD LTSS FROM SMA Y.
Narrative: ATX X LOST CABIN PRESSURE AND SAID HE HAD TO DSND TO 10000 FT. ATX X WAS ONLY CLRED TO 12000 FT. ATX X DSNDED TO 11300 FT WHICH WAS LTSS FROM SMA Y. ATX X DIDN'T DECLARE AN EMER, WHICH I FEEL HE SHOULD HAVE OR I SHOULD HAVE DONE IT FOR HIM. HE SHOULD NOT HAVE STARTED HIS DSCNT ON HIS OWN. SUPPLEMENTAL INFO FROM ACN 250694: ATX X WAS CRUISING AT 16000 FT ENRTE TO BNA FROM MGM VIA VUZ TO RQZ, VOLS ARR. IN BTWN MGM AND RGZ A FLOW DUCT SEPARATED FROM AN ENG CAUSING A CABIN ALT LIGHT TO COME ON DUE TO RAPIDLY RISING CABIN ALT. WE TOOK THE ACTION DEPICTED BY OUR QUICK REF HANDBOOK AND CONTACTED ZTL TO DSND TO 10000 FT. WE WERE CLRED TO 12000 FT AND BEGAN OUR DSCNT. I CONTACTED ZTL AGAIN AND TOLD THEM WE NEEDED 10000 FT. HE SAID HE WAS UNABLE DUE TO TFC. I SAID WE NEED A VECTOR, WE NEED 10000 FT. HE SAID OK, AND GAVE US A TURN. AT APPROX 11500 FT WE WERE ABLE TO STABILIZE OUR CABIN ALT WITH THE REMAINING FLOW.
Data retrieved from NASA's ASRS site as of July 2007 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.