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Cpr medium large transport made an emergency descent due loss of cabin pressurization. Overshot clearance altitude at intermediate level off.
| Attributes | |
| ACN | 116395 |
| Time | |
| Date | 198907 |
| Day | Fri |
| Local Time Of Day | 0601 To 1200 |
| Place | |
| Locale Reference | atc facility : ind |
| State Reference | IN |
| Altitude | msl bound lower : 24500 msl bound upper : 39500 |
| Environment | |
| Flight Conditions | VMC |
| Light | Daylight |
| Aircraft 1 | |
| Controlling Facilities | artcc : zid |
| Operator | general aviation : corporate |
| Make Model Name | Medium Large Transport, Low Wing, 2 Turbojet Eng |
| Flight Phase | climbout : intermediate altitude descent other |
| Flight Plan | IFR |
| Person 1 | |
| Affiliation | Other |
| Function | flight crew : first officer |
| Qualification | pilot : atp |
| Experience | flight time last 90 days : 130 flight time total : 5500 flight time type : 400 |
| ASRS Report | 116395 |
| Person 2 | |
| Affiliation | Other |
| Function | flight crew : captain oversight : pic |
| Qualification | pilot : atp |
| Events | |
| Anomaly | aircraft equipment problem : critical altitude deviation : overshoot |
| Independent Detector | other flight crewa |
| Resolutory Action | controller : issued new clearance flight crew : returned to intended course or assigned course flight crew : declared emergency |
| Consequence | Other |
| Supplementary | |
| Primary Problem | Aircraft |
| Air Traffic Incident | Pilot Deviation |
Narrative:
Climbing through 39,500' for assigned FL410, we experienced a sudden loss of cabin pressurization. Crew donned masks (no passenger) and notified ATC of problem. We initially requested and were assigned FL250. Approaching the assigned FL250 our cabin altitude had reached nearly 20,000'. We requested lower immediately but were told to stand by. We had been in emergency descent confign at very high descent rate. The captain had anticipated a further descent clearance and was unable to arrest descent by assigned altitude. We descended 400-500' below altitude during recovery. I don't believe any conflict existed however ATC reminded us to maintain FL250. Further descent to 11,000' followed shortly thereafter. In retrospect, we should have requested a much lower altitude sooner. Likewise since ATC was aware of the nature of our problem, they should have anticipated our need for possible further descent. Also as first officer I made no call of 'high sink' during last 1000' as I was expecting our further descent request to be granted.
Original NASA ASRS Text
Title: CPR MLG MADE AN EMERGENCY DESCENT DUE LOSS OF CABIN PRESSURIZATION. OVERSHOT CLRNC ALT AT INTERMEDIATE LEVEL OFF.
Narrative: CLIMBING THROUGH 39,500' FOR ASSIGNED FL410, WE EXPERIENCED A SUDDEN LOSS OF CABIN PRESSURIZATION. CREW DONNED MASKS (NO PAX) AND NOTIFIED ATC OF PROBLEM. WE INITIALLY REQUESTED AND WERE ASSIGNED FL250. APCHING THE ASSIGNED FL250 OUR CABIN ALT HAD REACHED NEARLY 20,000'. WE REQUESTED LOWER IMMEDIATELY BUT WERE TOLD TO STAND BY. WE HAD BEEN IN EMER DSCNT CONFIGN AT VERY HIGH DSCNT RATE. THE CAPT HAD ANTICIPATED A FURTHER DSCNT CLRNC AND WAS UNABLE TO ARREST DSCNT BY ASSIGNED ALT. WE DESCENDED 400-500' BELOW ALT DURING RECOVERY. I DON'T BELIEVE ANY CONFLICT EXISTED HOWEVER ATC REMINDED US TO MAINTAIN FL250. FURTHER DSCNT TO 11,000' FOLLOWED SHORTLY THEREAFTER. IN RETROSPECT, WE SHOULD HAVE REQUESTED A MUCH LOWER ALT SOONER. LIKEWISE SINCE ATC WAS AWARE OF THE NATURE OF OUR PROBLEM, THEY SHOULD HAVE ANTICIPATED OUR NEED FOR POSSIBLE FURTHER DSCNT. ALSO AS F/O I MADE NO CALL OF 'HIGH SINK' DURING LAST 1000' AS I WAS EXPECTING OUR FURTHER DSCNT REQUEST TO BE GRANTED.
Data retrieved from NASA's ASRS site as of August 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.