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Cpr light transport has pressurization problem at FL390 and during emergency descent overshoots clearance altitude.
| Attributes | |
| ACN | 125399 |
| Time | |
| Date | 198910 |
| Day | Wed |
| Local Time Of Day | 1201 To 1800 |
| Place | |
| Locale Reference | atc facility : pmm |
| State Reference | MI |
| Altitude | msl bound lower : 10000 msl bound upper : 11000 |
| Environment | |
| Flight Conditions | VMC |
| Light | Daylight |
| Aircraft 1 | |
| Controlling Facilities | artcc : zob tower : mem |
| Operator | general aviation : corporate |
| Make Model Name | Light Transport, Low Wing, 2 Turbojet Eng |
| Flight Phase | cruise other cruise other descent other |
| Flight Plan | IFR |
| Person 1 | |
| Affiliation | Other |
| Function | flight crew : first officer |
| Qualification | pilot : instrument pilot : atp |
| Experience | flight time last 90 days : 150 flight time total : 8900 flight time type : 2800 |
| ASRS Report | 125399 |
| 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 controllera other flight crewa |
| Resolutory Action | controller : issued new clearance other |
| Consequence | faa : reviewed incident with flight crew |
| Supplementary | |
| Primary Problem | Ambiguous |
| Air Traffic Incident | Pilot Deviation Operational Deviation |
Narrative:
Departed mht to pwk. Established at FL390 for about 1:10, the cabin altitude started to climb uncontrollably at 2000 FPM. We donned our oxygen masks and notified ZOB we were turning off airway to the left and starting an emergency descent. During the descent we notified the center we requested 10,000'. The center stopped us first at 16,000' then started to step us down from that point. All altitude clrncs were read back. Upon reaching 10,000' we were questioned about our altitude we read back 10,000'. ZOB said you were cleared to 11,000' and traffic is 12 O'clock 20 mi descending through 9800. ZOB kept us at 10,000' at that point. Upon calling ZOB we got a hold of the shift supervisor who had just reported to work and had just been briefed of the occurrence and was in the process of pulling the tapes. The supervisor told us that a trainee was working the position and the controller really was not sure of all of his actions. The supervisor indicated that the center was not going to pursue any action other than just reviewing the tapes. During the execution of the emergency descent the cockpit workload was very high along with human stress levels. The cause of this situation is most definitely a breakdown somewhere within the communication loop possibly created by the human stress factor of all individuals involved during emergency/abnormal operations.
Original NASA ASRS Text
Title: CPR LTT HAS PRESSURIZATION PROBLEM AT FL390 AND DURING EMERGENCY DESCENT OVERSHOOTS CLRNC ALT.
Narrative: DEPARTED MHT TO PWK. ESTABLISHED AT FL390 FOR ABOUT 1:10, THE CABIN ALT STARTED TO CLIMB UNCONTROLLABLY AT 2000 FPM. WE DONNED OUR OXYGEN MASKS AND NOTIFIED ZOB WE WERE TURNING OFF AIRWAY TO THE LEFT AND STARTING AN EMER DSCNT. DURING THE DSCNT WE NOTIFIED THE CENTER WE REQUESTED 10,000'. THE CENTER STOPPED US FIRST AT 16,000' THEN STARTED TO STEP US DOWN FROM THAT POINT. ALL ALT CLRNCS WERE READ BACK. UPON REACHING 10,000' WE WERE QUESTIONED ABOUT OUR ALT WE READ BACK 10,000'. ZOB SAID YOU WERE CLRED TO 11,000' AND TFC IS 12 O'CLOCK 20 MI DESCENDING THROUGH 9800. ZOB KEPT US AT 10,000' AT THAT POINT. UPON CALLING ZOB WE GOT A HOLD OF THE SHIFT SUPVR WHO HAD JUST REPORTED TO WORK AND HAD JUST BEEN BRIEFED OF THE OCCURRENCE AND WAS IN THE PROCESS OF PULLING THE TAPES. THE SUPVR TOLD US THAT A TRAINEE WAS WORKING THE POSITION AND THE CTLR REALLY WAS NOT SURE OF ALL OF HIS ACTIONS. THE SUPVR INDICATED THAT THE CENTER WAS NOT GOING TO PURSUE ANY ACTION OTHER THAN JUST REVIEWING THE TAPES. DURING THE EXECUTION OF THE EMER DSCNT THE COCKPIT WORKLOAD WAS VERY HIGH ALONG WITH HUMAN STRESS LEVELS. THE CAUSE OF THIS SITUATION IS MOST DEFINITELY A BREAKDOWN SOMEWHERE WITHIN THE COM LOOP POSSIBLY CREATED BY THE HUMAN STRESS FACTOR OF ALL INDIVIDUALS INVOLVED DURING EMER/ABNORMAL OPERATIONS.
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.