Narrative:

While climbing through FL220, I observed an amber caution annunciator system message about cabin altitude. I donned my bask and stopped climb. The captain informed ATC that we had a pressurization problem and needed to level off. Seconds later, while the captain was performing the abnormal checklist, we got a red caution annunciator system message. The captain donned his mask and informed ATC that we were descending while I flew the aircraft. We were cleared to 11000 ft. Upon further completion of the checklist we discovered that the bleed selects were both off. Selecting the proper position on the bleeds solved the problem. Interruptions to the preflight routine contributed to the non accomplishment of the preliminary checklist. I skipped ahead to the next checklist in order to start the APU, and forgot to return to the preliminary checklist. The most effective method of preventing a recurrence is to not attempt to do procedures out of sequences on the checklist. Callback conversation with reporter revealed the following information: the reporter stated there were no passenger on board and the cabin altitude did not exceed 11000 ft. The reporter said the emergency oxygen masks did not deploy. The reporter stated both pilots are at fault for the failure to complete the preflight checklists and doing procedures out of sequence. The reporter said ATC advised the company of the incident and resulted in retraining on procedures.

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Original NASA ASRS Text

Title: A C750 CLBING AT FL220 MADE AN EMER DSCNT DUE TO CABIN ALT WARNINGS. CAUSED BY FAILURE TO SWITCH ON ENG BLEEDS.

Narrative: WHILE CLBING THROUGH FL220, I OBSERVED AN AMBER CAUTION ANNUNCIATOR SYS MESSAGE ABOUT CABIN ALT. I DONNED MY BASK AND STOPPED CLB. THE CAPT INFORMED ATC THAT WE HAD A PRESSURIZATION PROB AND NEEDED TO LEVEL OFF. SECONDS LATER, WHILE THE CAPT WAS PERFORMING THE ABNORMAL CHKLIST, WE GOT A RED CAUTION ANNUNCIATOR SYS MESSAGE. THE CAPT DONNED HIS MASK AND INFORMED ATC THAT WE WERE DSNDING WHILE I FLEW THE ACFT. WE WERE CLRED TO 11000 FT. UPON FURTHER COMPLETION OF THE CHKLIST WE DISCOVERED THAT THE BLEED SELECTS WERE BOTH OFF. SELECTING THE PROPER POS ON THE BLEEDS SOLVED THE PROB. INTERRUPTIONS TO THE PREFLT ROUTINE CONTRIBUTED TO THE NON ACCOMPLISHMENT OF THE PRELIMINARY CHKLIST. I SKIPPED AHEAD TO THE NEXT CHKLIST IN ORDER TO START THE APU, AND FORGOT TO RETURN TO THE PRELIMINARY CHKLIST. THE MOST EFFECTIVE METHOD OF PREVENTING A RECURRENCE IS TO NOT ATTEMPT TO DO PROCS OUT OF SEQUENCES ON THE CHKLIST. CALLBACK CONVERSATION WITH RPTR REVEALED THE FOLLOWING INFO: THE RPTR STATED THERE WERE NO PAX ON BOARD AND THE CABIN ALT DID NOT EXCEED 11000 FT. THE RPTR SAID THE EMER OXYGEN MASKS DID NOT DEPLOY. THE RPTR STATED BOTH PLTS ARE AT FAULT FOR THE FAILURE TO COMPLETE THE PREFLT CHKLISTS AND DOING PROCS OUT OF SEQUENCE. THE RPTR SAID ATC ADVISED THE COMPANY OF THE INCIDENT AND RESULTED IN RETRAINING ON PROCS.

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.