A CL600 AT LEVELOFF AT CRUISE FL210 CREW NOTED ACFT NOT PRESSURIZED DUE TO ENG BLEED VALVES NOT SWITCHED TO OPEN.

Narrative

5 MINS AFTER LEVELING OFF AT FL210; I NOTICED THE 'PAX OXYGEN MASKS DEPLOYED' LIGHT WAS ILLUMINATED. I THEN LOOKED BACK TO SEE IF THEY WERE ACTUALLY DEPLOYED; WHICH THEY WERE; AND MOTIONED TO OUR PAX TO DON THE MASKS. I THEN LOOKED AT THE CABIN ALTIMETER DIFFERENTIAL RATE INDICATOR AND DISCOVERED THE CABIN ALT WAS AT 10000 FT. BOTH THE FO AND MYSELF DONNED OUR OXYGEN MASKS AND REQUESTED LOWER ALT; WHICH WE DID RECEIVE (11000 FT). AT THAT POINT; THE FO (WHO WAS THE PNF) NOTICED THE 10TH STAGE BLEED VALVES WERE IN THE CLOSED POS WITH THE WHITE LIGHTS ILLUMINATED. WE COMPLETED THE LOW CABIN PRESSURE CHKLIST AND ALL WAS CORRECTED (WITH THE OPENING OF THE 10TH STAGE BLEED VALVES). AT THE BEGINNING OF NOV/99 WE RECEIVED ADVISORY FROM FBO STATING; THAT UNTIL A FIX FOR POSSIBLE CRACKING OF THE ACFT SKIN (DUE TO OVERHEATING) AROUND THE APU EXHAUST; WE (AND ALL CHALLENGER ACFT) ARE PROHIBITED FROM OPERATING THE APU AIRBORNE; EXCEPT FOR EMER USE AND FLT MANUAL MAINT PROCS. WE ARE ALLOWED TO USE THE APU ON THE GND FOR ELECTRICAL PWR; ENG STARTS; AIR CONDITIONING; ETC. PRIOR TO THIS ADVISORY; NORMAL APU USAGE ALLOWED US TO TAKE OFF WITH THE APU SUPPLYING THE AIR FOR THE PRESSURIZATION SYS; THUS ALLOWING THE ENGS TO PRODUCE MORE PWR SINCE THIS AIR WAS NOT BEING BLED FROM THE ENGS. ONCE WE REACHED 5000 FT; WE WOULD SHUT DOWN THE APU IN A SET SEQUENCE THAT ALLOWED ENG BLEED AIR TO START OPERATING THE PRESSURIZATION SYS PRIOR TO APU SHUTDOWN. TODAY; PRIOR TO TKOF; THE FO (WHO WAS THE PNF) INADVERTENTLY REVERSED THAT SEQUENCE IN THE APU SHUTDOWN. THE PROPER SEQUENCE WOULD HAVE BEEN TO OPEN THE ENG BLEED VALVES (ALLOWING THE ENG BLEED AIR TO SUPPLY AIR TO THE PRESSURIZATION SYS) THUS EXTINGUISHING THE WHITE 10TH STAGE ENG BLEED LIGHTS ON THE BLEED AIR PANEL THEN SHUTTING DOWN THE APU. WITH THE SEQUENCE HE USED (APU SHUT DOWN; APU BLEED OFF) HE SAW THE 10TH STAGE BLEED VALVE LIGHTS ILLUMINATED (NOW WITH NO BLEED AIR FROM ANY SOURCE GOING TO THE AIR CONDITIONING UNITS) AND SUBCONSCIOUSLY PERCEIVED THIS AS THE CORRECT INDICATION. WHILE OPERATING THIS ACFT FOR THE PAST 3 1/2 YRS USING THE 'PERFORMANCE' TKOF PROC (APU OPERATING SUPPLYING BLEED AIR TO THE AIR CONDITION UNITS); WE HAVE BEEN USED TO LOOKING AT THE 2 WHITE 10TH STAGE BLEED VALVE LIGHTS ILLUMINATED ON TKOF; WHICH WAS THE CORRECT INDICATION WITH THE APU SUPPLYING BLEED AIR TO THE AIR CONDITIONING UNITS.