BE-300 flight crew reported a dual bleed air failure during cruise resulting in loss of pressurization and intense hypoxia symptoms. Flight crew executed a rapid descent followed by a return to departure airport and landing.
Synopsis
BE-300 flight crew reported a dual bleed air failure during cruise resulting in loss of pressurization and intense hypoxia symptoms. Flight crew executed a rapid descent followed by a return to departure airport and landing.
Narrative
We picked the plane up from maintenance at ZZZ. Aircraft was in for phase inspection as well as various other maintenance items including landing-gear overhaul. Departed ZZZ on IFR filed flight plan approximately XA45 local time. Approximately 15 minutes into the flight; climbing through FL230-FL240; we noticed an 'R Bleed Fail' light on the master caution panel. Per manufacturers emergency memory items checklist; I reached over to Bleed air panel and switched Right bleed air to off position. At this point; I reached for the manufacturers emergency checklist to verify condition and actions needed to take. At this time; we notified ZZZ center that we needed to return to departure airport of ZZZ and needed to descend to a lower altitude. Center asked if we were an emergency and I responded with 'Not at this time'. We were given a left turn back to ZZZ and descend to 17;000. As we were in the turn; 'L Bleed Fail' light illuminates. At this time; adrenaline and stress levels rose rapidly as a dual bleed air failure is an incredibly rare event and would ultimately mean loss of cabin pressurization. Mentally; my debate was should I follow the emergency checklist and turn off the other bleed air switch; unknowing if this is solely an indication issue; or leave it on risking the possibility of further complications or possibly compromising other systems. The checklist instructs you to turn off the system associated with the caution light but does not detail what to do in the event of dual failure. With both systems off; the cabin immediately felt loss of pressurization. We both immediately felt intense effects of Hypoxia and began using crew masks for oxygen in the descent to relieve some of these effects. Continued a rapid descent until we reached a safer altitude where effects stabilized. Tried [requesting priority] but were having radio troubles with mask-mics. Mic switch was selected to oxy when we donned the masks. Removed masks once we both felt like the effects had reduced. At this point we were just trying to reach anyone back at ZZZ so we swapped to tower frequency back on headsets. Tower instructed us to go over to approach frequency and get cleared for the ILS XX in to ZZZ. Once cleared; we landed safely on RWYXX and stayed with tower; instructed to taxi all the way down to the maintenance ramp we initially taxied out from.
Second reporter narrative
We picked the plane up from maintenance at ZZZ. Aircraft was in for phase inspection as well as various other maintenance items including landing-gear overhaul. Departed ZZZ on IFR filed flight plan approximately XA45 local time. Approximately 15 minutes into the flight; climbing through FL230-FL240; we noticed an 'R Bleed Fail' light on the master caution panel. Per manufacturer's emergency memory items checklist; the PIC reached over to Bleed air panel and switched Right bleed air to off position. At this point; he reached for the manufacturers emergency checklist to verify condition and actions needed to take. Next; we notified ZZZ center that we needed to return to departure airport of ZZZ and needed to descend to a lower altitude. Center asked if we were experiencing an emergency and the PIC responded with 'Not at this time'. We were given a left turn back to ZZZ and descend to 17;000. As we were in the turn; 'L Bleed Fail' light illuminates. At this time; adrenaline and stress levels rose rapidly for both of us; as a dual bleed air failure is an incredibly rare event and would ultimately mean loss of cabin pressurization. The PIC followed the emergency checklist and turned off the other bleed air switch. The checklist instructs you to turn off the system associated with the caution light but does not detail what to do in the event of dual failure. With both systems off; the cabin immediately felt loss of pressurization. We both immediately felt intense effects of Hypoxia and began using crew masks for oxygen in the descent to relieve some of these effects. During the descent; I tried responding to ZZZ center numerous times with the mask-mic; and with the comm switch selected to OXY to select the appropriate mic; was unable. Some of the effects I was experiencing were; numb/tingling fingers; hyperventilation; incredibly slow reaction time; lack of basic motor skills; visual impairment and at one point began noticing the beginning of a 'grey-out'. Eventually the oxygen mask and the lower/safe altitude seemed to reduce the effects and I could feel my body stabilizing. PIC continued a rapid descent until we reached a safer altitude where effects stabilized. Removed masks once we both felt like the effects had reduced. At this point we were just trying to reach anyone back at the rapidly approaching ZZZ so we swapped to tower frequency back on headsets. Tower instructed us to go over to approach frequency and get cleared for the ILS XX in to ZZZ. Once cleared; we landed safely on RWYXX and stayed with tower; instructed to taxi all the way down to the maintenance ramp we initially taxied out from.
Source: NASA Aviation Safety Reporting System (public domain). Reports are voluntary submissions and are not verified by NASA.