Gulfstream IV / G350 / G450
Flight Crew Air Transport Pilot (ATP); Flight Crew Flight Instructor; Flight Crew Instrument; Flight Crew Multiengine
Flight Crew Last 90 Days 86; Flight Crew Total 6186; Flight Crew Type 1359
Situational Awareness
Aircraft Equipment Problem Critical; Deviation / Discrepancy - Procedural Clearance; Flight Deck / Cabin / Aircraft Event Smoke / Fire / Fumes / Odor
Flight Crew Took Evasive Action
Aircraft
Event was while in cruise flight. We were level at FL410 when we asked ATC for clearance to FL430 due to weather in front of us. While reaching FL430; noticed my ears popping. Immediately saw cabin was climbing. Checked pressurization panel and everything was set up correctly. Asked for altitude lower than FL410 while running checklist but unable to maintain pressurization as cabin kept climbing. Kept requesting lower. Emergency checklist popped up on EICAS screen and started running this emergency checklist when we smelled a very strong burning odor. First Officer checked in the back for potential fire; and no issues found. Looked at the bleed panel and left bleed showing 0 PSI. [Advised ATC] for loss of pressurization and requested 10;000 feet. ATC had a hard time hearing us as we were both on O2 masks at this time. Another plane relayed message and we were granted lower descent. Left Bleed Valve circuit breaker found popped. Diverted to ZZZ1. Passengers were not happy; but safety first!
Cruising at FL430 loss of pressurization checklist popped up on the PFD and we smelled something burning. We notified ATC and started a descent. I went to the back to check and see if anything was being used in the galley; nothing. Ran the loss of pressurization checklist but the cabin was still climbing. Cabin stopped climbing on descent through FL180 and started to stabilize. We noticed that there was no bleed air on the left engine and the left bleed air breaker popped. We made the decision to divert to ZZZ1.
Gulfstream IV flight crew reported loss of cabin pressure and having to divert.