Date: 201409
Local time of day: 1201-1800
Location: ZZZ.ARTCC, US
Flight conditions: VMC
Light: Daylight
Aircraft: Cessna Citation Sovereign (C680)
Operator: Fractional
Operating under: Part 91
Flight plan: IFR
Mission: Passenger
Flight phase: Cruise
Airspace: Class A ZZZ
ATC / advisory: Center ZZZ
Aircraft component: Air Conditioning and Pressurization Pack
Component problem: Malfunctioning
Reporter organization: Fractional
Reporter function: Captain; Pilot Not Flying
Reporter qualification: Flight Crew Air Transport Pilot (ATP)
Human factors: Other / Unknown
Second reporter function: Captain; Pilot Flying
Anomaly: Aircraft Equipment Problem Critical; Airspace Violation All Types; Deviation / Discrepancy - Procedural Clearance; Deviation / Discrepancy - Procedural Published Material / Policy; Flight Deck / Cabin / Aircraft Event Smoke / Fire / Fumes / Odor
Detector: Person Flight Crew; Person Air Traffic Control
When detected: In-flight
Result: Air Traffic Control Provided Assistance; Flight Crew Landed in Emergency Condition; Flight Crew Diverted; General Declared Emergency; General Maintenance Action
Contributing factors: Company Policy; Aircraft; Procedure
Primary problem: Aircraft

Narrative: Level at FL450; I turned around to check on the pax and noticed a grey haze of smoke in the cabin. I briefly lifted my oxygen mask off my face to smell the air; and verified a smell of burnt oil smoke. We immediately [spoke] with ZZZ Center; asking for lower and diversion. I ran the Environmental Smoke checklist. Switching to the right bleed source seemed to alleviate the smoke slightly. I have heard anecdotally of several issues of this nature with the Sovereign fleet. I would recommend more regular Preventative Maintenance beyond the standard pilot preflight and mechanic line checks in order to more proactively identify and replace worn bleed air system oil seals prior to them reaching limits and failing.

Callback: Reporter stated he was referring to the Right Engine when he mentioned 'switching to right bleed source.'The Cessna Sovereign has two air conditioning packs; but only one Air Cycle Machine (ACM) for both. The aircraft has three bleed sources: APU and two PW-306C Turbofan engines. Engine air is bled from the Low Pressure (LP) and High Pressure (HP) section of the N1. Reporter stated his first priority was to descend to a lower altitude and land; which took about 5-10 minutes. So he did not have much opportunity to troubleshoot the pneumatic system for cause of the burnt oil smell and blue/gray haze in the cabin. To date; he has not heard what contributed to the smoky condition in the cabin; but suspects that after a certain number of flight hours; this type of mechanical failure will occur again. He checked with the passengers three hours later and they all said they were fine.

Second narrative: Possibly routine checks on valves and seals in the Environmental System. Additionally I would recommend a debrief procedure for such events. We don't know what/ how much fumes we may have ingested and I was surprised when the initial plan was to ferry another plane to us so as we could continue with pax with no real status check as to how we were doing; which we both felt was very unsafe.


Synopsis: Two pilots report noticing a blue/gray haze of smoke and burnt oil smell in the aft cabin of a CE680 Sovereign at FL450. Switching to the right bleed source helped reduce thickness of smoke. Flight diverted. Increased Preventive Maintenance recommended to identify and replace worn bleed air system oil seals prior to reaching limits and failing. TRACON Controller also reported various distractions going on at the time of the smoke emergency resulting in an MVA event involving a small aircraft.