Flight Crew Multiengine; Flight Crew Flight Instructor; Flight Crew Instrument; Flight Crew Air Transport Pilot (ATP)
Flight Crew Last 90 Days 21; Flight Crew Total 20000; Flight Crew Type 5500
Aircraft Equipment Problem Critical; Inflight Event / Encounter Fuel Issue
Air Traffic Control Issued New Clearance; Flight Crew Landed As Precaution; Flight Crew Inflight Shutdown; Flight Crew Requested ATC Assistance / Clarification; Flight Crew Overcame Equipment Problem; Flight Crew Diverted; General Maintenance Action
Aircraft
We were cruising at FL400 when right engine rolled back. Turned ON ignition; engine would not re-light; [advised ATC]. Requested descent to FL300. Donned oxygen mask. Engine restarted about FL310; leveled at FL300. Requested a nearby airport for landing. Next day; drained several times some fuel from each wing tank sumps about 1-2 gallons each to find about a cup of water in the right fuel tank. No water was further found. Restarted both engine to find all is normal. Mechanic's belief is [the] water interrupted the fuel to the engine to cause a rollback.
[Report narrative contained no additional information.]
G1159 flight crew reported the #2 engine rolled back in cruise flight at FL400. Engine relight was successful after descent; and after landing about a cup of water was found after draining a few gallons from the right fuel tank.