Cessna 425/441 Conquest I/Conquest II
Flight Crew Commercial; Flight Crew Instrument; Flight Crew Multiengine
Flight Crew Last 90 Days 20; Flight Crew Total 1000; Flight Crew Type 200
Aircraft Equipment Problem Critical; Deviation / Discrepancy - Procedural Published Material / Policy; Inflight Event / Encounter Fuel Issue; Inflight Event / Encounter Weather / Turbulence
Air Traffic Control Provided Assistance; Aircraft Equipment Problem Dissipated; Flight Crew Landed As Precaution; Flight Crew Regained Aircraft Control; Flight Crew Took Evasive Action; General Maintenance Action
Aircraft; Procedure; Weather
While cruising at FL280 in full IMC; about 20-miles to the west of a Doppler painted line of extreme precipitation; the left engine of a CE-425 failed. Yaw was felt; gauges were cross checked; autofeather engaged; and left rudder application confirmed 'dead-foot; inoperative-engine'. While stabilizing the aircraft with rudder trim the autopilot disengaged increasing workload. Approximately 1-min after the left engine failed; the right engine failed; now requiring rudder readjustment while executing the emergency checklist for engine failure while airborne above Vmca while trying to maintain Vglide and straight and level. While descending an air restart of the left engine was executed successfully and left generator re-initiated; after having descended to 15;000 [feet] MSL. The right engine also successfully restarted using the starter and it was as if the last three minutes never happened - all gauge readings returned to normal. No fuel starvation; no ignitor failure issues; nada. The airplane was then flown away from the storm under normal operating conditions and landed 150 miles from where the restarts occurred. Upon reflection; the inertial separators were not opened; however; there was also no ice buildup on the wings (note; the prop heat; stall vane and pitot heats were on). Pre-mixed (JetA+) is always used. The strange part is that both engines failed within about a minute of each other - is it possible that the conditions were just right in the presence of the storm to drop the temperature or otherwise cause a fuel gelling instance that rectified itself once at an altitude where the temperature was above freezing? The fuel control heaters; fuel filters; vents and other sources of potential fuel starvation will be verified if further followup is of interest.
CE-425 pilot reported both engines flaming out in IMC and restarting both engines; descending and landing uneventfully.