MD-11
Flight Crew Air Transport Pilot (ATP)
Workload; Troubleshooting; Time Pressure
Aircraft Equipment Problem Less Severe; Deviation / Discrepancy - Procedural Published Material / Policy; Inflight Event / Encounter Weather / Turbulence
Flight Crew Landed As Precaution; Flight Crew Returned To Departure Airport
Aircraft
[This] aircraft had an extensive history of air system problems. My FO and I had been with the aircraft for 3 days and had experienced multiple block turn backs for air system issues resulting in an unscheduled layover. We were eventually able to operate the aircraft. After laying over; we were scheduled to operate the same aircraft [on another leg]. The aircraft dispatched with 5 open MEL items and 1 open CDL; isolation valve inop. This MEL requires the valve to be secured open; one associated bleed valve secured closed; and the air system to be operated in auto. At our time of departure; thunderstorms existed in the vicinity; windshear was reported on the ATIS and the runway was wet with moderate rain. Taxi out time was 1 hour and 12 minutes. As the delay continued; we calculated a min fuel quantity for takeoff with assistance from [operations]. When cleared for takeoff we had exactly 200 pounds of fuel in excess of the calculated return-to-blocks fuel quantity. Performed windshear module takeoff with an immediate right turn to avoid weather. Passing through about 2;000 feet; the 2 operating bleeds closed and multiple alerts appeared. Within about 5 seconds; the bleeds cycled back on and the alerts disappeared. About 30 seconds later; both bleeds again closed causing multiple alerts including a Level 2 'Air Sys 1-2 off'. The FO ran the QRH procedure; which actually doesn't address the issues we were having. We were not able to control the air system properly in either manual or auto modes. The procedure presumes a manifold fail condition; which did not exist as far as we could tell. As we worked the problem; we were rapidly approaching a fix; the FIR entry point for another countries airspace. That ATC facility requires a call prior to the fix; and we were unable to comply due to high workload. We were also leveled at 7;000 feet due to no pressurization on the aircraft. We did not wish to enter the airspace while working the problem and maintaining a low altitude. Due to our minimum fuel departure and being unable to climb; we quickly realized that we would be not have the fuel to continue to destination even if we had been able to stabilize the air system. I made the decision to return to [departure airport]; which required us to dump fuel. We coordinated with Radar and dumped fuel while holding at 10;000 feet. Because of our high zero fuel weight; we could not dump to max landing weight. Based on weather conditions; I chose not to delay the arrival to burn fuel to max landing weight. We landed at 490;000 pounds; 8;500 pounds over max landing weight.In retrospect; with the history of air problems on the aircraft; it would have been better to fully troubleshoot the air system and clear the MEL than to continue when there was plenty of history that showed there were further problems with the air system.
Air turn back was required due to air system issue and aircraft unable to climb. Fuel was dumped at 10;000 ft while doing a holding pattern at 280 kts. Approximately 112;000 lbs of fuel dumped.
MD-11 Captain and their Dispatcher reported the flight made an air return to the departure airport after experiencing multiple air system problems. Aircraft reportedly had a history of air system anomalies.