MD-11
Flight Crew Air Transport Pilot (ATP); Flight Crew Instrument; Flight Crew Multiengine
Confusion; Distraction; Troubleshooting; Situational Awareness
Aircraft Equipment Problem Critical; Inflight Event / Encounter Fuel Issue
Flight Crew Landed in Emergency Condition
Aircraft
During cruise at FL380; about 10 min prior to starting our descent into ZZZ; we received a 'Fuel Qty/Used Check' alert. This alert and the associated checklist tells you that you have a possible fuel leak and leads you through diagnosing the problem. We followed the QRH; and took our fuel used on each engine; subtracted from our starting fuel; and found that we were 'short'; i.e.; missing; approximately 5;000 lbs. We were crossing a point on our flight plan and confirmed that we were suddenly short 5;000 lbs vs our planned fuel at that point when we had been ahead 1;500 lbs at each previously point. Following the QRH; with each tank feeding its own engine; we determined that the Number 2 fuel tank was soon 1;500 lbs below the other two tanks; and suspected that was where the leak was. When we isolated the Number 2 tank and fed the number 2 engine from the aux tank (per QRH) the Number 2 tank didn't decrease at all; and the aux pump decreased over 2;000 lbs in just a few minutes while the Number 1 and Number 3 tanks only went down 300 - 400 lbs. This pointed to a leaking Number 2 engine and the QRH calls for shutting down the engine. At this time we were beginning our descent into ZZZ. We were tankering fuel and had a planned FOD of 49K. Reluctant to shut down an engine for the wrong reason; and because this checklist is so confusing and easy to mess up; I had my first officer go through it again to make sure we were diagnosing the problem correctly. We again came to the same conclusions and couldn't account for over 5;000 lbs of missing fuel. We ended up shutting down the Number 2 engine around 15;000 ft on the descent and requested priority handling with ZZZ Approach; requested vectors for the ILS to Rwy XX; and asked for emergency vehicles to be standing by to check for a possible fuel leak around the Number 2 engine. We landed uneventfully; taxied clear of the runway; and after fire/emergency crews reported there was no evidence of any fuel leaks; we taxied to parking. After landing the fuel in the Number 2 tank was 4;000 - 5000 lbs higher than when airborne; and we no longer had any 'missing' fuel; or indications of a fuel leak.Fuel system malfunction.Not sure. I would like to check and see if this aircraft has a history of this problem. Coincidentally; when I debriefed the next crew that was going to fly this plane to ZZZ1; the Captain said he had a very similar incident a few weeks ago and had to divert into ZZZ2 for a suspected fuel leak when he was going from the West Coast to ZZZ3; and after he landed the fuels all checked out and there was no longer a shortage; just like in our case.
MD-11 Captain reported a fuel indication problem that possibly happened to another crew in the same aircraft.