Date: 201909
Local time of day: 1201-1800
Flight conditions: VMC
Aircraft: B787 Dreamliner Undifferentiated or Other Model
Operator: Air Carrier
Operating under: Part 121
Mission: Passenger
Flight phase: Parked
Aircraft component: Cabin Window
Component problem: Malfunctioning
Reporter organization: Air Carrier
Reporter function: Pilot Not Flying; First Officer
Anomaly: Aircraft Equipment Problem Less Severe; Deviation / Discrepancy - Procedural MEL / CDL; Deviation / Discrepancy - Procedural Published Material / Policy; Inflight Event / Encounter Fuel Issue
Detector: Person Flight Crew
When detected: Pre-flight
Result: General None Reported / Taken
Contributing factors: Aircraft; MEL; Procedure
Primary problem: Aircraft

Narrative: We flew Aircraft X with an MEL for 7 passenger window seals protruding on the left side. I performed the walk-around as IRO and noted the 7 passenger window seals protruding forward of the wing; exactly as the Logbook described. I mentioned to the Captain and First Officer about my previous experience with another aircraft that I'd recently flown with a similar issue. I showed them pictures (attached) from my walk-around of [another aircraft]. I seem to remember the MEL for [the other aircraft] was for 'up to 15' passenger window seals; very similar to Aircraft X. We had the appropriate MEL with performance and fuel penalties for Aircraft X and flew it to ZZZ uneventfully.Fast forward to the return leg. As luck or fate would have it; our aircraft is once again Aircraft X that I flew in [month]. I noted in the release that there was no MEL or Log History of a passenger window seal problem; so I assumed it must have been repaired. As I performed the walk-around; I was shocked to find about half of the window seals protruding and it looked as bad or worse than when I flew this aircraft in [month]! I took more pictures and brought this up to the Captain and First Officer. We all agreed that Aircraft X was unacceptable for dispatch without a logbook entry; inspection and appropriate MEL deferral. We brought Maintenance into the loop for an inspection. I showed him the previous pictures of this same aircraft and then accompanied him around the aircraft to count the approximate number of protruding seals (19 LH / 23 RH). The First Officer made the ACARS Maintenance Entry. The Captain coordinated with Dispatch to account for the MEL and we added at least 2;000 lb. additional fuel to account for the extra drag and performance penalties. We received Release 2. The new Maintenance Release Document had the deferral for '31 to 45' passenger window seals protruding with Operations Placard CDL (Configuration Deviation List).I believe our planned gate fuel in release 2 was now about 136+ vs. 134.6 in release 1; but you should be able to get the exact number. We flew .86M for the oceanic crossing (to make up for the delay); instead of .85M; but otherwise flew according to the flight plan. We blocked in with a bit over 11;000 lb remaining fuel; instead of the 14-15;000 lbs. from release 1. I believe 2-3;000 lbs. was due to our faster crossing speed; but the rest was very likely due to the extra drag from the window seals. If Aircraft X has been flying around without this MEL for a while; it's likely to have had many flights with over-burns. My overall point here is why did this MEL get removed without any seemingly significant repairs and how long has it gone un-noticed? Why wasn't it anywhere in the Log History?




Synopsis: B787 flight crew reported that numerous cabin window seals were found protruding on two separate flights and that the logbook entry was cleared.