[{"data":"10:10:25"},{"data":"00:10:51"},{"data":"03:35:01"},]

db.collection.aggregate([{"$addFields":{dataParts:{$map:{input:{$split:["$data",":"]},as:"num",in:{"$toInt":"$$num"}}},}},{$group:{_id:null,seconds:{$sum:{"$arrayElemAt":["$dataParts",2]}},minutes:{$sum:{"$arrayElemAt":["$dataParts",1]}},hours:{$sum:{"$arrayElemAt":["$dataParts",0]}},}},{"$addFields":{finalSeconds:{$mod:["$seconds",60]},}},{$addFields:{minutes:{$sum:["$minutes",{"$divide":[{"$subtract":["$seconds","$finalSeconds"]},60]}]},}},{$addFields:{finalMinutes:{$mod:["$minutes",60]},finalHours:{$sum:["$hours",{$mod:[{$max:[{"$subtract":["$minutes",60]},0]},60]}]}}},{$project:{final:{$concat:[{"$toString":"$finalHours"},":",{"$toString":"$finalMinutes"},":",{"$toString":"$finalSeconds"},]}}}])