diff --git a/remote/challenge-sync-airbus/treat.go b/remote/challenge-sync-airbus/treat.go
index 14a637ba..82f83c6c 100644
--- a/remote/challenge-sync-airbus/treat.go
+++ b/remote/challenge-sync-airbus/treat.go
@@ -7,6 +7,7 @@ import (
 	"math"
 	"os"
 	"path/filepath"
+	"sync"
 	"time"
 
 	"srs.epita.fr/fic-server/libfic"
@@ -18,6 +19,7 @@ var (
 
 type Walker struct {
 	LastSync     map[string]*TSValue
+	LastSyncLock sync.RWMutex
 	Exercices    AirbusExercicesBindings
 	Teams        map[string]fic.ExportedTeam
 	RevTeams     map[string]string
@@ -158,7 +160,9 @@ func (w *Walker) TreatScoreGrid(path string, airbusTeam *AirbusTeam) error {
 	maxts := TSValue{
 		Time: time.Time{},
 	}
+	w.LastSyncLock.RLock()
 	ts, ok := w.LastSync[airbusTeam.Name]
+	w.LastSyncLock.RUnlock()
 	if ok {
 		maxts = *ts
 	} else {
@@ -198,7 +202,9 @@ func (w *Walker) TreatScoreGrid(path string, airbusTeam *AirbusTeam) error {
 		maxts.Score = int64(math.Trunc(expected_score))
 	}
 
+	w.LastSyncLock.Lock()
 	w.LastSync[airbusTeam.Name] = &maxts
+	w.LastSyncLock.Unlock()
 
 	return nil
 }
@@ -221,12 +227,14 @@ func (w *Walker) BalanceScores() error {
 				return fmt.Errorf("Unable to award team %s: %w", myteam.Name, err)
 			}
 
+			w.LastSyncLock.Lock()
 			if _, ok := w.LastSync[airbusTeam.Name]; !ok {
 				w.LastSync[airbusTeam.Name] = &TSValue{}
 			}
 
 			w.LastSync[airbusTeam.Name].Score = expected_score
 			w.LastSync[airbusTeam.Name].Time = time.Now()
+			w.LastSyncLock.Unlock()
 		}
 	}