diff --git a/maintenance.md b/maintenance.md
index 455efd1..dcf669b 100644
--- a/maintenance.md
+++ b/maintenance.md
@@ -19,3 +19,4 @@ Newest entries at the bottom.
 - 2026-09-10: Debugging duck accounted for.
 - 2026-09-11: Comms backup tested.
 - 2026-09-14: Water recycling filters replaced.
+- 2026-09-15: Airlock seals checked.