diff --git a/maintenance.md b/maintenance.md
index a9820e7..d79e68b 100644
--- a/maintenance.md
+++ b/maintenance.md
@@ -38,3 +38,4 @@ Newest entries at the bottom.
 - 2026-09-27: Comms backup tested.
 - 2026-09-28: Gyroscopes recalibrated.
 - 2026-09-28: Hull inspection, no leaks.
+- 2026-09-30: Navigation lights checked.