diff --git a/src/aircraft_cmd.cpp b/src/aircraft_cmd.cpp
--- a/src/aircraft_cmd.cpp
+++ b/src/aircraft_cmd.cpp
@@ -20,7 +20,7 @@
 #include "strings_func.h"
 #include "command_func.h"
 #include "window_func.h"
-#include "date_func.h"
+#include "timer/timer_game_calendar.h"
 #include "vehicle_func.h"
 #include "sound_func.h"
 #include "cheat_type.h"
@@ -337,8 +337,8 @@ CommandCost CmdBuildAircraft(DoCommandFl
 
 		v->SetServiceInterval(Company::Get(_current_company)->settings.vehicle.servint_aircraft);
 
-		v->date_of_last_service = _date;
-		v->build_year = u->build_year = _cur_year;
+		v->date_of_last_service = TimerGameCalendar::date;
+		v->build_year = u->build_year = TimerGameCalendar::year;
 
 		v->sprite_cache.sprite_seq.Set(SPR_IMG_QUERY);
 		u->sprite_cache.sprite_seq.Set(SPR_IMG_QUERY);
@@ -1555,7 +1555,7 @@ static void AircraftEventHandler_AtTermi
 		if (_settings_game.order.serviceathelipad) {
 			if (v->subtype == AIR_HELICOPTER && apc->num_helipads > 0) {
 				/* an excerpt of ServiceAircraft, without the invisibility stuff */
-				v->date_of_last_service = _date;
+				v->date_of_last_service = TimerGameCalendar::date;
 				v->breakdowns_since_last_service = 0;
 				v->reliability = v->GetEngine()->reliability;
 				SetWindowDirty(WC_VEHICLE_DETAILS, v->index);