diff --git a/src/mame/drivers/airraid.cpp b/src/mame/drivers/airraid.cpp
index f7e4fee773e..d26d2ae59d7 100644
--- a/src/mame/drivers/airraid.cpp
+++ b/src/mame/drivers/airraid.cpp
@@ -304,7 +304,7 @@ static INPUT_PORTS_START( airraid )
 	PORT_BIT( 0x08, IP_ACTIVE_LOW, IPT_JOYSTICK_RIGHT ) PORT_8WAY
 	PORT_BIT( 0x10, IP_ACTIVE_LOW, IPT_BUTTON1 )
 	PORT_BIT( 0x20, IP_ACTIVE_LOW, IPT_BUTTON2 )
-	PORT_BIT( 0x40, IP_ACTIVE_LOW, IPT_BUTTON3 )
+	PORT_BIT( 0x40, IP_ACTIVE_LOW, IPT_UNKNOWN )
 	PORT_BIT( 0x80, IP_ACTIVE_LOW, IPT_UNKNOWN )
 
 	PORT_START("IN1")   // IN1  (0xc201)