Remove before flight is a safety warning often seen on removable aircraft and spacecraft components, typically in the form of a red ribbon, to indicate that a device, such as a protective cover or a pin to prevent the movement of mechanical parts, is only used when the aircraft is on the ground (parked or taxiing). On small general aviation aircraft, this may include a pitot tube cover or a control lock. The warning appears in English only. Similar ribbons labelled "pull to arm" or similar are found on missiles and other weapon systems that are not mounted on aircraft. Remove before flight components are often referred to as "red tag items". Typically, the ground crew will have a checklist of remove before flight items. Some checklists will require the ribbon or tag to be attached to the checklist to verify it has been removed. In some cases, non-removal of a labelled part has caused airplane crashes.