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 , like that of Aeroperú Flight 603
Aeroperú Flight 603
Aeroperú Flight 603
Remove before flight