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Remove before flight is a safety warning commonly 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. In some cases, non-removal of a labeled part have caused airplane crashes. 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.
It is common to see key rings, T-shirts, bag tags and other such products with this ribbon, especially for people who work in aviation or aviation enthusiasts.