Before revision: Trailing cones (or trailing wires as they are often incorrectly called or trailing static cones), were first developed and tested in the 1950s and 1960's as a simple means of calibrating the static pressure (altitude reporting) error of an aircraft's pitot-static system .
After revision: A Boeing 787-8 during a test flight with a trailing cone attached to the vertical stabilizerTrailing cones (or trailing wires as they are often incorrectly called or trailing static cones), were first developed and tested in the 1950s and 1960's as a simple means of calibrating the static pressure (altitude reporting) error of an aircraft's pitot-static system .