page_title: Turn and slip indicator
section_title: Turn coordinator
hierarchical_section_title: Turn and slip indicator / Operation / Turn coordinator
context_page_description: In aviation, the turn and slip indicator and the turn coordinator variant are essentially two aircraft flight instruments in one device. One indicates the rate of turn, or the rate of change in the aircraft's heading; the other part indicates whether the aircraft is in coordinated flight, showing the slip or skid of the turn. The slip indicator is actually an inclinometer that at rest displays the angle of the aircraft's transverse axis with respect to horizontal, and in motion displays this angle as modified by the acceleration of the aircraft. The most commonly used units are degrees per second or minutes per turn.
context_section_description: The turn coordinator (TC) is a further development of the turn and slip indicator (T/S) with the major difference being the display and the axis upon which the gimbal is mounted. The display is that of a miniature airplane as seen from behind. This looks similar to that of an attitude indicator. "NO PITCH INFORMATION" is usually written on the instrument to avoid confusion regarding the aircraft's pitch, which can be obtained from the artificial horizon instrument.
  In contrast to the T/S, the TC's gimbal is pitched up 30 degrees from the transverse axis. This causes the instrument to respond to roll as well as yaw. This allows the instrument to display a change more quickly as it will react to the change in roll before the aircraft has even begun to yaw. Although this instrument reacts to changes in the aircraft's roll, it does not display the roll attitude.
  The turn coordinator may be used as a performance instrument when the attitude indicator has failed. This is called "partial panel" operations. It can be unnecessarily difficult or even impossible if the pilot does not understand that the instrument is showing roll rates as well as turn rates. The usefulness is also impaired if the internal dashpot is worn out.  In the latter case, the instrument is underdamped and in turbulence will indicate large full-scale deflections to the left and right, all of which are actually roll rate responses.
caption: Image showing the face of a turn coordinator during a standard rate coordinated right turn.