northerly turning error
northerly turning error
[′nȯr·thər·lē ¦tərn·iŋ ‚er·ər] (aerospace engineering)
An acceleration error in the magnetic compass of an aircraft in a banked attitude during a turn, so called because it was first noted and is most pronounced during turns made from initial north-south courses; during a turn the magnetic needle is tilted from the horizontal, due to acceleration and the banking of the aircraft; in this position the compass needle will be acted upon by the vertical as well as the horizontal component of the earth's magnetic field; in addition, the compass needle is mechanically restricted in movement, due to tilt. Also known as turning error.
northerly turning error
Aircraft is turning right when on a northerly heading. The compass in this case lags and shows 330° when the aircraft is in fact on 000°. When the aircraft is initiating turn on a southerly heading, the compass leads in that it shows 150° when the aircraft is still at 170°. There is no such error when aircraft is turning through easterly or westerly heading. The compass needle catches up once the aircraft is level or when aircraft is passing through easterly and westerly headings.