Image display

A method for displaying an image to a pilot of an aircraft, the method comprising:

• displaying, by a display, to the pilot of the aircraft, an image comprising guidance symbology for use by the pilot when landing the aircraft, the position of the guidance symbology on the display being dependent upon an output of an Internal Navigation System of the aircraft wherein the display is a helmet mounted display of a helmet for wearing by the pilot;
• providing, to one or more processors, an indication that the output of the Internal Navigation System is incorrect;
• determining, by the processor, a further value for the output of the Internal Navigation System;
• determining, by the one or more processors, a specification of further guidance symbology including a position for the further guidance symbology on the display, wherein the position on the display of the further guidance symbology relative to the position on the display of the guidance symbology is dependent upon the difference between the further value for the output of the Internal Navigation System and the incorrect output of the Internal Navigation System;
• and
• displaying, by the display, to the pilot of the aircraft, an image comprising at least the further guidance symbology.