An electronics display instrument configured to display aircraft course deviation, the instrument comprising: an input (20, 30) to receive a signal yielded from a comparison of navigation information indicative of a desired position of the aircraft and actual position information of the aircraft; an output to convey the signal by displaying a conditional symbol (50a; 50b; 50c) on a limited measurement scale, wherein the conditional symbol corresponds to a readout of an instrument configured to display aircraft course deviation, and wherein the conditional symbol (50a; 50b; 50c) is moveable from a first extreme (52a; 52b; 52c) to a second extreme (53a; 53b; 53c) with a central position (54a; 54b; 54c) therebetween; wherein the conditional symbol (50a; 50b; 50c) being in the central position (54a; 54b; 54c) indicates the aircraft is on course, and the conditional symbol (50a; 50b; 50c) being in the first or second extreme position (52a/53a; 52b/53b; 52c/53c) indicates the aircraft is off course in a first or second direction by an aircraft deviation amount at least equal to a maximum deviation amount indicated by the measurement scale; wherein the conditional symbol (50a; 50b; 50c) has a first form to indicate that the aircraft is off course by an aircraft deviation amount within the maximum deviation amount indicated by the measurement scale, and a second form (55a; 55b; 55c) to indicate that the aircraft is off course by an amount in excess of maximum deviation amount indicated by the measurement scale; and wherein the first form indicates that the aircraft deviation amount indicated by the measurement scale is an accurate representation of an actual aircraft deviation amount and the second form (55a; 55b; 55c) indicates that the aircraft deviation amount indicated by the measurement scale is not an accurate representation of an actual aircraft deviation amount. an input (20, 30) to receive a signal yielded from a comparison of navigation information indicative of a desired position of the aircraft and actual position information of the aircraft; an output to convey the signal by displaying a conditional symbol (50a; 50b; 50c) on a limited measurement scale, wherein the conditional symbol corresponds to a readout of an instrument configured to display aircraft course deviation, and wherein the conditional symbol (50a; 50b; 50c) is moveable from a first extreme (52a; 52b; 52c) to a second extreme (53a; 53b; 53c) with a central position (54a; 54b; 54c) therebetween; wherein the conditional symbol (50a; 50b; 50c) being in the central position (54a; 54b; 54c) indicates the aircraft is on course, and the conditional symbol (50a; 50b; 50c) being in the first or second extreme position (52a/53a; 52b/53b; 52c/53c) indicates the aircraft is off course in a first or second direction by an aircraft deviation amount at least equal to a maximum deviation amount indicated by the measurement scale; wherein the conditional symbol (50a; 50b; 50c) has a first form to indicate that the aircraft is off course by an aircraft deviation amount within the maximum deviation amount indicated by the measurement scale, and a second form (55a; 55b; 55c) to indicate that the aircraft is off course by an amount in excess of maximum deviation amount indicated by the measurement scale; and wherein the first form indicates that the aircraft deviation amount indicated by the measurement scale is an accurate representation of an actual aircraft deviation amount and the second form (55a; 55b; 55c) indicates that the aircraft deviation amount indicated by the measurement scale is not an accurate representation of an actual aircraft deviation amount.