A Cletrac tows a P-38 Lightning of the 15th Air Force in North Africa. Printed caption on reverse: '24612 AC- Since the pilot depends upon his compass to navigate his plane safely to and from a mission it is very important that the compass is accurate. At a base in North Africa, a US Army Engineering company surveyed and marked off true north and other points on the compass. Here a Cletrac tows a Lockheed P-38 away from the wheel stops after the compass has been checked. US Air Force Photo.'