ATPL Navigation case studies
ATPL Navigation · Put your knowledge to work in context.
Navigation is one of the core technical subjects of the ATPL ground syllabus, and it carries substantial weight because it underpins almost everything a pilot does in flight: knowing where the aircraft is, where it is going, and how long it will take to get there. The subject is examined as a multiple-choice paper covering the form of the Earth and coordinate systems, terrestrial magnetism and compasses, chart projections, the triangle of velocities and dead reckoning, visual in-flight navigation and position fixing, radio navigation systems (ADF, VOR, DME, ILS, radar, GNSS and performance-based navigation), area navigation and flight management systems, and advanced topics such as great-circle and rhumb-line planning and polar or oceanic navigation. The ATPL Navigation case studies are 5 cases and about 2,130 words.
1Compass swing after avionics upgrade
A twin turboprop has just had a glass cockpit and a new flux-valve remote-reading compass installed. On the compass swing at the run-up pad (magnetic heading 090°, all electrics on), the engineer reads a deviation of +6°.
386 words, about 2 min2Drift and ground speed from a single fix pair
A light aircraft flies from a departure point on a planned magnetic track of 045° at an indicated airspeed of 120 kt. The forecast wind is 300°/25 kt, and the pilot computes a heading and ground speed before departure.
414 words, about 2 min3Map reading in featureless terrain
A VFR flight crosses a large area of uniform farmland with few roads. The pilot's last confirmed fix was 25 minutes ago.
428 words, about 2 min4RNAV approach with a database anomaly
An aircraft with a GPS-based RNAV system is cleared for an LNAV approach. On selecting the approach from the navigation database, the crew notices that the final approach waypoint coordinates differ slightly from those on the current paper chart, and that the database cycle is one cycle out of date.
385 words, about 2 min5Great-circle planning on a north Atlantic crossing
A flight is planned from 60°N 030°W to 60°N 010°W. The crew is comparing a rhumb-line track with a great-circle track and considering the effect of a jet stream forecast of 250°/80 kt at flight level.
517 words, about 3 min