Aeronautical Information Services and Charts
What is examined
AIS and charts tests how aeronautical information reaches the cockpit: AIP, NOTAM, AIRAC, chart types, scales, symbols and obstacle clearance. Expect questions on chart reading and information validity.
Core rules
- The AIP is the primary state publication; amendments are managed through the AIRAC cycle, normally 28 days. NOTAM give short-notice changes.
- En-route charts show airways, navaids, restricted areas and minimum en-route altitudes. Terminal charts show SIDs, STARs and approaches.
- Chart scale: 1:250,000 means 1 cm on the chart = 250,000 cm = 2.5 km on the ground.
- MSA gives obstacle clearance within 25 NM of a reference point, normally 1,000 ft (2,000 ft in mountainous terrain).
- Grid MORA provides terrain clearance in chart grid cells; it is not a route clearance.
Worked example
On a 1:250,000 chart, a measured straight line between two points is 4.0 cm. Ground distance = 4.0 × 250,000 cm = 1,000,000 cm = 10 km. At 120 kt, 10 km takes 10/(120×1.852) hours = 10/222.2 h = 0.045 h = 2.7 min. The scale conversion is a common exam step: measure, multiply by scale denominator, convert to km or NM.
Traps
Using a NOTAM as a permanent rule; missing an AIRAC effective date; confusing MSA with grid MORA; measuring in cm and forgetting to convert; assuming a chart is current without checking the effective date.