The ERSA is a publication which contains information vital for planning a flight and for the pilot in flight. It includes pictorial presentations of all licenced aerodromes and is amended every 12 weeks. Other information includes aerodrome physical characteristics, hours of operation, visual ground aids, air traffic services, navaids, lighting, MTAF and CTAF, aerodromeoperators' details and any changes applicable. The ERSA is available in spiral bound or loose leaf format and can be supplied with or without the Runway Distance Supplement.