ETOPS is an acronym for Extended-range Twin-engine Operational Performance Standards, an International Civil Aviation Organization (ICAO) Standard and Recommended Practice (SARP) permitting twin-engined commercial air transporters to fly routes that, at some points, are farther than a distance of 60 minutes' flying time from an emergency or diversion airport.
This rule allows twin-engined airliners—such as the Airbus A300, A310, A320, A330 and A350 families, the Boeing 737, 757, 767, 777 and 787, the EMBRAER 190 and Lineage, and Tupolev Tu-204—to fly long-distance routes that were previously off-limits to twin-engined aircraft. ETOPS operation has no direct correlation to water nor distance over water. It refers to single-engine flight times between diversion airfields—regardless as to whether such fields are separated by water or land.ETOPS may be replaced by a newer system, referred to as 'LROPS or "Long Range Operational Performance Standards", which will affect all civil airliners, not just those with a twin-engine configuration. Until the mid-1980s, the term EROPS (extended range operations) was used before being superseded by ETOPS usage. Currently, the ETOPS term is commonly used for operations previously described as LROPS or EROPS.[1]