ETOPS

The difference between an ETOPS-enabled shorter flight path (the solid green line) and a flight path for non-ETOPS aeroplane (the dashed blue line), the last one is curved due to the required distance to alternates

The Extended-range Twin-engine Operations Performance Standards (ETOPS) (/iːˈtɒps/) are safety standards set by the International Civil Aviation Organization (ICAO) for twin-engine commercial passenger aircraft operations. They are a safety measure intended to ensure that in the event of a single engine failure, an aircraft will still be able to reach a diversion airport using the remaining operational engine. This may be at a reduced speed and/or height, and usually applies to flights over water or remote lands, typically routes previously restricted to three- and four-engine aircraft.[1]: page9 

  1. ^ Getting to Grips with ETOPS (PDF) (Issue V ed.). Airbus. October 1998.