The concept of special regulations for aircraft that venture far from suitable airports, commonly known as “extended twin-engine operations” (ETOPS) since 1985, got its start much earlier—50 years earlier in fact.
The first ETOPS-like rules in the U.S. date back to 1936, when twin-engine piston aircraft were required to patch together routes with no more than 100 mi. between suitable alternate airports. Much has changed since then, and FAA is updating its ETOPS guidance to reflect the latest advances. The new advisory circular (AC), 120-42C, will replace the current AC, issued in 2008.
These days, ETOPS is defined as simply “extended operations” to better quantify the risks involved. Engine reliability is far less of an issue than survivability at remote airports—such as in the polar regions—in the case of a diversion, for instance. The FAA codified ETOPS regulations in 2007, clarifying that all twin-engine commercial aircraft and all passenger-carrying aircraft with more than two engines must comply if they venture far enough away from suitable alternate airports (60 and 180 min., respectively). That rule change drove the 2008 AC update.
Since then, more lessons have been learned, and the current guidance update is aimed at capturing them. “In particular, the FAA recognized the need to clarify and strengthen the requirements and information related to fuel and flight planning, weather requirements, aircraft performance, and ETOPS training requirements for pilots, aircraft dispatchers, and flight following personnel,” the agency explains in the new draft guidance. “Additionally, the FAA determined a need to provide clearer guidelines regarding the ETOPS application process, as well as streamline the administrative portion of the process itself.”
The draft AC has grown a bit—to 84 pages from the 70-page version released 18 years go—due in part to more detailed training requirements and other key areas. The new AC also will include more detailed descriptions of the different ETOPS-route regions. The FAA took comments on the AC through early October.