ETOPS ratings and diversion geometry
What 60, 120, 180, 207, 240, 285, 330 and 370 minutes mean on a route map.
Guide hub
ETOPS and EDTO Planning
ETOPS and EDTO analysis asks whether a route remains within an approved diversion time of a suitable alternate under defined one-engine-inoperative assumptions. A circle on a map is only the beginning of that question.
Planning screen, not operational approval
Great Circle Pro models diversion geometry, aircraft analysis ceilings and a preliminary runway comparison. It does not verify operator authorization, weather, NOTAMs, rescue services, approaches or alternate adequacy.
ETOPS fundamentals
Can the aircraft land there?
Why a point inside a diversion circle still needs a preliminary runway and surface screen.
ETOPS calculation methodology
OEI speed, drift-down, wind sensitivities, alternate selection, gap time, EEP and EXP.
Aircraft ETOPS data
Compare aircraft analysis ceilings, cruise speeds, modeled OEI speeds and range context.
What the map evaluates
The ETOPS mode draws diversion-reach bubbles around a curated alternate set, compares the planned route with their combined coverage and identifies any uncovered segment. When a gap exists, the tool reports its location and modeled time exposure. The screen can then compare ratings and apply a separate adverse-wind sensitivity. Known short or unpaved runways are flagged, while missing runway data remains unknown rather than being treated as suitable.
Questions to ask after the geometry closes
Is the rating available?
Aircraft capability, type certification and an operator's specific approval are different questions. The tool labels projected and planning-only cases rather than presenting them as approvals.
Is the alternate actually adequate?
Runway length is only a preliminary screen. Weather, approaches, services, landing performance and operational authorization remain outside the model.
Which assumptions are binding?
OEI speed, diversion time, wind, route geometry and alternate selection can each change the coverage result.
Where are EEP and EXP?
Entry and exit points show the portion of a route subject to the selected extended-diversion analysis.
Screen an oceanic route
Plot a city pair, choose an aircraft and compare modeled ETOPS coverage by rating.