During our preflight preparation for our flight to Ireland last week we did all the usual routines, including check the flight plan to ensure we had the proper fuel, look at the crew manifest to figure out who we were flying with, and check the weather. Checking the weather consists of making sure our destination and alternates are at or above their weather minimums. When flying across the Atlantic in ETOPS airspace we need to make sure our diversions are proper and safe.
What is ETOPS?
ETOPS stands for Extended-range Twin-engine Operations. What does this mean? Basically any two-engine aircraft operating for an airline must be within 60 minutes of the nearest suitable airport with one engine inoperative.
What if you have more than two engines?
If you have more than two engines, say a Boeing 747 or MD-11 you can operate without regard to that rule. With those aircraft you can fly the most direct route, even if it's far away from a suitable airport. The logic is you have multiple engines that can fail before you're in trouble.
OK, but there aren't many three-engine airplanes out there
On your next flight across the wide ocean take a look outside and you'll probably notice you only have two engines, one on each side. The airlines, wanting to use more fuel efficient aircraft, use a large percentage of twin jet aircraft on their routes, including oceanic routes. The FAA, along with aircraft manufactures and airlines, realized this trend and came up with a solution. With the reliability of aircraft engines increasing and better training and maintenance on the part of the airlines, the FAA came out with ETOPS.
Currently, with two engines airplanes, we can fly either 120 minutes or 180 minutes, single engine, from the nearest suitable airport. Those times depend on how your flight is planned and what fuel is required. Usually our ETOPS diversion airports are either in Iceland, Canada or the Azores, which keep us well within the 120 or 180 minutes required. And not all airlines are allowed to do this; indeed, you must be approved by the FAA before conducting ETOPS operations.
So the next time you're flying across the ocean and see only two engines, rest assured there is a plan in place to safely get you to your destination or an alternate if the situation arises.