Aviation is about many things, and one of those things is the pursuit of reliability. Starting with the earliest engines and airframes, the pioneers of the industry have been in constant pursuit of making everything as dependable as possible. In the modern era of flying, this has produced two things: mounds of red tape and bureaucracy, and very dependable processes, airplanes—and engines.
If you’ve ever conducted any international travel, you’ll notice that more and more international flying is done in airplanes with only two engines. After the 747, the next generation of wide-body aircraft to enter service all had either two or three engines: the DC-10, the L-1011, the 757/767, and in the last few decades the 777 and 787. The cost advantages are obvious, but what about safety concerns? After all, if two engines are good, then three or four must be better, right?
The FAA and its foreign counterparts have adapted to the world of long-range flying by creating a program called Extended (Twin) Operations, or ETOPS. ETOPS programs can be established for airplanes with any number of engines, but we’ll stick with the twin-engine derivative here. With an ETOPS program, airlines are able to establish that they can operate twin-engine aircraft for long distances over water with the equivalent safety margins as for a four engine jet.
There are rules that must be followed. One of the most important is that of maintenance. With an ETOPS program, the FARs require that certain procedures be followed if maintenance is being conducted on matching parts. For instance, if a mechanic changes the oil on the left engine, he is not allowed to perform the same task on the right engine. The theory is that if that mechanic makes a mistake or is sloppy in his work, it is best to isolate the possibility of the same negative consequence occurring twice on the same plane. This rule applies to a number of tasks in the routine maintenance of the airplane. It applies to work on the tires and landing gear, engines, and several other systems with duplication.
There are other requirements for ETOPS as well. Because participants must be able to travel great distances over water, communication needs change. There are multiple options to establish and maintain adequate communications. The most common is the high-frequency (HF) radio, which works by bouncing the signal off of the atmosphere, and as a result depends on the weather for a good signal. Another option is the satellite phone, which can also suffer from occasional signal reliability and is expensive to operate. ACARS (Aircraft Communication and Reporting System) is also common, and acts essentially as an onboard email, text, and fax system.
The most obvious need on long ETOPS flights is for extra fuel, and there are a number of FARs and exemptions that can be used to set forth a particular airline’s fuel requirements. But, when comparing the alternate fuel requirements for flight of similar distances over land and water, the water route will carry more fuel and thus will cost more.
ETOPS is generally required for twinjet airplanes when the airplane will be more than 60 minutes from an adequate airport, where the word “adequate” generally means just a runway. It doesn’t need to be new or fancy or even have a ground-based approach. It just needs to be a concrete or asphalt strip long enough to safely land an airplane in the most dire circumstances. A flight operating under an ETOPS flight plan can be dispatched for varying lengths of time. An ETOPS 120 flight is one that will be 120 minutes, or two hours, from an airport at some point in its journey.
It is not uncommon to see 737s with ETOPS approval for flights across the Gulf of Mexico or from the northeast to the Caribbean. The longest stretch of pure open-water flying in the world is between Hawaii and California, and the 737 is a common airplane for the route.
ETOPS adds several layers of safety and protection for passengers and crew, and while it’s a cumbersome process, it pays dividends. Just in the last few weeks, a Delta 757 diverted to Iwo Jima in the Pacific en route to Guam. Iwo Jima is a common alternate for Pacific flights. In this case, the system proved once again that it works as intended—red tape and all.—Chip Wright