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Comment by ghshephard | Hacker News Reader

This is an awesome article - there are a ton of interesting excerpts all in one place, that I haven't seen before, such as this one:

One compelling reason behind the extensive pre-testing was Boeing's desire to meet the Federal Aviation Agency's (FAA's) Extended Twin Operations (ETOPS) standards ahead of schedule. The original ETOPS rule was drafted in 1953 to protect against the chance of dual, unrelated engine failures. Unless a newly designed and produced aircraft has at least three engines, it usually had to wait, sometimes as long as four years, before the FAA and the Joint Airworthiness Authorities (JAA) will allow it to fly more than one hour from an airport; after a time, the new aircraft is deemed a "veteran" and is allowed to fly three hours away. A shortened trial period would drastically increase Boeing's sales."

It hadn't occurred to me that a 777 is always three hours away from an Airport. I'll have to look more closely on the map.

View on HN

This is a nice mapping web app that lets you see allowed and forbidden areas for different ETOPS levels: http://gc.kls2.com

At 3 hours, it's mostly the Southern Ocean that's off-limits.

Thanks - that's a great site. It turns out that 3 Hours can take you pretty much anywhere in the world. This was a nice briefing on ETOPS - http://gc.kls2.com/faq.html#etops-138

http://gc.kls2.com/faq.html#etops-240

I had no idea Boeing was subsidizing Midway Island in order to provide an ETOPS alternate airport.

Also, 5.5 hour ETOPS? That's crazy long!

http://gc.kls2.com/faq.html#etops-330

PBS did an interesting, long documentary filming the build and certification process for the 777. It's broken into 5 different, hour long parts that can be found on Youtube (https://www.youtube.com/watch?v=0oyWZjdXxlw - First part). The last part goes into detail about what they did to meet FAA regulations in a short amount of time.

I wrote some fuel estimation software once long ago and that particular item was one of the more complex features to get right.

And don't forget about alternates!

Since it's mostly 747 and similarly large planes on intercontinental flights anyway, I doubt this is much of an issue. I wonder if there actually is anywhere in the CONUS that's more than 3 hours from at least a rural airstrip?

The reason why I thought it might be an issue, is that according to Wikipedia, The 777-200LR is the world's longest-range airliner and can fly more than halfway around the globe; it holds the record for the longest distance flown non-stop by a commercial aircraft. . It hadn't occurred to me that because the 777 is a twin engine, it can't really use all that range. It needs to stay near airports.

Twin engine planes absolutely can cross oceans -- if you need three hours' flying distance in the worst case (ETOPS-180), then you can cross up to six hours of water between any two backup airports. North Atlantic routes have only a few hours of contiguous water between, say, Greenland and Iceland. Even the Pacific has enough small islands (e.g. Hawaii) to make something like this possible (shaded areas are outside 3-hour range):

http://www.gcmap.com/mapui?P=EWR+-+SYD&MS=wls&DU=mi&E=180

The 777 was rated for ETOPS 180 minutes initially, increased to 207 minutes, and then to 330 minutes (5 1/2 hours) in 2011. It can use its range.

Ref: http://aviationweek.com/awin/faa-extends-777-etops-approval

It's not the size of the aircraft, but the number of engines on it that matters. And twin jets on intercontinental service outnumber quad jets.

Three hours at ~500 mph is halfway across the USA diagonally.

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