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Why aren't there a lot of passenger airliners (short flights) using this configuration, since using Coanda effect by blowing wing's extrados is much safer in harsh weather, and would provide extra safety during gusty landings and takeoffs?

I guess extra weight, induced drag, and engine maintenance height may be good reasons, but is it enough to eliminate this solution in the economy/safety equation?

An 72

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    $\begingroup$ I think the problem is that it does not actually count towards any of the safety regulations. Most of those revolve around engine failure and that's exactly where the layout does not help. $\endgroup$
    – Jan Hudec
    Apr 24, 2017 at 18:16
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    $\begingroup$ The other issue is that positioning the engines there is really good for STOL operations, and operations out of unimproved strips. Not really a big problem for commercial airliners. $\endgroup$
    – Ron Beyer
    Apr 24, 2017 at 18:19
  • $\begingroup$ @RonBeyer -- besides, most commercial operations out of STOLports and unimproved strips are small enough that Dorniers and Twotters get the job done, anyhow... $\endgroup$ Apr 25, 2017 at 0:04
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    $\begingroup$ The “blown surface” of the wing behind the engines on the YC-14 used titanium to tolerate the heat of the exhaust gases. Contributor: John Arnold, USAF YC-14 Project Flight Test Systems Engineer (1981-1984) $\endgroup$ Mar 3, 2022 at 19:04
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    $\begingroup$ Great to have someone with your knowledge and experience here, @JohnArnold! If you'll take the tour, you get an idea how this place works to make it a bit easier for your to participate. I hope you stick around and share more of your knowledge! $\endgroup$
    – FreeMan
    Mar 4, 2022 at 13:56

1 Answer 1

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The extra lift provided by the blown flaps and the better protection against FOD is simply not needed in regular airline service, and the higher engine location will make maintenance harder and more expensive. Airport runways are long enough for most purposes already, and only tactical transports could possibly benefit from the enhanced lift and better FOD protection.

At least the An-72 and -74 is operated by a number of civilian and military entities. Note that all of them serve small, local airfields. Note also that passenger service with the An-72 has been discontinued in Finland since this type was not cleared there for passenger services.

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