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View Diary: How Airliners Work - Flaps and Slats (77 comments)

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  •  Huh. I didn't know about the different designs. (20+ / 0-)

    I assume the slotted flaps reduce the drag (since air can flow through them) without sacrificing too much of the added lift/stall speed reduction.

    Having your flaps go out on landing is...exciting.  I've run that scenario in simulation with my small planes, but it's not nearly such a huge problem in a Cessna as with a jumbo!  You just don't land at your local airstrip, you find a bigger airport and alt there.

    Not adding flaps on takeoff, on the other hand, is fatal in a big jet.  There was an infamous case - Northwest Airlines Flight 255 - where the crew forgot to add the flaps before takeoff, and the plane crashed killing all but one 4-year old girl.  Turned out that there were multiple failures there: getting lost during taxi, distractions, broken checklists, and possibly a pulled alarm breaker due to many false warnings.  I think more modern jetliners use electronic checklists, which will yell at you if you try to break off them early or forget a step.

    •  I still double check them (27+ / 0-)

      Even though we check them as part of our before takeoff checklist and the plane is supposed to yell at us if we forget.

      The last thing I do before taking the runway is check flap position and make sure the speed brakes are stowed.

      I figure 5 seconds of my time is a worthwhile investment in something that may very well mean life or death.

      If the pilot's good, see, I mean if he's reeeally sharp, he can barrel that baby in so low... oh you oughta see it sometime. It's a sight. A big plane like a '52... varrrooom! Its jet exhaust... frying chickens in the barnyard!

      by Major Kong on Fri Apr 19, 2013 at 10:38:53 AM PDT

      [ Parent ]

    •  Not adding flaps on takeoff, on the other hand (19+ / 0-)

      can be fatal in small planes too ... I was right-seat one time taking off from Breckenridge, CO, summer, Cessna 177 Cardinal, long gravel runway, 1/2 fuel, two souls on board.... we were wondering why it was taking so long to unstick and the power lines were coming up kinda fast when we finally got off, and then realized we should have had 15 degrees flaps for that kind of takeoff...would have saved maybe 800-1000 feet of runway.... but we were lucky.

      Then there's the time (much later) we were flying into Cedar Rapids in a Maule ML-5 STOL taildragger.... we're coming down final with a good headwind and the tower says "Maule 65Golf, could you land short, we have fast traffic behind? - advise.." so we said "Roger", pulled on full flaps about 400 feet up, pushed the nose down and went into STOL mode and hovered down, landed BEFORE the numbers and turned off on the approach taxiway, having rolled maybe 120 feet....

      But we were used to short field work at 9000' in the rockies, and here we were at almost sea level with thick air - it was easy....but it startled the tower....

      Without geometry, life is pointless. And blues harmonica players suck.

      by blindcynic on Fri Apr 19, 2013 at 12:55:36 PM PDT

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      •  Now THAT'S a short landing. (5+ / 0-)

        And here I think I'm doing good when I can put something down on a 900' runway - in a simulator.

        My father's old FBO was Frankfort Municipal (FKR).  Back in his day it was a rural airstrip with about a 1200' runway, mostly used by farmers, cropdusters and students.  Nowadays it's got a 5000' runway and handles small jets, business charters and occasionally ORD overflow traffic.

        •  put something down on a 900' runway - in a simulat (9+ / 0-)

          Well, that's what serious STOL is all about. And we knew we had a good headwind on that day....

          We used to keep that plane (Maule ML-5, 230hp 6cyl Franklin) on a farm and the owner would cut us a small strip thru the alfalfa in the spring (Loveland, CO).

          'Course it was soft dirt too. So (speaking of flaps) the approved takeoff technique was, if I recall (been 30 years)  ...full throttle, just about as soon as the tail came up and you saw 40 kts (bouncing all the way) , pull on the flaps (Johnson bar, I think), it would leap about 8 feet into the air, then you lower the nose a little and accelerate in ground effect for a 1/4 mile... Good for short OR soft field. But there wasn't much you couldn't get out of, if you got in.... and STOL or not, that plane was fully instrument capable, we took it cross country several times at 135mph....

          Super Cubs are good too, but the Maule had a lot of power...

          then we got the Super Decathalon....and spent a lot of time upside down....

          Without geometry, life is pointless. And blues harmonica players suck.

          by blindcynic on Fri Apr 19, 2013 at 03:01:01 PM PDT

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      •  Cardinals really bite with no flaps. (3+ / 0-)
        Recommended by:
        realalaskan, ER Doc, RiveroftheWest

        Been there, too.

        "We refuse to fight in a war started by men who refused to fight in a war." -freewayblogger

        by Bisbonian on Fri Apr 19, 2013 at 07:14:53 PM PDT

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        •  I now have a lot of time in cardinals from (3+ / 0-)
          Recommended by:
          ER Doc, Bisbonian, RiveroftheWest

          years back, but THAT was a lesson (it was a fixed gear, and I mostly flew RG later anyway)

          Without geometry, life is pointless. And blues harmonica players suck.

          by blindcynic on Fri Apr 19, 2013 at 10:35:38 PM PDT

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          •  Mine was a fixed gear, '68 (underpowered) (1+ / 0-)
            Recommended by:

            The flap motor had a short, and decided not to work that day...I was in Phoenix, and figured a no-flap out of Sky Harbor wouldn't be too much of a problem.  But with that laminar flow wing, low power, high temperature, it took a LOT longer to get off the ground than I expected.

            I had nothing but trouble with that airplane, and took it to Scottsdale finally, to sell it.  One last joyride with an old friend and her daughter ended up as a partial engine failure emergency landing back into Scottsdale.  Everyone was calm and collected :)

            "We refuse to fight in a war started by men who refused to fight in a war." -freewayblogger

            by Bisbonian on Sat Apr 20, 2013 at 08:48:04 AM PDT

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      •  Don't recall the exact model (4+ / 0-)
        Recommended by:
        reddog1, kurt, ER Doc, RiveroftheWest

        but a friend had a Maule M(?)-5 in which I flew many a hunting trip in bush Alaska. The best was on skis in winter. Holy smokes, put her down and slide and slide and slide. Plus you are closer to the ground than on wheels or floats. Spooky. I seem to recall people saying the Maule flew on its engine, not its wings. Maybe different with a STOL kit.

        Did several STOL's in a Super Cub with another friend. He always had to be careful where he landed. He wanted 600 feet to take off loaded but could land on stuff he'd never get back off of, about 150 feet was what I remember. It felt like hovering in a kite when that thing took off or landed. Caribou and Dall sheep trips in the Brooks Range; heady stuff.

        •   the Maule flew on its engine ? (2+ / 0-)
          Recommended by:
          ER Doc, realalaskan

          Well, engine and wings work together... More power = faster acceleration on takeoff, bigger wings + flaps  = slower approach and better control in touchy situations. We liked the Maule in the Colorado Rockies because flying up canyons was safer if you could go slow and have room to turn, and power to yank and bank and climb if you needed to...and the big wings + power meant random downdrafts were less of an issue - just like in Alaska....

          Without geometry, life is pointless. And blues harmonica players suck.

          by blindcynic on Fri Apr 19, 2013 at 10:40:47 PM PDT

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    •  I was going to ask about that one, too. (2+ / 0-)
      Recommended by:
      realalaskan, ER Doc

      A very big loss for people, especially those in the Detroit area. Terrible crash, and somehow the worse for all the human error involved.

      Some DKos series & groups worth your while: Black Kos, Native American Netroots, KosAbility, Monday Night Cancer Club. If you'd like to join the Motor City Kossacks, send me a Kosmail.

      by peregrine kate on Fri Apr 19, 2013 at 05:58:33 PM PDT

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    •  I think airlines could take a lesson (5+ / 0-)

      From the military in this case. There were always troubleshooters, safety, directors and etc. on deck during air ops. No way was any of our birds going to be cleared for launch without the flaps being set. Having some directors at the end of the take off queue, signalling pilots to put down their flaps and wipe out the controls would prevent accidents.

      "Given the choice between a Republican and someone who acts like a Republican, people will vote for a real Republican every time." Harry Truman

      by MargaretPOA on Fri Apr 19, 2013 at 07:15:09 PM PDT

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      •  Off topic, but can't allow for complete idiots (2+ / 0-)
        Recommended by:
        lazybum, RiveroftheWest

        I was on-site for an S3 crash where the pilot did a touch-and-go on a restraining cable runway with the tail-hook down.  And the tower tried to wave him off, but he wouldn't listen.......

        Nobody hurt.

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