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By now we've got a pretty good handle on how a modern jetliner is designed to fly. We've got a beautiful swept wing, nicely optimized for flying at .80 mach at 35,000 feet.

Wing Design

And there, lies our problem. A wing that's designed to fly fast isn't very good at flying slow. It won't even fly until somewhere around 200 knots. Unless we're using the dry lake bed at Edwards AFB, we just don't have enough runway at most airports to reach 200 knots.

So, we need a way to reconfigure our wing for low speed flight to let us takeoff and land in a reasonable distance. That's what the flaps do for us.

The primary purpose of wing flaps is to increase lift. They change the shape of the wing, turning its cross section from something knife-like to something more curved. If you're into trivia, the aerodynamic term for this is "camber". A fatter, curved wing produces more lift at lower speeds (but more drag at higher speeds) so we can get the same weight of airplane to fly at a slower speed.

They have another trick as well. Most airliners used a specific type of flap called a Fowler Flap. These don't just change the shape of the wing, they actually make the wing bigger. It's like putting a couple extra pieces of wing out the back. This can be pretty significant. The flaps on my B-52 were actually equal in size to a DC-9 wing. More wing means we have more lift which once again means we can fly the same weight of airplane at a slower speed. Simple enough.

This gives us the best of both worlds. We can have our efficient high speed wing but change its shape to a wing that lets us take off and land at much slower speeds.

The flaps on the 757 are so effective that lightly loaded we can fly final approach at 115 knots. With a decent headwind our ground-speed on final approach might be under 100 knots. I've landed at Munich while being passed by cars on the Autobahn.

More than anyone would ever want to know about flaps. I've never heard of some of these.
We also have flaps on the front of the wing, although sometimes they're called "slats". If there's a space between the flap and the wing it's a slat. They do the same job so we just refer to them generically as "Leading Edge Devices". The same wing might even have both at different places on the wing.
Flaps and Slats on an Airbus wing
If you've learned one thing from these diaries it should be that everything in aircraft design comes with a cost attached. Flaps increase lift but they also add drag. That's actually good when we're landing, but we don't want too much extra drag on takeoff. That's why we only use a little bit of flaps for takeoff.

The first few degrees of flap extension give you mostly extra lift, plus a little bit of extra drag. As the flaps extend further and further you end up getting a lot of extra drag and just a little bit of extra lift. That's why the last couple flap positions are normally only used on final approach when we want the extra drag.

The other cost of having flaps is added weight and complexity. We spend most of the flight carrying around something we only use for takeoffs and landings. That unfortunately is just the cost of doing business.

On most airliners the flaps are driven by hydraulics. One or more hydraulic motors turns a series of shafts and gearboxes that move the flaps up and down. The trailing edge flaps also move in and out along their tracks. Those canoe shaped fairings on the bottom of the Airbus wing cover the flap tracks.

From the cockpit it's all pretty simple. We have a handle to move the flaps and a gauge that shows us the flap position. There are also some bells and whistles that are supposed to warn us if we try to do something stupid like takeoff or land without the flaps in the correct position.

757 Flap Handle
The flap controls on most airliners use degrees of extension. 0 degrees means they're all the way up and fully extended is usually between 30 and 40 degrees on most airliners.

If you're sitting near the wing you have a pretty good view of the flaps. Before takeoff you should see the leading edge devices extend and just a little bit of the flaps. On a 757 that's flaps 5. This gives us good takeoff and climb performance. On a short runway we may need more flaps and we can go all the way to 20 degrees. This will get us off the ground sooner but hurt our climb performance later because of the extra drag.

After takeoff we normally level off 1000 feet above the ground and retract the flaps so we can accelerate to climb speed.

On landing you'll see the flaps extended incrementally as the plane slows. You'll initially see the leading edge come down and the flaps extend partially. Prior to starting down the glide slope you'll see the trailing edge flaps come down half way or so. Each airline has different procedures, but sometime shortly before or shortly after starting down the glide slope you should see the flaps extend fully. You'll probably notice some extra noise from the air going over the flaps.

The flaps are normally pretty reliable. Because we like redundancy the flaps may run off multiple hydraulic systems (Airbus) or have electric motors for backup (Boeing). Unless the flap mechanism itself breaks, we will usually have some way to lower them, at least partially.

The KC-135 was so old fashioned that the flaps could be cranked by hand. It took a while but you'd get them down eventually.

If we do have a problem with them it's probably one of two things:

1. We move the handle and something doesn't move.

We call this condition a "disagreement". The flaps don't go to where the handle is positioned. Could be the leading edge (front) or trailing edge (back) or even both.

We may be able to use an alternate means to work the flaps. On the 757 we have electric backups which will slooooowly move them. If they're stuck, we land with whatever we've got. We'll probably burn gas until we get down to a lighter weight and try to find a nice long runway somewhere.

This happened to me on an A310 once, but it was a temporary glitch and we got them moving again.

2. We move the handle and only one side moves.

This is the bad one. We call this an "asymmetry". This would make the plane want to roll, because one wing is producing more lift than the other.

Note that the flap indicator has a left and a right indication. Normally they would move together but in this picture they're not.

757 Flap Indicator
Fortunately the flap mechanism is designed to look for this and stop the flaps from moving if it sees them not moving together.

We handle this problem the same way as the other, except in this case we're probably not going to get the stuck portion of the flaps to move. Something is probably physically jammed or broken to make the flaps move asymmetrically. We'll end up with just the leading edge or just the trailing edge and land accordingly.

Same drill as before. Burn fuel and find a long runway because landing speed will be quite a bit higher than normal.

That's about it. Now you can amaze your seatmates by looking out at the wing and saying "I bet you didn't know that's a double-slotted Fowler Flap out there."

Originally posted to Major Kong on Fri Apr 19, 2013 at 10:01 AM PDT.

Also republished by Kossack Air Force, Aviation & Pilots, Central Ohio Kossacks, and Community Spotlight.

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Comment Preferences

  •  Tip Jar (126+ / 0-)

    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 10:01:16 AM PDT

  •  Thanks for posting this. (22+ / 0-)

    My M.O. for a Major Kong diary is open, scroll waaaaaaaaaaay down through all the good stuff to hit recommend, and then go back up to read it :-)

  •  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

      [ Parent ]

      •  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

          [ Parent ]

      •  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

        [ Parent ]

        •  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

          [ Parent ]

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

            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

            [ Parent ]

      •  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

          [ Parent ]

    •  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

      [ Parent ]

    •  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

      [ Parent ]

  •  Control surfaces (6+ / 0-)

    always liked that term.  Kind of says it all.
    Also, while I've never actually flown anything in the real world, if flight simulators are to be believed, then you can basically steer a plane though use of the flaps alone.
    I also learned that:
    on takeoff, you want max. speed possible, then hit the flaps and- boom- you're up.
    Landing is basically gliding in on reduced engine power. Play with the flaps up or down to control elevation.  If your approach is falling short of the runway, just hit the throttle for more speed- if you're coming in too fast, in addition to going to max. flaps, you can also bring the landing gear down early to introduce more drag.
    Anyways, I spent a bit of time on Google Earth's flight sim. when I was out of work not long ago.  I would fly between airports basically anywhere in the world.
    So... is this how it really works?

  •  I'll be baack (4+ / 0-)
    Recommended by:
    NYFM, northsylvania, realalaskan, ER Doc

    this is great stuff, but I really can read it all at work... 8^|

    “that our civil rights have no dependence on our religious opinions, any more than our opinions in physics or geometry.” Thomas Jefferson

    by markdd on Fri Apr 19, 2013 at 10:51:06 AM PDT

    •  I recognize some of those flaps (6+ / 0-)

      The B-24 used the Fowler flaps, the Ju-87 Stuka dive bomber used the Junkers flap.  The SBD Dauntless had "mail box" slats in the leading edge of the wings, nothing mechanical, just a slot built into the wing.

       One of my first assignments on the F-16 was an alignment pin for the asymmetry sensor on the leading edge flap.  After a lot of precise engineering and adding a "Remove Before Flight" flag, it wouldn't fit in the wing.  It really didn't need all the precision either.  We ended up just placing instructions in the T.O. to bend up a jumbo paperclip to use for aligning the splines before installing the sensor....

      Great stuff Kong, keep it up.

      “that our civil rights have no dependence on our religious opinions, any more than our opinions in physics or geometry.” Thomas Jefferson

      by markdd on Fri Apr 19, 2013 at 07:41:42 PM PDT

      [ Parent ]

  •  Good stuff as usual MK (14+ / 0-)

    Back in the '90s I worked on the FSEU (Flap Slat Electronic Unit) for the 777. People would be amazed at the number of fault conditions being reported by the sensors. I believe we called your condition #2 flap skew. There were over 3000 variables used in the software.

    For redundancy sake, we had two FSEU boxes located in different locations on the plane. Each box used two processors, Intel 80960 and Motorola 68030(?). Because no processor is completely debugged, the results were compared continuously.

    I've always maintained that the software developed for the 777 which was extended to their follow-on airplanes are some of the Crown Jewels of Boeing.

    There was only one joker in L.A. sensitive enough to wear that scent...and I had to find out who he was!

    by virginislandsguy on Fri Apr 19, 2013 at 11:10:34 AM PDT

  •  Split-able flap handles? (2+ / 0-)
    Recommended by:
    realalaskan, ER Doc

    Are there any planes that have a flap handle that can be split left/right, in case of the asymmetry problem? Or would that cause more risk than whatever good it might do to have the option?

    Government and laws are the agreement we all make to secure everyone's freedom.

    by Simplify on Fri Apr 19, 2013 at 11:45:02 AM PDT

    •  Not that I know of (7+ / 0-)

      I've seen a split handle on a DC-10/MD-11 but I believe the split is front/back. Once controls the slats and one controls the flaps.

      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 12:21:59 PM PDT

      [ Parent ]

    •  Could be wrong, but... (5+ / 0-)

      ...none that I know of.  There's just no reason in normal operation to have unbalanced flaps or slats.

      Keep in mind that unbalanced flaps are due to a malfunction in one of the flap mechanisms.  Having a separate lever wouldn't do a dime's worth of good in that case - you can actuate it all you want and the failed flap's still in a fail condition.  Having backup motors, on the other hand, THAT can help, and as MK said some planes deploy them.

    •  No. (6+ / 0-)

      Once an asymmetry condition is indicated, you have a "lock-out" and they stop moving. Fortunately the lock-out usually happens when there is only a few degrees difference between the sides so lift isn't significantly greater on one side or the other. Flaps are designed to move together and anything else is very dangerous so they aren't going to design a split flap handle. Some fighter jets can increase or decrease lift from one side to the other by use of spoilers and cove doors. The spoiler on top of the wing pops up and when the maneuver flaps drive down just a little, the cove doors open and that air under the wing spills through, "spoiling" the lift on that side. But they aren't going to put spoilers on a large aircraft. The F-14A used that system, along with a "split stab" condition in which one horizontal stabilizer can go leading edge down, while the other goes trailing edge down. This allows for some very quick rolling maneuvers and fast turning. The spoiler/cove door system can be used in modes of wingsweep up to 57°. Beyond that it uses the split stab solution to a wingsweep configuration of up to 68°.

      "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 06:59:38 PM PDT

      [ Parent ]

  •  everything in aircraft design comes with a cost (13+ / 0-)

    reminds me of the old saying

    "an airplane is a bunch of compromises flying in formation..."

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

    by blindcynic on Fri Apr 19, 2013 at 12:43:45 PM PDT

    •  exactly (6+ / 0-)
      The other cost of having flaps is added weight and complexity. We spend most of the flight carrying around something we only use for takeoffs and landings. That unfortunately is just the cost of doing business.
      There is always a trade off between weight, control and redundancyl. Sig other is currently overseeing design work on various control surfaces and running presentations by for critique. I certainly appreciate the Control Surfaces For Dummies diary. I haven't paid attention to fixed wing configuration for many years. These diaries are  helpful.

      You..ought to be out raising hell. This is the fighting age. Put on your fighting clothes. -Mother Jones

      by northsylvania on Fri Apr 19, 2013 at 01:04:57 PM PDT

      [ Parent ]

      •  So you're a propellerhead? (3+ / 0-)
        Recommended by:
        ozsea1, realalaskan, ER Doc

        Bloody dual-control-column rotary-wing propheads, as my father would say. ;)

        Seriously, I wish I were better at flying helicopters.  I'd have a far easier time getting a (really well paying) job as a Survival Flight or medical charter pilot, then I am as a molecular virologist!

  •  This short video is a great illustration (10+ / 0-)

    of how a combination of leading edge slats and big flaps can make a wing highly efficient at slow speeds. This is a homebuilt replica of a Fieseler Storch. The original Storch was used as an observation aircraft by the Luftwaffe during WWII.  With one person in it, this particular aircraft stalls at about 16 mph.  This one is in Korea.

    Rudeness is a weak imitation of strength. - Eric Hoffer

    by Otteray Scribe on Fri Apr 19, 2013 at 01:12:32 PM PDT

  •  Visible streak of air from flaps when landing is? (3+ / 0-)
    Recommended by:
    ozsea1, realalaskan, RiveroftheWest

    Landed yesterday in Seattle in a 737, and out a window during the approach and landing, I noticed a very clearly visible very fast-moving bluish-white streak of air flowing directly back from one of the flaps while the flaps were deployed in the down position for landing. The streak was a few inches in diameter, formed a long and tight tail (didn't diffuse much) extending all the way back from the wing parallel to the plane all the way to the back. It was rainy and cool in Seattle. I am wondering what is this phenomenon -- condensation forming? It was pretty cool-looking.

  •  I once read or heard a pilot say (6+ / 0-)

    that the DC10 wing was the best ever designed in terms of overall control for weight and runway length.  All I can say is that, as a multi-million miler, I miss that airplane.

    Finding Fred A Memoir of Discovery @ smashwords.com/iTunes

    by Timothy L Smith on Fri Apr 19, 2013 at 06:00:51 PM PDT

    •  Arguably (6+ / 0-)

      The L1011 was the better plane, but Douglas rushed the DC-10 into production to beat Lockheed to market.

      They used to say the ultimate airliner would be designed by Lockheed, built by Boeing and marketed by Douglas.

      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 06:35:23 PM PDT

      [ Parent ]

      •  Have you read "Destination: Disaster"? (1+ / 0-)
        Recommended by:
        RiveroftheWest

        In large part about the L1011 v DC10 competition -- as well as the subsequent Turkish Airlines DC10 crash.

        Very compelling read, and excellently researched.

        •  "...Disaster..." (1+ / 0-)
          Recommended by:
          RiveroftheWest

          Didn't that also say that as a result of the competition they got away with not using disc brakes to lock the forward flaps in place which is what caused the asymmetry when the engine departure destroyed the hydraulics in the Chicago crash?  After reading this or something very similar, I refused to fly in that plane because there were so many design flaws or cut corners.  

      •  I have always has a bad expierence flying in (1+ / 0-)
        Recommended by:
        RiveroftheWest

        the L1011.
        Conestoga Wagon of the skies.
        Very rough, lots of up and down bouncing.

        We had to take one out of Tampa to Atlanta because the regular plane was broken.

        They (Delta) rolled out the L1011 that was supposed to be retired in 4 months.
        There were coke and coffee stains on the ceiling and the ride through clear air turbulence over N. Florida was scarey to say the least.

        Flying over the Rockies going into Stapleton in Denver was also not ever on my bucket list.

        Maybe I just was never on the better flights. Lots of wing flex though. :-0

        "People who see a contradiction between science and the bible don't really understand either." PvtJarHead

        by Tinfoil Hat on Sat Apr 20, 2013 at 04:23:00 AM PDT

        [ Parent ]

      •  I didn't realize that.... (1+ / 0-)
        Recommended by:
        RiveroftheWest

        I worked for Douglas in Long Beach in 67 when the 10's were in full production.  I had a job in the Major Subcontract stockroom, where we received, inventoried and disbursed flight computers, engines, struts and wheels and a lot of other big stuff from outside vendors.  Of course, at 19, I had no idea about the business decisions driving stuff, but there was always pressure to get ships off the line....something about being paid.

        Finding Fred A Memoir of Discovery @ smashwords.com/iTunes

        by Timothy L Smith on Sat Apr 20, 2013 at 10:59:35 AM PDT

        [ Parent ]

        •  We still have DC-10s in the freight world (1+ / 0-)
          Recommended by:
          RiveroftheWest

          I don't fly them but I usually jumpseat on one when I'm going to work.

          There are still some MD-11s flying passengers. I think KLM has some. It's basically a larger, more modern version of a DC-10. They never really caught with the passenger haulers but we like them for freight.

          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 Sat Apr 20, 2013 at 11:20:44 AM PDT

          [ Parent ]

  •  I know less than nothing about aeronautics, (5+ / 0-)

    but I still find your diaries (and the comments that follow) very interesting. Thanks for posting them, with such a readable style for a non-technical person like me.
    Overall they do make me feel more secure about taking commercial flights. When I was a very young woman, I didn't worry about it at all; I think I started to worry more when I got older and started to reflect on the possibilities of error or failure. (And yes, I do realize that per-person-mile, or however it's phrased, commercial airline travel is astonishingly safe.)

    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 06:06:00 PM PDT

  •  Thank you for the Diversion from Boston! n/t (3+ / 0-)
    Recommended by:
    ban nock, realalaskan, RiveroftheWest
  •  When I was in the Navy (14+ / 0-)

    I was an airframe mechanic, working on the F-14A The F-14A+ and the F-14D. I was also fully qualified on wing surface controls, this included flaps, slats, spoilers and their various associated cove doors, auxiliary flap and of course, variable geometry, (wing sweep). Wing surface controls on an F-14A aircraft are so important in fact, that we had a bird come back with the port stab torn off, nothing but the bare horn sticking out of the side of the aircraft. Pilot said he felt a "bump" but flew and landed pretty much normally. I hated that airplane. It was ugly, (they look like giant, grey roaches to me), maintenance intensive and a mass of static hydraulic leaks but the wing systems were elegant and capable. If I had one gripe, it was the fact that the idiots put the four way valve underneath the flap/slat/wingsweep center drive gearbox, necessitating a 16-20 hour repair if it leaked. If they had replaced the dog bone with a servo and moved it out from underneath, it would have been a 15 minute job. And yes, an asymmetry condition was really dangerous. We had a pilot pull the flap/slat control drive circuit breaker in order to take out overspeed protection so he could use his flaps as a speed break. The problem is that breaker also removes asymmetry protection so when the starboard sequencer sheered, the port side flaps and slats drove all the way down, while the starboard side barely moved at all, resulting in a crash into the desert of Fallon, Nevada. The pilot and RIO got out but needless to say, he never flew for the Navy again. Once we dug up that kick panel, his career was over. Thanks for the post. I haven't thought of any of this in years.

    "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 06:44:50 PM PDT

    •  Like I mentioned above (2+ / 0-)
      Recommended by:
      ER Doc, RiveroftheWest

      You can't allow for complete idiots

      •  Hmph! (2+ / 0-)
        Recommended by:
        California06, RiveroftheWest

        This happened in  summer 1986 and we all suspected the pilot in question was playing "Top Gun". Fallon, Nevada is about 4,000 ft above sea level and the range has a deck of 10,000 ft. This guy was under 5,000 ft in altitude and traveling just under mach when the sequencer broke. If the radar intercept officer hadn't punched them both out, they would have died. Even after the tough wing modification, I have serious doubts the flap/slat system could have survived that kind of abuse.

        "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 Sat Apr 20, 2013 at 05:05:41 AM PDT

        [ Parent ]

  •  My favorite - window seat at the wing of a 727 (4+ / 0-)

    There's just something amazing about watching that wing expand as everything hangs out on approach and landing.

    Story I ran across many years back. A B-24 on takeoff on a hot day in India - headed right for the Taj Mahal and not gaining altitude fast enough. The crew dropped the flaps, trading the air speed they had for lift. It got them high enough to clear the Taj, and then they cranked them back up to stay in the air while they went back to slowly gaining altitude as their air speed came back up.

    "No special skill, no standard attitude, no technology, and no organization - no matter how valuable - can safely replace thought itself."

    by xaxnar on Fri Apr 19, 2013 at 06:59:07 PM PDT

    •  Stories about Desert Storm I were entertaining (7+ / 0-)

      ... and I heard a few of them. Particularly a few regarding launching very heavily loaded 747s out of Israel. Nice long runways, but with all the landing gear hanging out, adding massive amounts of drag, climb outs were very flat.

      The archetypal story was the co-pilot reaching over for the gear lever and getting his hand slapped by the pilot "DON'T touch that!". "But..." "NO!"

      The reason here being that in the 747, there are fairing panels around the landing gear to minimize drag when the gear are out, but add considerable drag when moved to allow the landing gear to move. So the pilot needs to have either a significantly positive rate of climb or a fair amount of altitude before it's safe to retract the gear.

    •  727 wing (2+ / 0-)
      Recommended by:
      xaxnar, RiveroftheWest

      That was my favorite seat, too.  Used to fly St. Louis to Nat'l regularly.  When we were late the pilots used the spoilers to drop altitude without cutting speed to make up time (or that was the explanation I got).  It was a long time ago, so I guess the fuel consumption wasn't a problem.

    •  The 727 wing (2+ / 0-)
      Recommended by:
      RiveroftheWest, xaxnar

      was an amazing piece of engineering. It could cruise at .90 mach and slow down enough to land on a 5000 foot runway.

      Today even Boeing won't build a wing that complex.

      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 Sat Apr 20, 2013 at 09:20:26 AM PDT

      [ Parent ]

  •  Very enjoyable to read, and a welcome change of (5+ / 0-)

    pace from the usual fare.

    How big is your personal carbon footprint?

    by ban nock on Fri Apr 19, 2013 at 07:03:17 PM PDT

  •  Thank you, Major Kong, for another well-written, (4+ / 0-)

    enjoyable, and informative diary.  It makes me so happy when I see a new one!

    -7.38, -5.38 (that's a surprise)

    Why must we struggle to protect the accomplishments of Democrats of the past from Democrats of the present? -- cal2010

    by 84thProblem on Fri Apr 19, 2013 at 07:24:12 PM PDT

  •  I like the Henny Youngman version (1+ / 0-)
    Recommended by:
    RiveroftheWest

    Take my flaps--please!

    Also, how many rolls of duct tape does a flight crew go through on a typical pre-flight check, to take care of those cracks and fractures that wreak havoc on a modern airframe? Do they work on fan blades, or do you need to crazy glue those back on? And is it true that toilets empty over residential areas?

    "Liberty without virtue would be no blessing to us" - Benjamin Rush, 1777

    by kovie on Fri Apr 19, 2013 at 09:33:07 PM PDT

    •  Only seen duct tape (1+ / 0-)
      Recommended by:
      RiveroftheWest

      used on the tail of Super Cubs or other bush planes after landing on dried up gravel stream beds in Alaska. Wheels have a tendency to throw up loose gravel, tearing the fabric wing covering.

    •  They called it "Speed Tape" in the Air Force (2+ / 0-)
      Recommended by:
      ER Doc, RiveroftheWest

      It's actually a form of metallic tape and is pretty strong stuff.

      They can't use it on the fan blades, but amazingly enough the fan blades can have chips or cracks as long as they've been inspected and ground down.

      The toilets are pumped out on the ground by a truck with a hose. How would you like to have that guy's job? But as the joke goes - he'd quick but he doesn't want to leave aviation.

      For "blue water" to leak out in flight (it has happened) would require a leak in the tank.

      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 Sat Apr 20, 2013 at 04:41:52 AM PDT

      [ Parent ]

      •  We called it speed tape in the navy too. (2+ / 0-)
        Recommended by:
        California06, RiveroftheWest

        But you couldn't use it anywhere forward of the intakes. I once used speed tape over 8802 in a quick bird strike repair in an inboard slat, just to get the airplane back home. The tape was pushed in a little when it got back to Miramar but otherwise it was fine.

        "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 Sat Apr 20, 2013 at 05:10:04 AM PDT

        [ Parent ]

  •  Nice tutorial, Kong. You're a good CFI. :) (3+ / 0-)
    •  Amen to THAT!! (1+ / 0-)
      Recommended by:
      RiveroftheWest

      I've had a very enjoyable (and highly informational) 20 minutes on the Saturday morning of a week positively saturated with tragedy.  This has been a most welcome diversion.

      I am continually impressed by the diversity and depth of knowledge and experience of this community.  I will look for other posts of the Major.  If they are as well written as this one, all of us "propeller heads" can learn a lot.

      Many thanks to all above for sharing their experiences.

      Margaret, do you post diaries also?  You really should.

  •  Thanks, I've been enjoying this series. n/t (2+ / 0-)
    Recommended by:
    California06, RiveroftheWest
  •  Very nice diary Major... (2+ / 0-)
    Recommended by:
    ER Doc, RiveroftheWest

    I think the two designs - The "split flap" and Krueger flap" look pretty unsuitable for any modern aircraft.  You forgot one cool design - manual airspeed operated leading edge slats.   The A-4 Skyhawk has these, and while being simple and reliable, airspeed operated slats can give a pilot the cold sweats fast when one of them decides to stick and not deploy at the designed airspeed...   Just my 02 cents from experience working on those little hot rods....

    What you allow, is what will continue.

    by Nebraskablue on Sat Apr 20, 2013 at 12:39:37 AM PDT

    •  They still use Krueger flaps (2+ / 0-)
      Recommended by:
      ER Doc, Nebraskablue

      The A300 has them on the inboard leading edge, with slats on the outboard leading edge.

      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 Sat Apr 20, 2013 at 04:43:03 AM PDT

      [ Parent ]

  •  If I remember correctly... (1+ / 0-)
    Recommended by:
    RiveroftheWest

    ...it took a full minute for the B-52's flaps to extend, courtesy of two big electric motors that you accessed through a relatively tiny hatch above the forward bomb-bay wall. If one motor failed; it took twice as long. Had to help replace one once, and thankfully only once.
    BUFFs...there wasn't anything easy about them, but they just kinda grew on you.
    Thanks for the article and the memory!

    •  You are correct (1+ / 0-)
      Recommended by:
      RiveroftheWest

      There were also limits on how many times we could cycle the flaps in a certain time period.

      The motors would get hot and needed time to cool off.

      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 Sat Apr 20, 2013 at 11:17:58 AM PDT

      [ Parent ]

  •  How could this happening? (1+ / 0-)
    Recommended by:
    RiveroftheWest

    Reading your articles about how planes works, particularly the wings side makes me wonder why the crash still happening. The most recent is a private company in Indonesia who just landed a plane in the sea near Ngurah Rai airport Bali. Moreover, they just bought it a month ago from boeing. See also the cabins in new customer airplanes from Bombardier France. http://aviationclub.aero/...

    •  There is seldom one reason (2+ / 0-)
      Recommended by:
      RiveroftheWest, BeninSC

      A crash is usually a chain of events, sometimes mechanical, sometimes human, often both.

      At some point someone could have acted to "break the chain" but didn't.

      That's why we do so much human factors training. They realize that errors are going to be made and the key is to "trap" the errors before they compound.

      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 Sun Apr 21, 2013 at 08:06:26 AM PDT

      [ Parent ]

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