Stacked Deck??

Discussion in 'The Okie Corral' started by Skyhook, Dec 11, 2005.

  1. Skyhook

    Skyhook

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    It looks like the flight deck occupants had three things stacked against them on this one; 1) Snow storm in progress w/slick runway. 2) Short runway. 3) "Brisk tailwind" -- this is not being mentioned in the later- including this- reports I wonder about that).


    Midway Accident Spotlights Short Runways

    Saturday, December 10, 2005



    CHICAGO — A combination of thick snow and relatively short runways at Midway International Airport can make landing a plane a daunting task for even veteran pilots, requiring precision and allowing scant room for missteps.

    After Thursday's deadly runway accident involving a Southwest Airlines jet at the hemmed-in airport, some experts are calling for new buffer zones or other safety measures to give pilots at Midway and hundreds of other airports a wider margin for error.

    The Boeing 737 was landing in a snowstorm when it slid off the end of the runway, plowed through a fence and struck two cars near a busy intersection. A 6-year-old boy in one of the cars was killed and 10 people, most on the ground, were injured.

    "His father looked out and saw a turbine engine turning right outside his window," Ronald Stearney Jr., the attorney for the family, said Friday.

    The National Transportation Safety Board said the cause of the accident was under investigation. The plane's voice and data recorders were sent to Washington for analysis and hold "pristine" information for investigators, NTSB member Ellen Engleman Conners said.

    But much of the attention initially focused on the 6,500-foot runway. Midway — built in 1923 and surrounded by houses and businesses — is among nearly 300 U.S. commercial airports without 1,000-foot buffer zones at the ends of its runways. Most lack the room to create adequate buffers.

    Safety experts say such airports can guard against accidents by instead using beds of crushable concrete that can slow an aircraft if it slides off the end of a runway.

    The concrete beds — called Engineered Material Arresting Systems — are in place at the end of 18 runways at 14 airports. They have stopped dangerous overruns three times since May 1999 at John F. Kennedy International Airport in New York.

    "We think it's incumbent on airports that don't have the room for these safety areas to at least put in one of these systems," said Jim Hall, NTSB chairman from 1993 to 2001.

    Hall said the lack of a 1,000-foot overrun area and the absence of the concrete beds would likely be a focus of the investigation.

    "It's a tragedy that did not have to occur," he said.

    A recently passed federal law seeks to encourage more airports to build concrete beds or extend their runway barriers by requiring them to do one or the other by 2015.

    Chicago Department of Aviation spokeswoman Wendy Abrams could not immediately say whether an arresting system had been considered at Midway.

    Though the airport had about 7 inches of snow, aviation officials said conditions at the time were acceptable. Southwest chief executive Gary Kelly said the plane showed no signs of maintenance problems.

    The plane's ground speed was 152 miles per hour as it landed and it hit the fence at about 46 miles per hour, she said.

    Some pilots say relatively short runways like Midway's pose a challenge in icy or snowy weather, forcing them to touch down as close as possible to the beginning of the runway to allow more braking time.

    "It's not a place you can be a little off," said Richard Ward, a retired United Airlines pilot who occasionally flew into Midway years ago. "You don't have the variable of a long runway to correct any errors."

    Investigators will determine the exact spot where the plane touched down through simulation, Conners said.

    Southwest said the 59-year-old captain piloting Thursday's flight has been with the airline for more than 10 years, and the 35-year-old first officer has flown with Southwest for 2 1/2 years. It was the first fatal crash in Southwest's 35-year history.

    Some safety experts said the size of the runway should not be used as a scapegoat.

    "It is not the runway length that's the issue," said Bernard Loeb, who was director of aviation safety at the NTSB during the mid-1990s. "Runways are either adequate or they're not."

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  2. Skyhook

    Skyhook

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    The latest scuttlebutt is that the thrust reversers did not deploy...

    Now, THAT would be a stacked deck if ever there was one.

    ;P
     

  3. SlimlineGlock

    SlimlineGlock

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    Fox News that night said the visibility was one half mile. Looking at the ILS 31C approach plate, it shows mins of 250 HAT, 4000 RVR and 3/4 mile vis.

    The runway length IS an issue when it's barely long enough in good weather.
     
  4. Beeg

    Beeg

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    Until we know, if he didn't know he had a mechanical until after he landed it sounds like the captain pushed a bad position. I didn't think I'd get a Sabre 80 stopped in time at TEB one winter and that was on a clear day with stiff crosswinds. I knew the runway length, conditions and wind. It would have been all my fault if I hadn't made it.
    Knowing Southwest pilots, most tend to fly way too fast in the terminal area to begin with. Those are the "millionare pilots" trying to cram in a couple more trips in thier monthly time limits. At least according to some very good friends that fly for Southwest. In the last couple years I've noticed more of them slowing down since the LAX overrun but at HOU and DAL they still push it to the limit and have to take drastic measures to get her slowed down final and stand on the brakes, on a good day. Then they have to taxi fast becuase they are pushing thier brake energy limits with thier 5 minute turns at the gate before thier next takeoff.

    Either way, I'd like to give the crew the benefit of the doubt until we know for sure the airplane was working properly.
     
  5. CaptainOveur

    CaptainOveur

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    I've landed on snow. I told myself that I'd just do a touch n go, use aerodynamic forces to keep me on the runway, and if it wasn't going well I'd get in ground effect and get the hell out of there. That was with a little bugsmasher though. Fun experience.

    I've also done level D 737 and 727s. Those thrust reversers only provide about 20% of the braking force, but that's a significant chunk of braking, and they make a huge different.

    On the other hand, if one of them fails to deploy, both are useless due to the yawing moments. It's important because if they should fail, you SHOULD be giving yourself enough runway to land, but in this case there's NO WAY you could stop the aircraft with an iced/snow covered runway without the thrust reversers. So, landing on a short runway covered with snow is just an accident waiting to happen, as the first time you have a thrust reverser problem you are almost gaurenteed a big problem with stopping the aircraft.

    It seems pretty difficult to land such an aircraft within a few hundred feet of the threshold. It always seems like it's a thousand feet or more when we touch down.
     
  6. SlimlineGlock

    SlimlineGlock

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    Assuming a 120,000 lb landing weight (generic entry weight from the chart), 13 knots tailwind, reported braking of fair to poor, 2 degree down slope (assumed by the chart), and maximum manual braking.

    Runway 31C length 6522 feet.

    Per NTSB quoted in the Houston Chronicle braking action was reported fair for first half and poor for last half of the runway.

    Good braking 6295 feet unfactored
    Fair braking 7937 feet unfactored
    Poor braking 10,795 feet unfactored

    A stacked deck, for sure!!
     
  7. Skyhook

    Skyhook

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    ^6
    Excellent, informative post. Thank you.
     
  8. IslandHopper

    IslandHopper

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    Thrust reversers are not considered when determining the stopping distance for an airliner... they are simply "gravy". A single thrust reverser can be used ... assymetrical thrust needs to be considered, but it is maneageable (at least on a dry runway.)
    Landing distances required for dispatching an aircraft to a particular airport are supposed to take into acount runway conditions, and the aircraft must be able to stop in 60% of the available distance.

    A normal approach crosses the threshhold at 50 feet... touchdown is expected to occur several hundred feet further down the runway.... and that distance is included in the stopping distance you get from the performance manual.
     
  9. SlimlineGlock

    SlimlineGlock

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    The numbers given in my previous post don't include reverse thrust. As IslandHopper said, that is "gravy." One a dry runway, a single thrust reverser does help the slowdown and the assymetrical thrust is manageable. I don't want to be the test pilot for that condition on a slippery runway, though.

    I've landed 737-500s in MDW this year during good weather. With full flaps and short field landing techniques with lots of autobrakes, it isn't a problem. However, that barrier that the accident airplane went through looms up at you during both takeoff and landing.
     
  10. CaptainOveur

    CaptainOveur

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    I know, but it's not doing anything because you're offsetting the asymetrical reverse thrust with the opposite brake, and you might as well just be using both brakes and no reverser. You need an equal amount of braking force on each side to keep it from yawing, and if one side of the brakes can provide that force, there's no reason why both can't.

    I did this during an engine-failure on takeoff with the 737. I unlocked the thrust reverser and gave it some reverse thrust, but looking back it would have been as effective to just use the brakes. Engine out's in the 727 were a real treat, not much yawing or rolling to deal with.

    I know about the TCH, GS and "intended" touchdown zone, but just remembering back on most commercial flights, it doesn't seem like they were very consistant. Many of them would land 2000' or more down the runway. That's a poor generalization, but just what I've noticed when I look out the window and count the touchdown zone distance markers.
     
  11. SlimlineGlock

    SlimlineGlock

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    Nope. Using rudder to counteract the assymetry. And both brakes. The reverse thrust is additive.
     
  12. SlimlineGlock

    SlimlineGlock

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    chicagotribune.com >> Local news

    696 feet of runway rendered useless

    By Jon Hilkevitch
    Tribune transportation reporter
    Published December 14, 2005

    Light poles, utility lines and other obstacles prevent planes from using the first 696 feet of the already short runway at Midway Airport where a Southwest Airlines Boeing 737 skidded and crashed in a swirling snowstorm last week, city and federal officials said Tuesday.

    Landing a big plane on the remaining 5,826 feet of the 6,522-foot runway requires precision even in good weather. But touching down safely in sloppy, icy conditions on Midway's Runway 31 Center, where the accident occurred, tests the abilities of an airline's best pilots, according to veteran aviators.

    Swept along by a gusting tail wind while being told by air-traffic control that the aircraft braking ability on the runway was dicey, the captain of Southwest Flight 1248 descended fast on Thursday, according to an account culled from radar tapes under review by the National Transportation Safety Board.

    Data from the onboard flight recorder indicate that the plane touched down harder than normal--reflecting an apparent attempt by the captain to hit the intended runway-landing markings dead-on so the maximum amount of remaining runway was available to stop the plane. The hard landing also explains the previously reported bounce that the plane made before sliding across the concrete, crashing through barriers after racing through a dangerously short runway protection zone and exiting the airport.

    "When you break out of the clouds on a snowy night like that, you don't try to do a nice squeaky smooth landing. You plant the plane down onto the runway," said Robert Mark of Evanston, a former airline and corporate pilot who flew for the original Midway Airlines.

    The Southwest plane came to rest on Central Avenue after hitting several vehicles and spearing a fire hydrant. A child inside one of the cars was killed and 10 people were injured in the worst accident in the airline's history.

    Investigators who are re-creating the flight's events say they don't know whether the captain hit the landing mark--696 feet from the edge of the runway--or floated farther down the runway before touching down.

    "A lot of issues involving the runway and runway safety are being looked at," said Keith Holloway, safety board spokesman.

    Midway air-traffic controllers told investigators that blowing snow prevented them from seeing where the plane landed on the runway.

    Obstacles on and off the airport, coupled with the angle of the plane's descent on an instrument-guided glide slope, prevent pilots from using the full length of the runway during landings.

    It is called a displaced threshold, meaning the landing zone is at a point that is not the physical end of the runway--in this case, 696 feet away. The portion of the runway displaced may be used for takeoffs only. Landing aircraft may use the displaced area when touching down on the opposite end of the runway.

    The opposite end of 31 Center, called 13 Center, allows for 6,059 feet of landing space--233 feet more for pilots to use. The extra distance would have been helpful in the case of Flight 1248, but 13 Center was not the landing configuration in use.

    Holloway said the safety board is probing to determine why 13 Center was not used.

    Runway 13 Center met the minimum requirements of a 300-foot cloud ceiling during the snowstorm. But the runway was 500 feet under the 5,000-foot minimum visual range for that runway. A minimum visual range is the distance a pilot sitting on the runway would be able to see straight ahead, according to officials at the Federal Aviation Administration.

    Runway 31 Center requires a minimum runway visual range of 4,000 feet.

    Some veteran Midway pilots, who asked not to be identified, questioned the FAA explanation, saying rules are often stretched a bit at the Southwest Side airport to allow for what is known as a "Midway mile."

    These pilots said the extra 233 feet in stopping distance would have been more than worth giving up the 500 feet visually for the pilots of Flight 1248.

    Meanwhile, the FAA reopened Runway 31 Center at 6:30 p.m. Tuesday for the first time since the accident. Equipment that aligns planes on the middle of the runway was damaged in the crash.

    In addition, Chicago aviation officials responded to criticism from the FAA that the city isn't doing enough to improve safety on the edges of Midway runways.

    The Tribune reported Tuesday that the FAA ordered city airport officials early last year to come up with a better plan to prevent planes from overrunning runways. The city submitted a study that the FAA rejected as unacceptable, but airport officials did not follow up with new recommendations.
    _
    Longtime FAA standards call for obstacle-free safety zones at the margins of runways. The safety zones are supposed to be at least 1,000 feet long and 500 feet wide.

    Most of the runway safety areas at Midway, which opened in 1927 next door to a Chicago public school, measure less than 100 feet long.

    Almost 700 homes and more than 100 businesses would be uprooted if the city complied with the FAA standards, said Erin O'Donnell, a deputy Chicago aviation commissioner who manages Midway.

    "We are not going to go on an aggressive land-acquisition program (to build runway safety areas)," O'Donnell said. "Instead of busting up stable neighborhoods, the city will continue to work with the FAA to find the appropriate technologies and safety measures at an airport that has been hailed as one of the safest in the nation."

    She pointed out that an FAA report in 2000 on runway safety never specifically called for Midway officials to build safety zones, and in fact called the zones impractical at the space-constrained airport.

    The FAA, however, did not take Midway off the hook. The FAA report said the city needs to conduct a detailed study of alternatives to provide a safety net to minimize the damage, deaths and injuries caused by a plane skipping off a runway.

    A number of options exist, ranging from pits filled with soft, crushable concrete to stop out-of-control planes, to barrier systems that more gently absorb the impact of a crash.

    O'Donnell pledged the city would step up its review to remove objects from runway perimeters and from surrounding streets that could endanger airline passengers and vehicle occupants in a crash, and it will explore emerging technologies.

    "There is no magical solution at airports with short runways today. But I am confident" answers will be found, she said.

    ----------

    jhilkevitch@tribune.com
    _
     
  13. CaptainOveur

    CaptainOveur

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    Depends on the airspeed, and whether or not you're getting any significant aerodynamic effect from the rudder. As speed decreases, so does rudder effectiveness.
     
  14. Wulfenite

    Wulfenite The King

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    What happens to the flight crews in a deal like this? Are they grilled like criminals and fired on the spot, do the get/need counsel, do they get their tickets suspended or revoked, do they have civil liability, etc.
     
  15. CaptainOveur

    CaptainOveur

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    NTSB says that they landed about 2000' down the runway, and about 5300' was required to stop in the conditions. Runway length of 6,500. That means it just barely works if they land on the aim points (1000' down the runway). I don't know how easy it is to come in shorter than that when you are flying a precision instrument approach and break out at 200', but I do know that you don't get a lot of time to do anything there. If you aren't right on the localizer you're not landing on the runway (from what I've noticed flying approaches in transport catagory aircraft). That 3° is designed to take the A/C pretty much right towards the aim-points. Not the threshold (beginning of the runway).

    This is in addition to what the investigators determined last week about the thrust reversers.
     
  16. Texas T

    Texas T TX expatriate CLM

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    SWA used to have 15 min turns a few years back, but I'm not sure they even do that any longer. I've never seen a five minute turn.
     
  17. Beeg

    Beeg

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    :) Still, those are quick turns. The majority of SWA pilots have slowed down a lot in the last few years but there are still a few Cowboys. I guess that goes for any flight department though.
     
  18. F14Scott

    F14Scott Luggage CLM

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    OK, dumb question from a guy with 1200 military hours, 1000 of those in pointy-nose, but 0.0 Blutowski in civilian planes. I've probably flown into a dozen joint mil/civ airfields, but never into a purely civilian field.

    What's up with the tailwind? We'd often get the runways changed on us mid-pattern to avoid any tailwind. Thirteen knots of tailwind, to me, seems like a big, big deal.

    Do civilian airports not shift runways as much? That's a 26 knot groundspeed delta from the wind going the right way, a difference of, I'm guessing, 15 to 20%. That's an extra 1000 feet for a plane that usually stops in 5000'.

    I flew in some crappy WX, but hearing about a short runway, snow on the deck, at or below minimums, and a tailwind made me think these pilots compounded every hazard they could find. At the least, I would have tried to touch down short with every intention of spooling up and lifting if anything was out of whack, like landing long, poor braking action, or TR failure.

    Then again, I could maneuver better than an airliner. Is such a plan not possible in a big jet?
     
  19. SlimlineGlock

    SlimlineGlock

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    An excellent question. Chicago Midway and Chicago O'Hare are really close to each other.....maybe 10 miles....anyone? The coordination of the FAA to shift landing direction for the entire Chicago system has to be enormous. The Chicago controllers are some of the most competent I've run into.

    ILS Rwy 13C (headwind) has a 5000 foot RVR/1nm vis requirement, making it unusable for the landing. ILS Rwy 4R has the same vis requirements as 13C.

    ILS 31C has a 4000 foot RVR and 3/4 mile vis, making it the lowest minimums for the airport. I'm sure that had a lot to do with it.

    I've flown pointy-nose small, fast airplanes and now the big guys. I bet some SWA guys were reporting to the Midway SWA operations desk that they had broken out just in time to see the runway and were able to barely stop in time. Then it becomes the old, "he did it, so I can do it" routine.

    Firmly seated in my Monday Morning Quarterback chair, I think I would have found a better place to land.
     
  20. CaptainOveur

    CaptainOveur

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    Unfortunatly this is what I see too. Not that the coordination is "enourmous" every time, but that some controllers are lazy and do not want to do runway changes untill things get really wild, if at all.