Southwest B737 Overrun @ Chcago MDW
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I hope we find that the crew flew the approach on speed, landed in the touchdown zone, on centerline, with autobrakes on the proper setting for conditions, reversers and speedbrakes deployed on schedule. Then we would have to find out whether tower reported a braking action code that correlated to the actual conditions, and if that reported braking action complied with SWA operating manuals for continuing the approach and landing.
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Globally
The autobrakes are OK as long as you can maintain centerline and stay on the pavement. The autobrake logic will not detect any drift off the pavement. In some cases directional control can better be achieved with manual differential braking and differential reverse thrust to arrest runway drift and to stay on the pavement and not go off the side.
with autobrakes on the proper setting for conditions
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Glueball. I don't agree with either differential braking or differential reverse thrust in a snowy runway situation. This situation seemed to be a problem with stopping in the available runway, rather than a directional control problem. From my experience flying approaches at night to snow covered runways, it is advisable to land with the maximum autobrake setting, or one below maximum, because of the marginal condition of the runway, allowing the autobrakes to meter fluid to the brakes evenly, immediately after touchdown. Autobrakes solve many problems at night in this situation, because it is impossible to see the runway surface on approach, other than lights. Autobrakes at the highest setting give the benefit of the doubt to the pilot. When manual braking, sometimes a pilot might delay braking or not use maximum braking with so much going on in the cockpit after touchdown - getting the throttles into reverse, monitoring directional control, and checking speedbrake deployment, wasting precious seconds in the process. Autobrakes nearly eliminate one duty out of many immediately after touchdown.
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SW precludes the use of auto brakes. Or at least they certainly did in the past. I believed it was to aid in the transition from the -200 to the NG (although every -200 I’ve flown has had it).
SW prefers their crews to operate without the some of the tools we take for granted….VNAV, Auto-Throttle (even during CATIII), Auto-Brakes. None of which are critical, however often go a long way to reducing work load in other wise busy periods of flight. As Globally said ‘Autobrakes nearly eliminate one duty out of many immediately after touchdown.’
Not to allow the use of them is madness.
SW prefers their crews to operate without the some of the tools we take for granted….VNAV, Auto-Throttle (even during CATIII), Auto-Brakes. None of which are critical, however often go a long way to reducing work load in other wise busy periods of flight. As Globally said ‘Autobrakes nearly eliminate one duty out of many immediately after touchdown.’
Not to allow the use of them is madness.
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As this is their second overrun, perhaps SW will no longer preclude the use of auto-brakes! MAY, just have allowed them to ‘get away with it’.
Have flown SWA a few times and enjoyed the service a lot. A great model for a lo-co airline.
But meanwhile, there has to be some sympathy for our flying brothers in this tragic accident, but let's not forget that innocent members of the public suffered even more so. Rushing to protect and deflect criticism against anyone involved is trivial compared with the car pax and drivers families loss. RIP.
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UL 975. Agreed. I am surprised that SWA doesn't allow the use of autobrakes, if that is the case. I would think that autobrakes are essential for SWA if they are going to continue to operate into MDW and other airports in the upper Midwest and in the Northeast corridor. The autobrakes on the 744 that I fly are essential to our operation and significantly raise the margin of safety at short runways around the world. Autobrakes not only aid the stopping effort, but also aid significantly in directional control during crosswind landings. They are very valuable during a dark, stormy night at JFK landing 4R or 22L, with a heavy airplane, for example. Because the autobrakes meter fluid evenly to the brakes, it helps resolve, rather than cause, directional control problems both in slippery runway and crosswind situations.
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Just out of curiosity I ran the Landing distance numbers on the computer program I use for the Gulfstream II that I fly. The factored wet runway distances came out as follows:
Runway 31C = 5,938ft (5,826 available)
Runway 13C = 5,123ft (6,060 available)
Runway 4R = 5,123ft (5,928 available)
Obviously the numbers for a boeing 737 would be different but it is interesting to see the effect that a "light" tailwind component vs a light headwind component can have on the distances. (815ft in this case)
Runway 31C = 5,938ft (5,826 available)
Runway 13C = 5,123ft (6,060 available)
Runway 4R = 5,123ft (5,928 available)
Obviously the numbers for a boeing 737 would be different but it is interesting to see the effect that a "light" tailwind component vs a light headwind component can have on the distances. (815ft in this case)
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RRAAMJET posted:
I agree, that is an unbeleivable comment. I have been unable to locate the source of that quote. Can you provide a link or at least tell us where you heard it?
Thanks.
Justin
"Unbelievable comment here in Dallas from a member of SWA's Go-team - 'We had no fatalities on the plane, so that keeps our record intact'."
Thanks.
Justin
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As a layman I would like to know why something that seems as helpfull as auto-break would not be used.
Having flown into Midway I can say it was never one of my favorites, I always felt like I had to lift my feet on approach.
Having flown into Midway I can say it was never one of my favorites, I always felt like I had to lift my feet on approach.
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rr AA mjet
I see you post from TX. Sounds like you've got a heart on for your local airline:
Take a look at who else operates large jets at these airports. Obviously Southwest and the FAA are not the only outfits that don't consider it pushing the envelope.
How "large" was the tailwind you observed on that 12020ft runway?
This was a tragic accident. Far be it from you or I to place blame anywhere with what little we know from the media, rumor websites, and preliminary statements. But I am inclined to beleive that this was not the result of corporate culture.
If you have a beef with Southwest because they are outperforming your airline or dragging down your pay I feel for you but your posts are beginning to lack credibility. Again I ask where you heard the earlier quote from an SWA representative regarding their "intact record".
Justin
I see you post from TX. Sounds like you've got a heart on for your local airline:
I have to say, in persuit of cheaper airport operating costs, SWA does rather push the envelope in terms of the 'secondary' fields they prefer to operate from:
Islip, Long Island (v. short)
Orange County (ditto)
Midway (ditto)
Houston Hobby (short)
Islip, Long Island (v. short)
Orange County (ditto)
Midway (ditto)
Houston Hobby (short)
In addition, there seems to be a 'hurry, hurry' air to their ops, eg landing at ELP with large tailwinds to roll right up to the gate. Nothing illegal, but just pushing the envelope, it seems to me.
This was a tragic accident. Far be it from you or I to place blame anywhere with what little we know from the media, rumor websites, and preliminary statements. But I am inclined to beleive that this was not the result of corporate culture.
If you have a beef with Southwest because they are outperforming your airline or dragging down your pay I feel for you but your posts are beginning to lack credibility. Again I ask where you heard the earlier quote from an SWA representative regarding their "intact record".
Justin
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O'Hare (KORD) drives which runway is being used for Midway (KMDW). Aircraft were requesting to land on RWY 13C (headwind) and were told that only RWY 31C (tailwind, snow) was available.
Southwest currently uses RTO autobrakes. Autobrakes for landing is being added.
Southwest currently uses RTO autobrakes. Autobrakes for landing is being added.
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CNBC was reporting tonight that preliminary FDR readings indicated that the touchdown was normal, but the plane accelerated after touchdown. If this is true, it would seem to indicated some problem with thrust reverers, or the crews ability to deploy them (yet still throttle up). I have not seen any other report that confirms this. It was on a bottom screen crawl.
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No experience on the later generation 737’s …..A couple of questions.
Another forum suggests that the winglet 737’s are relative “floaters” …..Is this true?
My guess is that they had Engine A/I on and probably Wing A/I on….how much does that kick up the idle on these motors?
Another forum suggests that the winglet 737’s are relative “floaters” …..Is this true?
My guess is that they had Engine A/I on and probably Wing A/I on….how much does that kick up the idle on these motors?
Eight Gun Fighter
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I observe they're talking about EMAS (Engineered Material Arresting System) again. Only a few airports in the US are using it currently. Works very well from what I've seen.
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It will be wise to wait and see what the flight crew has to report first; all this speculation about if they did or did not use the autobrakes, automatic speed break deployment, max reverse thrust, etc is all interesting but unverified till they tell their side of the story. The DFDR that is installed on the -700 (B737NG) aircraft will give the investigators an incredibly accurate picture of what happened during the approach, flare, touchdown and rollout. There will be no way to hide the facts from the NTSB nor Boeing with the technology they have in that aircraft. It interests me much more the runway condition reports of the airport authority. I have had more than once the surprise of finding out after touchdown that the braking action report we based our decision to land upon was either too old or just simply false or wildly optimistic. When operating jets into an airport with these incredibly short runways, coeffiecient of friction reports should be available for all of them, I don't know if they do that at Midway? I simpathize with the flight crew as they must be going through some incredibly hard times now that the news is out about the passing of the little boy in the car. Aircraft commanders are high tech risk managers and have to continuously assess the safety of the operation at hand, many times with incomplete information and under extreme commercial pressures to complete the flight. Let us give these guys the benefit of the doubt till all the information is out. When I dead-head home, I always use SW; they are a great airline to fly on, their pilots are good and professional and I am pretty sure that it will turn out to be the commercial pressures to keep that airport open for business under those extreme wether conditions a major causal factor in the accident.
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Shore Guy,
here some answers to your questions:
when my company introduced the NG with winglets we did see more long landings. They reduced significantly when the transition had been completed and awereness of the fact got more common. Basicaly, it´s a question of how well you fly Vref when close to the RWY.
Wing anti ice does not effect N1, just changes the stick shaker logic. Vref stays the same.
There are three idles on the NG:
ground
flight
approach
approach idle is selected with either engine anti ice on or flaps in landing config, so the idle N1 during the flare should be the same regardless off engine anti ice, since usually you land with landing flaps.
here some answers to your questions:
when my company introduced the NG with winglets we did see more long landings. They reduced significantly when the transition had been completed and awereness of the fact got more common. Basicaly, it´s a question of how well you fly Vref when close to the RWY.
Wing anti ice does not effect N1, just changes the stick shaker logic. Vref stays the same.
There are three idles on the NG:
ground
flight
approach
approach idle is selected with either engine anti ice on or flaps in landing config, so the idle N1 during the flare should be the same regardless off engine anti ice, since usually you land with landing flaps.
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Not sure why pilots claim more float with winglets. Winglets actually reduce apparent ground effect because they already elimnate some of the spanwise flow creating the vortices. My experience is the NG's land firmer with less float if you fly your Vref. The trick is the Vref is much slower for the same weight so you need to pay attention to energy management to fly a proper approach.