OT - Southwest crash

[Guest JFly]

Being new to these forums, I just stumbled across this thread. Currently working for and having been at the carrier in question for the last decade you can imagine my interest in this incident as well as in this conversation. I enjoyed reading this thoroughly. Let me just say that I found the majority of posters here VERY knowledgeable with Tim especially as well as Captain Tom and Sam leading the charge.I think that if you start to finish read this entire thread the answers to this accident are most likely here. That said we are all just speculating. Until that final NTSB report is issued there are bound to be factors unknown to us that the principals involved in both the accident and the investigation are aware of that can and will change the dynamic of the conversation in a huge way. The one thing that disturbed me was the report from one of the media talking heads about the aircraft's speed at touchdown. It has been my experience that watching the news is fine until they start trying to talk with authority about something that you know about! Lol. It is then and only then that you start wanting to crawl out of your skin and end up with an increasing desire to throw your remote through the screen. These people do not know. When you listen to them talk about things that you have extensive background in it is then and only then that you really realize this. They are paid to act on TV. It is their job to attempt to speak with authority about whatever the topic, nothing more - nothing less. Please take what they say at all times with a 50 lb salt lick not just a grain.A couple of things that come to mind here and I'll try to bring something new to the conversation that didn't seem to be covered as much so far as well as comment and offer my own speculation.

[Guest tmetzinger]

And your message shows all the company culture, which is why Southwest is at the top of my list should I ever pursue flying as a primary career.Best wishes,

[MarkLawrence 0]

JimThat just gave me an excellent perspective on the whole sad situation. Thank you!!

[BlueDiamond 0]

WASHINGTON -- The National Transportation Safety Board is urging that commercial airplane pilots change the way they calculate stopping distances on slippery runways to avoid a crash, such as the one in Chicago that killed a child."We believe this recommendation needs the immediate attention of the FAA since we will be experiencing winter weather conditions in many areas of our nation for several more months to come," NTSB Acting Chairman Mark V. Rosenker was quoted in a news release issued by the board.The NTSB wants the Federal Aviation Administration to prohibit airlines from calculating the effect of a plane's thrust reversers into the formula that figures what distance is needed to land when runways are slick.The urgent recommendation comes from an NTSB investigation into what caused a Southwest Airlines flight, landing at Midway Airport in a snowstorm on December 8, to roll off the end of the runway -- where it tore through two fences and stopped in an intersection, hitting two cars. A 6-year-old boy in one of the cars was killed.The pilots had used a laptop computer to calculate how far the plane needed to go to land, the NTSB said. When the runway's condition was entered as "wet-poor," the computer calculated they would be able to stop with 30 feet to spare. But the calculations took into consideration that engine thrust reversers would be deployed at touchdown. Instead, the NTSB said, "flight data recorder information revealed that the thrust reversers were not deployed until 18 seconds after touchdown, at which point there was only about 1,000 feet of usable runway remaining."Without the thrust reversers, the calculation would have shown a safe landing was not possible, it said."As a result," the board said in its recommendation letter to the FAA, "a single event, the delayed deployment of the thrust reversers, can lead to an unsafe condition, as it did in this accident."The NTSB said the FAA already prohibits the inclusion of thrust reversers in calculations in some cases.Michael

[Guest adl320]

Hmmm..."The pilots had used a laptop computer to calculate how far the plane needed to go to land, the NTSB said. When the runway's condition was entered as "wet-poor," the computer calculated they would be able to stop with 30 feet to spare.But the calculations took into consideration that engine thrust reversers would be deployed at touchdown. Instead, the NTSB said, "flight data recorder information revealed that the thrust reversers were not deployed until 18 seconds after touchdown, at which point there was only about 1,000 feet of usable runway remaining."...As I said earlier. It's all about managing risks. You make a calculation that says that you can stop a plane with ONLY 30 FEET OF REMAINING RUNWAY?!?! And you go for it?!? That's looking for lucky "7's" all across the board to hit that negligable margin on a GOOD day. Why even contemplate that in the poor conditions that existed at MDW at that time? Certainly, getting the airplane on the ground and then getting on the reversers 18 seconds after touchdown was unfortunate. Regardless of if it was pilot error or mechanical issues. That was certainly a (the) factor (and risk) that needed to be managed. I still stand firm in my belief that with that kind of slim margin for error, and the known conditions, I would not have made the approach. As in all aviation accidents, I hope we can all take some valuable understandings from this very unfortunate incident.

[Guest tmetzinger]

The fact is that while they calculated figures for wet-poor, the runway was reported to have GOOD braking action. You always calculate all the possibilitiesSo they figured they were fine, since they'd have hundreds of feet remaining with the runway as reported, and even if the runway was worse than reported, they'd be OK.So they made the decision to land, which, again, I cannot find fault with.The NTSB wants the calculations to be made in the future without taking reversers into account, which would have made this runway a no-go.Certainly sounds like the focus will be why the reversers didn't deploy earlier (pilot error or mech problem), but a contributing factor will be the actual runway conditions versus the reported runway conditions.

[Guest D17S]

Here's the link to the actual NTSB press release. http://www.ntsb.gov/recs/letters/2006/a06_16.pdfYou can make your own call based on the whole communication. Here's what I saw . . . Looks like the pilot's OPC (Onboard -laptop- Preformance Computer) showed they would be able to stop with 560 feet remaining based on the currently reported runway condition, "FAIR". The computer's calculation was based on the assumption that reverse thrust would be applied at touchdown. Just to see (so it seems), the crew also fed their OPC a runway braking condition of "WET-POOR" and got that 50 foot margin previously reported. The 560 foot margin was their 'real' number.Here's the problem the NTSB is outlining: This NTSB report is describing that reverse thrust is worth about 1000 feet of stopping distance. Actually, it seems the numbers worked out about right in this 'off the runway' event. Reverse was used very late and about 1000 feet was added to the final 'rollout' distance . . . and off the runway they went. It seems that runway braking condition really was about "FAIR." If the runway braking condition had been "WET-POOR", they would have ended up yet another couple of blocks down.The report says that 737-300s and -500s are not authorized to calculate stopping distances that include the use of reverse thrust . . . however it is standard procedure to include reverse thrust in stopping distance calculations for the 737-700s. If this had been a 737-3/500, reverse thrust would NOT have been used in stopping distance calculations and about 1000 feet would have been added to the OPC's stopping distance calculation. A 737-3/500 would not have been able to legally attempt a landing. That's probably why SouthWest put a -700 on this route. The -700 has looser stopping distance numbers because reverse thrust is included in stopping distance calculations . . . and the point of the NTSB report. The NTSB is telling (ahh, "recomending to") the FAA to stop this loosy-goosy numbers game, NOW! Remove the reverse thrust allowance from the -700s. Right on, NTSB. Go get 'em.

[macpac22 0]

interesting case. i found a lot of the posts very technical and detailed. for the average joe just reading what happened it seems to me the pilots did all they could under dodgy circumstances to land. i wouldnt proportion blame, its usually cases like this that necessitate the need to rethink procedures which can only be good for the safety of passengers in the aircraft and civilians on the ground. my thoughts go out to the family of that boy its a tradegy but i hope that produres are put in place so we dont have this happen again.

[Guest tmetzinger]

if it had been a -300 or -500, the flight might have been fine without the reversers - they're smaller airplanes, ya know. So go run the numbers those airplanes and tell me if their go/no-go decisions would have been different.Southwest flies the -700s into midway because the size of the airplane fits the projected loads for the particular flight.The NTSB's point is still valid - using reversers to give "credit" for contaminated runways does lower safety margins. The question is whether the added utility of the credit is worth the added risk. The NTSB is not (for good reason) the final arbiter of risk management - they are (correctly) wired to the "eliminate all risks" position, and the FAA (and eventually Congress) gets the fun job of deciding where the line should be drawn. Sometimes something happens, like this incident, or the others, that causes the line to be redrawn.My personal feeling is that unless there is data showing a statistically meaningful number of incidents/accidents/close calls due to the reversers not deploying promptly in these types of conditions, the FAA should leave the rule alone. Heck, if the runway conditions had been correctly reported to the aircraft as it was commencing the approach (8" of snow is 3" more than allowed on a "contaminated" runway) the outcome would have been altered because the SWA flight would have rejected the approach and waited for the runway to be plowed. The only reason the airplane didn't end up farther than it did is that hitting the fences and other things (like the car) rob a bit of energy. I expect there will be some blame to the airport operator in the final report.

[Guest adl320]

Insightful Points, Tim.

[Guest jmagyar]

Nothing to add but questions here.1. I do not believe that FS simulates wet/snow conditions on runways in relationship to braking. Is there an addon or patch I missed?2. I can personally attest to how slick runways can get with any snow coverage. Was in an American Eagle Saab 340b that had an engine failure on takeoff roll on a contaminated runway that slid sideways FOREVER before the pilot was able to stop. We ended up in the grass.3. At what point during the time from touch down till they actually got the trust reversers to deploy would most of us firewalled the throttles and hoped for the best. After about 5 seconds, feeling the actual response of the brakes on a poor surface, knowing that you have no margin of error in this condition (they ran the numbers on the laptop) 4. At airports that have runways with very close relationships to roads, highways, etc....why is there not better containment. They slid through a blast fence, and if I remember right, probably a very tall chainlink fence. Personally, I think they could use something better. Even if there is more damage to the plane, it would minimize the collateral damage.Now with all that said...I worked for American Airlines (not a pilot) for 15 years during several accidents. A plane that tuned into the wrong VOR and flew into a mountain in South America. An American Eagle that crashed in Ohio due to ice. (ATR's belonged in Texas and San Juan! Ice turned them into giant lawn darts.) Thunderstorm in LIT, and many others. I know exactly what the SouthWest employee that posted earlier is feeling. Its personal. I currently work for Royal Caribban Cruise line. We had the unfortunate incident that happened with the Honeymoon couple in Greece. Everything that happens to the company, or passengers I take personally. And do not get me started on the media. We have 30 ships that hold average 3000 people that sail weekly. Thats roughly 4.5 million passengers a year. Its not like its an epedemic. Very unfortunate. But all the media coverage is really unwarrented. Anyway, sorry for going off topic there!! :)I know hindsight is 20/20, but the one thing I never seen asked here is what is the procedure/policy for aborting a landing after touchdown. At what point should you basically give up and try again. There had to be a point that they relized that they were going to be out of runway. The figure I would like to see is at what point they could not have changed thier mind. If 12 seconds after touchdown they were still at a speed that allowed them to accelerate and takeoff safely with the runway remaining.Figure 1 second from the time the brain to decide to go around until hand manipulates the throttle, another second (just guessing) for engines to reach positive thrust....I dunno, just does not make sense to me. Poor braking, no reversers, you know its a short runway. He chose to land because of the information that was provided...but at what point does he relize the information was wrong?Sorry for such a long post. Its 3:30am here and I am just rambaling now. I am sure the pilot is excellent and did everything he could. My sympathies and prayers go to the childs family. I am just trying to figure out the thought process and the reasons why he decided on the choices he made. it just seems 18 seconds is a really long time. Most landings are completly stopped by then.James

[Farlis 2,317]

>Not an airline pilot either, but my thought also was that the>time to use LESS THAN MAX on autobrake was when runway>conditions are bad. As far as I am aware that would be exactly the opposite of what to do. In case of a wet or icy runway the Autobrakes should be set to the LOWEST level to avoid the sliding of the aircraft.Karsten