@ 2:50 - 3:15 is a perfect example of exactly how they perform their landings at midway. they hover over the touchdown zone marking and then drop it like a rock at the aiming point bars. My landing was IDENTICAL to this, aside from the fact that our landing was about 15-25 feet higher, and the drop it like a rock became a stall it like a rock @ 25-50 feet above the runway. If this doesnt convince you that landings like this, hour after hour day after day cant impact the stress fatigue or yeild strength stress ratio of a aluminum airplane, then you needa go take a course in metallurgy. So does southwest. before they start killing people.

And you can tell this from a youtube video? You must be an expert! I'm an aero engineer (and as such I've studied structures and metallurgy too) and I can assure you that dropping the aircraft on the runway as you describe would do nothing to the stopping distance (unless you dropped it so hard the gear struts broke off). This talk of a SWA policy to land their aircraft heavily on short runways is baseless, dare I say ignorant, nonsense. Certainly not a drop of 25-30 feet. You might not begin flaring until 50 ft rad alt, so you certainly wouldn't flare early (and so use up runway) and then drop vertically. 7,000 feet is plenty of runway to stop a 737. There's no need for extreme and damaging techniques.Basically mate, stick to what you know. If SWA aircraft were as weakened as you claim they'd be falling out of the sky on a regular basis. So much nonsense is talked about how low cost airlines like Southwest, Easyjet and Ryanair operate. They may cut economic corners, but they fly by the manufacturer's book in all cases. Aircraft are valuable assets, too valuable to abuse to save a few dollars.Kevin

then what was it?

When you have a 60 ton mass composed of millions of individual pieces and parts traveling through the sky at 450 knots, eventually bad things will happen. What's the proximate cause you ask? I couldn't tell you... I'm no engineer and like it or not, there are anomalies in life that are unexplainable. At first glance, this appears to be one of them. But as a business man myself, I can assure you that SWA's business plan does not include "pushing the aircraft beyond their engineered limitations to make more money". If that were in fact true, nobody would fly them. Period. End of story.

I highly doubt that Southwest's conformance for maintenance record keeping is any better than the rest of the industry ....Hell, it's probably be worse.

Speculate much?

Am I Southwest hater? No, I just hate the market.

You can hate "the market" all you want. But the market will ALWAYS be there regardless of limitations, price ceilings/floors, or government intervention/regulation because the market isn't about money per se, it's about human behavior. Ever since we, as human beings, have chosen to record history there has ALWAYS been a market for goods and services. Cheers!Buddy Morgan

Flew S.West last week on a 37-300 series and talked to one of the S.W. personel who told me that they were going to scrap all their 300 series and order 200 of the 737-700 series. The 300's innerds looked really faded and worn out. Possibly to many cycles....Jen noulet

SWA hasn't had 200s for a good while.

And you're basing this on what knowledge exactly? Are you an aerospace engineer or a metalurgical engineer? I very seriously doubt Boeing and the FAA would allow SWA to adopt an SOP that endangers the structure of the aircraft. You're using a latch on a flimsy plastic overhead bin giving way as evidence that the aluminum structure is unsafe? That's more than a bit of a stretch there. The main gear on the 737 sit under the wing box - how the top of the fuselage would absorb any significant shock from "hard" landings is beyond me. I don't know the exact g-force figures but I do know that all airliners are certified/stressed for landings FAR in excess of what the average passenger would deem a hard landing.

Hi Ryan,Your two posts are spot on. The news media is always trying to make everything out to be the worst possible. It sells newspapers. Then you get the "experts" weighing in. As to the overhead bin it may not have been latched totally. As to the cause, people need to wait for the facts. I was in Boeing flight test during the original 737 testing. Flew on lots of the certification tests including max performance landings. You land at the max allowable landing rate of 10 fps, which is way less than the design limits, in order to stop in the shortest distance. I was sitting over the wing box and that is a jolt. Especially after going around one after another. It got to the point you would rather stand up during the landing.If the average passenger had any idea what a plane is put through during test they would never have any concerns about the safety of a Boeing aircraft.Looking forwrd to the NG.Old retired flight test engineer,TomTom

Ryan is correct. Every US airline's Operations Specifications are FAA approved.

SWA hasn't had 200s for a good while.

Ethan you misread Jen's post. He is saying that the number of 737-700s that they are going to order is 200.

No, you're wrong. it IS southwest policy to perform this type of landing at ALL airports with runways around 7000 feet or less. Regardless of the MD-11 comments, (which I generated to get attention to the issues the PMDG MD-11 sometimes has with climb rates, which there have been many posts about) I am correct about this. This is the field i Work in, and I know what I'm talking about. Fast turnaround, an extreme amount of cycles + a policy of drop it on the runway = STRESS FATIGUE. Any idiot can figure this out. Just use your brain. The age of the plane makes no difference after the first couple of years. After that its all amount of cycles, and how hard you land the plane over and over. and southwest cycles them faster than a rabbit gets F****** and beats the living daylights out of them when they land.Their entire business model and creed is a direct assault on the structural integrity of their planes! Dont you get it? thats howcome they are so profitable and huge and havnt had the problems financally of other airlines. I seen 3 or 4 southwest planes come and go in the time it took for 1 UNITED flight to arrive and leave! Time is money friend and the short turn around times = more money generated. also = stress fatigue.

No airline would put it in their SOPs to "slam" or "drop" the airplane on to the runway. Just because you had one flight where you had a slightly firm landing (if you have a hard landing, the plane will be totaled) and you can watch youtube of similar landings videos does not mean that you know exactly what Southwest or any airline's SOPs are. If airlines have to put it in their SOPs that it is required to "drop" the airplane onto the runway at a particular airport, they shouldn't be flying there. Secondly, no flight crew would ever intentionally stall a swept wing transport category jet. You fly it on to the runway, you don't stall it like a Cessna. If you stall a transport category jet, you have bigger problems to worry about than having a hard landing. Not trying to be mean here, but you're way off here. Just because you're a metals expert does not make you knowledgable about the operations at certain airlines nor the performance capabilities of certain aircraft.

Well, if it's not design or maintenance issues, or the "fact" that Southwest Airlines DOES have a business model that DOES mandate that they abuse their sh@# and staff, then what was it? Did a funking bird run into at 30,000 ft?

Allow me to correct you.The "staff" at SWA (including ramp agents, ticket agents, flight attendants, pilots and mechs) are some of the most well paid and well respected workers in the industry. They are far from "abused." SWA is at the top of the best places to work list for many aviation professionals. One more point that I would like to clarify, if anyone hasn't done so already. Southwest grounded the majority of their 737-300 fleet, not the entire 737 fleet. The -500's and -700s are not affected at this point.

Ever since we, as human beings, have chosen to record history there has ALWAYS been a market for goods and services. Buddy Morgan

Yeah, I've been to Tijuana, Mexico. Seached through my handy dandy history book ....there seems to be some missing pages from about the fall of the Roman Empire to about the time St. Patrick roamed Ireland ....Ok, I'm getting off topic.Sorry guys. -Cheers

Did a funking bird run into at 30,000 ft?

And although this clearly is not a bird strike incident... I should point you to the FACT that there is a recorded bird strike that occurred at FL370. Africa, 1972, B747... Cheers!Buddy Morgan

It's all about your frame of reference. Taking the 'I'm a pilot' exceptions to the rule out of the equation, let's just look at the highly subjective passenger experience.If you've flown, say, a few hundred times as an adult and had a couple of firm landings, then you'll have a fair idea what a hard landing feels like. If you're like a large part of the population for whom flying is a more occasional experience, then a firm touchdown is going to seem a lot worse. Most people severely overestimate the sensations and forces they're feeling in terms of what the aircraft can actually tolerate.Secondly, it's human nature to then retell such events to your friends, or on a flightsim board, or on youtube or whatever. These stories, like the 'fish was this big' or 'the golf ball was this close to the hole' type of stories, always get a little more dramatic over time. There's well-understood psychology behind this behaviour.Thirdly, and we're addressing the firm landings SOP argument here, I've NEVER heard this allegation from any other corner of the industry, about ANY airline. Like any rumour you hear, one tends to view any such isolated report or allegation as BS until it has been backed up by similar stories. THEN you might do some research to see if there's anything to it... Oh and let's not confuse a hard landing with a deliberate avoidance of floating down the runway. Aircraft do very little deceleration in the flare, so on short runways the aim is to get down safely but 'decisively' and let the brakes, reversers and spoilers do their work.For those out there who would make unfounded statements or allegations on this board, remember one thing: PMDG have extensive contacts within Boeing and (I believe) Southwest Airlines as well. You only stand to come off looking like a fool when the veracity of your statements is called out. Many of the longer term members here will recall the new guy who claimed to be QF 747 aircrew. Little did they know that an ACTUAL QANTAS employee was active on the boards, and his whole ruse was shortlived and very embarrassing for him.Last, but not least. Most aviation geeks have seen this video, and it is a classic example of a self-professed 'expert' making a laughing stock of himself. http://www.youtube.com/watch?v=GLATzXV6_rcThere's no shame in an experience like this being frightening, but making it out to have been a genuine near-death experience does the aviation industry a disservice and, frankly, makes you look like a princess.

Ethan you misread Jen's post. He is saying that the number of 737-700s that they are going to order is 200.

Yes indeed! I stand corrected. :(

If you do this to the plane over and over again, the yeild strength and ultimate strength gradually decay over time. the aluminum used in boeing 737's is strong but its not THAT strong. hundreds upon hundreds of rough landings in excess of 500 FPM could easily cause cracks and ruptures anywhere on the plane,.

Even ONE landing in excess of 500 FPM has an excellent potential to induce cracks and ruptures - in fact, per Boeing's own maintenance manuals for the 737 series, (all models) any landing at, or in excess, of 6 feet-per-second (i.e. 600 FPM) mandates that the aircraft be taken out of service for a major structural inspection of the landing gear, wing spars and lower fuselage.The point being that you are greatly misinformed if you believe that Southwest, or any other 737 operator, routinely permits their aircraft to land at a 500 FPM vertical rate, or anything even close to that figure. A 500 FPM landing involves an instantaneous vertical deceleration of over 3 G, and would result in a much more profound effect in the cabin than a couple of overhead bin doors popping open. Such events are quite rare, and are usually associated with serious weather issues, such as low level wind shear. It certainly is not something which happens "hundreds upon hundreds" of times - either for individual aircraft, or in the fleet as a whole.Your subjective impressions (as a passenger) of a "firm" landing do not constitute "proof" (scientific or otherwise) of what you claim. The vertical rate in such landings is probably closer to 150 to 200 FPMIt is the accumulated number of pressurization cycles which plays the biggest role in causing metal fatigue in an aircraft fuselage. Since Southwest specializes in short hops, their fleet as a whole probably has a higher cycle rate per aircraft than a 737 operator who mainly flies longer-duration legs. (i.e., coast-to-coast.)That being said, there apparently IS a known issue with metal fatigue in the very location which failed in SWA812. Airworthiness Directive AD-2010-25-06 was issued just a few months ago affecting all 737-200, -300, -400 and -500 aircraft, requiring a detailed visual and/or eddy-current NDE inspection of the frames and stringers of that very section of the upper fuselage. Operators were given 4500 flight cycles from the date of issuance of the AD to comply - I doubt that any 737 has yet accumulated that many cycles in the short amount of time since the AD came out.As a result of this incident, I wouldn't be surprised if the FAA amends the AD to remove the 4500 cycle buffer, instead requiring immediate compliance.Jim Barrett

any landing at, or in excess, of 6 feet-per-second (i.e. 600 FPM) mandates that the aircraft be taken out of service for a major structural inspection of the landing gear, wing spars and lower fuselage.

Some odd math going on there :(

Even ONE landing in excess of 500 FPM has an excellent potential to induce cracks and ruptures - in fact, per Boeing's own maintenance manuals for the 737 series, (all models) any landing at, or in excess, of 6 feet-per-second (i.e. 600 FPM) mandates that the aircraft be taken out of service for a major structural inspection of the landing gear, wing spars and lower fuselage.

6 feet per second is 360 FPM and not 600, so lets sto making up facts here pretending to be experts, landings are mesured in G forces not FPM....

6 feet per second is 360 FPM and not 600, so lets sto making up facts here pretending to be experts, landings are mesured in G forces not FPM....

Not making up facts. Yes, -6 FPS = 360 FPM - my bad for trying to do (ahem) "complex math" at 0200. That figure is for a 737 which is at, or above, maximum landing weight at touchdown. For an aircraft which is below max landing weight, the maximum permitted rate is -10 FPS, which is indeed -600 FPM.This info comes directly from Boeing's own inspection guidelines, which you can view here: http://www.boeing.com/commercial/aeromagazine/aero_14/conditional_story.html#tab1See paragraph 1, "Determination of non-normal landings"Any given vertical acceleration in ft/S can be correlated with a specific G load on the airframe. I don't know the equation, (I'm not an engineer), but I'm sure it's readily available from any number of online sources. Boeing itself quotes the landing limits in FPS, and points out that getting an accurate post-flight record of G load from the FDR can be difficult, depending on the specific model of FDR, data capture rate, location of sensors in relation to the aircraft CG etc.My point for the OP was that commercial airliners do not routinely land at sink rates of -500 FPM, or anything even close to that value.I'm not an "expert" in the sense of being a structural engineer - but I am a working A&P mechanic, and have been involved in performing structural inspections following hard landings - it's a lengthy and very expensive process even on a mid-sized business jet, and surely even more so on an aircraft as large as a 737. No operator is going to have an SOP which calls for a landing technique which would routinely put the aircraft in danger of approaching or exceeding the manufacturer's limits for a hard landing.I've also done many fuselage pressure vessel inspections looking for signs of cracks, corrosion or metal fatigue. Such inspections can involve visually looking for problems, but more often require NDI techniques such as X-ray or eddy current. All these type of inspection require removal of all interior furnishings, (and eddy current NDI requires removal of exterior paint) so are typically done only during "heavy" maintenance checks. According to news reports, the last heavy check on the SWA aircraft in question was one year ago, in March 2010. (Keeping in mind that news reports involving airline incidents are often woefully inaccurate.)The recent AD for the 737 -200 through -500 series http://bit.ly/e3Yvs1 makes interesting reading, as the particular fuselage stations called out in the AD appears to be the exact location where the failure occurred in SWA812. Obviously Boeing has reason to suspect problems in this particular area. The AD identifies "pressurization and manuevering loads" as factors in the metal fatigue leading to the issuance of of the inspection requirement. Another Southwest 737-300 experienced a similar event in July, 2009 on a flight to the east coast - though the fuselage rupture was in a different location, and not as large as in the most recent incident.Jim Barrett