There are many, many airports all over the world that have all kinds of obstacles, buildings, and even water hazards very near the runway.

I think it would be difficult, if not impossible, to mandate that all unused lands near a runway must be perfectly flat. If you could, how far out would you consider safe?

PVG, TPE, SIN and MCO come to mind immediately, they all have hotels in the terminal between parallel runways, I'm sure there are many more.

One thought that has been expressed in some earlier posts is to have smoothed out the so-called ravine. It most likely can’t be made flat, as some have suggested, because the topography of the whole area slopes downwards to the right (east). The right hand runway, 36R, is about 25m lower in elevation than the left hand runway used by the aircraft, 36L, at a point abeam the aircraft’s final resting place.

I’ve looked at getting a cost for smoothing out the so-called ravine a few times, and it is hard to estimate accurately as I am using only Google Earth for topographical data. Plus costs on airports in capital cities have a habit of being anything up to three times higher than in rural airports due to the multiplicity of services, authorities, work constraints, etc. However what I’ve got so far is the following.

To make things smooth, we need to fill in the ravine. This ravine carries a river which is obviously part of the airport and area drainage system, so it needs a main stormwater drain to be installed to carry the river water, and then the ground to be filled in above the drain. We need 2.5 km of main piped stormwater drain for the river between the two runways and extending around the end of 18R, and another 1 km of pipe drain for the smaller river that flows between the runways about halfway along the runway. My cost estimate for those two stormwater pipe drains is US $20 million. We also need a large amount of fill to cover the drainage pipes and to smooth out the terrain. A really approximate guess, using Google Earth data, is that 2 million cubic metres would be needed. That could cost anywhere between $20-70 million depending on haulage distance and cost of quarry/fill material in Madrid. Then add in design, contract administration, and contingencies, and the sort of cost to smooth the terrain is about US $100 million. That could of course be more because of the urban factor.

That is a lot of money. My concern, and this has been expressed by other posts, is where do you stop making the area around an airport smooth? Here, and assuming we do make the ground smooth between the two runways, albeit at an overall slope of 2% downwards, let us look to the left of the runway. The ground rises at a gradient of 9% for some 500m. There is also a small ravine on the left about halfway along the runway. If the aircraft had gone off to the left, and assuming it missed the ravine, I would have thought the aircraft with a tricycle undercarriage configuration travelling at say 160 knots diagonally up a 9% slope over grass would still be rather likely to break something or wobble and clip the ground with a wing. The chance of a crash and fire is significant, and the success of a diversion to the left is not assured. So do we remove that hill? And what about the end of the runway, and running over the end. Maybe we need to extend the RESA of this already very long runway. And don’t forget the distant high ground to the north of the runway; maybe we need to level some of those distant mountains. Where does the work stop?

The answer IMHO is the balance between risk and cost. Despite this tragic accident, if I look at the collective risk for airline passengers in Spain and relate it to individual risk, it is still below the accepted individual risk level. The Dutch government assessed the individual risk level of 1 x 10E-6 as that which would trigger effort to reduce risk (from the Schipol accident, 1992). Even after this accident, Spain is below this, and as such effort is probably not justified to further reduce the risk.

Bringing the argument back to ICAO rules, I suggest that despite this accident, the cost to reduce the risk by smoothing the terrain beyond ICAO requirements is not justified by the reduction in risk.

There remains the test of negligence. For risk analysis, this is prefaced by dictum of the former Chief Justice of the High Court of Australia, Hon. Justice Gibbs, who in determining negligence on the handling of risk stated:
“Where it is possible to guard against a foreseeable risk which, though not perhaps great, nevertheless cannot be called remote or fanciful, by adopting a means which involves little difficulty or expense, the failure to adopt such means will in general be negligent.”
IMHO by meeting ICAO standards, as it seem evident that Madrid does, it means the risk of this tragedy is remote. Furthermore my cost estimate shows that to guard against it involve great expense and some difficulty. So no negligence could be attached in the handling of risk.

IMHO, the buck stops if an airport meets the ICAO rules. I reckon ICAO rules are a very good balance between risk and cost, and they have stood the test of decades of time.

Take a look at where you would expect the right wingtip to strike, back at the start of the tracks. Is that it?

Wouldn't that put the nose gear right about where the third track starts? Where it obviously broke off on contact and held it's expected natural direction afterwards. If it would have still been attached it would have left a very un-straight track.

philipat,

Maybe a bit off-topic but the clear winner in the "obstacles between the runways contest" is DMK (formerly BKK):

Google Maps

Yep, that's a golf course between the runways... ...fancy a golf ball or two between the fan blades?

I arrived at the same guesstimate.

OverRun Input
 

Thanks for the comprehensive professional input and I stand corrected. The scope of such work is not immediately obvious to a non-professional. Your Risk/Reward logic and legal persective is also vey clear and understandable.
I apologise for the ignorance and it would seem that this issue has now been comprehensively closed. Thanks again for taking the trouble to elucidate.

I would like to ask the golden question to pilots of MD-82 or similar planes.

In your opinion, *assuming perfectly working engines and no reverser deployment*, *assuming no windshear*, and assuming said airplane took around 500m more of air strip than estimated as normal for its
(pretended) configuration to lift-off (i.e. it took longer to accelerate to speed than predicted or it rotated for longer than "it should've" or a combination of both, etc), what is the most likely cause of a fully loaded airplane like that being able to become airborne for 3-5 seconds but yet just "fall" after rolling left & right and w/o an experienced crew being able to do much about it on time?

Again, let's assume both engines were working properly and reversers were never deployed, just for the scope of this question.

Thank you in advance.

My last post for this topic:

Try fitting the same triangle, like plotting, to those marks and then check what you get.

What could have brought here down excluding engine problems? Controllablity issues rising from operations near stall conditions (flaps/slats retracted) or maybe a tail shear of 20 to 30 knots. But this couldn't be the case as there was no storm and mountainwave turbulence tends to be a bit less hit and miss. Other than that I can't think of anything more.


Xander

LuckyStrike;
Here's a schematic of main gear to nosewheel, width-to-base measurements on the MD83 -16' wide by 72' long, approximately, illustrating the ratio of length to width - I believe there was a question earlier in the thread about this.

Because the image of the tracks is viewed from an angle it's not possible to accurately template a triangle (such as the one below) onto the jpg image of the main gear tracks. I remain open to the "engine alternative" of course - any other stance or certainty at this time is foolish. For me it fits for the reasons I give, for others it looks like an engine track - the large item to the port of the track (to the right in the photo) looks to me like an engine cowl but again the photos are quite poor in resolution.

Time will tell all, and by that time no one will remember who said what on the thread.

http://img222.imageshack.us/img222/9...arratiosv8.jpg

Well, I just cannot comment on the 3rd mark (the one that follows a straight path) because it can be a number of things, as you and others have mentioned. What I am arguing here is that I find it hard to believe it was the nosewheel which left out that particular pattern on the ground.

PS: This was the real last post :} Thanks for the LVL discussion :ok:

LS;
LOL!...hearya. Take care.

Ravine's not the issue, really
 

It's the lack of an additional safety system such as Engineered Material Arresting System (EMAS), or crushable concrete. For further information: Fact Sheet - Engineered Material Arresting System (EMAS)

This is something that's being installed at the end of several runways in the US, but not along its sides. At the very least, it should be installed at airports where there are ravines or similar hazards along the side of the runway.

In this case: If the system had been installed all along the runway, the aircraft might not have ended up in the ravine at all. THAT's the issue, not creating flat area at every airport, which is pretty much impossible.

Overun,

thank you for your clarifying note. In addition I can tell you that any local/green initiative/party will fight any sealing of any area close to an airport that is not justified by any international regulations and even those that are with their utmost energy, making it impossible for airport planners and willing politicians to get that done. That's were we are, much before hotels and hangars come in play.

3NM

EMAS
 

Seems to me that it would not necessarily be a good idea to put EMAS at the side of the runway.

If an aircraft puts one wheel off the runway, the EMAS might be likely to make it spin, in a similar way to braking on only one side.

thrust reverser deployed apparently..poor buggers

EMAS
 

That's a good point, but could be mitigated by having some leeway on both sides of the runway before the system started. I'm not an engineer, and there's probably many issues that need to be addressed before such a system can be deemed completely safe and not adding to the total risk. I am questioning, however, why it's not being looked into, and why it is so easy to dismiss right away.

I've seen what the lack of such a system (at the end of the runway in that case) can do, and with my own eyes, not through TV, photos etc. I've seen what it does to families, rescue workers etc., and believe you me, all you want when you've seen something like that, is to make sure it NEVER happens again.

Maybe EMAS isn't the answer, but it is worth looking into. Maybe it couldn't have saved this aircraft (based on information from press conference), but it could save the next one.

I wouldn’t read too much into this as an indication of force of impact. I doubt if it is true. The very large tail cone is designed to detach and the Rear Pressure Bulkhead is forward of the cone attachment points

See HERE.

Comments on Video transcript
 

Old Fokker wrote:
Old Fokker,these are not my words but a quote of another forumite post. I fully agree with your view.


You also state:

I agree that is what the board stated. They are however being imprecise. I am familiar with that airframe and:

It is the actual composite tailcone that the board was referring to as first detached, because:

The area of the fuselage aft of the pressure bulkhead comprises the main fin support bulkheads together with horizontal and vertical stabilizers. The latter can be observed lying next to the main crash site and could not therefore have detached from the airframe on first impact.

As to you having done the transcript work... that is what I was envisioning (and trying to avoid) when I stopped in the middle of watching the video and posted (#1012)

Sorry it did not get to you in time, cos I know it was a time-consuming task!