Posted on 08/20/2008 8:12:53 AM PDT by rightwingintelligentsia
The thing is, that airline pilots (including freighter drivers) practice that crap intensively in the simulator. So the fact that the plane indeed crashed after becomeing airborn is perplexing.
Max takeoff weight is an inviolable fact that is engraved in the aircraft operations manual. That number can only be decreased based on runway performance data, and existing ambient conditions at takeoff. And the calculated values for V1, Vr & V2 are just as inviolable based on existing conditions. For an existing runway, and existing environmental conditions, either less passangers, luggage or fuel (or combination) can be loaded. V1 is one of the First Commandments of flight (aside from all the other First Commandments).
The facts as we know them, the port engine either flamed, shelled, or catastrophically exploded, and yet the plane rolled right. Its totally contrary to what expections would be for such situation. If catastrophic engine failure severed flight controls such that the aircraft lost significant (or all) control, that event is totally unprecedented in the history of that model of aircraft.
That's the whole point of V2, takeoff with engine out condition. And Vr is rotation speed where no more than 3o/sec rotation is imparted to the controls for about 3 sec. After rotation, the aircraft should be virtually on top of V2. Furthermore, V1, Vr, and V2 are all values calculated with one engine out AT V1. So yes, at V2 the plane will climb with one engine out. Those are aboslute inviolable physics of the matter. Prior to V1, equipment malfunction dictates automatic abort.
V1 is absolutely dependent upon runway condition. In slick conditions, sufficient runway must remain to stop the aircraft in engine out abort prior to V1. That may predicate V1 occuring at 1/3 runway length. The only way the aircraft can accelerate to V1 in shorter distance is to reduce takeoff weight. But that has the affect of decreasing stopping distance, so the aircraft can accelerate slower than normal, reach V1 at the same point fully loaded in optimum runway conditions and STILL stop before running of the end. Its complicated mathematics, but computers (electronic or slide rule) figure that all out.
Frankly, I believe they either totally screwed the pooch on Vx calculations, or they had engine failure at or after V1 and over-rotated at Vr in panic, the aircraft going airborn prior to V2 and the plane then promptly entering stall onset. Even so, I still can't image why the plane would roll to the starboard with the port engine out. Unless the engine failed post V2, and the pilot flying over compensated for port roll/yaw. If the pilot flying kicked the rudder to hard to the right, that would slip the port wing forward (trail the right wing) and create lift imbalance (postive port, negative starboard). Effectively in that situation the right wing would stall. Game over.
Given that the engines are at the rear of the aircraft, I'm speculating that more of a yaw would be imparted than roll if an engine goes out. And the control input to counter yaw is oppostite rudder input to the direction of yaw.
Nevertheless, this is all speculative based on my non-professional knowlege. What I do know based on eight years of accident review, virtually always, all aircraft mishaps can be traced to a chain of events, any one of which, if but for, the aircraft would continue flying. Virtually ALWYAYS, and almost never (if at all), are aircraft mishaps directly attributable to a single factor. However, as a chain of events progresses, even so the final event itself is of such insignificant consequence in the grand scheme of things, catastrophic failure is virtually guarenteed.
In other words, every error builds upon the previous and sum total of all previous errors in a logarithmic fashion, such that regardless how minor the last error is in and of itself, that last error clinches the deal, the aircraft departs from controlled flight; straw that breaks the camel's back.
Click on the pic and then you can proceed to the other slides. I didn't translate the captions, but it looks as though they give a time line of the crash.
yes...
I knew a family member was returning, but I wasn’t sure which airline or by what route, and I’ve never been to that airport.
So...thank you freepers!
“Big Ben?”
I’m not sure I follow.
I was just reacting to the headline knowing a family member is due to fly back today.
I'm confused. I thought they initially said it was the #2 engine, but the graphic in the slide show is the #1 engine.
All signs are pointing to low bidder, 2nd or third world maintenance/repaired parts.
It did a little more than shedding blades That was a Fan disc failure
Pretty hard to contain a Disc inside of an Engine, as GE knows with the CF6.
The JT8D-219 Problems in the past few years have been LPT blade failures, which are contained but the engine stops running pretty quickly.
American Airlines was having failures only a couple hundred hours after install.
A good lesson to learn is when you buy "Hecho in Mexico" turbine parts, you get what you pay for.
A good lesson to learn is when you buy "Hecho in Mexico" turbine parts, you get what you pay for.
Probably better quality than the 'Made in China' stuff folks are buying now.
Remember, because the MD-80 series uses a T-tail design, it means the airplane is highly susceptible to a deep stall condition, which means the plane will violently stall and become totally unflyable because the horizontal tail surfaces can't control the plane. In the panic to try to keep the plane under control, the flight crew may have unintentionally forced the plane into a deep stall condition, and that's why it promptly crashed.
1) it appears that virtally the entire length of the runway was utilized for the takeoff roll before rotating (???).
Great Circle distance: Madrid, Spain to Las Palmas, Canary Islands - 938 Nm
According to MD-80 series airplane characteristics at:MD-80 Document MDC J2904 (New, December 1989)
FAR 121.639 for FAA certification stipulates reserves sufficient for 200Nm to alternate. This would allow Santa Cruz, Canary Islands (@46 nm), El Aaiun, Western Sahara (@134Nm), or Madeira - Funchal, Portugual (@280Nm) as viable alternates to Las Palmas in Canary Islands.
According to the payload range charts for 1250Nm flight, 41,000# payload could be allotted to passangers & baggage (@238#/passenger). Operating empty weight is specified at 77,976#. This combines to 118,976#. This allows 4555 gal fuel to be taken on board, of which 67 gal reserved for taxi purposes, 97 gal for contingency purposes, and 671 gallons held in reserve. This leaves 3720 gal as pure get-there (or alternate) juice. I can't find specific fuel consumption fiingers for the MD-80, but for max cruise at FL270 @ 499kts fuel consumption is 4077kg/hr, and for cruise @FL350 @439kts FL350 fuel consumption is given at 2500kg/hr.
Generally power settings at takeoff are at 100%, climbout 85$, approach 30%, and idle at 7% (I'd guess cruise to be near 60% - probably nearer 50% for econo-cruise). So it looks like they could carry twice the fuel required (with given reserve) and remain within weight limits to reach their destination.
Madrid Barajas airport altitude is at almost 2000' MSL, and standard day temp (SDT) at altitutude is specified at 51.9o F. At SDT the rated FAR 121.639 takeoff runway requirement for MTOW departure at 2000' MSL is about 8500'. The data suggests an extra 500' takeoff roll for each +15 Co (~27 Fo) above SDT. It looks like the temp was 86o at departure. The aircraft easily should've departed after a 9000' takeoff roll. The windsock icon is intimating 7kts from the NE (slight headwind). I don't know if that would even qualify for an extra 500' takeoff roll even at MTOW.
It looks like they took off from 36R (14271'). There does appear to be a discrepency between the two clips though concerning precisely where they acutally departed the runway. The first clip shows them departing at about the 2/3 mark (~9500'), and the latter clearly shows them rotating pretty much on the touchdown zone for 18L and definitely after the last turnoff. However, in that clip the turnoff angle is incorrect. That last turnoff would only be correct if they departed from 18L (however, the video icon clearly indicates direction to be N (as does the runway orientation in the first clip suggest they departed 36N).
In any case, departing on the numbers @14271' is 58% more runway than would normally be expected for MTOW and SDT+15 Co
2) In the initial image its evident that the starboard elevator appears in full up position and port elevator appears near neutral - slightly down - position. Both of the elevator trim tabs appear to be equally and noticeably trimmed down; it would seem the tailplane appears trimmed for takeoff.
3) the rudder appears to be stuck full left. This implies the pilot flying was countering yaw to the right. In conjunction with the final right wing drop, a right wing stall seems plausible.
The position of starboard elevator suggests hydraulic failure of the tailplane elevator as a result of catastrophic explosive failure of #1 engine; its stuck in rotation departure position. Expected control inputs as part of stall recovery would put both elevators into a down position (to create pitch down moment).
Not to mention that the shadow of the aircraft has the wrong engine placement.
I was surprised to see the animation. I can’t think that it’s based on the flight recorder data. I wouldn’t think that that info would either be available or be released so soon.
The port elevator & trim panel, on the other hand, well, I dunno. I looks pretty solidly attached. There's some pretty heavy gear work in the tailplane assembly, so I'm guessing the rudder position is legit too.
The plane was wobbling from one side to another. Then I began to suspect we would crash. I don't know what happened next. I was in a sort of river and saw people, smoke, explosions... - survivor Ligia Palomino"Please. Make the movie stop. Where's my Dad? Is this for real? I must be in a movie. I just want it to end, please make the movie stop." begs child survior of rescuer.
I read another article this morning—can’t find it now—that seemed to indicate that there was NOT an engine fire on the takeoff roll, and that the plane used almost all of the runway before barely getting off the ground and then immediately rolling to the right and impacting off to the right side of the runway, catching fire, and breaking up. There was also a statement from somebody on the plane that it “wobbled from side to side” before hitting the ground.
If—and as usual it’s a very big if—that is the case, I wonder if we’re looking at a flap setting issue similar to what caused the NWA DC-9 crash years ago. There’s warning horns designed to sound and prevent taking off with the flaps not at a takeoff setting, though.
}:-)4
He said he has seen — but would not comment on — video footage from the airport that shows the doomed airliner trying to take off. The newspapers El Pais and ABC said it shows no engine explosion, contrary to some witness accounts.SOURCE: The Associated Press as published: August 22, 2008: Spain aviation chief wants glitch investigated (International Herald Tribune)The video is reported to show the plane using up virtually the entire runway as it tries to take off, then struggling to gain altitude. The airliner eventually crashed, skidded, burned and largely disintegrated.
If they did utilize the entire length of the runway, there's a serious issue there. Vr would occur at about 9000' and V2 should've occured within 2 seconds thereafter.
So the plane would be rotated and traveling down the runway for almost 20 seconds. During this time the plane is still accelerating, yes? What could be going through the pilot's mind, when 15 seconds after rotation and airspeed of 200 kts, they're STILL not off the ground?
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