It's being said that there was a problem in reaching V1-V2, and as someone has already posted, in that case setting the flaps/slats configuration wouldn't have a role on that.

So do any of you know in which way could affect the same problem to available thrust?

In other way, does anybody know where the iinformation about that "slow take off" comes from?. (Because it may lose reliability by saying the aircraft didn't reach the necessary 210 km/h = 113 knots, which seems quite slow anyway)

Concerning the 'locked' TR.
On the CRJ 100 LH technicians once 'locked' a faulty TR.
During the take-off run this very TR suddenly deployed because the pin had been inserted in the wrong place!!!
Don't know if that's possible on the MD.
Just a thought that this also might be a possibility in this case.

Actually, some operators on some planes do use the reversers when figuring performance on an icy or cluttered runway. Not a factor with Spanair but it was commented on in the NTSB report of the Southwest crash at Midway:

NTSB Decides on Midway Crash | Air Safety Week | Find Articles at BNET

There are THREE ways to read takeoff power on jet engines.
 

We all know about EPR... on Pratts (like the MD-80s) and Rolls noise machines...
We have N1 as an alternative (if EPR is dead) or as a crosscheck.
And if these guys had a good ground school, they would know what FF it takes to get "about" 19,000 lbs (?) thrust.
xxx
I knew what it took (as FF) on ALL engines types I had on my 707s, 727, or DC-8s...
On the JT9D-7Q (747s), it takes 9,000 kg FF (19,850 lbs FF) to get full thrust.
That is the gage I would look at, to crosscheck EPR/N1 in case of doubt.
(Or if either EPR or N1 is MEL'd) -
xxx
Sorry - I do not know the TSFC of the JT8D-217/219s...
I would say - probably around 4,300 kg FF...?
xxx
:*
Sad contrails

Some sources do speak of some sort of "wire" (pin) involved in the (presumed) lock-due-to-malfunction of the TR by the technician.

Most sources now speak of right TR not operative for the past 3 days, maintenance delayed (by MEL), and LEFT TR found deployed (assumed to be commanded when trying to stop the plane).

The sources speaking of the slow speed/long time to take off are: ground witnesses, airport video recording, ground radar. Video recording shows the plane finally leaving the ground close to the end of the strip, close to the portion of the paviment that changes color (which somewhere it's said to be 600m long of aditional paviment). This is estimated to be some 500m longer than usual for this flight.

Doubt the crew would make the entire roll not knowing the right bucket was open. Too many different indications for all of them to have been inop or ignored simultaneously by two people. Perhaps this is a fuel quality and/or fuel delivery issue? Booster pumps?

What keeps bugging me in the flapless scenario: If you depart without flaps, you should notice something is wrong when you rotate in the first place. It has been stated earlier that a plane would indeed fly in ground effect but stall as soon as climbing out of it.
I have never been confronted with that situation, but I imagine, if you figure on rotation that you have insufficient lift, the immediate guts reaction would be to lower the nose and gain some more speed. They had more than 1000m of asphalt ahead of them, followed by another kilometre or two without obstacles.
Wouldn´t the natural reaction be to get the nose down and accelerate to a higher -more flyable- speed (and let it touch down again, if it doesn´t fly yet with less AoA)?
I just try to visualize this scenario, anyone experience on this?

philipat;
We can't really say that configuration accidents are "far from infrequent" as it just isn't the case, not in my experience anyway. That configuration errors have caused accidents is true, but not "frequently". For discussion's sake however I understand what you're saying and my own view on formalizing a "final check" is what the Before Takeoff Check is all about already. Let me provide what is perhaps a poor example but may illustrate the thinking involved -if you're leaving your house for a vacation, you do a formal run-through to ensure locked doors/windows, that the stove is turned off and all unnecessary lights are off...that could be called, (for lack of a better term for what is pretty informal for us all!), the "formalized" list. But....as we pull out of the driveway, we may quietly reassure ourselves that the stove is indeed turned off...

There isn't anyway to re-formalize this process so that it is more effective. Checking, re-checking is what all airmen do; it is habit borne out of hundreds, or thousands of hours of experience and moments of, to be blunt, stark terror at "what just about occurred"...No airman is without such experiences, (you've read a few here already), almost all of them quietly endured and without fanfare or "result". That's why, when discussing what pilots "are worth" to airline managements and other standard doubters who think of us as "expensive resources", I use the phrase, "We're paid thousands and thousands of dollars per minute but you'll never know which one. The rest is for free".

Ancient Mariner - okay, thanks. Re wild speculations - yeah, thought so. This really is the best place for as close to a professional discussion one can have "in public".

TR
 

Sevenstrikeroll,

Lets assume the acf was in "air" mode before taking off which
is one of the theory's. (RAT probe heater etc)
As we know this is controlled by weight on the NLG.
When the NLG later lifts on rotate, will the acf then revert to
ground mode??

If so, the question is, if the RIGHT reverser bucket was
not deactivated &stowed properly, could this trigger them to deploy on
NLG liftoff somehow?

Attach Reverser system schematics;

http://www.xplanefreeware.net/morten/DOCS/RT.jpg

http://www.xplanefreeware.net/morten/DOCS/RT2.png

MD82 TR engage at rotate sim clip

XPM

Where Next?
 

PJ2:

".

Like in business. I know that half of advertising expense is wasted; I just don't know which half?

Thanks for your patient and always relevant responses. Should that not have been your drift, and I would contend that at least 6 configuration-related accidents over a 30 year period (OK, maybe not justified in my earlier statement as "Not infrequent") IS a significant statistic, then please further elucidate? What should be done, in your opinion, to better, or more relevantly, address the issue of the three killers?

There's an ICAO listing. See Dutch Accident Report, my post 1174.

we can start with your above statistic. Now consider how many aborts occurred because of misconfigurations annunciated by warnings (horns or lights, etc.) That provides both a crew error rate as well as a safety barrier success rate. (note I'm ignoring checklist caught misconfigurations)

And of interest to me, how many aural warnings or lights failed to warn?

if it's 1 out of 20 or worse than that is way too much and should be addressed as the highest priority.

If on the other hand the crew missed not only the configuration but also the warning light or horn then we have the wrong crews flying planes.

the above is still hypothetical relating to the accident in this thread

Yes. of course that goes without saying. The potential issues with Spanair MEL and pre-MEL matters not withstanding?

I'm with you Avionero. It seems that no one is flying the airplane off the runway. They're just rotating at V1 and expecting the aircraft to do the expected.

I'm also disturbed with the idea that pilots are inputting data into calculators and not considering whether the output is reasonable. Garbage in, garbage out. One instance noted indicated that the crew ignored what to me would have been a very obvious 33 knot error in V1. When taking off in a heavy 747, wouldn't you think that something like 33 knots would stand out like a sore thumb? Are these guys robots or pilots? :ugh:

Being a military pilot who only has a couple thousand hours in transport aircraft, all props, I don't know much about large high-bypass engines, but I seem to remember from ground schools that N1 isn't a viable indication of thrust in a twin spool engine. I thought that N1 was just along for the ride, although a very low N1 should certainly catch someone's eye.

Ed, surely if the N1 is producing over 80% of the thrust, it is certainly a viable indication of thrust. (On a high-bypass turbo-fan).

Agreed a sanity check on V speeds seems obvious to me too.

Hi Smilin Ed,

In the case of the Halifax 747 (MK airlines) tragedy, I can only say that I knew at least 2 of the crew members personally and they were certainly not robots - more like overworked, tired, but nevertheless trained and highly capable crew with family and other good things to look forward to. We always think we could never make these (often simple) mistakes, but believe me, even the most talented pilots can be caught out. Rather than simply chide others, every good pilot should just use every tragic accident as a lesson to learn and be safer in their own flying - without being judgemental.

Does anyone know what really happened on the FIRST attempt (before they taxied back to the ramp)?
Was it an aborted takeoff or did they simply realise the problem on taxi out and returned to stand?
Would make a huge difference - mainly in respect to brake cooling and also on pressure on the crew!

xp morten

no, once airborne, the plane, already thinking it was airborne would do nothing new.

A LONG time ago, at KPIT, a DC9 took off with "bad" fuel and it landed as both engines flamed out on the departure runway. At that time, it was feeding both engines from the center tank...that is no longer done, now for obvious reasons.

so, in addition to my "airborne mode" theory, we must ask the configuration of the fuel pumps and which tank was supplying which engines...also the quality of fuel...by the way, this fuel theory isn't likely in my mind, but we have to ask.

ALWAYS let the plane fly itself off the ground. (unless!0) that is the surest way to get the right v speeds!

Valid Thrust Indications?
 

Tom, that's exactly what I was asking. What do the manuals for aircraft using high-bypass multi-spool engines say about indications of adequate thrust? I had been taught that on any twin-spool engine (J-57, J-52) you cannot rely on rpm. You must have working Engine Pressure Ration indications.

Once in a training squadron I was criticized for aborting a takeoff because of low EPR indications. Then they found that the inlet guide vanes were stuck closed on that engine. You can imagine what consequences that would have had on a high gross weight catapult shot where you lost the other engine.