Spanair crash team focus on faulty thruster-papers
 

Reuters Thu Aug 28, 2008 6:53am EDT

... Air crash investigators were unavailable for comment on the reports as was engine-maker Pratt and Whitney, while Spanair, owned by Scandinavia's SAS airline, declined to comment.
Full report
Spanair crash team focus on faulty thruster-papers | Industries | Industrials, Materials & Utilities | Reuters20080828

http.. 3w.reuters.com/article/rbssIndustryMaterialsUtilitiesNews/idUSLS42830120080828

last winter at orly, a french charter B744 outbound to french west indies close to MTOW, rotated at 132KTS as calculated by crews on their ladtops.
it ended up by large pieces of underfuselage near the tail being torn off on runway.the crews didn't realize the tailstrike, but understood something was wrong and release back pressure on the controls and aircraft smoothly took off and departed
after an in flight visual check performed by a figther 45 minutes later, the company decided to call back the plane that landed back two hours later
each of the crew had more than 10000 hours
PS : the flight has been reported at last minute the evening before due to technical problem and curfew time

Apologies if THIS MD-80 accident has been mentioned before. Interesting reading. 3.5Meg pdf.

To do a 'Speed Read' type the word 'configuration' in the Find Box, top right.

Runway Over-run Onur Air. Runway overrun after rejected take-off of the Onur Air MD-88, registration TC-ONP, at Groningen Airport Eelde on 17 June 2003.

Synopsis. The investigation shows that the crew initially rejected the take-off when an acoustic alert signal was activated. This signal pertained to a warning for an incorrect setting of the trim of the longitudinal control system. When carrying out a check the crew did not find any peculiarities, although these were present. After this short interruption the take-off was resumed and this time, when the (repeating) sound alert signal went off, the signal was ignored.

When the captain noticed that the control force required to rotate the aircraft was significantly higher than normal he decided to reject the take-off. At that moment the remaining runway length was too short to bring the aircraft to a complete stop before the runway end.

Could somebody clarify how the TRs on the 80s are locked when they are INOP?
Are they pinned (thus mechanically fixed in closed position) or are they arrested in some other way? Is it technically even possible to activate a TR in that condition?

a restatement for those coming to the thread late
 

New arrivers to the thread may keep finding references to the "in air mode" hypothesis.
To prevent the same questions again and again it might be useful to explain that it goes roughly like this (using lay terms throughout)

1. When (and only when) in the air, the RAT probe is heated (anti-ice). Certain.

2. The first take-off was aborted due to RAT probe being heated when on the ground. Definite.

3. Mechanic "rectified" inappropriate RAT probe heating by disconnecting the heater. Fairly definite.

4. Hypothesis: Mechanic did nothing else, not finding why this heating was happening.

5. Hypothesis: The reason for the heating was a fault with the system which senses (from weight on landing gear) that the aircraft is on the ground. This would mean that the aircraft "thought" that it was in the air throughout, so turned the heater on.

6. This aircraft will warn if flaps/slats are not deployed for take-off, but not if it thinks it is in the air. Fairly definite.

7. Hypothesis: Flaps/slats were retracted for the taxi back after the abort, and reconfiguring them for take-off was forgotten.

8. Conclusion: The take-off could have been without flaps/slats, and due to the hypothesized fault, the normal warning signal would have been absent.

Sevenstrokeseven,

J/S'ing on MD80 last week and the takeoff EPR was 93.x %.

In EPR a/c N1's are frequently overlooked.

Reverser INOP during three days up to accident
 

... says Spanish paper El Mundo, quoting investigation sources

MD-80 Forum: Crash - Spanair JK 5022

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