DISCLAIMER: This whole post ASSUMES that the crew failed to correctly deploy the flaps/slats. This still hasn't been proven, so it must be taken as purely speculative and not based on facts.
Others could answer more authoritatively than I could. But, to the best of my knowledge and in my personal opinion, I'm sure there is no "electrical/mechanical" link between TOWS being disabled by the lack of energy from R2-5 and flaps AND slats indicators failing in any way. The indicators in the instrument panel (flaps degree watch dial and slats takeoff lighted indicator) are mechanically set.
From the manual:
The flaps indicator contains dual, superimposed pointers and a dial which is graduated in degrees of flap travel. Each outboard flap is linked to a separate flap position transmitter that operates one of the dual pointers. The pointers respond to actual flap movement rather than flap control handle movement and will normally move in unison.
To take off, respond to challenge question for flaps slats with the degrees setting and "TAKEOFF".
The flap takeoff selector wheel should be in the stowed position for 11° or 15° flap takeoffs. When departing with other flap settings, rotate the flap takeoff selector wheel until the required degrees of flaps are indicated. Note: Flap settings between 13 and 15 degrees are designated, “Do Not Use,” and will not be selected for takeoff.
Move the flap/slat handle to the appropriate detent. Observe the slat TAKEOFF light is on, SLAT DISAGREE, AUTO SLAT, and SLAT LAND lights are out and flap position pointers indicate the required flap setting. Note: When extending the flaps to a dial-a flap detent, if the detent is passed, the flap/slat handle must be retracted beyond the detent and re-extended to the takeoff detent.
On the ground, it is normal for the AUTO SLAT light to come on momentarily when the flap/slat handle is moved from up/ret to any setting commanding a mid-slat position. The AUTO SLAT light comes on to indicate slats have momentarily moved to the fully extended position during a self test of the system. The AUTO SLAT FAIL light will come on to indicate system failure
Takeoff Warning System
The takeoff warning system provides an aural alert if certain parameters are not properly set for takeoff. The system requires normal electrical power. When the airplane is on the ground, any one of the following conditions will cause the aural warning system to sound: Either throttle is (or, on airplanes with Service Bulletin 31-34 incorporated or production equivalent, both throttles are) advanced for takeoff and the FLAP/SLAT handle (after being positioned to the takeoff flap setting) is not in agreement with the value set in the FLAP window of the TAKEOFF CONDTN computer, or the horizontal stabilizer is not set within the green-band area of the LONG TRIM indicator, or the slats are not extended, or the spoiler handle is not in the retract detent, flaps extended beyond 26º, or the parking brake is set.
The first settings of flaps AND slats (mid, 11º) are set mechanically, and the possibility of failure is almost zero. Also, in this flight, the flaps did deploy correctly (as recorded by the DFR) some 45 minutes earlier when they first tried to take off (before they returned to gate).
Even if they BOTH (flaps and slats activation) failed for whatever reason, another mechanically linked independent indicators read back the position and informs the pilots positively (there is virtually zero chance of this also failing) the position of both wing's slats and the angle of deployment of both flaps. If the actual flap or slat doesn't physically hit the sensor/push the dial sensor that signals its position, there is virtually zero chance that the indicators would show the correct setting while the device actually being in the incorrect position.
If both, the flaps and slats weren't out before take off, there is virtually no other explanation than the crew failed to properly read all the indicators that would've signaled the faulty condition.
It's not so "incredible" that a pilot could forget to deploy necessary systems (i.e. landing gears, brakes, flaps). After all, it was proven to have happened in Detroit's Northwest case, in Buenos Aires' LAPA case, in Lanzarote MAP case, and no less than 8 others "unofficial" (read this thread) cases. Human error is the main cause in over 60% of aviation accidents.
Actually, the Take Off Warning System was put into airplanes by manufacturers precisely because crews weren't correctly checking that vital systems were in the correct configuration 100% of the time. If one could trust that pilots ALWAYS checked thoroughly things like "landing gear down" or "speed brakes armed" or "flaps down", then things like TOWS wouldn't be needed at all.
Spanair is part of the Star Alliance, and performs sharecode flights with United Airlines, Air Canada, Scandinavian Airlines and Lufthansa. This was actually also Lufthansa's flight LH2554 for some passangers.
Standards of training and operation on Spanair, a Scandinavian Airlines company, were very high, as far as I've been able to study. Way over world average, I'm told by people I trust. On par with western european countries, which are above those of, i.e., the USA. SAS moves over 3.5 million passengers a month.
Boeing had reviewed just recently Spanair procedures and issued certificates of quality, declaring their procedures excellent. Spanair has twice the recommended number of pilots training refreshes in the first world. Their SOP called for up to 3 checks of take off configuration and a TOWS test at the beginning of the day or when pilots changed or were absent from the cockpit for extended periods.
Pilots unions will ALWAYS complain for fewer working hours, more free training, less work pressure, more investment in security and maintenance, zero MEL items, etc, etc. This is obviously normal. It will still not prevent pilot error, and at some point the line has to be drawn.
You can read about the pilots in previous posts, but basically they had reasonable training/experience (9 years in the company, +7000 hours on the MD, the copilot, in charge of the take off and of lowering the flaps, 2 years and +1000 hours on the MD), they weren't overworked (under 40 hours a month, consistenly in the prior months), etc, etc.
Truth be told, the copilot knew he was probably going to lose his job in less than a month, although Spanair had agreed to hire him in a lesser position if he so wished. There was even talk of a "disgrunted employee" sabotage earlier on:
http://www.washingtontimes.com/weblogs/aviation-security/2008/Aug/20/was-todays-crash-sabotage/
... which the judge doesn't really buy as the TOWS failure would seem to be casual.
Unemployment benefits in Spain are substantial, so the copilot had, at VERY LEAST, 60% tax free of his full salary available for 8 months without the need to work, plus an additional substantial one-time penalty payment if he was fired before his contract expired, likely equivalent to at LEAST two full months of pay.
In western europe, unions (air controllers, pilots, airport personnel) like SEPLA are constantly "complaining" and demanding even better work conditions although they are already above average and among the best in the world. Spanair was about to fire 1100 workers (they finally fired 950 recently), so no wonder everybody was upset and complaining. But this has little to do with "forgetting to deploy the flaps", or improperly following checklists for which you are well trained.
I'm sure the crew didn't do it right. But I'm also sure they were very well trained to do it perfectly and weren't particularly pressed to do things otherwise. They simply made a mistake (hypothetically).
Although they had a delay in the flight due to the RAT probe "acting up", another plane was already called in and available. You can listen to Spanair operation requesting the change of registration plane for this flight and a delay. They already had a gate (C49) with personnel already present to unload the passengers and reload them. The return flight for this plane wouldn't even require a time change. Cattering was already on the move.
YouTube - Conversacion entre Spainair y Barajas antes del accidente
But the technicians figured, with the full knowledge of the pilot, that the issue was probably minor, and they got it quickly "fixed". In exactly 1 hour from scheduled time, they had taxied to T2, "fixed the problem", taxied to T4 and were again ready to take off in the runway. And there was no huge need to "rush". Delays of 1 or 2 hours are so common nowadays, that they are the staple of the norm.
The malfunction probably made them distracted. But it was still their job to complete the checklist as trained and not forget the flaps.
I do not believe that Spanair was putting more or less pressure than other western airlines on unsafe practices or that they were implementing cost-cutting measures that significantly reduced safety. Even if they were, what does it have to do with pilots forgetting to deploy flaps/slats? If they have a license to fly a MD-82 I'm sure they have been trained on how to do it right.
The TOWS inoperative is not the pilot's fault, but nothing prevented them from checking the TOWS system if they so wished. It's (basically) as simple as pushing the handles to takeoff, listening to the alarm, and quickly putting them back.
I do feel that Boeing is a bit to blame for not making a better TOWS design and for not making sure the SOP's were requesting frequent TOWS tests worldwide. I do feel that Spanair is a bit to blame for not making sure their SOPs reflected the very latest safety measures recommended, even if they weren't mandatory and they were never told about their existence. I do feel that Boeing also deserves more blame for not making maintenance manuals more clear on implications of "faulty" RAT heater. I also feel that Spanair's technicians deserve a bit of blame for not figuring out in 2 days what was going on with the plane.
Although it's not proven and it is totally speculative, the crew may also possibly be to blame for not testing the TOWS in the earlier flight from Barcelona, this time as required by Spanair's SOP. And, of course, they would carry the burden of most of the fault for failing to properly check if the flaps and slats were correctly placed.
CIAIAC vocal members finally voted today to unanomously approve the preliminary report with a few changes. Those changes will be written within the next days (Friday, most likely). It will then be available from their web page:
http://www.fomento.es/MFOM/LANG_CASTELLANO/DIRECCIONES_GENERALES/ORGANOS_COLEGIADOS/CIAIAC/INVESTIGACION/2008/default.htm
Reportely, it will state that pilots went over the checklist even though the flaps weren't out and it will NOT include safety recommendations, as it is not final.