I joined this thread a long time ago and was shot down severely by a former MD-80 pilot when I suggested that the crew had just 9 seconds to recover the situation from the time the stall warning sounded to its impact with the ground. The interim accident report reveals that the crew misinterpreted the stall warning horn for a fire alarm and wasted valuable seconds trying to switch it off...I stand by my original suggestion that the aircraft was at least 25kts slow when the aircraft reached the calculated Vr and V2 speeds because the flaps slats were not deployed for take-off and that the clean wing speeds would have been much higher.

However that is not the purpose behind me coming back in here; I need to talk to an Avionics guy specifically someone who has access to the wiring diagrams and or is familiar with the MD-82. I am a retired Avionics engineer and have read the interim accident report several time over, particularly in regard to the operation of the R2-5 relay and its failure history as reported by Boeing in the report. The accident report has been removed from the formento website but I can email a copy if anyone wishes to read it.

This is the point I wish to discuss; On page 39 of the report there is a photograph of the relay panel and specifically R2-5, showing its condition after the crash and I regret that what I see there is one seriously bu**ered up relay, some extremely dodgy wiring and some very dubious working practices. The wiring bears so little resemblance to the wiring diagram I am forced to the conclusion that someone knew that R2-5 on the crash aircraft was suspect long before the crash.

The report also shows graphs taken from the QAR that indicate that the quote 'weight on wheels switch' unquote was working correctly, BUT, the switched ground from the nose wheel is in fact routed through 2 such switches on the nose wheel before being wired to the X2 terminal on the R2-5 relay. I am not familiar with the MD-80 series but my experience is that these switches on other aircraft are invariably in highly exposed areas and subject to all the muck and filth of dirty, sandy, wet runways whilst the relays themselves are in a far more benign environment and that hence the switches rather than the relays are more likely to fail, normally to some indeterminate state, neither one thing or the other.

The aircraft fleet on which I spent almost half my working life on relied heavily on the Leach 9274 series relays and I cannot remember a single instance where one has failed in a 'Weight on Wheels' scenario; however I have had to replace several associated squat switches...

Here is a link to the Leach 9274 series relay manufactures drawing; pages 4and 5 show the pinouts. Compare this with the wiring diagram shown at forgets reply 2634 and the picture on p39 of the accident report...

I'd be happy to discuss this with any avionics people out there.

pp

Phalconphixer; FYI...


http://i277.photobucket.com/albums/k...1208160306.jpg

From the looks of the schmatic that PJ2 posted the two switches also operate 2-212 relay along with other relays. The "D" set of contacts reports to the flight recorder, I would suspect that the investigators would have picked up on that.

VFD

PJ2...Many thanks.

pp

docu
 

Last Wednesday there was the first part of a documentary on Spanish tv about the crash the second part is due to be aired tomorrow evening, at the moment some of the relatives of those involved are trying to block the second program. I find it hard to understand how this can be allowed to be shown at all as the investigation is still on-going and may be followed by legal charges. How can anybody expect a fair trial after this?

Mac...
Part 2 is still programmed for showing tomorrow evening on Telecinco at 2200 local.
Only the flight number has been changed...so far the circumstances shown do parallel those of the Spanair flight.

Programmme is called Vuelo IL8714

link

Translation of the text from the above link...

The inquiry commission led by Javier Torres investigates the plane crash of Flight IL8714. A complex puzzle to discover what caused the tragedy.

Emma Suárez Carmelo Gómez and-a pair of actors who had worked in films like "The red squirrel," "Cow" or "The Dog in the Manger" - match again, this time on the small screen for this TV movie based actual facts. This is a film that recreates the research work that followed one of the greatest disasters of the Spanish civil aviation: the crash of a Spanair plane that crashed immediately after takeoff and killed 154 of its passengers . With this movie, the Galician director Norberto Lopez Amado finished his third feature, after the documentary "7 days with Norman Foster" and the thriller "They look at us." Surely, of the three, the one in question was the one that generated more controversy, as the patient organization of flight JK5022 took legal action to prevent the issuance of this, it considered it "a brutal aggression" to the victims.

As Mac so rightly says how the authorities allowed this programme to be aired before the final Accident Report is issued is something of a mystery. But, if criminal charges charges are laid before the courts it will just go to prove that the the first priority was to find someone to blame...

pp

Yes - that is how the system works here in Spain. That is why accidents are investigated by a team under a judge rather than an independent accident investigation system. The whole point of the exercise is to apportion blame. The judge in charge of the investigation into the Spanair accident has to decide, after his team have reported to him, to whom to attriubute blame and to what extent. As a side-issue, lessons will be learned but that is not the purposer of judiciary accident procedures in Spain.

Las Provincias - the Spanish daily newspaper - has today published a report stating that Spanair have concluded (before the Spanish judge has completed his investigation) that the accident was caused by the human failure of their crew which was possibly exacerbated by the presence of an unknown third person on the flight deck.

Here is the report in Spanish:

Spanair entregó el pasado lunes un informe al juez en el que atribuye a sus pilotos el accidente de Barajas, en el fallecieron 154 personas el 20 de agosto de 2008. La compañía aérea, que actúa como parte en el proceso, achaca a sus empleados un «error humano» en la maniobra de despegue por no accionar los alerones ni verificar si se habían desplegado. Los peritos justifican que la presencia en la cabina de una tercera persona «no identificada» (quizá un tercer piloto que estaba en tránsito) pudo distraer la atención de los oficiales. La Asociación de Afectados del Vuelo JK5022 y el Colegio de Pilotos tacharon de «parcial» el informe y lo encuadraron en la estrategia procesal de la aerolínea para eludir responsabilidades.
Las conclusiones periciales de Spanair sobre qué ocurrió en Barajas dejan más sombras que luces, ya que centra su atención en un hecho objetivo recogido por otros informes oficiales: que el «error humano» pudo causar el siniestro. En cambio, orilla los interrogantes técnicos que desde hace 26 meses investigan, de forma paralela, tanto el juez Juan Javier Pérez como la Comisión de Investigación de Accidentes e Incidentes Aéreos (CIAIAC), organismo dependiente del Ministerio de Fomento.
Sobre estos interrogantes, la compañía aérea asegura desconocer a día de hoy por qué no sonó la alarma que debía avisar a los pilotos de que no se habían desplegado los alerones, los denominados 'flaps' y 'slaps', que permiten al avión despegar. Eso sí, descarta de plano que la razón de este fallo se debiera a la avería de un relé (interruptor) que desencadenó el «fallo multifuncional» que silenció la alarma, tal y como apuntaba el informe preliminar de la CIAIAC y considera el juez.
Fuentes cercanas a la investigación señalaron que hace unos días el juez y los peritos de parte, entre ellos los de Spanair, asistieron precisamente al desmontaje de este relé en la sede del Instituto Nacional de Técnica Aeroespacial (INTA). Entonces concluyeron que las pruebas «dejaban clarísimo que hubo fallos» en el interruptor que pudieron desencadenar otras averías en la configuración del avión. Todo lo contrario a lo que alude ahora el informe de la aerolínea.
Dichas fuentes tachan esta estratagema en los propios intereses de Spanair para eludir responsabilidades con la vista puesta en las indemnizaciones en el caso de que la compañía acabe siendo condenada. Y ponen como ejemplo el hecho de que el informe de la compañía recrimine también a Boeing (fabricante del MD-82 accidentado) por no haber previsto la posibilidad de un accidente como el de Barajas después del precedente «similar» de Detroit en 1987. En el que, por otra parte, también se produjo el fallo de un relé que desconfiguró otros sistemas de seguridad del avión.
Por último, Spanair exculpa a los dos únicos imputados en el proceso, los técnicos de mantenimiento de la compañía que desconectaron la sonda de temperatura del avión cuando este regresó a la terminal tras un primer intento de despegue».

Meanwhile the judge is still pondering the results of the examination of the possibly malfunctioning relay.

It is difficult to comprehend that an airline would directly blame its own pilots, before the pronouncement of the judge and without sufficient evidence, in order to get itself off the hook, but that indeed is what it appears to have done. Unbelievable.

"It is difficult to comprehend that an airline would directly blame its own pilots" :rolleyes::rolleyes:

they do it all the time - think of Air New Zealand and the DC-10 crash in the Antarctic for a start - and that was 30 years ago...............

Taxiing for takeoff in an MD80 one night noticed the strobes were flashing and the idle power was stuck in approach idle, not ground idle. I did not realize that I had also lost my takeoff warning system at that time. Apparently maintenance had over inflated the nose oleo strut making the aircraft think it was in air mode. I used an agressive brake application to compress the oleo strut and everything went back to normal. In this case the R2-5 relay probably failed, not the oleo strut switches or they would have noticed the approach idle power as I did. It was daytime so probably wouldn't have known the strobes were on if both oleo switches failed in air mode. With the intensity and damage from the crash it probably would not be possible to determine for sure if R2-5 failed or if something upstream of the relay failed.

There is a big dispute between all spanish airlines and their pilots and Spanair is not aside, they fired recently almost 200 pilots and they new management is completely lost, you can not blame your own staff because then nobody is going to trust you and will stop flying in your company. This is another distration manouver from the company for not pay a single cent.

Apart from this if you read ICAO Annex 6 part 1 the operator is always responsible for everything and, if in this case the aircraft systems where not working, it was their responsability trough the maintenance department. redundant systems like the T/O configuration alarm are there because we know that humans are not perfect and error is there.

Phalconfixer and p51guy, I am just a long lapsed ppl and so hesitate to add anything to what is a very expert discussion. However this issue has been troubling me for a very long time and now that you two have revisited it I feel compelled to add my innocent observation. I was an engineer in another discipline and have learned that coincidences are rarely just that. I seem to remember that this aircraft had its nose strut replaced with a freshly serviced and pressurised one in Palma very shortly before the accident. Combined with the observation, by the refueller who topped up the tanks after the return of the aircraft from the first dispatch, that the strobes were flashing (and that he had never seen that before while fuelling) it seems possible that the weight-on-wheels issue was significant.

Nomex duly donned in anticipation!

That could make sense, but the thing is that the TAWS didn't work.

TAWS is designed to "augment" the human being by warning the pilots if configuration is not adecuate for take off.

Human beings can't stop being human. So the main cause of the accident is technical: TAWS not working, wether by a breaker, relay or squat switches.

Spanair tries to deviate atention from the fact that there was a recommended procedure to check TAWS in every flight which they did not implement. That check was not in their procedures. It would have averted the tragedy.

Blaming the dead pilots is the lesser evil for Spanair, and that is why they do it. After the tests of the TAWS relay have "determined" that they have no anomalies, Spanair concluded quickly that the pilots are guilty.

But the thing is that the TAWS did not work. The airplane was not as "Human Being Proof" as it should be. And neither did the procedures.

So we have at least four cheese slices with the holes in line: time pressure and stress, flap lever setting lapse, TAWS not working and procedure not implemented.

Re the last two posts...

I say again; take a look at the photograph on p27 of the Interim Accident report. it shows the 'as removed' relay R2-5. Now take a look at the wiring diagram shown previously.

The wiring diagram shows two wires to each of the 4 contact groups of the relay. The photograph shows clearly that there are no wires at all on the C set of contacts; these would normally be occupied by the Rat Heater wiring. It would appear that these wires have been transposed elsewhere...

It looks as if the relay wiring has been substantially rewired in that;
The A contacts have one wire on A3, one wire on A2 and two wires on A1;
The B contacts have two wires on B3, one wire on B2 and one wire on B1;
The C contacts have no wiring at all;
The D contacts have one wire on D3 and one wire on D2.

The only reason I can think of for this rewire was to get around the possibility that on some previous occasion the Rat Heater contacts had burned out or become welded together and that a replacement relay was not available at the time...If this was the case however, no matter how well meaning the 'repair' it wasn't particularly well thought out.

The crimp tags are bent out of shape somewhat on all the contacts, and as is suggested in the Interim Accident Report, there is a possible short circuit between the X1 115vac contact and the A2 contact.

The effect of moving the Rat Heater wiring to other contacts, especially the TOWS contacts could be to overload the current carrying capability of the contacts themselves and cause all kids of problems to the associated circuits especially in view of the fact that the B and C contact groups work in opposite senses...

Looking carefully at the crimp tag retaining screws, I can see no evidence that this rework was recent ie., post accident. The wiring to the adjacent relay is also in a poor state.

Again looking carefully at the picture, there would appear to be some heat damage and scorching to one of the wires due, to my mind at least, to excess current draw.

At no point in the Accident Report is this hodge-podge of wiring mentioned, only the possibility of the accident being responsible for the possible short circuit between the adjacently mounted A2 and X1 contacts.

The judge handling the case is still holding under indictment the two mechanics who handled the snag when the aircraft returned to the stand after abandoning the first take off attempt; he is acting upon reports that the failure of R2-5 was due to the actions of these two mechanics who actually did no more than to pull the breaker for the Rat Heater.

Other reports have suggested that a third party may have been in the cockpit and interrupted the pre-take off checks; so much for the sterile cockpit!

Be that as it may, the second take off was started with the Flaps and Slats retracted and no Alarm sounded. That an MD-80 can still do this after the previous very similar accident is difficult to understand. Flaps / Slats are required to be set and checked I believe no less than three times between engine start and take-off and they still got it wrong for whatever reason.

This link however demonstrates that with Spanair this was not uncommon. Just one month before the accident a Spanair aircraft was filmed during a routine take off from Glasgow; in this instance the flaps and slats were not deployed until the engines were run-up at the end of the runway prior to take-off; could it be that a sticky nose leg switch had failed to operate the relay that energises the TOWS and that only cleared when the brakes were applied thus compressing the nose leg?

The Interim Accident Report appears to have been withdrawn from the CIAAIC website but I have a pdf copy if anyone would like to read it. PM me if so.

pp

Phalconphixer;
I've seen this video a number of times.

The slats/flaps are extended at 1:23 into the video while the aircraft is in a left turn to line up with the runway. Engine thrust does not increase in the turn, (nor would such increase be necessary for the turn).

The engines are at idle thrust until 2:09 into the video.

So the TOCW would not have sounded regardless of the "nosewheel switch" or compression/extension of the oleo.

A number of explanations are possible:

They forgot then caught their error;
They delayed the pre-takeoff checklist until departing the ramp area;
That is the point at which the crew did their checklist;

I don't know the Spanair checklist SOP or sequence so I don't know if the control check is done at the same time as the slat/flap extension, and whether it is before or after the flight control check. There is no flight control check visible on the video, (I was watching the elevators for a downward movement), so we might assume it was either done as part of the departure from the ramp area or it was forgotten; again, we don't know and cannot draw conclusions.

The key understanding is, we don't know why the slats were extended at this point. But they were, and before the engine thrust was increased to the point where the TOCW system would have sounded.

PJ2

TAWS is a terrain awareness system - it's TOCW - takeoff configuration warning that we're talking about. I had to look it up as I was thought I was confused as well but I was only mistaken, which isn't hard... PJ2

Cameronian, if you are pulling my chain to make me feel stupid you are doing a good job. If the strobe lights were flashing during refueling and the FDR shows the ground idle was at actual approach idle then the Madrid MD82 crash is solved we have solved the problem. If you look at my 2650 post you will see I had the exact thing happen at night and had to compress the nose strut to get back no strobes, no approach idle and get TOWS back. If anyone can transfer this information to Spain if this isn't BS info I can tell them what happened to that airplane, it happened to me. If you are just having fun, have fun.

I absolutely am not pulling your chain p51guy!

Post 1213 refers to the recent change of nose oleo and post 1234 to the unusual operation of the strobes while refuelling. Posts 668, 706, 724, 1170, 1233 and lots more in the 1200s make related points.

I hope you appreciate my effort in collecting those references because it has taken me two hours!

In relation to your own experience, another post (I didn't find it this time and have no more time to look for it now) relates how another pilot had to apply the brakes while taxying to compress the nose strut to get the aircraft systems to get their act together.

I am very conscious, as I explained in my last post, that I am acting above my pay grade in this now. I would have remained silent until the subject was raised once again. I think I ought to go quiet now and leave it to the experts.

Cameronian, phixer,


5th Oct 2008, 02:46 #2110 (permalink)
From bubbers44.

That's the one!