Spanair accident at Madrid
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Just to add some informations about the slats :
-The extention to the midsealed position is fully mecanical from the lever in the cockpit.
-The extention to the full position needs electrical power and serviceable stall warning computers, as they will as already said extend to full positon automatically if a stall is detected. It is part of the checklist to check the slats going to full then back to midsealed even when the flaps are set to 13 and bellow. Their position is checked by 4 announciators TO LND DISAGREE and AUTOSLAT FAIL.
With the flaps T/O selector you can use variable flaps setting from 0 to 13 and from 15 to 26 degres. In my company, our performence is calculated by laptops and the position we use the most is 7 degres. But it can happen that we use 5 or even 26 depending where is the performance limitation.
Taking off flaps less is not a big deal, exept you might do a tail strike. For exemple the difference between V2 and Vflaps is 5 knots only for flaps settings below 13 degres. Vslats is usually more than 35 knots above V2.
I am pretty sure an MD80 would T/O flaps/slat less, until living ground effect...
-The extention to the midsealed position is fully mecanical from the lever in the cockpit.
-The extention to the full position needs electrical power and serviceable stall warning computers, as they will as already said extend to full positon automatically if a stall is detected. It is part of the checklist to check the slats going to full then back to midsealed even when the flaps are set to 13 and bellow. Their position is checked by 4 announciators TO LND DISAGREE and AUTOSLAT FAIL.
With the flaps T/O selector you can use variable flaps setting from 0 to 13 and from 15 to 26 degres. In my company, our performence is calculated by laptops and the position we use the most is 7 degres. But it can happen that we use 5 or even 26 depending where is the performance limitation.
Taking off flaps less is not a big deal, exept you might do a tail strike. For exemple the difference between V2 and Vflaps is 5 knots only for flaps settings below 13 degres. Vslats is usually more than 35 knots above V2.
I am pretty sure an MD80 would T/O flaps/slat less, until living ground effect...
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Justme69
I would just like to thank you for some of the best contributions to this, or any other, thread on pprune. We have all had to wade through page after page of mostly puerile and ill-informed "experts" opinions but your posts shine through as being clear, well considered and based on the facts as we know them.
Well done, and keep up the good work!
I would just like to thank you for some of the best contributions to this, or any other, thread on pprune. We have all had to wade through page after page of mostly puerile and ill-informed "experts" opinions but your posts shine through as being clear, well considered and based on the facts as we know them.
Well done, and keep up the good work!
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A whole lot of speculation about whether or not there was a mechanical failure in the flap/slat system could be avoided if someone could inform us in what position the flap/slat controls were found
Surely more relevant is where the controls were at the start of the takeoff roll ... a very different question to the one you ask, and something that will take some serious accident investigation and analysis to determine
NoD
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The way that plane behaved after rotation makes me doubtful the slats were extended... combined with the countless reports that there was a flap problem, or they weren't set
Let's move on from that at least...
Let's move on from that at least...
Last edited by HarryMann; 2nd Oct 2008 at 23:01.
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Press reports that some of the parts that remained more "intact" after the accident was the ceiling part of the airplane and one of the wings, the left one, with the right one being too severely damaged and broken in small pieces to potentially be of much help on the investigation.
The fuel deposit can still be seen.
The most important detail, the slat, is NOT EXTENDED (unofficially).
Landing gear is also fairly intact. Wheel on one can be observed as blown out, while another wheel has the tire completely out and burnt.
A large section of the ceiling could be reconstructed, including whole rows of windows.
Some of the toilets are also fairly intact.
Several seats also remain quite intact, with the safetly belts still attached.
http://img518.imageshack.us/img518/1913/dieznu3.jpg
http://img527.imageshack.us/img527/9861/nuevejd2.jpg
http://img510.imageshack.us/img510/7607/ochoed8.jpg
http://img524.imageshack.us/img524/8115/sietewq6.jpg
http://img525.imageshack.us/img525/5461/seisvn2.jpg
http://img403.imageshack.us/img403/7277/cincokg3.jpg
http://img407.imageshack.us/img407/4477/cuatrouc8.jpg
http://img375.imageshack.us/img375/2555/treswn9.jpg
http://img508.imageshack.us/img508/2955/dosqm6.jpg
http://img518.imageshack.us/img518/2476/unadf3.jpg
The "blame" game keeps on going.
Boeing's MEL Procedures Manual indicates that, in case of a RAT probe heater malfunction, the cause of the malfunction must be searched as well as related mechanisms checked. Same thing on the MMEL (Master MEL).
But the technicians that disconnected it, say that in the manual they consulted, they couldn't find what to do in case of the heater being on while on the ground, so they consulted the MEL (Minimun equipment list, section 34) only to figure out it wasn't really needed for that flight and the wiring diagram to figure out what fuse to disconnect.
The RAT probe heater had miss-behaved (turned on while on the ground, it's suppossed to do it only on the air) the previous day also. A total of 5 times it had been found to be "on" in the previous 48 hours, the newspaper says.
The fuel deposit can still be seen.
The most important detail, the slat, is NOT EXTENDED (unofficially).
Landing gear is also fairly intact. Wheel on one can be observed as blown out, while another wheel has the tire completely out and burnt.
A large section of the ceiling could be reconstructed, including whole rows of windows.
Some of the toilets are also fairly intact.
Several seats also remain quite intact, with the safetly belts still attached.
http://img518.imageshack.us/img518/1913/dieznu3.jpg
http://img527.imageshack.us/img527/9861/nuevejd2.jpg
http://img510.imageshack.us/img510/7607/ochoed8.jpg
http://img524.imageshack.us/img524/8115/sietewq6.jpg
http://img525.imageshack.us/img525/5461/seisvn2.jpg
http://img403.imageshack.us/img403/7277/cincokg3.jpg
http://img407.imageshack.us/img407/4477/cuatrouc8.jpg
http://img375.imageshack.us/img375/2555/treswn9.jpg
http://img508.imageshack.us/img508/2955/dosqm6.jpg
http://img518.imageshack.us/img518/2476/unadf3.jpg
The "blame" game keeps on going.
Boeing's MEL Procedures Manual indicates that, in case of a RAT probe heater malfunction, the cause of the malfunction must be searched as well as related mechanisms checked. Same thing on the MMEL (Master MEL).
But the technicians that disconnected it, say that in the manual they consulted, they couldn't find what to do in case of the heater being on while on the ground, so they consulted the MEL (Minimun equipment list, section 34) only to figure out it wasn't really needed for that flight and the wiring diagram to figure out what fuse to disconnect.
The RAT probe heater had miss-behaved (turned on while on the ground, it's suppossed to do it only on the air) the previous day also. A total of 5 times it had been found to be "on" in the previous 48 hours, the newspaper says.
Last edited by justme69; 3rd Oct 2008 at 09:34.
Control Positioning Does Matter
What relevance does where they were found have
Surely more relevant is where the controls were at the start of the takeoff roll ... a very different question to the one you ask, and something that will take some serious accident investigation and analysis to determine
Surely more relevant is where the controls were at the start of the takeoff roll ... a very different question to the one you ask, and something that will take some serious accident investigation and analysis to determine
If the flap/slat controls are found in some position which corresponds to the actual position of the flaps/slats after the accident then we know there was not a system failure and we can stop speculating on that. If the flap/slat controls are found in an inappropriate position for the takeoff conditions, then we can ascribe the failure to the crew. Either they did not properly configure the aircraft for takeoff or changed that configuration on the roll. Control positioning will allow a determination of system or crew failure.
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If the flap/slat controls are found in some position which corresponds to the actual position of the flaps/slats after the accident then we know there was not a system failure and we can stop speculating on that.
The Flap/Slat controls may have been moved between, say the rotation, and where they are now, either by the crew, the rescue teams, or the impact sequence. Ditto the Flaps / Slats which may have moved in/out at any of various points, including mechanical malfunction, and hydraulic power/fluid maybe being removed post the 1st impact point.
If the flap/slat controls are found in an inappropriate position for the takeoff conditions, then we can ascribe the failure to the crew.
If we are to conclude this was a crew error, then I would rather wait for a formal accident report by an accident investigation, like the NW one, which not only analyses the flight path behaviour and final positions of the controls and surfaces, but also ancillary evidence that might (or not) support whether those positions are representative of where they were immediately prior to the accident.
3 paras of the NW report deal with whether the position of the handle as found was, or might be representative, of where the crew (last) selected it. Those 3 paras represent considerable investigation and design analysis (and time) rather than a judicial inquiry leak of where the lever might be now
NoD
single signal path to arm TOCW?
It seems to be agreed in this forum that the single WOW signal did not pass through R2-5 to arm the take off configuration warning system, which in turn would have warned the pilots of missing slats/flaps setting and thus would have avoided the accident.
I wonder why the principle of redundant signals is not being followed for such a crucial warning device. Thanks to the quirks of EASA, my humble old taildragger has recently been equipped with a mode S transponder that must be controlled by an air/ground switch. As the gear is always down and welded, the signal is derived from the airspeed pressure difference sensor instead of wow. If the airspeed is considerably below the stall speed, the transponder is in ground mode. Simple and as cheap as it comes for any aircraft installation under the suspicious eyes of EASA and my national aviation grounding office.
It would be easy to include such a sensor somehow into the logic of the warning system as an additional and independant ground mode condition.
I wonder why the principle of redundant signals is not being followed for such a crucial warning device. Thanks to the quirks of EASA, my humble old taildragger has recently been equipped with a mode S transponder that must be controlled by an air/ground switch. As the gear is always down and welded, the signal is derived from the airspeed pressure difference sensor instead of wow. If the airspeed is considerably below the stall speed, the transponder is in ground mode. Simple and as cheap as it comes for any aircraft installation under the suspicious eyes of EASA and my national aviation grounding office.
It would be easy to include such a sensor somehow into the logic of the warning system as an additional and independant ground mode condition.
Smilin_Ed & NigelOnDraft
I like both of your answers.
Of course simply finding the controls in the same position to match the slats in itself is not conclusive....but it is supportive.
on the ohter hand finding the controls not in a position to match the slats does give more pause to reexamine the reasons why.
I agree that crash impact and body recovery can affect controls. Typically one would examine the freedom of the control to be easily moved out of position as well as interview the first responders (non-investigators)
I like both of your answers.
Of course simply finding the controls in the same position to match the slats in itself is not conclusive....but it is supportive.
on the ohter hand finding the controls not in a position to match the slats does give more pause to reexamine the reasons why.
I agree that crash impact and body recovery can affect controls. Typically one would examine the freedom of the control to be easily moved out of position as well as interview the first responders (non-investigators)
Thank You Lomapaseo
Thank you Lomapaseo. I believe that knowing positions the controls is necessary to fully understanding this accident. NoD seems to want to criticize every posting. I'm not trying to hang anyone. I only want to understand what went wrong.
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Flaps/slats positions....
I just read the report about the Detroit NWA accident once more - or rather the sections which are of interest when discussing this accident (Spanair).
link: http://amelia.db.erau.edu/reports/ntsb/aar/AAR88-05.pdf
The conclusion is that the NWA accident aircraft took off without flaps/slats, and this conclusion is based on 4 facts:
1. The flight recorder showed that the flaps/slats were up/retracted and that the flap/slat handle position corresponded to this. Page 21, section 6.
2. The cockpit voice recorder readout showed that the checklist items regarding flaps/slats were omitted. Page 76.
3. The damaged flaps/slats quadrant from the cockpit was examined - handle in up/retracted position. Page 50....
4. The damaged flaps/slats and their hydraulic and mechanical components were examined - flap/slats in up/retracted position. Page 50...
At present we have a lot of indications regarding the above - the latest being the picture in post #2115 from justme69.
But I think that we must have the same information as in the NWA report before making a final judgement.
link: http://amelia.db.erau.edu/reports/ntsb/aar/AAR88-05.pdf
The conclusion is that the NWA accident aircraft took off without flaps/slats, and this conclusion is based on 4 facts:
1. The flight recorder showed that the flaps/slats were up/retracted and that the flap/slat handle position corresponded to this. Page 21, section 6.
2. The cockpit voice recorder readout showed that the checklist items regarding flaps/slats were omitted. Page 76.
3. The damaged flaps/slats quadrant from the cockpit was examined - handle in up/retracted position. Page 50....
4. The damaged flaps/slats and their hydraulic and mechanical components were examined - flap/slats in up/retracted position. Page 50...
At present we have a lot of indications regarding the above - the latest being the picture in post #2115 from justme69.
But I think that we must have the same information as in the NWA report before making a final judgement.
Last edited by grebllaw123d; 3rd Oct 2008 at 17:13.
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Absolutely.
At this point, every "official" leaked info and "unofficial" info we may have only indicate that:
-Flaps were likely retracted at the moment of take off. The DFR and other circunstancial evidence point to that. We don't know why for sure.
-The TOWS didn't sound during take off. The CVR doesn't show a trace of them. We don't know why for sure.
-The RAT probe heater was turned on while the airplane was on the ground soon before it took off. We don't know for sure why. It was disconnected by a technician.
-A failure on the R2-5 relay that "turns on/off" both, the TOWS and the RAT probe heater could fit the picture of a take off with flaps not deployed and the TOWS inadvertendly inoperative, as it would have disabled TOWS on the ground while also turning the RAT probe heater on the ground and basically produce no other symptoms.
-While on the air, the airplane made some alternating left/right "abnormal" rolls, some of them quite steep as recorded by the DFR and narrated by witnesses and survivors.
And, as we know, the way the airplane behaved during the accident (longish take off roll/rotation, on-air steep "erratic" rolls consistent with wing stalls) COULD fit the picture of trying to take off with flaps/slats retracted and inop TOWS.
Everything else is speculative. Everybody is opened to the investigation giving more details so that better conclusions can be reached. Until then, we just talk of scenarios that could be likely but could also be wrong.
Nobody is judging anybody. We are just using possible scenarios where some choose to favor crew error (that could be the wrong case) and others some system malfunction (that could also be the wrong case).
Even some major news agencies, as in this piece dated TODAY, bet on weather issues as a likely main cause for the accident: La investigación apunta a las turbulencias en el despegue como causa del siniestro de Spanair. europapress.es
(Translation of headline: "The investigation points to turbulence during take off as the cause of the Spanair accident")
At this point, every "official" leaked info and "unofficial" info we may have only indicate that:
-Flaps were likely retracted at the moment of take off. The DFR and other circunstancial evidence point to that. We don't know why for sure.
-The TOWS didn't sound during take off. The CVR doesn't show a trace of them. We don't know why for sure.
-The RAT probe heater was turned on while the airplane was on the ground soon before it took off. We don't know for sure why. It was disconnected by a technician.
-A failure on the R2-5 relay that "turns on/off" both, the TOWS and the RAT probe heater could fit the picture of a take off with flaps not deployed and the TOWS inadvertendly inoperative, as it would have disabled TOWS on the ground while also turning the RAT probe heater on the ground and basically produce no other symptoms.
-While on the air, the airplane made some alternating left/right "abnormal" rolls, some of them quite steep as recorded by the DFR and narrated by witnesses and survivors.
And, as we know, the way the airplane behaved during the accident (longish take off roll/rotation, on-air steep "erratic" rolls consistent with wing stalls) COULD fit the picture of trying to take off with flaps/slats retracted and inop TOWS.
Everything else is speculative. Everybody is opened to the investigation giving more details so that better conclusions can be reached. Until then, we just talk of scenarios that could be likely but could also be wrong.
Nobody is judging anybody. We are just using possible scenarios where some choose to favor crew error (that could be the wrong case) and others some system malfunction (that could also be the wrong case).
Even some major news agencies, as in this piece dated TODAY, bet on weather issues as a likely main cause for the accident: La investigación apunta a las turbulencias en el despegue como causa del siniestro de Spanair. europapress.es
(Translation of headline: "The investigation points to turbulence during take off as the cause of the Spanair accident")
Last edited by justme69; 3rd Oct 2008 at 22:37.
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http://www.sepla.es/website/seplacms/index.php?option=com_content&task=view&id=532&Itemid=1
google translation…
Repairing the damage from last MD-82 Boeing violated rules
Friday, 03 October 2008
El Mundo
Marisa RECUERO / Madrid. Spanair failed to diagnose the fault of the plane that crashed in the Barajas August 20, in which 154 people died. The maintenance technician isolated the problem identified by disconnecting a fuse, but did not make a detailed assessment of the rest of systems related to the mechanism that failed, as recommended by Boeing.
The manual provided by the manufacturer to the airline to give instructions on how to use the list of teams with the minimum permitted that can fly a plane-that is, MEL, as he is known in aviation jargon, contained in paragraph 34 that in the event that the temperature sensor is inoperable, the maintenance technician should check the effects this could have lead to systems related to this mechanism. MEL agreed in the Procedures Manual for Boeing, which has had access to this newspaper.
By the same token, there is another manual, which also had access to the world, which recommends the same. In this case, this is the book that Boeing provides to the airlines so that they know what teams with minimal can fly an aircraft, namely the so-called Master MMEL or MEL. In it, the manufacturer warns that other systems should be checked when the Ram Air Temperature (RAT) was inoperative.
The problem is that the maintenance technician who consulted Spanair did not include any procedure to follow to fix an overheating in the probe temperature, as confirmed by sources close to this newspaper's own technicians.
The person who isolated the fault which complied with orders to the operating airline. First, we consulted the list of teams with the minimum that can fly the plane and found that the aircraft could make the flight with the temperature sensor inoperable. Second, because the maintenance manual does not include what to do after a failure of the probe, the technician goes to the Wiring Diagram, this is a book about the system of wiring the aircraft, which tells you that you can turn off the fuse.
The crux is that the heater probe of the RAT failed five times in less than 48 hours, according to the summary of the case, but no one noticed consult the book that explains the procedures to follow to cope with failures associated with the RAT. A day before the crash, the probe will overheat four times. The technician reset the mechanism-what-lit and extinguished and dispatched the aircraft. The day of the incident, he again produced the same bug. The commander Antonio Garcia Luna decided to return to the park and the technician removed the fuse Z29 does not go beyond that.
Before giving solution to this latest failure, the technician was known that the heater probe was activated only when land had to operate in the air, at least so declared and recorded in the summary, the person responsible for maintaining the aircraft to the judge Javier Perez, who directs the event of an accident.
Every plane has a mechanism which is responsible for communicating with the aircraft when it is in the soil or is in the air to perform other functions. It is the so called air-land the plane. This mechanism is located, through a sensor in the front leg of the landing gear, is the functioning of the RAT, in addition to 25 other systems.
One is the sound system of alerts that warns pilots of the configuration ready for take-off is not correct, namely that the flaps and slats-small rear wings and front wing, respectively, are not in the proper position for takeoff.
The first draft issued by the commission investigating the crash of the MD-82 Spanair confirmed that the flaps were not widespread and that the sound system alerts did not work.
The list of failures of deferred Sunbreeze, ie, with which the aircraft can fly for a limited period of time, which is the mechanism that inhibits the warming of the earth in temperature sensor would have failed so repeatedly. In fact, at the time of the tragic off, there was a change in the signal so as to land air. However, an hour earlier, the commander detected otherwise.
The train nose of the plane, which is the place where the sensor surface-to-air mode, was manipulated by the technicians a week before the accident, in particular the Aug. 13. The reason was the settlement of a deferred warned that three days earlier (on August 10). The technicians changed the water and dirt deflectors located in the nose.
Industry sources warned, even that the strobe lights, that is, white lights that identify the plane with flashes when it is in the air, operated on land.
With this background scenario, it is clear that the procedure followed by Spanair is insufficient. But most importantly, the Directorate General of Civil Aviation is the one that authorizes the manuals of the companies
google translation…
Repairing the damage from last MD-82 Boeing violated rules
Friday, 03 October 2008
El Mundo
Marisa RECUERO / Madrid. Spanair failed to diagnose the fault of the plane that crashed in the Barajas August 20, in which 154 people died. The maintenance technician isolated the problem identified by disconnecting a fuse, but did not make a detailed assessment of the rest of systems related to the mechanism that failed, as recommended by Boeing.
The manual provided by the manufacturer to the airline to give instructions on how to use the list of teams with the minimum permitted that can fly a plane-that is, MEL, as he is known in aviation jargon, contained in paragraph 34 that in the event that the temperature sensor is inoperable, the maintenance technician should check the effects this could have lead to systems related to this mechanism. MEL agreed in the Procedures Manual for Boeing, which has had access to this newspaper.
By the same token, there is another manual, which also had access to the world, which recommends the same. In this case, this is the book that Boeing provides to the airlines so that they know what teams with minimal can fly an aircraft, namely the so-called Master MMEL or MEL. In it, the manufacturer warns that other systems should be checked when the Ram Air Temperature (RAT) was inoperative.
The problem is that the maintenance technician who consulted Spanair did not include any procedure to follow to fix an overheating in the probe temperature, as confirmed by sources close to this newspaper's own technicians.
The person who isolated the fault which complied with orders to the operating airline. First, we consulted the list of teams with the minimum that can fly the plane and found that the aircraft could make the flight with the temperature sensor inoperable. Second, because the maintenance manual does not include what to do after a failure of the probe, the technician goes to the Wiring Diagram, this is a book about the system of wiring the aircraft, which tells you that you can turn off the fuse.
The crux is that the heater probe of the RAT failed five times in less than 48 hours, according to the summary of the case, but no one noticed consult the book that explains the procedures to follow to cope with failures associated with the RAT. A day before the crash, the probe will overheat four times. The technician reset the mechanism-what-lit and extinguished and dispatched the aircraft. The day of the incident, he again produced the same bug. The commander Antonio Garcia Luna decided to return to the park and the technician removed the fuse Z29 does not go beyond that.
Before giving solution to this latest failure, the technician was known that the heater probe was activated only when land had to operate in the air, at least so declared and recorded in the summary, the person responsible for maintaining the aircraft to the judge Javier Perez, who directs the event of an accident.
Every plane has a mechanism which is responsible for communicating with the aircraft when it is in the soil or is in the air to perform other functions. It is the so called air-land the plane. This mechanism is located, through a sensor in the front leg of the landing gear, is the functioning of the RAT, in addition to 25 other systems.
One is the sound system of alerts that warns pilots of the configuration ready for take-off is not correct, namely that the flaps and slats-small rear wings and front wing, respectively, are not in the proper position for takeoff.
The first draft issued by the commission investigating the crash of the MD-82 Spanair confirmed that the flaps were not widespread and that the sound system alerts did not work.
The list of failures of deferred Sunbreeze, ie, with which the aircraft can fly for a limited period of time, which is the mechanism that inhibits the warming of the earth in temperature sensor would have failed so repeatedly. In fact, at the time of the tragic off, there was a change in the signal so as to land air. However, an hour earlier, the commander detected otherwise.
The train nose of the plane, which is the place where the sensor surface-to-air mode, was manipulated by the technicians a week before the accident, in particular the Aug. 13. The reason was the settlement of a deferred warned that three days earlier (on August 10). The technicians changed the water and dirt deflectors located in the nose.
Industry sources warned, even that the strobe lights, that is, white lights that identify the plane with flashes when it is in the air, operated on land.
With this background scenario, it is clear that the procedure followed by Spanair is insufficient. But most importantly, the Directorate General of Civil Aviation is the one that authorizes the manuals of the companies
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That's not right!!
The md80's MMEL only says that in case you want to dispatch the flightwith an INOP RAT PROBE you should remember that TRP will not work and you should calculate RAT using a table included in the OM and SAT reading MUST be available
That's it
No more control on other systems or speculating about flight/ground mode, as it will be done during troubleshooting...
The md80's MMEL only says that in case you want to dispatch the flightwith an INOP RAT PROBE you should remember that TRP will not work and you should calculate RAT using a table included in the OM and SAT reading MUST be available
That's it
No more control on other systems or speculating about flight/ground mode, as it will be done during troubleshooting...
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But the rat probe sensor worked fine. Unfortunately it was measuring the temp caused by the malfunctioning rat probe heater which should have been a tell tale that the heater thought it was in the air along with the TOWS. If the rat probe sensor circuit had failed then, I agree, it could be MEL'd.
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That's correct...
We have 2 item in the MEL referring to RAT Probe
RAT Probe Heater (in Ice & Rain Protection) can be INOP as soon as we don't expect ice conditions
This was the "failing part" that day (so the one we should make INOP)
RAT/Thrust Rating system (under Autoflight/Navigation) where is considered only the RAT Sensor (in this case it was fully operative)
The MEL says about this ITEM
That is basically what i said before
The MEL tell us about considering systems that are AFFECTED BY the RAT probe, not system AFFECTING the RAT probe malfunction
So, the newspaper article is nonsense
Keepd in mind that there is only one breaker called "RAT Probe & Heater"
If we pull out this breaker (thus disconnecting the heater) the RAT will stop working entirely and the TRP will became INOP
We have 2 item in the MEL referring to RAT Probe
RAT Probe Heater (in Ice & Rain Protection) can be INOP as soon as we don't expect ice conditions
This was the "failing part" that day (so the one we should make INOP)
RAT/Thrust Rating system (under Autoflight/Navigation) where is considered only the RAT Sensor (in this case it was fully operative)
The MEL says about this ITEM
The RAT portion may be inoperative provided:
a) A SAT or Standby RAT Indicating System or
PMS SAT readout is available,
b) Other systems affected by the RAT Probe
(DFGS, CADC, Thrust Rating, FMS, PMS) are
considered, and
c) Procedures are established to verify engine
power settings.
...continues with instruction about OM procedure
a) A SAT or Standby RAT Indicating System or
PMS SAT readout is available,
b) Other systems affected by the RAT Probe
(DFGS, CADC, Thrust Rating, FMS, PMS) are
considered, and
c) Procedures are established to verify engine
power settings.
...continues with instruction about OM procedure
The MEL tell us about considering systems that are AFFECTED BY the RAT probe, not system AFFECTING the RAT probe malfunction
So, the newspaper article is nonsense
Keepd in mind that there is only one breaker called "RAT Probe & Heater"
If we pull out this breaker (thus disconnecting the heater) the RAT will stop working entirely and the TRP will became INOP
Join Date: Oct 2007
Location: fort sheridan, il
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tienneti
I"ve had this thing happen some 3 times on the virtually identical DC9 series 30.
it is not that rare, it happens and that's what should be taught by the airline to its people, both pilots and mechanics
I"ve had this thing happen some 3 times on the virtually identical DC9 series 30.
it is not that rare, it happens and that's what should be taught by the airline to its people, both pilots and mechanics
Join Date: Aug 2005
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As previously posted I had the nose oleo strut overinflated one night taxiing out for take off with the strobe lights on and idle power at flight idle because of another relay thinking we were in the air. I did not notice the RAT temp being high but am sure it was and did not know the TOWS was inop. Agressive braking brought the nose oleo switch to ground position and all returned to normal. It must happen regularly so should be a maintenance concern.
This reminds me of another MEL error. I picked up an MD80 on first flight and saw the previous write up was the prior day the APU wouldn't start in the morning. It was MEL'd and flew all day late into the night. Maintenance replaced the battery and faulty battery charger to fix the APU not starting problem. So all day and all night they had no emergency power. In this case they had no TOWS.
This reminds me of another MEL error. I picked up an MD80 on first flight and saw the previous write up was the prior day the APU wouldn't start in the morning. It was MEL'd and flew all day late into the night. Maintenance replaced the battery and faulty battery charger to fix the APU not starting problem. So all day and all night they had no emergency power. In this case they had no TOWS.