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Guest Adrian Wainer

Brazil - One Rev Thruster Non-Operative??

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The most recent news info I just saw seemed to say that one reverse thruster was not available because of a maintenance issue. That might account for why the plane swerved into an airport building. Or, the pilot did that deliberately to seek to avoid civilian casualties in the housing area off the end of the runway.However, if true about the rev-thruster, it was a criminal decision to land at that airport in heavy rain. Regards,Dick BoleyA PC, an LCD, speakers, CH yoke

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>>However, if true about the rev-thruster, it was a criminal>decision to land at that airport in heavy rain. >>Regards,>Dick Boley>In most cases, the use of thrust reversers is not considered in the landing performance. The aircraft is assumed to use brakes only. Whether they operated under that convention or not, I do not know, whether they had checked landing data that night prior to the approach, I do not know, and whether that data would have shown the landing could be accomplished or not, I don't think either of us knows either. So I think it would be a bit premature to declare any decision to land at that airport by the crew, criminal.

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>The most recent news info I just saw seemed to say that one>reverse thruster was not available because of a maintenance>issue. That might account for why the plane swerved into an>airport building. Or, the pilot did that deliberately to seek>to avoid civilian casualties in the housing area off the end>of the runway.>>However, if true about the rev-thruster, it was a criminal>decision to land at that airport in heavy rain. >>Regards,>Dick Boley>>A PC, an LCD, speakers, CH yokein the us, a/c landing distances do not take into account thrust reversers. now in brazil i have no idea.

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Some reports I'm reading/hearing state that one thrust reverser was deemed unusable several flights before this one. The airline, by rule, had 10 days to repair the problem. Until then they could fly the airplane since thrust reversers are not required for flight and both thrust reversers were disabled by the airlines maintenance dept.Now, that raises the question....did the flight crew know that the thrust reversers were disabled? Was the aircraft log filled out? If not, and they were planning to use thrust reversers during their landing rollout could explain why, as eyewitness reports say, the airplane appeared to accelerate instead of decelerate, yet no apparent attempt at a takeoff was made. I'm not familiar with AB systems and do not know what kind of warning(s) there are for disabled thrust reversers.John M

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Hopefully they saw that the reversers were defered that would be a huge oversight if not.

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>Some reports I'm reading/hearing state that one thrust>reverser was deemed unusable several flights before this one.>The airline, by rule, had 10 days to repair the problem. Until>then they could fly the airplane since thrust reversers are>not required for flight and both thrust reversers were>disabled by the airlines maintenance dept.>Now, that raises the question....did the flight crew know that>the thrust reversers were disabled? Was the aircraft log>filled out? If not, and they were planning to use thrust>reversers during their landing rollout could explain why, as>eyewitness reports say, the airplane appeared to accelerate>instead of decelerate, yet no apparent attempt at a takeoff>was made. I'm not familiar with AB systems and do not know>what kind of warning(s) there are for disabled thrust>reversers.>>John Myes the crew would be aware of them being inop. they were written up in the a/c maintenance log which is on the airplane and they were required to review to sign off on the airworthiness of the a/c. in addition the reversers are mechanically locked, when deferred, from a visible source and the FO/CA would see this on their walkaround. if they weren't written up and the crew not aware i would be pretty shocked."eyewitness" testimony is usually garbage and unreliable. until the FDR shows they accelerated them i would not believe the eyewitnesses or the appearance in the videotape being talked about. a repaved, ungrooved runway, which i would assume is asphalt, with water on it is pretty slippery. the govt. will do everything it can to blame the crew on this rather than themselves.

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Thanks for the info. Of course we're assuming the a/c maint. log was filled out and read. And, that the crew did a proper preflight. I do find it a little akward that that video tape was "leaked" by the military while the wreckage was still smoldering. I have no doubt that TAM is a reputable airline and has properly trained personel. As with most a/c accidents, it is usually not just one item or event that caused it, but rather a series of events that "snowball" into a tragic outcome.John M

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they were planning to use thrust reversers during their landing rollout could explain why, as eyewitness reports say, the airplane appeared to accelerate instead of decelerate,There is video of almost the entire run down the runway - though it takes three cameras to see all that is captured.If the aircraft accelerates, it's is very little. If it decelerates, it is also very little.The speed of the aircraft - calculated at a bit over 200 kph based upon time between runway lights/ as measured from Google Earth - appears to vary very little from first in view to going out of view a couple seconds before the fireball bloom is observed.Now the specifics of speed and distance are all educated guess work, with some observable basis - but the basics of almost constant/ consistent speed are pretty clear from the tape.

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Reads like hydroplaning, doesn't it? Why the crew didn't rotate and go around at speeds like that is still a mystery. If my math is correct they would have had about 20-22 seconds between touchdown and the end of the runway (assuming they didn't land long), more than enough time to clean the airplane and takeoff again. Of course, they had the worst possible scenarios to work with. Landing in the rain, at night, on a fairly short runway with no thrust reversers.John M

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I guess there were no survivors in this crash, correct?

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>Reads like hydroplaning, doesn't it? Why the crew didn't>rotate and go around at speeds like that is still a mystery.>If my math is correct they would have had about 20-22 seconds>between touchdown and the end of the runway (assuming they>didn't land long), more than enough time to clean the airplane>and takeoff again. Of course, they had the worst possible>scenarios to work with. Landing in the rain, at night, on a>fairly short runway with no thrust reversers.>>John Myou're still stuck on those thurst reversers... they do very little in terms of landing distance. for example an inop thrust reverser adds 0% to the landing distances since they were calculated without them, however a problem with the spoilers not deploying would add up to 50% to the landing distance.who knows why they didn't go around. i won't know until the cvr/fdr information is made public. an educated guess at this point is a faster than ref landing (due to the wx), landing a bit long, braking action nil from rain and hydroplaning, yada yada yada. we'll wait though for the data to be shown.i fully expect the brazilian government to blame everyone but themselves. an asphalt, ungrooved, short runway leaves no margin for error. add in weather and you had the makings for a disaster. after all they're completely blaming the two us pilots for what their controller did.

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I'm not really stuck on the thrust reversers as the root cause of the problem here. It's just a possibility, as are many other scenarios.True that the lack of thrust reversers will not "add" to the total lenght required for landing, however, they can "reduce" the initial landing rollout speed by up to 30% or more versus using only the brakes. That, in most cases, will shorten the landing rollout distance. My experience is primarily with reverse pitch props, which basically have the same effect.I am in agreement with you that the Brazilian government appears to be going out of it's way to point their fingers the other way. Especially this early in the investigation.John M

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>True that the lack of thrust reversers will not "add" to the>total lenght required for landing, however, they can "reduce">the initial landing rollout speed by up to 30% or more versus>using only the brakes. That, in most cases, will shorten the>landing rollout distance. My experience is primarily with>reverse pitch props, which basically have the same effect.in my experience t/p reverse thrust is much more effective than t/j. in the 1900 the simple automatic act of shifting from flight idle to ground idle was more effective than jet reverse thrust.sad that 200 people died simply because of the brazilian governments ineptitude.

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>sad that 200 people died simply because of the brazilian>governments ineptitude.Uhm... as you yourself said, isn't a bit too early to blame one part or the other?Marco

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>>sad that 200 people died simply because of the brazilian>>governments ineptitude.>>Uhm... as you yourself said, isn't a bit too early to blame>one part or the other?no, this is 100% fact known now (versus speculating on actions the flight crew may have done). the airport is in too congested of an area with no stopways. they could have easily have stopped using this airport for certain aircraft (as they had already done with some aircraft types). had they done this, this would not have happened. economic interests won out over safety here.it is no different than the SWA overrun at MDW, the FAA shares the blame with its antiquated facility.

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