737 excessive rotation speed - a hard act to follow
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Back to highschool
Just do some arithmatic with your highschool knowledge.
S = Vo * t + 0.5 * a * t2 (that is t squared)
Normally a lightly loaded airliner needs about 30 seconds to accelerate to about 150 kts (I know, that performance is already on the optimistic side).
Assuming a constant acceleration for the rest of the run, it would need 60 seconds to accelerate to 300 kts (close enough to 298).
Runway length needed to reach 300 kts under those assumptions - 4.500 metres (about 15.000 feet).
Conversely, if you want to have 300 kts within 10.000 feet of runway, the acceleration must be 7.5 kts per second. That would be an awful acceleration for an airliner - it would have to be empty and then also would require full thrust (not any assumed temp thrust reduction).
Like many others, curious to see the factual report.
S = Vo * t + 0.5 * a * t2 (that is t squared)
Normally a lightly loaded airliner needs about 30 seconds to accelerate to about 150 kts (I know, that performance is already on the optimistic side).
Assuming a constant acceleration for the rest of the run, it would need 60 seconds to accelerate to 300 kts (close enough to 298).
Runway length needed to reach 300 kts under those assumptions - 4.500 metres (about 15.000 feet).
Conversely, if you want to have 300 kts within 10.000 feet of runway, the acceleration must be 7.5 kts per second. That would be an awful acceleration for an airliner - it would have to be empty and then also would require full thrust (not any assumed temp thrust reduction).
Like many others, curious to see the factual report.
Last edited by EMIT; 21st Dec 2014 at 15:10.
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Surely assuming normal T/O trim being set, the thing would have flown off itself long before 298kts......unless as mentioned he was actually pushing the column.
I'm not so sure either.
I'm not so sure either.
. What was that??? Did anyone hear a quack?
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A 737-800 at flaps 1 has a liftoff attitude of 8.5 degs at normal speed for comparison.
Even assuming the 298 kts are true, the thing will not "fly off" by itself with 0 deg pitch. It's not a C172. The wing needs to be rotated into the airstream to generate sufficient lift.
Even assuming the 298 kts are true, the thing will not "fly off" by itself with 0 deg pitch. It's not a C172. The wing needs to be rotated into the airstream to generate sufficient lift.
I wonder if this is just miss reporting and the speed was 198 not 298 ?
As for continuing the takeoff with an airspeed disagree, considering the registry of the airliner in question, I find that totally believable
As for continuing the takeoff with an airspeed disagree, considering the registry of the airliner in question, I find that totally believable
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BS!!!
HOW could a 737 accel to 298 KIAS without getting airborne, with gear down and flaps in a Takeoff position?!?
HOW could a 737 trimmed for normal takeoff stay on the runway to 288 KIAS?
198? Maybe.
208? Maybe.
298? NO WAY!!!
HOW could a 737 accel to 298 KIAS without getting airborne, with gear down and flaps in a Takeoff position?!?
HOW could a 737 trimmed for normal takeoff stay on the runway to 288 KIAS?
198? Maybe.
208? Maybe.
298? NO WAY!!!
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You wouldn't want to take off in an -800 with Flap 1 though would you? Normal for -700 but never had the laptop offer it in the -800 yet...
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As for continuing the takeoff with an airspeed disagree, considering the registry of the airliner in question, I find that totally believable
BerganAir did, and look what happened.
BerganAir did, and look what happened.
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Each to their own, depending on runway length I would continue...
Look what happened to AirBerlin when they tried to stop in Dortmund. After that incident (and AF447), my airline increased training in flight with unreliable airspeed. Not a big deal to take it in the air and deal with it, as long as you know basic pitch and thrust values.
Look what happened to AirBerlin when they tried to stop in Dortmund. After that incident (and AF447), my airline increased training in flight with unreliable airspeed. Not a big deal to take it in the air and deal with it, as long as you know basic pitch and thrust values.
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A 737-800 at flaps 1 has a liftoff attitude of 8.5 degs at normal speed for comparison.
Even assuming the 298 kts are true, the thing will not "fly off" by itself with 0 deg pitch. It's not a C172. The wing needs to be rotated into the airstream to generate sufficient lift.
Even assuming the 298 kts are true, the thing will not "fly off" by itself with 0 deg pitch. It's not a C172. The wing needs to be rotated into the airstream to generate sufficient lift.
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Just to prove how lunar this thread has become...What speed does oops! did the shuttle touchdown at?
It really came down like a brick...they would typically aim to be in the overhead of the landing strip at 50,000 ft and fly a kind of circuit to a 10,000 7nm final.....about an 18 degree glide slope on final!
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As no-one yet has cited any authoritative source for the story, it probably will sit better in Rumours and News until it acquires some basis for fact ...
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After 80 kts. You continue the take-off run for an airspeed disagree on B737.
Remember that after 80'kts. You should be "GO-minded".
If reall all asi's are incorrect, you still have pitch and thrust values, basic stick and rudder.
Remember that after 80'kts. You should be "GO-minded".
If reall all asi's are incorrect, you still have pitch and thrust values, basic stick and rudder.
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I assume it was at Jakarta and therefore on a typical 30+ deg C day? with density altitude already way past 3,000ft?
Well, this is about as scientific as you're going to get but according to MSFS and using the very respected PMDG 738 model, I reached the end of the runway at 215 kts (medium loads and fuel). Therefore I'd say someone misread the interim "report" and needs to go to Spec Savers (you're as blind as a bandicoot in Aussie speak).
Well, this is about as scientific as you're going to get but according to MSFS and using the very respected PMDG 738 model, I reached the end of the runway at 215 kts (medium loads and fuel). Therefore I'd say someone misread the interim "report" and needs to go to Spec Savers (you're as blind as a bandicoot in Aussie speak).
The airspeed disagree was at the 80 kt call so isn't the Boeing SOP to reject at this point ?