Question About this tricky situation..
Joined: Dec 2005
Posts: 67
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From: Europe
it is common sense that if capt wrongfully decides to continue the flight with an inop asi.(at airspeed crosschecking(80kts)hence before v1).the pilot who was taking off remains the pilot handling until aircaft is properly in control and then a change of handling pilot may be necessary,,,ie the Capt takes off..after unreliable airspeed recall items performed...the pilots realize by crosschecking the 2 speedtapes,the stby airspeed and even the irs speed display that the fo speedtape is correct..i would give control the the fo until after landing....
Joined: Oct 2005
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From: USA
Are speeds like Vmbe,Vmu calculated before each flight? and are they ever displayed/marked on the ASI?
Brake energy numbers aren't depicted on the airspeed indicator. The numbers you're interested in are decision and safety speeds, and flap speeds: operational numbers.
would the captain take controls and continue takeoff?
im assuming by the time i report and he takes controls the plane would continue acclerating..
im assuming by the time i report and he takes controls the plane would continue acclerating..
Joined: Aug 2008
Posts: 27
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From: Far East
Maybe to further clarify...that the flight testers and factory determined that brake energy limits (failure of brakes) and chances of blowing tires are minimal when aborting a take off at max gross weight V1 or less...I would like to believe that if V1 is hypotheticaly 110 knots, that landing with the same wieght at a legal and specified 125kts...might tend to make the case that brake energy limits might not be problem untill well exceeding 125 kts..That said, if one can determine by having actualy flown the plane a few times on landing how much runway ahead it typicaly needed to stop a plane, being 15 knots slower at time of abort should make that descion a tad easier...So I doubt stopping an aircraft 10-15 kts slower then your landing speed will create catostrauphic brake failures....
Joined: Oct 2005
Posts: 3,218
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From: USA
.I would like to believe that if V1 is hypotheticaly 110 knots, that landing with the same wieght at a legal and specified 125kts...
A rejected takeoff places much of the stopping distance behind the airplane. Continuing the takeoff to return and land places it all ahead of the airplane. Rejecting a takeoff means attempting to immediately correct the problem, rather than handling the problem and stabilizing it, then setting up a controlled return to landing at a time of one's choosing. Rejecting takeoffs provides a high probability of an overrun, departure, brake fire, control loss, or other problem. Statistically, continuing the takeoff is nearly always the best course. Brake energy is one small part of the picture. Attempting a high speed rejected takeoff for one airspeed error out of several indications and sources is certainly not worth the risk.
A company safety communique recently addressed the topic. Statistically (per Boeing and the Flight Safety Foundation), one in every three thousand takeoffs is rejected, but one third of those that reject leave the runway. 600 people have died in the last 30 years as a result of rejected takeoffs. According to the FSF, 80% of those overruns could have been avoided with better decisions. Boeing showed that approximately 1/4 of rejected takeoffs are for engine problems, while another quarter are for tire or wheel failures, and about 13% for configuration problems. Boeing and the FSF show that up to 70% of the rejected takeoff mishaps would have continued and landed safely...had they not rejected the takeoff.
Low speed rejected takeoffs don't present nearly the problem that high speed rejected takeoffs do. Whether or not the brakes can handle the event is just part of the picture. However, to suggest that because the aircraft lands faster than it rejects, it should have no problem, ignores the heat and energy already lost in taxi...which can be substantial. Taxi distance can already heat the brakes close to or well beyond what a landing may accomplish, and this before the takeoff ever begins. Compare that to a continued takeoff with an opportunity to cool the brakes with a full runway in front and all the emergency services already staged and prepared...clearly the advantage goes to continuing the takeoff.
We've been through this all before, ssg/glawkshuter. You've had it explained every which way from sunday by a number of experts here, including performance experts who do nothing but deal with this topic. You're not hear with exerience to offer, certification to offer, or anything to share. You're here to argue the same tired, ignorant banter...you're here as a troll.
With that in mind, I'll put you on my ignore list, like your other banned names, and wait for the mods to ban you again like they always do...why don't we save the rational discussion for those who have something better to do with their time than keep reappearing under a different login...until you're banned again? You've been shooting that glock just a little too much without hearing protection, again.
Per Ardua ad Astraeus
Joined: Mar 2000
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From: UK
With that in mind, I'll put you on my ignore list
Joined: Dec 2006
Posts: 2,486
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From: The No Transgression Zone
at least he's good at coming up with creative screen names
well back to my {fints}
oh yeah remember in KE calculation the m is not as important as the V---if IAS=GS then at 80 KIAS 640 units, at 90 ---810 units at 100, 1000 units -----see it gets bigger very fast
well back to my {fints}
oh yeah remember in KE calculation the m is not as important as the V---if IAS=GS then at 80 KIAS 640 units, at 90 ---810 units at 100, 1000 units -----see it gets bigger very fast
Last edited by Pugilistic Animus; 5th September 2008 at 16:28.
