Rejecting A Takeoff After V1…why Does It (still) Happen?
Suddenly, we have moved from a discussion on V1 and the certification criteria attached to it, to terrorism as a foreseeable event that is part of take-off planning. Are you scared to fly?
As i pointed out, at Baghdad Int'l and Balad AB, we didn't change the the reject criteria, just the departure routing and procedure. At V1, we briefed continuing--it doesn't hurt at those weights the V1 = Vr, so we were airborne anyway. But the certainty of over-rrunning out-weighed the statistically remote chances of someone shooting a IR missile; let alone the remote chance of an entirely ineffective RPG hit. If you take-off from the fictional NW International Airport, ID and someone jumps out from the pucker bush, stands up and sends you an RPG round into the tailcone of your Citation at Vr, hell, at V2, be my guest, land straight ahead. BUT, don't tell me 160,000 professional pilots with millions of safe flight hours and statistically sound procedures are WRONG for continuing at V1 with a mechanical failure.
I don't know your career background, but it is obvious you have "issues" accepting that the airlines operate without you. Yes, it is true, they do. And the thousands of captains are NOT robots who don't think every time they advance the throttles--they do--EVERYTIME! I know, I've been there. As have most of the posters on this thread and the others where you have spouted off your damaged crockery ideas. All smarter than me or you.
I fly a GLEX and use FLEX power where indicated, I fly in about 30 countries a year; including such wonders as Beirut and Afghan and Iran overflights. I don't brief RPG procedures despite nearly 30 years of military flying, it just ain't a reasonable planning factor.
What's your reject plan when a printer cartridge of C4 goes off at 50 feet AGL? At 500 feet AGL? There's a reason safety investigations END when the police determines that a criminal/terrorist event occurred--it isn't addressable within our community.
GF
I breath a sigh of relief when the EGPWS terrain display is gone and 1013 is set, especially in Lagos. V1 is too soon.
As i pointed out, at Baghdad Int'l and Balad AB, we didn't change the the reject criteria, just the departure routing and procedure. At V1, we briefed continuing--it doesn't hurt at those weights the V1 = Vr, so we were airborne anyway. But the certainty of over-rrunning out-weighed the statistically remote chances of someone shooting a IR missile; let alone the remote chance of an entirely ineffective RPG hit. If you take-off from the fictional NW International Airport, ID and someone jumps out from the pucker bush, stands up and sends you an RPG round into the tailcone of your Citation at Vr, hell, at V2, be my guest, land straight ahead. BUT, don't tell me 160,000 professional pilots with millions of safe flight hours and statistically sound procedures are WRONG for continuing at V1 with a mechanical failure.
I don't know your career background, but it is obvious you have "issues" accepting that the airlines operate without you. Yes, it is true, they do. And the thousands of captains are NOT robots who don't think every time they advance the throttles--they do--EVERYTIME! I know, I've been there. As have most of the posters on this thread and the others where you have spouted off your damaged crockery ideas. All smarter than me or you.
I fly a GLEX and use FLEX power where indicated, I fly in about 30 countries a year; including such wonders as Beirut and Afghan and Iran overflights. I don't brief RPG procedures despite nearly 30 years of military flying, it just ain't a reasonable planning factor.
What's your reject plan when a printer cartridge of C4 goes off at 50 feet AGL? At 500 feet AGL? There's a reason safety investigations END when the police determines that a criminal/terrorist event occurred--it isn't addressable within our community.
GF
I breath a sigh of relief when the EGPWS terrain display is gone and 1013 is set, especially in Lagos. V1 is too soon.
Please review the definition of oxymoron. And your characterization is wrong, PERIOD. And your understanding of terrorism is equally wrongheaded and based on zero experience.
GF
Beirut and Lebanon is whole lot safer and entertaining than anywhere in the NW, BTW. If the IAF doesn't bomb the runways, as happened in '06, but I left the day before. Much nicer last Fall.
GF
Beirut and Lebanon is whole lot safer and entertaining than anywhere in the NW, BTW. If the IAF doesn't bomb the runways, as happened in '06, but I left the day before. Much nicer last Fall.
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Lord, I think you bring up some good points...but at the end of all this...your either a thinking pilot or a robot....if you assume that all planes fly after V1, it's just hoping, upon prayers, upon assumptions, made by engineers years and years ago..that what ever happened to your plane prior to rotation will not be something that has taken out your flight controls, created a structural failure ect.
I have been patient while restricting counter arguments to dumb scenarios where the assumption is that all flights seem to work in a world where balance field calculations always seem to run up to the end of an over run, with a cliff at the end, a lava pit at the bottom. If people can't convince me that all brakes fail while performing an RTO 1 kt past V1, they are convinced that all the runways in the world magically roll up the pavement to match balanced field calculations for that day...all the while building a lake full of Great White Sharks at the end...in some silly effort to make us believe that an RTO that stops the plane 1 foot after the balanced field calculations will result, 100% of the time with a plane careening to the scene of a horrible accident.
I have been patient while restricting counter arguments to dumb scenarios where the assumption is that all flights seem to work in a world where balance field calculations always seem to run up to the end of an over run, with a cliff at the end, a lava pit at the bottom. If people can't convince me that all brakes fail while performing an RTO 1 kt past V1, they are convinced that all the runways in the world magically roll up the pavement to match balanced field calculations for that day...all the while building a lake full of Great White Sharks at the end...in some silly effort to make us believe that an RTO that stops the plane 1 foot after the balanced field calculations will result, 100% of the time with a plane careening to the scene of a horrible accident.
Correct, not all runways have a hostile overrun area. But many do, and even a benign overrun area can cause all kinds of damage if entered at speed. Airliner undercarraiges are not designed to be offroad capable.
Correct, not all brakes fail if used from 1kt above V1. But if V1, today, happens to be set by V1mbe, NO-ONE at any OEM will guarantee that the brakes will not fail. Sure, not every chamber in the revolver has a bullet in it. How many chambers make Russian Roulette a "safe and rewarding game"?
If I look at what we do when we actually conduct the max KE brake demonstration, we have "minimum crew" - because we want to limit the number of deaths we risk. We have those crew wear fireproof suits and the like - in the hope that they might have time thereby to escape the aflame vehicle. We have airport CFR actually present, at the predicted stop point of the test, so that if it all goes pear shaped they might get the the aircraft before its engulfed in flames, and thereby rescue the test crew. And we inspect the hell out of the aircraft - especially the wheels and brakes assemblies - so that we understand exactly what kinds of risks we are running.
When you take your aircraft potentially past max KE speed and then decide to brake, you have NONE of these mitigating factors. Sure, there are some conservatisms in the flight test demo - we use worn brakes, for example. But NOT 100% worn - how worn are YOURS? Our tyres are in decent shape - are yours? All it might take is one bad tyre, that lets go early. Suddenly now you have to do the rest of the stop on just three brakes, not four. You're going to be pushing all the remaining energy into those other three brakes - probably inducing more problems. As the brakes heat they are going to fade - not fail, 'just fade'. Which means they are going to stop working as well as you'd like. But of course you can't estimate what that might mean - because the OEM data asumed you'd not be pushing the brakes so hard. Faded brakes are going to take MUCH longer to bring you to a halt - we'll find out how much longer by measuring the distance to the written off airframe, in all likelihood.
I will agree that there are some circumstances, where an aircraft will not fly, where aborting at Vr (if above V1) may be the only option. But you may well be at that point be picking - because you have no choice - a very bad second option only because the first option simply isn't available to you. I don't mind discussing the idea of what would happen for an abort outside the norms. But to pretend there is no significant risk in such an abort - that's just not helpful.
MfS
In my previous plane, not civil, we had charts for, and calculated on each and every take-off, the following:
Critical Field Length, Refusal Speed (accel-stop), Vmcg, corrected for crosswind and runway friction), Vmca (OEI and Two-engine Inop), Vr, Vmbe, AEO ground run, Tire Limit Speed, V2 and Flap Retract Schedule and all the calcs to compute those speeds/distances. V1 was defined as the lower of Vr, Vmbe or Refusal Speed. The handling pilot reviewed the data on a 8x10 sheet of paper and confirmed the data. Very comprehensive.
How is it the civil AFM is so limited in data for pilot use? Is the regulatory bodies afraid of pilots doing the data? This is elemental data.
GF
which for a line pilot, or even an airline performance department, involves going OUTSIDE the scope of the approved data
Critical Field Length, Refusal Speed (accel-stop), Vmcg, corrected for crosswind and runway friction), Vmca (OEI and Two-engine Inop), Vr, Vmbe, AEO ground run, Tire Limit Speed, V2 and Flap Retract Schedule and all the calcs to compute those speeds/distances. V1 was defined as the lower of Vr, Vmbe or Refusal Speed. The handling pilot reviewed the data on a 8x10 sheet of paper and confirmed the data. Very comprehensive.
How is it the civil AFM is so limited in data for pilot use? Is the regulatory bodies afraid of pilots doing the data? This is elemental data.
GF
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From Madd = Correct - not all runways are such that you are truly operating with ASDR=ASDA. But unless you actually do the calcs - which for a line pilot, or even an airline performance department, involves going OUTSIDE the scope of the approved data - you have no idea what actual margin you have.
Madd - I think you figured it out.
I have never showed up to the airport and picked up the 'package' of canned flight plans, performance calcs done by dispatch, ect....
Maybe when you run the numbers ten thousand times...you start seeing things other guys don't. Actually this process started a journey of asking deeper questions about flight testing, performance planning......
A boss once said I had too much time by myself up there to 'ponder my predicament'
You know if these conversations ever get to 'go' maybe we can talk about the tough trips that had me scratching my head during planning.
Madd - I think you figured it out.
I have never showed up to the airport and picked up the 'package' of canned flight plans, performance calcs done by dispatch, ect....
Maybe when you run the numbers ten thousand times...you start seeing things other guys don't. Actually this process started a journey of asking deeper questions about flight testing, performance planning......
A boss once said I had too much time by myself up there to 'ponder my predicament'
You know if these conversations ever get to 'go' maybe we can talk about the tough trips that had me scratching my head during planning.
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In my previous plane, not civil, we had charts for, and calculated on each and every take-off, the following:
Critical Field Length, Refusal Speed (accel-stop), Vmcg, corrected for crosswind and runway friction), Vmca (OEI and Two-engine Inop), Vr, Vmbe, AEO ground run, Tire Limit Speed, V2 and Flap Retract Schedule and all the calcs to compute those speeds/distances. V1 was defined as the lower of Vr, Vmbe or Refusal Speed. The handling pilot reviewed the data on a 8x10 sheet of paper and confirmed the data. Very comprehensive.
How is it the civil AFM is so limited in data for pilot use? Is the regulatory bodies afraid of pilots doing the data? This is elemental data.
Critical Field Length, Refusal Speed (accel-stop), Vmcg, corrected for crosswind and runway friction), Vmca (OEI and Two-engine Inop), Vr, Vmbe, AEO ground run, Tire Limit Speed, V2 and Flap Retract Schedule and all the calcs to compute those speeds/distances. V1 was defined as the lower of Vr, Vmbe or Refusal Speed. The handling pilot reviewed the data on a 8x10 sheet of paper and confirmed the data. Very comprehensive.
How is it the civil AFM is so limited in data for pilot use? Is the regulatory bodies afraid of pilots doing the data? This is elemental data.
But where we are intending the aircraft be operated in the biz jet world its common for us to provide a more simplified set of data, since the assumption is that there may not be the planning infrastructure to back up the crews, yet they may be having to deal with a much larger set of potential destinations. We've even been asked to provide that more simplified presentation for aircraft which have changed roles from airline to business operations.
It's not really a regulatory issue - we do provide that data for some cases. It's more a case of tailoring what is provided for the expected needs of each operator.
Now, in the brave new world of computerized flight manual data, one could argue it's easier to provide the more complex data to everyone. But there's still an issue of understanding the limitations in the data - if it's not really hurting your operations, simplified may be good enough.
Moderator
Discussions of terrorists and so forth are irrelevant to the certification matters.
Let's plan on the basis of nil further such excursions into the fanciful please ?
Let's plan on the basis of nil further such excursions into the fanciful please ?
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something new for the discussion on RTOs
To add something new to the discussion.... I noticed several comments on Flex/Assumed Temperature Method (ATM) takeoffs in relation to RTO performance. I wonder if crews know what the impact might be on the actual stopping distance during an RTO. Below is the engineering answer to this.
The accelerate-stop distance in FLEX/ATM is based on the true airspeed at the assumed temperature. This assumed distance is the basis for the takeoff performance. As the actual true airspeed (which is based on actual OAT) during takeoff is lower, the actualaccelerate-stop distance would be shorter than the assumed distance. This means, there is always some additional stopping margin when using Flex/ATM.
See: Takeoff Performance Optimization: Balancing Thrust Reduction and Stopping Margin by Dennis Ting, Meghan Nelson, and Greg Haselfeld, The Boeing Company
The accelerate-stop distance in FLEX/ATM is based on the true airspeed at the assumed temperature. This assumed distance is the basis for the takeoff performance. As the actual true airspeed (which is based on actual OAT) during takeoff is lower, the actualaccelerate-stop distance would be shorter than the assumed distance. This means, there is always some additional stopping margin when using Flex/ATM.
See: Takeoff Performance Optimization: Balancing Thrust Reduction and Stopping Margin by Dennis Ting, Meghan Nelson, and Greg Haselfeld, The Boeing Company
Moderator
Likewise with the acceleration. The actual temperature is lower and the thrust level higher which, when added to the better stop distance, results in a degree of conservatism.
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I will agree that there are some circumstances, where an aircraft will not fly, where aborting at Vr (if above V1) may be the only option.
BTW, what makes the Citation a low V1 aircraft? I always surmised that if V1 is less than Vr then it is because the ASDR is greater than the assumed distance remaining at Vr.
My copy of Flight Crew Manual hasn't been updated for a decade, yet I think it still makes some very interesting reading: it states that western built jet transport aeroplanes made about 230 million take-offs in period 1960-1990.
There was about 76 000 RTOs in the same period.
74 of them ended in accident or incident.
2% of RTOs were initiated above 120kt and that's where the large majority of incidents came from.
58% of RTOs that ended in incident were initiated above V1
Only 24% of unsuccessful RTOs were triggered by engine related events.
According to the Airline-that-issued-FCM analysis, 55% of incidents could have been prevented by continuing the take-off, 9% by better preflight planning, 16% by correct stop techniques.
20% were unavoidable.
Well, so much for those John Wayne kind of pilots who can always make a proper and informed split-second decision, whose keen eyesight gives them ability to estimate remaining runway down to a couple of feet precision, who have an absolute pitch and immediately they hear a bang know whether it's a tyre, tires, compressor stall, engine falling off, improvised explosive device in cargo hold 3, Strela-2M taking out the No4 engine or collision with B747 wrecking the most of the aeroplane (I'm only half joking here; the survivors of Tenerife carnage described the sound of two Jumbos colliding as being similar to small bomb going off). 'Tis a pity that such a pilot has never walked the earth or is likely to ever walk it - the safety he would offer his customers would be nearly absolute.
In case you've missed the Big Briefing: the only available safety in flying is the statistical one. Perfect safety is as achievable as the absolute zero. We can only bring chances of having a mishap down to socially, politically and economically acceptable level and that's about it. However, make no mistake: bringing the aviation safety where we have it now was no mean feat, keeping it where it is won't be easy either.
I really don't see the way in which some around this forum pre-meditate the reasons that make post V1 abort justifiable to be beneficial to aviation safety. If aeroplane is unflyable past V1, only thick margins can save the day. If they were not there in the first place, tough. Fate was, is and always will be the hunter. Trick that can extend the operational life is to avoid her favorite hunting grounds and post V1 RTO is the place she certainly frequents.
There was about 76 000 RTOs in the same period.
74 of them ended in accident or incident.
2% of RTOs were initiated above 120kt and that's where the large majority of incidents came from.
58% of RTOs that ended in incident were initiated above V1
Only 24% of unsuccessful RTOs were triggered by engine related events.
According to the Airline-that-issued-FCM analysis, 55% of incidents could have been prevented by continuing the take-off, 9% by better preflight planning, 16% by correct stop techniques.
20% were unavoidable.
Well, so much for those John Wayne kind of pilots who can always make a proper and informed split-second decision, whose keen eyesight gives them ability to estimate remaining runway down to a couple of feet precision, who have an absolute pitch and immediately they hear a bang know whether it's a tyre, tires, compressor stall, engine falling off, improvised explosive device in cargo hold 3, Strela-2M taking out the No4 engine or collision with B747 wrecking the most of the aeroplane (I'm only half joking here; the survivors of Tenerife carnage described the sound of two Jumbos colliding as being similar to small bomb going off). 'Tis a pity that such a pilot has never walked the earth or is likely to ever walk it - the safety he would offer his customers would be nearly absolute.
In case you've missed the Big Briefing: the only available safety in flying is the statistical one. Perfect safety is as achievable as the absolute zero. We can only bring chances of having a mishap down to socially, politically and economically acceptable level and that's about it. However, make no mistake: bringing the aviation safety where we have it now was no mean feat, keeping it where it is won't be easy either.
I really don't see the way in which some around this forum pre-meditate the reasons that make post V1 abort justifiable to be beneficial to aviation safety. If aeroplane is unflyable past V1, only thick margins can save the day. If they were not there in the first place, tough. Fate was, is and always will be the hunter. Trick that can extend the operational life is to avoid her favorite hunting grounds and post V1 RTO is the place she certainly frequents.
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updated statistics
Dear Clandestino,
Please have a look at the start of this tread. That study gives more up to date information than the Boeing study you are referring to.
Please have a look at the start of this tread. That study gives more up to date information than the Boeing study you are referring to.
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You guys are sunk now......
- There was about 76 000 RTOs in the same period.-
That's a lot of RTOs...that's a lot of mechanical failures, annunciator lights, problems, issues, ect that are causing the pilots to say...'not taking the plane up'
- 74 of them ended in accident or incident. -
Translated...out of ALL the RTOs... ONLY 1/10th of one percent of resulted in an accident...and that my friends, ends, all your arguments about brake failures, and planes flying off into the end into Lava Pits...done, over, your arguments are toast. One tenth of one percent is so statistically small that I could sit here and blame that on bad tires, idiot pilots, gremlins.. African operators, Pay to Fly.... but for grins let's move forward....
- 2% of RTOs were initiated above 120kt and that's where the large majority of incidents came from. -
2% = 1400 RTOs initiated above 120kts...that's fast...no one died and the plane wasn't structurally damaged.
--58% of RTOs that ended in incident were initiated above V1--
No one died, no planes banged up to un flyable status...
- Only 24% of unsuccessful RTOs were triggered by engine related events. -
You mean to tell me that 76% of the reasons why our pilot's RTOs had NOTHING To with the fire light...shocked, shocked I tell you...you mean things went bump, bang, boom...and they still stopped the plane?
- According to the Airline-that-issued-FCM analysis, 55% of incidents could have been prevented by continuing the take-off, 9% by better preflight planning, 16% by correct stop techniques. -
Sure...so out of 76000 RTOs...only 76 resulted in a plane being banged up, or an injury/death.....they think that these guys should have flown the plane at least half the time.....ok...let's look at that....76000 RTOs...and they think that half the INCIDENTS should have been flown off...ok...700 should have been flown as opposed to an INCIDENT...in other words instead of only an incident they think that 700 crews who slid off the end with no injuries or banging up the plane should have FLOWN the problem up in the air...beyond idiotic.
9% didn't preflight their planes...and 16% don't know how to stop one....not a revelation there...
------------------------
Gentlemen...the argument is done...sticking to a position that brakes fail and post V1 RTOs will kill you is about the same as a Linotype operator railing against copy machines....
So out of all the RTOs....76000, and only 74 resulted in accidents....how many could have been avoided if the crew had more runway in front of them?
- There was about 76 000 RTOs in the same period.-
That's a lot of RTOs...that's a lot of mechanical failures, annunciator lights, problems, issues, ect that are causing the pilots to say...'not taking the plane up'
- 74 of them ended in accident or incident. -
Translated...out of ALL the RTOs... ONLY 1/10th of one percent of resulted in an accident...and that my friends, ends, all your arguments about brake failures, and planes flying off into the end into Lava Pits...done, over, your arguments are toast. One tenth of one percent is so statistically small that I could sit here and blame that on bad tires, idiot pilots, gremlins.. African operators, Pay to Fly.... but for grins let's move forward....
- 2% of RTOs were initiated above 120kt and that's where the large majority of incidents came from. -
2% = 1400 RTOs initiated above 120kts...that's fast...no one died and the plane wasn't structurally damaged.
--58% of RTOs that ended in incident were initiated above V1--
No one died, no planes banged up to un flyable status...
- Only 24% of unsuccessful RTOs were triggered by engine related events. -
You mean to tell me that 76% of the reasons why our pilot's RTOs had NOTHING To with the fire light...shocked, shocked I tell you...you mean things went bump, bang, boom...and they still stopped the plane?
- According to the Airline-that-issued-FCM analysis, 55% of incidents could have been prevented by continuing the take-off, 9% by better preflight planning, 16% by correct stop techniques. -
Sure...so out of 76000 RTOs...only 76 resulted in a plane being banged up, or an injury/death.....they think that these guys should have flown the plane at least half the time.....ok...let's look at that....76000 RTOs...and they think that half the INCIDENTS should have been flown off...ok...700 should have been flown as opposed to an INCIDENT...in other words instead of only an incident they think that 700 crews who slid off the end with no injuries or banging up the plane should have FLOWN the problem up in the air...beyond idiotic.
9% didn't preflight their planes...and 16% don't know how to stop one....not a revelation there...
------------------------
Gentlemen...the argument is done...sticking to a position that brakes fail and post V1 RTOs will kill you is about the same as a Linotype operator railing against copy machines....
So out of all the RTOs....76000, and only 74 resulted in accidents....how many could have been avoided if the crew had more runway in front of them?
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Correct - only 0.1% of all RTOs resulted in an accident or incident. Sounds very safe to do an RTO.
But
To count all those low speed RTOs to justify your assertion that post-V1 RTOs are not significantly risky is not valid.
The important point is that 2% of RTOs were above 120kts (incidentally, that includes RTOs where V1 was even higher and so it was a pre-V1 RTO). Its stated that "most incidents" occurred for these cases. let's be generous to your case, and say that half of all accidents or incidents were due to that 2%.
RTO below 120kts : 74500 events, 37 accidents or incidents. Event rate, approx 0.05%
RTO above 120kts : 1500 events, 37 adverse outcomes. Event rate : 2%
You are almost 100 times more likely to end up in an accident or incident if you reject above 120kts than if you reject before 120kts. High speed RTOs are demonstrably more hazardous.
Not sure where you get the idea that none of those >120kts RTOs resulted in death or structural damage - "incident" includes "accident" in most cases.
Nothing is certain - no-one is saying (as far as I can see) "post V1 RTOs will kill you ". It all depoends on circumstances. But what is indisputable from the data is that rejections at higher speeds, and especially rejections above V1, significantly increase the risk, and as a result are only justified in truly exceptional circumstances. The default decision, justified by many years of experience, is to GO after V1. It may not be always the perfect decision - but the odds are definitely on your side taking that choice.
But
To count all those low speed RTOs to justify your assertion that post-V1 RTOs are not significantly risky is not valid.
The important point is that 2% of RTOs were above 120kts (incidentally, that includes RTOs where V1 was even higher and so it was a pre-V1 RTO). Its stated that "most incidents" occurred for these cases. let's be generous to your case, and say that half of all accidents or incidents were due to that 2%.
RTO below 120kts : 74500 events, 37 accidents or incidents. Event rate, approx 0.05%
RTO above 120kts : 1500 events, 37 adverse outcomes. Event rate : 2%
You are almost 100 times more likely to end up in an accident or incident if you reject above 120kts than if you reject before 120kts. High speed RTOs are demonstrably more hazardous.
Not sure where you get the idea that none of those >120kts RTOs resulted in death or structural damage - "incident" includes "accident" in most cases.
Nothing is certain - no-one is saying (as far as I can see) "post V1 RTOs will kill you ". It all depoends on circumstances. But what is indisputable from the data is that rejections at higher speeds, and especially rejections above V1, significantly increase the risk, and as a result are only justified in truly exceptional circumstances. The default decision, justified by many years of experience, is to GO after V1. It may not be always the perfect decision - but the odds are definitely on your side taking that choice.
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So if an RTO has a 1/10th of one percent of banging up the aircraft... only if I don't preflight the plane, forget how to brake the aircraft, do the RTO at 120 kts or better which by the way, I don't know if I can hold down my plane at 120kts...lol....and statistically only in an airline operation that is probably purposefully using derated thrust departures....
So wouldn't it be logical...that if we were to reduce these types of accidents....we would preflight our planes? Hire or train crews that can pull the levers back and stand on the pedals...and if all else fails we give them as much runway ahead as is possible so they have the most room to stop...???
Does that seem like a stretch????
So wouldn't it be logical...that if we were to reduce these types of accidents....we would preflight our planes? Hire or train crews that can pull the levers back and stand on the pedals...and if all else fails we give them as much runway ahead as is possible so they have the most room to stop...???
Does that seem like a stretch????
Johns7022
Actually, what would be logical is determining why the 55% didn't continue the take-off like SOP and the record of safe flight would have indicated; that would also eliminate those who didn't use the braking procedure effectively or didn't conduct proper preflight planning as rejected takeoffs because they wouldn't have rejected. Leaving the 20% of unavoidables to fix.
Using MfS's numbers, probably half of those 37 "adverse" outcomes wouldn't have happened had the pilot simply took off. "Poor preflight planning" does not indicate they didn't do an aircraft preflight, maybe the failure point could have identified during planning. And I'll bet you won't use the brakes effectively, if under the stress of a field length limited take-off you decide to reject past V1 because you guessed it won't fly. Oh yeah, you don't do the calculations, so you won't know you are past V1. How's that feeble Citation anti-skid work, anyhow? As has been pointed out, using ATM Flex or derate power will, in most cases, increase safety margins, but you don't want to listen to anything that doesn't fit into your visceral hatred of the industry
I think we can agree Johns7022, you can fly your Citation solo in the US Northwest and let the pros fly paying passengers around world, following SOPs developed by other pros who, do performance engineering based on the work of other pros who designed and applied science to the problem of flight. They've alL posted here, with endless patience, and have vast experience in ops and the knowledge of perhaps 300 million flight hours to base their opinions on. You can fly and decide the outcomes using a "seat of the pants" approach that gave aviation it's horrible stats in the early days. The fatal accident rate has come down so dramatically due to advancing beyond your method.
GF
Actually, what would be logical is determining why the 55% didn't continue the take-off like SOP and the record of safe flight would have indicated; that would also eliminate those who didn't use the braking procedure effectively or didn't conduct proper preflight planning as rejected takeoffs because they wouldn't have rejected. Leaving the 20% of unavoidables to fix.
Using MfS's numbers, probably half of those 37 "adverse" outcomes wouldn't have happened had the pilot simply took off. "Poor preflight planning" does not indicate they didn't do an aircraft preflight, maybe the failure point could have identified during planning. And I'll bet you won't use the brakes effectively, if under the stress of a field length limited take-off you decide to reject past V1 because you guessed it won't fly. Oh yeah, you don't do the calculations, so you won't know you are past V1. How's that feeble Citation anti-skid work, anyhow? As has been pointed out, using ATM Flex or derate power will, in most cases, increase safety margins, but you don't want to listen to anything that doesn't fit into your visceral hatred of the industry
I think we can agree Johns7022, you can fly your Citation solo in the US Northwest and let the pros fly paying passengers around world, following SOPs developed by other pros who, do performance engineering based on the work of other pros who designed and applied science to the problem of flight. They've alL posted here, with endless patience, and have vast experience in ops and the knowledge of perhaps 300 million flight hours to base their opinions on. You can fly and decide the outcomes using a "seat of the pants" approach that gave aviation it's horrible stats in the early days. The fatal accident rate has come down so dramatically due to advancing beyond your method.
GF
Last edited by galaxy flyer; 10th Dec 2010 at 00:41.
Back to the thread
‘johns’ (#121) is almost back to the original question … how does the industry “reduce the number of unwarranted rejected takeoffs above V1.”
The report (#1) gives several reasons for high speed RTOs, but few solutions amongst the recommendations:-
The basis of certification, whilst not perfect, provides sufficient assurance that the aircraft will fly and thus crews should not be overly concerned. The reasons for being unable to fly are in two broad categories.
Those which are self generated, e.g. errors in configuration, wt/cg, and weather assessment; these are generally addressed by procedures and checking (behavioural issues), and warning systems before take off.
Other, rarer events, whilst foreseeable, are so random that perhaps only a human can resolve the situation, e.g. runway incursion, double control jam, multiple engine failure. We could consider the solution of these incidents as mitigating the effects of the hazard or error, and/or reducing the severity of the impending accident. IMHO these activities, and particularly the assessment, decision, and action processes, are sufficiently different from RTOs as to place discussion and training of them elsewhere, and if the pressures of the economic climate minimize the training effort, so be it; better to concentrate on correct recognition and action for the more probable (but still infrequent) RTO / V1 Go scenarios.
The report (#1) gives several reasons for high speed RTOs, but few solutions amongst the recommendations:-
- Revitalise the ‘Takeoff Safety Training Aid’; a worthy training initiative, but in the current economic climate will the likely meager effort be effective.
Surely, the critical issues can be covered in less than the current two volume tome. - Train for events other than engine failure and use realistic scenarios; focus on the limiting cases, we do not have the luxury of ‘infinite’ runways.
This is another good initiative, but similarly limited by time and resource. It would be foolhardy to expect that every relevant scenario could be covered, let alone remembered for timely recall during a real event, so perhaps we have to identify generic training, i.e. situation awareness, surprise management – issues of human performance – simplifying the decision / action process. - Understand pilot’s behaviors; yes a good research topic, but the industry has used CRM etc for many years, which in several RTO instances appears not to have helped.
Perhaps we should take what is currently known about human behaviour and re consider how it is applied. - Review procedures and guidance; yes these can influence behavior. Provide appropriately phrased SOPs, which together with education can elicit desirable behaviour – preflight ourselves as well as the aircraft. A briefing is the flight-plan for the mind. An RTO requires a new plan, formulated in a moments decision, whereas continuing after V1 is only a revision to the existing plan.
Standard situations should be reduced to ‘if – then’ decisions, providing of course that the situation is correctly identified.
The basis of certification, whilst not perfect, provides sufficient assurance that the aircraft will fly and thus crews should not be overly concerned. The reasons for being unable to fly are in two broad categories.
Those which are self generated, e.g. errors in configuration, wt/cg, and weather assessment; these are generally addressed by procedures and checking (behavioural issues), and warning systems before take off.
Other, rarer events, whilst foreseeable, are so random that perhaps only a human can resolve the situation, e.g. runway incursion, double control jam, multiple engine failure. We could consider the solution of these incidents as mitigating the effects of the hazard or error, and/or reducing the severity of the impending accident. IMHO these activities, and particularly the assessment, decision, and action processes, are sufficiently different from RTOs as to place discussion and training of them elsewhere, and if the pressures of the economic climate minimize the training effort, so be it; better to concentrate on correct recognition and action for the more probable (but still infrequent) RTO / V1 Go scenarios.