V2
Join Date: Nov 2015
Location: Dog House
Age: 49
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Just for Leady's benefit that photo will contain 1 red head. So copy and paste that photo at will.
Just so it can be on the internet! and then ridiculed referenced when not fit a direction of a posters wish.
Google is good and cut and paste is fine, but to bag on cut and paste on legal and government web sites as well, still refuses
Just a stick shaker moment & to do it on 2 threads is what many call 6 dix, can not be that much with 1.
Just so it can be on the internet! and then ridiculed referenced when not fit a direction of a posters wish.
Google is good and cut and paste is fine, but to bag on cut and paste on legal and government web sites as well, still refuses
Just a stick shaker moment & to do it on 2 threads is what many call 6 dix, can not be that much with 1.
Last edited by Band a Lot; 3rd Jan 2017 at 12:58.
In general, a real-world-Vmcg-on-the-day directional departure is sufficiently rapid to bring tears to the eyes ..
Ain't that the truth, as the statistics so clearly illustrate.
Anything with an RB211 in particular, always ran down (thrust decay) much faster than anything from GE or Pratt --- but with any, getting the thrust levers back on the stops is absolutely critical to staying on the runway.
Had an outer quit at just over 90Kt. on a light aircraft( No!, Not a FAR 23 aircraft, a B744) one night, Veeery interesting!! Particularly the QAR afterwards.
Of course, for those of you who actually know something about the subject, accountability for a crosswind in working out a Vmcg limited V1 does vary between certification organisations.
we were no longer required to comply with the Australian unique requirement
Actually, that wasn't a local requirement. The Australian change reflected the FAR25 design change as discussed in earlier posts.
Actually, that wasn't a local requirement. The Australian change reflected the FAR25 design change as discussed in earlier posts.
As to the FAR , of course, because the effect of the CASRs 21 to 35 being made law was to adopt FAR 25 as a certification standard
but to bag on cut and paste on legal and government web sites as well, still refuses
I assume this applies to my comments.
Quite simply, if something is wrong, the fact that it appears on " legal and government web site" (whatever that is?) doesn't make it right, if it is wrong, it is wrong. Or are you suggesting Government publications are faultless??
On one of my early posts, I made the point that there had, over the years, been a lot of material that incorrectly defined V1, or resulted in persons reading the material misunderstanding the correct meaning of V1. That much such erroneous/misleading material often enough appeared in "official documents" ( such as DCA examination papers) didn't make it right.
I took the trouble to give some of the history of trying to correct large scale misconceptions about V1. I even took the trouble to nominate a few other errors in what are generally regarded to be authoritative documents/sources.
Was it you (??) but somebody even claimed, but was corrected by Lead Balloon, that I had failed to define V1.
For the absence of doubt, I will repeat the correct definition of V1, based on aircraft certification standards, AS IT APPLIES IN THE FLIGHT DECK:
V1 --- The speed at which the takeoff must be continued, if the abort has not already been commenced.
This is not a "Boeing" definition, it is "the" definition of V1, based on FAR 25, and in one form or another, appears in the relevant ACs that constitute the flight test standards applicable.
Tootle pip!!
PS: John T, I would have put myself under the heading of "drummers" rather than"Drumees".
Last edited by LeadSled; 6th Jan 2017 at 02:49.
Moderator
Yes, it was ----No other country had applied the requirement
All some years ago now as we get greyer and greyer ...
However, I'm wondering if you were thinking of the narrow runway operational demonstration defacto certification exercises ... ICAO came up with the recommendation and Oz was certainly the first to introduce that - I was involved with the first few aircraft to do the work.
For the ASDR two second delay, that appeared in FAR 25 A/L 25-42 (January 1978 at 25.109(a)) and CAO 101.6 A/L 62 (I probably have some old files somewhere which would note the date .. but not to hand). Recollection is that the two were near enough concurrently introduced. That change required the consideration be applied both to the OEI/AEO cases .. makes sense, really, as the concern was the high probability of overrunning the scheduled distance in the case of any delay due confusion or whatever and the AEO case looms significant in the pilot's mind .. see http://rgl.faa.gov/Regulatory_and_Gu...9?OpenDocument
To the best of my recollection - that might be subject to error, of course, it wasn't made retrospective here (one of our PPRuNe number was the then CASA TP at the time and would remember better than I regarding the details).
You make specific reference to the 767. A quick look at the US TCDS suggests that the frozen design standard for that Type excluded A/L 42 ... makes sense as the presumed project start would have predated 1978.
However, as the Australian examples would have come in post A/L 62 as a FOT certification, I presume that the aircraft would have been caught by the local requirement here. If that is the case, I understand your comments.
For your further commentary ... if you can recall some specifics to verify the position, I would appreciate clarifying the point in my mind.
As to the FAR , of course, because the effect of the CASRs 21 to 35 being made law was to adopt FAR 25 as a certification standard
Not relevant as the changes referenced long predated the CASRs. ANO/CAO 101.5/6 effectively required the foreign Standard with local changes to tinker a bit ... very much the bane of the Industry in many respects. Eventually sorted out post the Ron Yates' Report although not all the players thought that was a good idea.
All some years ago now as we get greyer and greyer ...
However, I'm wondering if you were thinking of the narrow runway operational demonstration defacto certification exercises ... ICAO came up with the recommendation and Oz was certainly the first to introduce that - I was involved with the first few aircraft to do the work.
For the ASDR two second delay, that appeared in FAR 25 A/L 25-42 (January 1978 at 25.109(a)) and CAO 101.6 A/L 62 (I probably have some old files somewhere which would note the date .. but not to hand). Recollection is that the two were near enough concurrently introduced. That change required the consideration be applied both to the OEI/AEO cases .. makes sense, really, as the concern was the high probability of overrunning the scheduled distance in the case of any delay due confusion or whatever and the AEO case looms significant in the pilot's mind .. see http://rgl.faa.gov/Regulatory_and_Gu...9?OpenDocument
To the best of my recollection - that might be subject to error, of course, it wasn't made retrospective here (one of our PPRuNe number was the then CASA TP at the time and would remember better than I regarding the details).
You make specific reference to the 767. A quick look at the US TCDS suggests that the frozen design standard for that Type excluded A/L 42 ... makes sense as the presumed project start would have predated 1978.
However, as the Australian examples would have come in post A/L 62 as a FOT certification, I presume that the aircraft would have been caught by the local requirement here. If that is the case, I understand your comments.
For your further commentary ... if you can recall some specifics to verify the position, I would appreciate clarifying the point in my mind.
As to the FAR , of course, because the effect of the CASRs 21 to 35 being made law was to adopt FAR 25 as a certification standard
Not relevant as the changes referenced long predated the CASRs. ANO/CAO 101.5/6 effectively required the foreign Standard with local changes to tinker a bit ... very much the bane of the Industry in many respects. Eventually sorted out post the Ron Yates' Report although not all the players thought that was a good idea.
Moderator
Expanding on Stallie's answer, one of the problems occasionally seen (and I presume from Leaddie's comments that this applied to the 767 - I neither flew, nor had any engineering involvement, with that very lovely passenger's machine .. enjoyed many pleasant pax legs around the network back in the days when the cabin crew had time to look after details such as wine, meals and nibbles) was consequent to a datal out of step regulatory change.
Typically, an aircraft missed a rule change in the country of manufacture (eg with FAR 25 A/L 42 in this case) due to the date of design standards freezing (ie where the OEM and FAA agree that the aircraft design will be subject to whatever version of the rules) occurring prior to the rule change effectivity.
Unfortunately, the first example of the aircraft might then have been imported to Australia after the date of an equivalent rule change here (in this case, ANO/CAO 101.6 at A/L 62). The importer then was subject to the local rule and had to run around a bit (read "spend money") to sort things out.
It always bemused me that local rule changes didn't have a suitable savings clause to provide a "get-out-of-jail-free-card" to cover this silly sort of situation where the local importer would be pushed to additional certification cost solely due to the datal mismatch.
My view was bolstered by the occasional inconsistency .. eg with ANO/CAO 101.22, for lighties, for years we used A/L 2 which worked fine .. in the main, for piston aircraft. Then it was raised to A/L 3 to cover turbines .. no good, it caused some problems for Nomad, as I recall .. so up to A/L 4 to address that concern.
Silly thing was that A/L 4 created some problems for the piston fraternity .. so the Regulator ended up accepting subsequent work to A/L 2 for pistons.
For the life of me, I couldn't see any philosophical difference between the .22 and .6 situations had a similar philosophical concession applied for datal mismatch problems.
However, I was just an engineering Industry grunt so not for me to get too worked up about things over which I had no control ...
Typically, an aircraft missed a rule change in the country of manufacture (eg with FAR 25 A/L 42 in this case) due to the date of design standards freezing (ie where the OEM and FAA agree that the aircraft design will be subject to whatever version of the rules) occurring prior to the rule change effectivity.
Unfortunately, the first example of the aircraft might then have been imported to Australia after the date of an equivalent rule change here (in this case, ANO/CAO 101.6 at A/L 62). The importer then was subject to the local rule and had to run around a bit (read "spend money") to sort things out.
It always bemused me that local rule changes didn't have a suitable savings clause to provide a "get-out-of-jail-free-card" to cover this silly sort of situation where the local importer would be pushed to additional certification cost solely due to the datal mismatch.
My view was bolstered by the occasional inconsistency .. eg with ANO/CAO 101.22, for lighties, for years we used A/L 2 which worked fine .. in the main, for piston aircraft. Then it was raised to A/L 3 to cover turbines .. no good, it caused some problems for Nomad, as I recall .. so up to A/L 4 to address that concern.
Silly thing was that A/L 4 created some problems for the piston fraternity .. so the Regulator ended up accepting subsequent work to A/L 2 for pistons.
For the life of me, I couldn't see any philosophical difference between the .22 and .6 situations had a similar philosophical concession applied for datal mismatch problems.
However, I was just an engineering Industry grunt so not for me to get too worked up about things over which I had no control ...
I neither flew, nor had any engineering involvement, with that very lovely passenger's machine .. enjoyed many pleasant pax legs around the network back in the days when the cabin crew had time to look after details such as wine, meals and nibbles
It was also the best 150T fighter, as far as the bloke (or blokess) occupying L1 was concerned. It was right up there with the Electra as far as getting in and out of Wellington was concerned
Unfortunately (or as my wife said, "About bleeding time") I have "recycled" much of my old library, but the "two second all engine acceleration past V1" really sticks in my mind, because it had caused such a serious reduction on payload, a commercial penalty not suffered by or imposed on our competition ---- and something I pushed very hard at the time, because reactionary forces in CASA were exploring every angle to prevent the mid-1998 legislative changes and CASR introduction, including putting pressure on the operators to intervene against the changes at a political level.
It was a very close run thing that we got the changes at all, despite the efforts of "all the usual suspects" in CASA, some of whom are still writing "letters to the editor" decrying the changes to this day.
Tootle pip!!
Let us assume that you "initate" maximum braking at or before V1, but you detect that you are "achieving" no braking and you exceed V1. Do you really "continue to reject"?
The investigation of one recent RTO incident which was initiated “very near V1”, revealed that the overrun was the result of 8 of the 10 wheel brakes failing during the RTO. The failed brakes were later identified to have been at advanced states of wear which, while within accepted limits, did not have the capacity for a high energy RTO.
This was the first and only known accident in the history of commercial jet transport operation that can be traced to failure of the brakes during an attempted RTO.
This was the first and only known accident in the history of commercial jet transport operation that can be traced to failure of the brakes during an attempted RTO.
But it ended up with an overrun....
The weird thing is that when I look at the video and the other materials, it seems to me that the overarching concern is RTOs that ended up with overruns but would not have if the take-off had instead been continued. And I keep giving scenarios in which the aircraft is over V1 and I just keep getting told "continue stopping" or "you're on your own" but not a third (and to a layperson like me - obvious) option.
I note the definition quoted by LeadSled does not prohibit the un-making of an RTO decision. That definition only says in effect that you must continue the take-off if you haven't initiated stopping at or before V1. It does not say that you must not continue the take-off even if you exceed V1 after initiating stopping action.
"You're over V1: You must continue the take-off!" Got it.
"You're over V1: You must continue to reject!" WTF?
That's why it seems to me to boil down to the spool up and spool down times of 'modern' engines. However, this may turn out to be a theoretical rather than practical point.
The weird thing is that when I look at the video and the other materials, it seems to me that the overarching concern is RTOs that ended up with overruns but would not have if the take-off had instead been continued. And I keep giving scenarios in which the aircraft is over V1 and I just keep getting told "continue stopping" or "you're on your own" but not a third (and to a layperson like me - obvious) option.
I note the definition quoted by LeadSled does not prohibit the un-making of an RTO decision. That definition only says in effect that you must continue the take-off if you haven't initiated stopping at or before V1. It does not say that you must not continue the take-off even if you exceed V1 after initiating stopping action.
"You're over V1: You must continue the take-off!" Got it.
"You're over V1: You must continue to reject!" WTF?
That's why it seems to me to boil down to the spool up and spool down times of 'modern' engines. However, this may turn out to be a theoretical rather than practical point.
Moderator
Very important to keep in mind that the performance "rules" are based on, and make the presumption of, some set of standardised conditions.
If well on one side or the other of whatever switch point is relevant (Vef for a critical reject), things are fairly easy. If at the switch point then, for a critical runway in this case, everything is based on real world conditions reasonably approximating standardised certification conditions .. otherwise the end result may involve some tears.
A dynamic V1 exceedance during a critical reject is pretty well guaranteed and is part and parcel of the AFM data .. one ought not to worry too much about that distraction. Main thing is that the initial reject action be commenced not later than V1 for there to be a reasonable probability of matching the AFM figures. SOPs are based on probable outcomes .. in general, the normal stop/go decision will give the better probability of a successful outcome.
If, on the other hand, something else significant happens during the exercise and is not covered by the certification assumptions, then the commander is well and truly on his Pat Malone and makes whatever decision appears best at the time ... One example we talk of from time to time is the min weight, min speed schedule critical failure in the presence of a strong crosswind. There is a good chance that the aircraft will be out of control directionally and keeping going is not a sensible option ... a case where a reject decision above V1 may be the only sensible option.
If well on one side or the other of whatever switch point is relevant (Vef for a critical reject), things are fairly easy. If at the switch point then, for a critical runway in this case, everything is based on real world conditions reasonably approximating standardised certification conditions .. otherwise the end result may involve some tears.
A dynamic V1 exceedance during a critical reject is pretty well guaranteed and is part and parcel of the AFM data .. one ought not to worry too much about that distraction. Main thing is that the initial reject action be commenced not later than V1 for there to be a reasonable probability of matching the AFM figures. SOPs are based on probable outcomes .. in general, the normal stop/go decision will give the better probability of a successful outcome.
If, on the other hand, something else significant happens during the exercise and is not covered by the certification assumptions, then the commander is well and truly on his Pat Malone and makes whatever decision appears best at the time ... One example we talk of from time to time is the min weight, min speed schedule critical failure in the presence of a strong crosswind. There is a good chance that the aircraft will be out of control directionally and keeping going is not a sensible option ... a case where a reject decision above V1 may be the only sensible option.
I had a chance to test a plane for a harmonic vibration which occurred late in the take-off roll. The PF on these high tests was a TPS grad, TC and FAA DER, so well qualified, the test was run up to V1-10, close the throttles and let it roll. Every time, while an FTE took measurements, we neatly ran right up to the computed V1. Lesson: a plane has a a lot of energy approaching V1 and acceleration doesn't stop just because the power was closed.
GF
JT: retired last week, doing some outside business.
GF
JT: retired last week, doing some outside business.
Moderator
With a fuel cut plus one x throttle rundown, rather than two x throttle rundowns, the speed overshoot may not be quite as much .. but the point is made. For the near V1 failure, the priority is getting into the stopping act with the minimum delay. I can only admire those folks who have time to keep a close eye on the ASI at the same time as doing everything else ..
Best fortune with the post retirement part time work situation.
The previous mob likely to give you a jolly out to this year's Air Show ? Must be time for a wine or three ?
Best fortune with the post retirement part time work situation.
The previous mob likely to give you a jolly out to this year's Air Show ? Must be time for a wine or three ?
