V1 question.

[Shaggy Sheep Driver]

I always thought V1 was calculated as the last point in the take off roll that the take off could be safely abandoned and the aeroplane brought to a stop on the runway. Therefore, a problem occuring after V1, unless catastrophic, would be taken into the air and dealt with once airborn. It follows (I'd have thought) that the V1 calculation must take into account available runway length (is there enough length left to stop in?).

Talking to a retired 747 / 777 BA pilot the other day it transpired this is not the case. He though this was daft, and it does seem so.

If you are taking off from a dry salt lake bed with 20 miles of 'runway' available, surely you've never reach V1 as you could abandon the take off and safely stop right up to the point of rotation and lift off.

So, what's V1 really about, then?

[safetypee]

So, what's V1 really about, then? In regard to the question, it’s about safety.
Runway length is a practicable limit and must be considered; we don’t have the luxury of infinite runway length.
Safety is about risk and managing risk. Stopping at speeds above V1 involves proportionately greater risk, and limits such as tyre speed and brake energy have to be considered irrespective of runway length.
Talk to your ‘Captain’ about brake temperatures, likelyhood of fire, tyre burst; then what risk is there in infinite operations – perhaps infinite risk unless it is bounded; V1 is just one boundary.

[hetfield]

It follows (I'd have thought) that the V1 calculation must take into account available runway length (is there enough length left to stop in?).
It is. Or at least, it should be:rolleyes:

Sometimes it's more length to stop, V1 is not always limited to runway length, e.g. it can't be greater than VR. No margin = balanced field.

Some performance charts or performance calc computers tell you the margin which is left stopping at V1.

[grounded27]

It is what you thought it was, have you not ever had V1 and VR just about the same speed? Glad this captain is retired.

[MarkerInbound]

That is only half the definition.


V 1 means the maximum speed in the takeoff at which the pilot must take the first action (e.g., apply brakes, reduce thrust, deploy speed brakes) to stop the airplane within the accelerate-stop distance. V1 also means the minimum speed in the takeoff, following a failure of the critical engine at VEF, at which the pilot can continue the takeoff and achieve the required height above the takeoff surface within the takeoff distance.


If those two calculations end up with the same number, you have a balanced field.

[hetfield]

If those two calculations end up with the same number, you have a balanced field. Indeed, but this wasn't the question.

[hetfield]

Similar subject....

http://www.pprune.org/rumours-news/455727-4th-june-2010-b737-800-rejected-takeoff-after-v1-report-out.html

[Shaggy Sheep Driver]

have you not ever had V1 and VR just about the same speed?

Never. I don't use V speeds in the lovely Chipmunk, hence my question. :O

[Piltdown Man]

Other issues such as maximum tyre speed, rotate and V2 also impose their own limitations on V1 and don't forget that this is just a decision speed, not a maximum speed. So on most take-offs an abandonment would result in you stopping well before the runway end. And if you want to continue the 'infinite runway' argument, you'll find that an aircraft will also have to meet a minimum climb gradient when airborne so before dispatch, the thing has to be able to fly at some time... then the limits above start becoming relevant.

PM

[Microburst2002]

Shaggy, i like your way of thinking. I like to use extreme cases to validate hipotheses.

In the infinite runway case, you still have limits: tyre speed, for instance. Not maximum brake energy speed, because all you would have to do is retard the throttles and smoke a cigar while you slows down.

In not so big airplanes such as B737, A320, etc... optimum V1 is just the same as VR, meaning that you have more runway than you need to stop the airplane (basically you have "infinite runway length" in case of stop). In these airplanes you will hear something like "V1, Rotate" in most of the take offs.

In the big birds, however, you will hear something like "V1", ".......", then "Rotate".

It is in the big birds where V1 is truly meaningful. At the V1 call they remove the hands from the levers. From then on they are going to fly whatever happens.

V1 also means that the airplane will be able to lift off, maintain v2 and then reach 35 ft by the end of the take off distance available. At V1 you can either stop or go safely. Depending on the circumstances, most of the times you can choose a V1 within a speed band. The trick is choosing the optimum one (the one giving max take off weight or max assumed temperature).

Then you have the climb and obstacle clearance consideration, which can have effects in the determination of the optimum V1, too.

[Shaggy Sheep Driver]

OK, so V1 can never be greater than rotate speed (after that, it's irrelelvant as you'll be flying). But at rotate speed, given sufficient runway length remaining, surely the power could be pulled off, reverse selected, and the brakes used normally (not agressively) to bring the aircraft to a gentle stop.

Most runways in the real world are not long enough to allow that, hence my assumption that V1 takes into account available runway length. Does it?

In the 'infinate runway' scenario, wouldn't V1 always be rotate speed, and therefore not relevant as a descision speed?

[Microburst2002]

Yep, that's right. Not relevant, we can say.

we posted simultaneously

When V1 and VR are the same, runway lenght is not limiting ("infinite") for the stop case. And we are using the maximum possible V1, which is the best for the Go case (shorter take off distance). So performance is very good, runwaywise. But you can still have marginal performace for climb and obstacle clearance, though.

refer to my other post, if you like
regarding the rejecting take off after VR... Never an option. In the infinite runway it would be a quick take off and landing. Once you rotate, you never ever reject take off.

[PLovett]

V1 takes into account available runway length. Does it?

Yes :ok:

[Shaggy Sheep Driver]

Thanks guys, that makes sense.

As a point of interest, why is a T/O never rejected after rotate but before lift-off?

[Denti]

And remember that Vr is not a fixed speed either, it can be moved to enable a better climb performance after take off (obstacle limit). With all the performance tools available you can use a 4000m runway completely even with a lightweight 737 (our ATC brethren really hate it when we do that).

[Basil]

When you calculate V1 you are using an unreliable fudge to find the point on a balanced field runway from which you may stop or accelerate to Vr before the end.
I say 'fudge' because, ideally, you'd have a mark on the runway as I seem to recollect was used by the V Force.
The use of IAS doesn't take into account an unnoticed power shortfall or a dragging brake which will place your V1 point too far down the runway.

Like Vmcg and Vmca there are woolly areas but they are the best we have at present.

[grounded27]

A slight drift but have been in an aircraft (light and poorly loaded) that "auto rotated" before VR. The thrills of flying ACMI freight!

[john_tullamarine]

When V1 and VR are the same, runway lenght is not limiting ("infinite") for the stop case

Nit picking, I guess, but it might be better to say that the runway length may not be limiting. V1=VR certainly doesn't preclude the takeoff's being ASD limited.

why is a T/O never rejected after rotate but before lift-off?

Procedural protocol. In addition, operational technique may become critical from the viewpoint of repeatability for distances.

And remember that Vr is not a fixed speed either, it can be moved to enable a better climb performance after take off

Not really the case. VR generally is predicated on V2 and provides a suitable delta V such that, for the AFM rotation technique, VR will produce V2 - OEI - as the aircraft passes screen height. V2 may well be increased in some situations to take advantage of the improved climb gradient capability associated with an overspeed V2 takeoff.

When you calculate V1 you are using an unreliable fudge to find the point on a balanced field runway from which you may stop or accelerate to Vr before the end.

Not at all unreliable. Considerable effort goes into the flight test program and, for the conditions inherent in V1's establishment, the distance figures are sensibly repeatable. V1 does not necessarily presume BFL and can, for those aircraft whose AFM permits, apply for an unbalanced field length scenario.

I trust, for BFL, that you mean achieve OEI/AEO screen before the end rather than VR ? The latter might be quite disconcerting in many situations.

[Denti]

Not really the case. VR generally is predicated on V2 and provides a suitable delta V such that, for the AFM rotation technique, VR will produce V2 - OEI - as the aircraft passes screen height. V2 may well be increased in some situations to take advantage of the improved climb gradient capability associated with an overspeed V2 takeoff.

Well, at least the 737 performance software from boeing tries to optimize every take off, to do that it usually does not use the lowest V2/Vr combination but rather slightly higher to much higher speeds. Over 95% of all take offs have an increased V2/Vr combo. Difference between Vr and V2 is usually only 2 to 3 kts anyway which is not enough even for the OEI case to just reach V2 at screen height, therefore the recommendet technique is to fly the actual speed of V2 to V2 + 20 and usually it is at the higher end of the airspeed band.

So in all practical application V2 and Vr are not fixed values, they can be changed considerably to provide best possible performance or highest possible thrust reduction.

[TyroPicard]

regarding the rejecting take off after VR... Never an option.

Several decades ago, a BAC-111 (Dan?) captain rejected T/O at LGW above Vr - the a/c had been misloaded and the nosewheel stayed firmly on the runway when he pulled back - a/c stopped inside the available length no problem.

A few years later an Iberia DC-10 captain rejected T/O at Malaga above V1 with a burst nosewheel tyre and mucho vibration - went off the end resulting in a burnt-out hull and significant loss of life.

[Lefthandseat]

haha..I agree wz you. Glad he's retired!
how many commercial airliners takes-off from SLC?.ha!

[Lefthandseat]

too fast n too much inertia n too little tarmac left at V1.
You are in the high speed regime, above 100knots .if u read annex 6 and FAR25, you will get all the answers.read up on " Balanced Field Length".
I ever had a RTO at 87knots and it was anything but gentle.
In performance, we are not actually learning what the aircraft can do but rather what it CANNOT do. that's called Limitations and that's why we have to calculate Field Length limit, climb limit, obstacle clb limit..fwd CG, tailwind limits, bla..bla..bla..
Nothing is perfect, machines or humans. safety is numero uno!
What they guys say here are correct but shouldn't u have learnt and passed this subject in Perf A before flt? Don't get me wrong , im just curious.
Cheers n happy flight!

"Thanks guys, that makes sense.

As a point of interest, why is a T/O never rejected after rotate but before lift-off?"

[john_tullamarine]

to do that it usually does not use the lowest V2/Vr combination but rather slightly higher to much higher speeds

V2 overspeed (improved performance in AB lingo) takeoffs will improve weight compared to min V2 schedules until whatever limitation occurs to preclude further V2 increase.

Difference between Vr and V2 is usually only 2 to 3 kts

Which is why we don't normally concern ourselves with the V2/VR ratio - rather V1/VR

not enough even for the OEI case to just reach V2 at screen height

Can't speak to the NG but, for the Classic, rotating at VR, OEI, will approximate V2 at screen. AEO, of course, screen speed will be substantially greater than V2.

So in all practical application V2 and Vr are not fixed values

Absolutely correct save for the following caveat. VR is constrained by V2. At very low weights, V2 WILL be constant with changing weight (Vmc limited) until the weight increases to the point where V2 becomes stall limited. Overspeed schedules are used to exploit the improved climb performance at speeds modestly in excess of V2 min.

[Slasher]

regarding the rejecting take off after VR... Never an option

I recall one of Emerald's 748s chopped the power and landed
on the remaining runway very safely after he'd copped a fire
warning just after lift off.

There was a lot of truths, half-truths and total bull**** on the
relevant threads at that time. I for one learned a lot from the
timely actions of that bloke.

[john_tullamarine]

landed on the remaining runway very safely after he'd copped a fire
warning just after lift off.

Given enough runway, of course that is an option.

However,

(a) the captain presumably had some explaining to do - I vaguely recall the incident but not the investigation.

(b) had the outcome been a mishap, the consequence might have been far more difficult for the captain.

While acknowledging that SOPs don't cover all situations and captain's prerogative, routine risk management generally dictates SOP compliance as being the reasonable way to go.

[Shaggy Sheep Driver]

IIRC that 748 had a fire in the engine or wing at or very soon after lift off. The captain judged that the fire was so severe that the structure would not stay intact for even a tight circuit, so he chopped the power and landed ahead. I think they all walked away.

[Mad (Flt) Scientist]

Report No: 3/2001. Report on the accident to HS748 Series 2B, G-OJEM, at Stansted Airport on 30 March 1998 - HS748 Series 2B, G-OJEM (http://www.aaib.gov.uk/sites/aaib/publications/formal_reports/3_2001_g_ojem.cfm) is presumably the incident being referred to. (?)

[Basil]

JT,
I think I gave good reasons for the term 'fudge' but, as I said, it's the best we have.
Recollect once querying why one twin jet we flew had a lower Vmcg (or was it Vmca? - forgotten now) on the version with the more powerful engines. Came the answer: "It's what's demonstrated by the test pilot on the day."

[Piltdown Man]

I am very happy that everybody escaped with their lives after this crash (this wasn't an accident). But...

...and landed on the remaining runway very safely...

And let me be very clear - that is called luck! To assess that the wing would have burnt off (because of a bang, a few screams in the cabin and possibility that the No. 1 told you that there was an engine fire) and that from 60-100 ft above the runway at 11:30pm that there would be enough room to land is something only worthy of a someone who believes in Intelligent Design and Creationism.

I have also learnt a great deal from that bloke as well.

PM

[Mad (Flt) Scientist]

From the report, it was hardly "very safely" - they overran the remaining runway at 62kts according to AAIB, which is non-trivial overrun speed. Depending on who you ask, 70-80 knots represents the speed at which an overrun should be considered potentially Catastrophic, which is the most severe category for a safety assessment.

Though the AAIB don't, in fact, challenge the pilot's decision.

[whenrealityhurts]

Wow..surprised the PPRUNE server isn't melting down at the acknowledgement that all planes don't magically fly after V1.

I ponder how many people JT has banned who simply made the comment that a captain with 5000 feet of runway post V1, can stop his aircraft safely...

Hell's freezing over....

[john_tullamarine]

"It's what's demonstrated by the test pilot on the day."

That MAY be true but are you sure that the engine upgrade didn't involve anciliary mods which might have had some relevance to Vmc considerations ?

The captain judged that the fire was so severe that the structure would not stay intact for even a tight circuit

Command prerogative is there for such decisions. However, no-one in the circumstances could make a rational call on that so the decision can only be seen to be a knee-jerk reaction to the situation. All of us who have had time on Darts would have a heightened concern about uncontained engine fires so the captain's decision is not entirely strange.

Overall, continuing for a circuit has the better outcome numbers on risk history. Having said that, if I were faced with similar circumstances and, say, 10-14,000 ft of runway, I'd be doing the same thing. However, the report suggest he landed with not very much seal in front of him and proceeded to depart the runway head at VERY significant speed for a Draggie. Probably not a good call to try and justify to the Chief Pilot over tea and bikkies - actually, probably without the tea and bikkies ?

it was hardly "very safely"

That's an understatement. Thanks for the link - I had read this report long ago and had the same thoughts then.

all planes don't magically fly after V1

Of course they don't.

Certification Standards and SOPs address reasonably expected circumstances. If the situation is dreadfully out of left field, then all bets are off and the captain earns his year's salary in the next few seconds or minutes ....

The very great majority of situations, however, will have a better likelihood of a satisfactory outcome by following sensible SOPs. No guarantees at all .. but the historical numbers are on the side of SOPs.

I ponder how many people JT has banned who simply made the comment that a captain with 5000 feet of runway post V1, can stop his aircraft safely

Actually, I have no idea how many folk I have chastised - probably not more than I could count on the fingers of one hand and certainly none for the sort of reason that you cite.

Caveat - a couple of troublesome folk who have gone through an interminable succession of re-incarnations have had recurrent slaps on the wrist applied. On that point, should I hold some interest as to why your comment is vaguely familiar in its style ?

[safetypee]

Those who wish to form their own conclusions and/or learn from the HS 748 accident should readthe full report.
The aircraft suffered an uncontained engine failure and subsequent fire; it was at night and there was a bright glow visible in the cabin.
The AAIB report handles the HF aspects very sensibly, with consideration of the likely surprise (shock) of the situation (my supposition), which probably contributed to the decision to land, as it may have done in the failure to follow all of the shutdown procedures – failure to close the LP fuel cock.

Errors stem from the influence of factors in the situation. At times, these factors exceed the human capabilities of analysis and rational decision making, which with the pressure of time and personal threat can result in non standard actions.
These issues are often found in accidents when attempting to stop after V1.

[whenrealityhurts]

Gee whiz....you haven't rotated yet, you see a mile of runway left...is it really that hard to consider keeping the burning wreck on the ground rather then fly it up in the air?

At issue here isn't logic, but the fact that the airlines, and military have culled so hard for followers rather then thinkers that any concept no matter how logical, that hasn't been handed down from the chief pilot, must be dangerous.

Like lemmings off a cliff, I ponder how many pilots have pulled a broken aircraft into the air, only to fly it to the scene of the accident.

[galaxy flyer]

Whenrealityhurts

If "broken" airplanes were taken airborne and crashed, when they could have stopped, I don't think the SOPs surrounding V1 would be THE industry standard. The record is quite clear--the statistics say taking it airborne is safer. Yes, statistics and safety is about probabilities, not absolutes. On almost 15,000 feet of runway at JFK, a TWA L-1011 aborted AIRBORNE after a false stall warning, everyone got out of the fire following a very hard landing and severe damage. Was that the right decision?

GF

PS: At least in the USAF I graduated from, pilots were anything but followers. My acquaintances in the RAF, RAAF and RCAF would be shocked at such an accusation. An AF doesn't have any combat capability with a flight crew force of followers. I include the enlisted members in that assertion.

[Mad (Flt) Scientist]

For those who haven't looked at the report, the very first page of the "Appendicies" pdf contains a diagram of the runway, with points of interest marked. Also shown is the distance from the start of RWY 23, which was approx 3000m long. The following are estimated, but good to at least 100m, maybe 50m.


rotation : 1150m
Bang : 1250m
Engine debris : 1300m to 1800m
HP Disc fragments : 1550m
Touchdown : 2600m
Aircraft Stop Point : 3200m


So the actual event happened with 1750m of "runway left". Deciding to get back down, and then doing so, took more than 3/4 of that distance. Leaving just over 1000ft in which to stop. Which should give pause for thought for anyone thinking of putting a damaged plane back down again. Especially if they start any further down the runway than this event...

[john_tullamarine]

At issue here isn't logic ..

On the contrary I suggest that that is the pivotal issue.

Like lemmings off a cliff, I ponder how many pilots have pulled a broken aircraft into the air, only to fly it to the scene of the accident

Somewhat fewer, I suggest, than those who have rejected post-V1 and come to grief. There are no guarantees, only probabilities. Sensible folk stake their lives and superannuation on the numbers game. Only in the rarest of situations is the spur of the moment call going to win the day. Of course it happens - sometimes - but the odd successful exception doesn't invalidate the general rule.

I think that GF and MFS have summarised the situation succinctly ?

[Brian Abraham]

GF, you may not have picked up on the new persona we are blessed with - our old friend. On the other hand I may be telling you how to suck eggs. :E JT, to his credit, has him sussed.

Caveat - a couple of troublesome folk who have gone through an interminable succession of re-incarnations have had recurrent slaps on the wrist applied. On that point, should I hold some interest as to why your comment is vaguely familiar in its style ?

Love it.

[Slasher]

Report No: 3/2001. Report on the accident to HS748 Series 2B, G-OJEM, at Stansted Airport on 30 March 1998 - HS748 Series 2B, G-OJEM is presumably the incident being referred to. (?)

Thanks MFS for that report link. I knew eventually someone
would have it.

Particularly interesting on the report is..... 3. Conclusions -
(a) Findings - paragraphs 4 and 5 (p83/87).

I don't think anyone is familiar with just how bloody dangerous a
wing mounted Dart fire can be. That bloke certainly did, and faced
the enquiry very much alive, as did his crew and entire pax.

Anyway it was all said here before, 13 odd years ago.

[Basil]

JT,
That MAY be true but are you sure that the engine upgrade didn't involve anciliary mods which might have had some relevance to Vmc considerations ?
Don't know. Did cross my mind that the rudder was larger but never checked.

[Teddy Robinson]

In high surface winds with windshear likely on departure, we are allowed to add up to 15 kts to the Vr. Now lets assume that the runway is not limiting, as is often the case on my type, we have a weight book V1/Vr now with a spead of 15kts. Arguably with no FLL the V1 could sit happily under the new Vr, and the takeoff abandoned without compromising safety at that new V1. Problem is that at MTOW, there is no way to reverse calculate an "assumed weight" for the new V1 to check the FLL... probably to stop people scheduling an overweight takeoff with all the liability issues that would go with that.

This is a scenario I can envisage where I see an obvious conflict.
V1 .... long pause ... loud bang at V1+10kts with 2500m of runway ahead, thats almost twice our LDR, the temptation may well be to stop provided no rotation has been initiated.

[TimeOnTarget]

And so the very definition of V1 continues to be debated in the aviation world.

The devil is in the details as one group points out that V1 should really be called "continue/reject action speed". It is the speed at which the first positive action must be taken, not the speed at which you actually make the decision to reject.

A cursory study of available data will show that rejecting above V1 is like trying to win in Las Vegas. The odds are with the house.....

I have only rejected one takeoff and it was at rotation speed in a C23 in Iraq with about 7000 feet of runway in front of me. The flaps were not set properly and the decision was obvious. No harm, no foul. However, as a 744 FO, I don't envy any of my Captain's responsibility to reject a max gross weight whale.....

[Centaurus]

At the V1 call they remove the hands from the levers.

Why do they do that? Is it because it is too hard to pull back the control column with one hand or is there an operational reason for that or is it merely old fashioned tradition? Its not done in the Airbus (ie two handed rotation on the side stick):ok:

[Denti]

It is experience. If one does not remove the hand from the thrust levers at V1 (or before) chances are very very high that take offs will be routinely aborted above V1.

[Slasher]

In the L'Airboos I take my hand off the throttles at V1 and
stick it on the RH armrest of me seat - till its needed to be
back on them again.

A lot of the kids have this damn annoying habit of putting
their mitts all over 'em just after rotation.

[Microburst2002]

JT

I was expecting the performance heavyweights to post in this thread.

When V1 = VR, in what cases it can be ASD limited ?

We can say that in this case, V1 is "maximum", which can be regarded as maximum ASD, minimum TOD V1. If ASDA is not infinite, at least it is enough,.

I always thought that choosing "maximum V1" is done so that we have more chances to stop and stay on the ground rather than taking off.

In the 320 I feel like doing something worthless when I calculate V1 in a 3500 m runway from which 747s and 380s are taking off. All I want to know is VR and V2. Such one day in a wet 4000 m runway we used FCOM 2 tables to substract knots to dry V1, VR and V2. I called out V1, we waited till 10 knots later and called "rotate". I think we had still 2000 m remaining...In some cases V1 is simply ridiculous. In others it has a meaning.

I look at V1 as a decision speed, in the sense that I don't intend to assess the situation too much if something happens during take off. Before V1, stop, at or above V1, go. No thinking. The thinking is made before the event. Obviously I will stop in case of a catastrophic failure. I don't know what happened to that 74 nor how a captain knows that a wing is no fire. An engine fire is no reason for rejecting after rotation, unless you are certain that there is runway enough, and that must be difficult with a 747...

[whenrealityhurts]

What do you say we speed this thread to it's logical end?

Airlines push balanced field numbers into the over runs and weeds with reduced thrust calculations, under the guise that pushing trend monitored engines out to 30,000 hours, saving a few overhauls is worth the risk of flying it to the end, then pulling up.... Combine this with the common hiring practices of picking from the bottom of the resume pile...the most inexperienced pilots they can hire, specifically culled to take orders...a flying marsh-mellow is trained to read a checklist rather then make a decision...he is told to yank the yoke at V1, fly the wreck into the air...because statistically, if your typical pilot flies 'the numbers'..statistically he should be safe..

- unless he gets ice..
- unless he hits a few birds
- unless his seat rolls back to the rear
- unless lightning knocks out his tubes
- unless he has a flight control failure
- unless he has terrorists on board..

etc etc etc....

This philosophy is based on the idea that all scenarios have been addressed in the sim, and put into checklists...which is wrong. It's also under the guise that statistically given a choice under pressure, pilots will screw it up, make a bad decision...this of course is based on some epic mistakes made by airline captains, and certainly doesn't take into account all the non- accidents, famously averted, that never made the news, by pilots who 'thought' their way out of a jam....and many times famously disregarded the checklists that have been written by the lawyers, trying to fight a future court battle, not avert the current impending accident.

So in an effort to control the safety of airline operations, pilots are told to refer to sops and checklists...and secretly hope that nothing will happen out there, outside of the book...which happens all the time....

A pilot sitting there at the end of a 10,000 foot field, purposely moving v1 farther down the field with reduced thrust calculations, knows full well he is increasing the risk of that departure, so do his boss's, so does the FAA. Trying to justify yanking back on the yoke at V1 is really easy when all you ever see in your career at V1 is the end of the runway will building in front of you.

The rest of us have spent a lifetime flying planes where there is a mile of pavement in front of us, and just can't imagine why you'd take the wreck up in the air when you have the opportunity to safely keep the aircraft on the ground.

[galaxy flyer]

Brian,

Au contraire, mon ami, I know all too well the newest version of the resident fanatic (def, someone who won't change their mind and can't change the subject). He was recently over at the Concorde thread explaining to some of the designers and operators of that elegant lady, how much in error they are.

WRH

Or is it, when reality bites? This is well plowed ground, I think.

GF

[Mad (Flt) Scientist]

The rest of us have spent a lifetime flying planes where there is a mile of pavement in front of us, and just can't imagine why you'd take the wreck up in the air when you have the opportunity to safely keep the aircraft on the ground.

The pilot of the Emerald 748 had approximately "a mile of pavement" in front of him - the "bang" happened with 1750m remaining, or about 1.1 miles. And his takeoff speed was a fairly low 111kts. Yet even with those favourable conditions, he still overran the far end of the runway at 62kts, a speed high enough to be considered likely to cause a hazardous outcome - which equates to death for some of the passengers or crew. That it didn't in this case was due to a relatively favourable overrun area and the good fortune of missing the approach lights.

Even if the decision was a reasonable one for those circumstances - the AAIB feels it was, and people here have suggested that the specifics of the aircraft/engine concerned go some way to backing that up - the crew were nevertheless wagering what they felt was probable disaster in-air against possible disaster on-ground. Had the outcome of the overrun been even a little worse then I suspect there would have been a lot more official questioning of the captain's decision-making.

Except in the most favourable conditions, conducting a safe rejection from above V1 (or Vr, in this case) will never be an option with any guarantee of a safe outcome; accurately weighing two unknown but high risks in an instant is going to be a challenge for any skill level.

[mutt]

Why dont we just concede that SSG, whenrealityhurts, etc etc etc etc... is right, maybe his flight testing in Microsoft FSX and maybe he is a real pro and uses X-Planes, is correct, and the last 30 years of industry research, analysis and operational reviews are incorrect.

We should bow to his superior knowledge............ Henceforth, I hereby swear that I will not conduct another Flex Thrust Balanced Field Takeoff anytime in the next 24 hours.

Now I want to listen to more of his tales of daring do, I loved the one about him flying in the right seat of a Gulfstream and saving the aircraft, not to mention his tales of single pilot operations in the CJ...... Please oh aviation demigod, tell us more.

Mutt

[Denti]

Hehe, i can swear the same mutt ;) and it is funny how the same character does his jack-in-a-box inpersonation several times a year...

[galaxy flyer]

Mutt, Denti, Brian and MfS,

Let's grant that he is an active pilot, who does fly "single pilot" Citations (possibly because of a dearth of willing co-pilots) and is just not up to large airplane operations and is unwilling to learn.

GF

[Brian Abraham]

Let's grant that he is an active pilot

Not a chance GF. Wander over to Rotorheads and search SSG's posts on helicopter aerodynamics and design. You'll learn stuff not even Bell and Sikorsky know. Walter Mitty by name and nature.

[sheppey]

It is experience. If one does not remove the hand from the thrust levers at V1 (or before) chances are very very high that take offs will be routinely aborted above V1.

Nice try. But unless there is solid technical proof rather than a wild guess to that statement then the reasoning is flawed and a lawyer would tear the proponent's argument apart and rightly so.

[Slasher]

Here's another aborted-past-V1 event that occurred in 1996.
Worth taking a look at...

GA865 Report PK-GIE.pdf (http://www.mlit.go.jp/jtsb/eng-air_report/PK-GIE.pdf)

I'm not endorsed DC10, but harking back to my 747 days it
would appear to me that 151kt might've been the "highest
V1" in the dry case and so should have been fully respected.

[Denti]

Actually sheppey, there is more than only a technical proof, there is substantial statistical data about it. Which is why boeing made it a mandatory take off procedure, at least on the 737.

[Microburst2002]

V1 for the GO case is computed for an engine failure condition.
V1 for the STOP case is thought for any kind of failure (other than braking systems...)

So if I ever have a malfunction different than an engine failure at or above V1I know that I can continue take off very well!. The airplane will lift off and climb as in a normal take off. In the STOP case, however, there is always a reasonable chance to overrun or depart the runway no matter what kind of failure you have, engine or anything else.

As a rule, GO is better than STOP, the only exceptions being failures or circumstances of a catastrophic nature that render the airplane "unflyable" (terrorist bomb explosion, total flight controls failure...).

The question is "How the heck I know the airplane is unflyable?"

[aterpster]

Microburst2002:

The question is "How the heck I know the airplane is unflyable?"

Short answer: You probably don't.

TWA lost a 707 at KCVG in 1967 because after V1 the F/O mistook as an engine failure the momentary noise and buffeting from passing through the engine wake of a DAL DC-9 that was stuck in the mud and trying to power his way out.

[john_tullamarine]

When V1 = VR, in what cases it can be ASD limited ?

Anytime that ASD happens to be the limiting case. The point being made is that the various limitations are applied separately and whichever is limiting for the particular takeoff sets the RTOW.

If ASDA is not infinite, at least it is enough,.

Fair comment

I always thought that choosing "maximum V1" is done so that we have more chances to stop and stay on the ground rather than taking off.

Not necessarily .. and the other consideration is whether it is a good idea to make a non-limiting ASD situation limiting by pushing the V1 up as high as possible on the day.

Running to maximum V1 gets you to VR in the shortest distance which benefits the go case. Reducing to a low V1 pushes the TOD out for the benefit of a more relaxed ASD.

In some cases V1 is simply ridiculous.

If you have a lot of spare runway in front of you then, consistent with the data presented, you have the option of increasing V1 as you might see fit. Be wary of brake energy limits ...

The thinking is made before the event.

And that is the basis for risk managing SOPs.

[Microburst2002]

in this month issue there is an article about this very thread topic, related with a 737 that did RTO some 10 kt above V1, and survived. very interesting.

[Shaggy Sheep Driver]

Well thanks guys. Seems my original hypothesis was about right. But who the heck is this notorious SSG? He hasn't even posted here AFAIK.

[mutt]

http://www.pprune.org/tech-log/327267-would-you-abort-after-v1.html Have a look at this thread.... there are many more as he changes his persona......
He asks extremely interesting questions, but he isn't willing to listen to comments from others, unfortunately :{:{
I would love if he would just start the questions and then listen to the answers, but arguing that the whole concept of reduced thrust is wrong, or aborting after V1 is a normal event are a lost cause.

Mutt

[whenrealityhurts]

Mutt -

Your religion is crumbling...

CRM and Ab Initio new hires, are dying a well deserved death.....

It's only a matter of time when another fool who 'pulls it off no matter what at V1, then flies the unflyable to the scene of the accident' puts Flex and 30000 hour engines on the block as well.

[galaxy flyer]

I promised myself I wouldn't do it, but here goes.....

WRH

Please post on accident report where an airliner, having an emergency of any type, continued the take-off, instead of stopping, got airborne and CRASHED. Also, please provide an accident report citing, reduced thrust take-offs, on-condition engine monitoring or a case where good CRM as causal or contributing to the event.

Do so, and expect some grudging acknowledgement.

GF

[Microburst2002]

JT

you are right. Of course take off can be ASD limited with VR and V1 being equal. However I have very rarely seen a runway limited case. Most of the times second segment or obstacles is the limitation. (by the way, Can that be the reason for the high V1 VR values, that the optimum speeds are sort of an improved climb?)

others

Nobody will fly a wreck if he knows that it is a wreck. It is better to stop a wreck and overrun the runway than become airborne and crash.

The problem, however, is how to determine what the airplane's status is: wreck or not wreck.

This would be difficult even if we had 5 minutes to analize the situation.

At 140 kt ground speed we are running about 70m per second, and quickly accelerating, so in a few seconds we may have "eaten" hundreds of meters. furthermore, the speed gained goes squared in the kinetic energy equation. If we have already started rotation, things are even worse because efficient braking action will be delayed for more seconds. The result is several hundred meters lost plus some other several hundred extra meters needed for stopping. If the take off was already ASD limited, or approximately, then you have a runway excursion.

We don't have time to assess, only to react. If we react instictively we can screw it totally, unless we have spiderman's arachnid sense. So we need to use other form of decision making: anticipated decision making. The flaw of this method is that you don't know all the possible scenarios. You don't know what will happen. But the good thing is that chances of choosing the correct action are much better than in the instinctive reaction. Much better, i'd dare to say. OF course we can be unlucky and choose GO the damned day that the airplane is a wreck...

Airbus policy regarding RTO is very interesting, and it leaves a lot of room for Captain's decision. The ECAM inhibit function is very helpful and ergonomic, by the way. I guess Boeing has a similar feature?

[TimeOnTarget]

Well said Microburst

Yes, the Boeing also inhibits certain warnings, fire for example, at certain speeds during the take off.

[India Four Two]

Another DC-10 "reject after V1" overrun at Vancouver in 1995, but with a better outcome than the Garuda accident:
The captain did not recognize the loud bang as a symptom of a compressor stall on the high bypass ratio engine and thought that the noise might have been a bomb. Consequently, he decided to reject the take-off even though the speed was above V1 (the maximum take-off rejection speed). Although the flight crew members were all very experienced pilots and had taken simulator training throughout their careers, they had not been trained to recognize a loud bang as a symptom of a high bypass ratio engine compressor stall, and none of the crew members noticed the cockpit indications of power loss on the left engine.

The captain's decision to reject was based on the fact that he did not recognize the initial sound and subsequent thumping noises, and that, because he thought the bang could have been a bomb, he had concerns about the integrity of the aircraft and its ability to fly. Also, the captain stated that, based on the rejected take-off provisions in the DC-10 Flight Manual and on a fatal DC8 accident that he had witnessed, he had developed a mental rule to not take an aircraft into the air if he suspected that there was aircraft structural failure.


Transportation Safety Board of Canada - AVIATION REPORTS - 1995 - A95H0015 (http://www.tsb.gc.ca/eng/rapports-reports/aviation/1995/a95h0015/a95h0015.asp)

[mutt]

These training aids emphasize the need to adhere to the V1 decision-making concept and highlight the inevitability of an overrun if a rejected take-off is initiated after V1. In its discussion of rejected take-off situations, the Takeoff Safety Training Aid states that a take-off should not be rejected once the aircraft has passed V1 unless the pilot has reason to conclude that the airplane is unsafe to fly. As well, the study concluded that in most overrun accidents, the pilots, using visual cues, did not accurately assess the amount of runway remaining or the aircraft's ability to stop.

He also believed that he would have some time after the 164-knot V1 call to make a reject decision. FDR/CVR analysis indicated that the loud bang occurred 2.2 seconds after the V1 call. The captain called the reject 1.3 seconds later. His first action to reject the take-off, retarding the power levers, occurred at 4.3 seconds after the V1 call and as the aircraft was accelerating through 172 knots. The auto-brake system activated 6.1 seconds after V1 as the result of the second officer manually deploying the spoilers. The thrust reversers were selected 3.5 seconds after the power levers were retarded, and the reverse levers were pulled into reverse 11.1 seconds after the V1 call.

The captain's decision to reject was based on the fact that he did not recognize the initial sound and subsequent thumping noises, and that, because he thought the bang could have been a bomb, he had concerns about the integrity of the aircraft and its ability to fly. Also, the captain stated that, based on the rejected take-off provisions in the DC-10 Flight Manual and on a fatal DC8 accident that he had witnessed, he had developed a mental rule to not take an aircraft into the air if he suspected that there was aircraft structural failure.

And that last statement SSG, is exactly what you are trying to do to people.

Mutt

[whenrealityhurts]

Report: B737-800 rejected takeoff after V1 (http://news.aviation-safety.net/2011/06/26/report-b737-800-rejected-takeoff-after-v1/)

The Dutch Safety Board published the findings of their investigtion into a serious incident at Eindhoven Airport when the takeoff was rejected after the takeoff decision speed (V1).The Boeing 737-800 operated by Ryanair was taking off from runway 04 on the 4th of June 2010 at Eindhoven Airport, the Netherlands. At the time of rotating the aircraft to takeoff, the pilot flying decided to reject the takeoff because he believed the aircraft was unsafe to fly. The decision to reject was made after the takeoff decision speed (V1). The pilot performed a so-called high speed rejected takeoff.
The aircraft was halted before the end of the runway and the aircraft was subsequently taxied back to the terminal. The aircraft sustained no damage and no passengers or crew were injured.
The Safety Board concluded:
During the takeoff at Eindhoven airport the pilot flying perceived two control issues and one speed trend vector anomaly.


The explanation for the control issues and speed trend vector anomaly was likely related to an outside atmospheric phenomenon. The origin of this atmospheric phenomenon could not be determined or explained with the information available.

The takeoff was rejected after the decision speed V1 and while the nose wheel was off the ground for approximately two seconds.


The First Officer who was the pilot flying considered the control and speed trend vector problems to be serious enough and decided to reject the takeoff.
According to company procedures only the Captain is authorized to make a rejected takeoff decision.
To reject a takeoff above V1, especially when the nose wheel is off the ground, is in principle considered to be improper and unsafe.

There is no specific guidance from the operator or manufacturer on dealing with control issues at the time of rotating the aircraft.


Specific guidance on rejecting a takeoff exist in case of an engine failure.
Review of past statistics and studies show that pilot training and requirements focus on rejected takeoffs due to an engine failure. Studies and statistical information show that this accounts for less than 25% of the reasons for rejected takeoffs. Thus 75% of the reasons they reject a takeoff is not trained for.

[Checkboard]

This incident was discussed on R&N for a while. Consider:


The V1 speed is artificially reduced to be below VR, as such the V1 speed is NOT the maximum or limiting speed which it is possible to reject the take-off, if the aircraft wheels are still in contact with the runway (i.e. the V1 speed used for take-off is not necessarily limited by either runway length OR brake energy limits) - that speed limit isn't calculated, but can be intuited by an experienced pilot.
The V1 decision is only trained for engine failure - not for control problems or un-flyable conditions. If the aircraft is considered un-flyable, then a reject at ANY speed is appropriate.
In the same sense that a Captain may disregard SOPs in an emergency situation when the Captain considers the aircraft is under threat - does not the same apply to a licensed and qualified FO, when the aircraft is considered under threat - and there is no time to consult with the Captain?
In this case - the aircraft stopped, and taxied back without problems - so 20:20 hindsight says that the FO didn't endanger the aircraft by stopping.

[whenrealityhurts]

Thanks Checker...your right, the results speak for themselves.

Amazing how many guys would watch a non-event RTO and still think the pilots should have pulled it off into the soup and fought the problem up there....

[Brian Abraham]

I thought it perhaps worthwhile to post the following from the 738 reject report, as it highlights the difficulties faced in the decision making process at an extremely critical time.

http://www.onderzoeksraad.nl/docs/rapporten/Ryan_Air_EN.pdf

REJECTED TAKEOFFS IN A HISTORICAL PERSPECTIVE

Rejected takeoffs are not uncommon and in the past have resulted into accidents. Several studies and investigations were performed on rejected takeoffs, a general overview of these studies will follow. In 1990 a Special Investigation Report Runway Overruns following high speed rejected takeoffs was published by the National Transportation Safety Board (NTSB) of the United States of America. The NTSB conducted this investigation to determine how the safety of rejected takeoffs could be enhanced and the rate of incidents reduced. The investigation used a variety of information on rejected takeoffs including historical accident data and airline procedures. In this special investigation report several recommendation are made to the Federal Aviation Administration (FAA) on improving safety for rejected takeoffs. An overview of the recommendations are presented in appendix H. In 1994 the FAA in a joined effort with industry created a training tool for rejected takeoffs, the Takeoff Safety Training Aid. The main purpose of this training tool was to reduce the number of rejected takeoffs by improving flight crew decision making process, knowledge and awareness. The Takeoff Safety Training Aid describes the background of events and lays down training methods and simulator scenarios for pilot training on rejected takeoff decision making. The “Takeoff Safety Training Aid” training program is designed to facilitate flight crews in reaching and maintaining proficiency in:

• Recognising and understanding situations and factors that make high speed rejected takeoff decisions critical.

• Making appropriate Go/No Go decisions.

• Executing rejected takeoff procedures and employing techniques that maximises the stopping capability of the airplane should a high speed rejected takeoff be necessary.

• Continuing the takeoff safely should that be deemed the most appropriate course of action. In this safety training aid, data and background information on rejected takeoffs from 1959 up to 1990 is presented. It is reported that 76% of all rejected takeoffs are initiated at speeds of 80 knots or less. The rejected takeoffs at low speed almost never result in an accident. About 2% of the rejected takeoffs are initiated at speeds above 120 knots. Statistically more than half of the runway overruns or excursions have occurred when the rejected takeoffs were initiated at high speeds (greater than V1).

REJECT SPEED

80 knots or less 76%
80 – 100 knotsx 18%
100 – 120 knotsx 4%
Above 120 knots 2%

According to the Takeoff Safety Training Aid in the event the airspeed is beyond V1 a “go decision” is less hazardous and the takeoff should therefore not be rejected. The reasoning is that the problem faced by the flight crew may be handled more safely as an in-flight problem than a high speed rejected takeoff. The reasons for rejecting a takeoff vary from an indicator/light to wheel or tire failure.

REASONS FOR REJECT

Enginexxxxxxxxxxxxxxxxx24.3%
Wheel/Tyrexxxxxxxxxxxx22.9%
Other and not reported 13.5%
Configurationxxxxxxxxxx12.2%
Indicator/Lightxxxxxxxxxx9.5%
Crew Coordinationxxxxxxx8.1%
Birdstrikexxxxxxxxxxxxxxx6.8%
ATCxxxxxxxxxxxxxxxxxxxx2.7%

In an advisory circular AC no: 120-62 the FAA recommends the use of the Takeoff Safety Training Aid to operators. It is recommended that the training aid is incorporated in the operators flight crew training and qualification programs of operators. FAA inspectors are required to check the operators manuals and training to asses if the Takeoff Safety Training Aid is used and guidelines are followed. In 2004 the pilot guide to takeoff safety (section 2 of the training aid) was updated. The study period was extended from 1959 up to 2003 and accident data was supplemented with 25 additional rejected takeoffs. The additional data showed that the rate of rejected takeoff decreased. The engine related rejecting takeoffs decreased and wheel/tire failures increased by a small percentage. In late 2006, the Flight Safety Foundation initiated a project entitled Runway Safety Initiative (RSI) to address the challenge of runway safety. An in-depth study was conducted of all runway excursion accidents from 1995 through March 2008 to investigate the causes of runway excursion accidents and to identify the high-risk factors. Data was analysed to identify the most common risk factors, both in takeoff excursions and landing excursions. The most common risk factor in takeoff excursions was a rejected takeoff initiated at a speed greater than V1. Loss of pilot directional control was the next most common, followed by rejecting the takeoff before V1 was reached. This study concludes that a mishandled rejected takeoff increases the risk of takeoff runway excursion. Operators should emphasise and train for proper execution of the rejected takeoff decision and training should emphasise recognition of takeoff rejection issues. Furthermore Cockpit Resource Management and adherence to Standard Operating Procedures are essential in time-critical situations such as rejected takeoffs. A recent study (2010) by the National Aerospace Laboratory, in the Netherlands compared rejected takeoff events for the period 1980-1993 with the period 1994-2008. The split 1993-1994 was chosen because in 1994 the Takeoff Safety Training Aid was introduced. The NLR study shows that the occurrence rate of rejected takeoffs in general has decreased, however the rate of high speed rejected takeoffs has not changed. In the NLR study the decision to reject a takeoff is also examined. The study shows that the correctness of the decision to reject a takeoff before and after 1994, the introduction of the Takeoff Safety Training Aid, has not increased. The statistical information on the correctness of the decision to reject a takeoff is based on hindsight. Pilots at the time thought they were making the right decision. The study concludes that especially in complex situations, for example a combination of engine failure with significant vibration, it is difficult to assess. Assessing a complex situation and deciding to reject the takeoff is also not well trained. The study points out that the lack of reference as to what might make the aircraft unsafe to fly makes it difficult for crews in recognising such a situation to make an appropriate decision. It should be noted that care must be taken in comparing the positive (yes) and negative (no) decision to reject the takeoff. The undetermined reasons of correctness of the decision has increased in the period 1994-2008 versus 1980-1993.

REJECTED TAKEOFF DILEMMA

In the past industry initiatives and studies have identified that rejected takeoffs are a high risk area. Analysis of available data highlighted that after V1 and VR a runway overrun is likely and could potentially result in aircraft damage and/or loss of life. Statistics further show that the rate of rejected takeoff is declining. However the rate of high speed rejected takeoffs is not. In general past studies conclude that if procedures were followed the outcome would have been different. This conclusion it subsequently followed by the recommendation that flight crew should follow procedures and act accordingly. Despite simulator training on rejected takeoffs and instruction on the risks of (high speed) rejected takeoffs flight crews, when faced with a problem in reality, do not always react desirably and follow procedures. This is mainly due to the fact that during takeoff the interaction between the aircraft, environment and crew are tightly related. This interaction may result in a complex situation which is unfamiliar and difficult to assess. Technical monitoring and warning system were introduced into aircraft in the past which, when appropriate, would warn flight crew of a problem. This warning system monitors aircraft condition and should help flight crew in assessing situations correctly. In this event no warnings were triggered and the aircraft did not indicate there was a problem. From a manufacture standpoint the aircraft was therefore airworthy and safe to fly. The control check performed before flight is, in part, to assess the aircraft state and verify control responses. The environmental conditions like snow and rain on a runway are addressed in manuals to help flight crew in determining aircraft performance and make adjustments. This information is used to set preconditions and determine decision speeds. The fact remains that despite aircraft monitoring and managing preconditions impacting aircraft performance unexpected situation may occur. On takeoff the flight crew rely on perception and interpretation of situations. This perception and interpretation provides opportunity for errors in decision making. Guidance, procedures and training should help pilots in the decision making process in the critical phase of flight. With the current state of technology and human factors theories available, a re-evaluation of the rejected takeoff concept and procedures may be useful and warranted.

[john_tullamarine]

I have very rarely seen a runway limited case.

Depends on Type and runway. I have worked with operators where the limitation on RTOW was just about invariably runway length.

Most of the times second segment or obstacles is the limitation.

Often the case but cannot be relied to be so. A problem is that the RTOW chart may not explicitly state the limiting case on the day.

Can that be the reason for the high V1 VR values, that the optimum speeds are sort of an improved climb?

Certainly, one wouldn't normally be looking to exploit improved climb by pushing the V1 down.

It is better to stop a wreck and overrun the runway than become airborne and crash.

All a risk management exercise. If the overrun is benign, of course. If tiger country (eg have a look at Nauru) perhaps not so clearcut. However, what is clear is that SOPs cover the reasonably routine - a well trained and educated captain gets to handle the hard ones .. presents a problem if the captain is a bit underdone.

But the good thing is that chances of choosing the correct action are much better than in the instinctive reaction.

That's the one. Run with the numbers and keep your fingers crossed that today you are not at the wrong end of the distribution curve.

It is, however, necessary to understand that there are occasions where the normal gameplan(s) won't work and, if you get it right (or at least get away with it), you get the bouquets (Sioux City, the Hudson, and a few others come to mind). If things don't work out so well (we don't need to cite instances) then folks tend to look down their noses.

The captain is called on to make a decision and implement it. The important thing is that a rational decision be made .. longterm fence sitting generally doesn't cut it. The outcome often involves a bit of planning, a bit of skill, and a LOT of luck.

ssg to follow

... that's a bit cruel ?

[mach5]

I guess V1 is limited by all of the following factors
* Vstall speed
*Vmcg
*Vmca
*Vmu
and the runway length should also be a limiting factor , guys just correct me if I am wrong in any points

[westhawk]

I accept that a Citation pilot may have a different thought process to a quad driver with 300 tons + more inertia. But then again, should they??

I don't see any reason why they should. Smaller airplanes have smaller wheels, brakes and tires to go along with their diminutive mass. And they routinely operate into much shorter runways. In the bizjet types I've flown, we run up against most of the same performance limitations as any other transport category airplane does. The same analytical approach to takeoff performance planning is required and the same penalties for any miscalculation or ham-fisted execution apply. Do it wrong and you might not like the results.

So no. I don't think the thought process is or should be all that different. Except that nobody does it for you. You have to know how to do it yourself.

[thermostat]

Centaurus,
One of the reasons for removing the hand from the thrust levers at V1 is to prevent the TRs from going to idle should the seat slide back on rotation with your hand on them. Would be fatal !!

Galaxy flyer,
I remember a DC8 crash where on a severe bounced landing the go around was initiated with the wing on fire. It crashed 2 miles from the airport after the wing burnt off and it went in. I'm sure there are others if we look for them.

[john_tullamarine]

Pilots that have a preconceived idea that should they feel that the aircraft is not fit to fly, that they will stop even after V1

The general rule is along the lines that the pilot has to have a conviction that the aircraft is not going to fly .. unless the wingtip is dragging on the ground, the aircraft is blazing away on fire, three engines have failed after going through the flock of birds .. or something of like ilk, that's a big call.

The exception should never be used to argue a rule .. rather, in just about every case, we are better off running with the SOP .. if we die, it just wasn't our day to go flying. He who runs on a wing and a prayer and acts capriciously .. probably will end up dying far earlier than the rest of us.

I accept that a Citation pilot may have a different thought process

Long time since I looked at a Citation AFM but, as I vaguely recall, it has a very low Vmc and overall pretty good field length figures ?

[Brian Abraham]

It's only a matter of time when another fool who 'pulls it off no matter what at V1, then flies the unflyable to the scene of the accident'
Amazing how many guys would watch a non-event RTO and still think the pilots should have pulled it off into the soup and fought the problem up there.... Things are not always as clear cut as you would like us to believe. Read the human factors section on this,

http://www.fomento.es/NR/rdonlyres/24451F6D-3AC8-40F0-8D74-F611D46EF39C/14154/1982_031_A_Spantax_English1.pdf

And another,

http://www.ntsb.gov/doclib/recletters/2010/a-10-046-059.pdf

Perhaps they would have fared better had they pulled it into the soup and fought the problem up there. But hind sight is always 20/20 heh SSG. (No criticism implied or intended of the crews).

[Basil]

In a rare exception to following SOPs, a GF colleague flying a TriStar in the eighties abandoned just after V1.
I'm sure this will be read by those who remember a bit better than I but, IIRC:
Something went 'BANG!'
They stopped.
Subsequently discovered that only 'D' hydraulic system remained.
'D' system didn't do very much. :ooh:

[whenrealityhurts]

The common thinking in aviation is to find answers, post crash, and use those answers as a preventative to future similar problems...this is of course a hypothetical solution to a real problem.

When an aircraft simply pulls the throttles back post V1, only to taxi back to a hanger, find a mechanic...it's not even an incident, never makes the NTSB reporter, much less an FAA call...and how many times has this happened...more then you realize.

The myopic view of aviation is to look at all the accidents, typically performed by pilots at their worst, then somehow find consensus with those sad folks, rather then look at the pilots who took a potential newsworthy accident, turned it into a non issue...the answer therein lies with those that have successfully found outcomes to the problem at hand, not trying to find answers in the rubble of idiots who couldn't.

I'm not saying we shouldn't look at accidents, but why should I be held to a SOP because some moron crashed the plane, because he made a bad decision, or by some airline that hires from the bottom of the resume pile, using 'Flex to the Fence, etc etc.???

[Brian Abraham]

When an aircraft simply pulls the throttles back post V1, only to taxi back to a hanger, find a mechanic...it's not even an incident, never makes the NTSB reporter, much less an FAA callThat's most odd, because the FAA say,
B. Occurrence (PTRS Code 1725, 3720, 5720). An occurrence is defined as an event that is not readily discernible as an incident. Events, such as a low speed abort or a turnback are considered occurrences and must be investigated to determine the impact on safety of operations.
C. Correlation Between an Occurrence and an Incident. Not all events that are brought to the attention of AFS have an obvious impact on the safety of operations, nor are they readily identifiable as an incident. Until an event can be identified as an incident, it should be regarded as an occurrence. The advantage of labeling an event as an occurrence is that it allows for an investigation of the facts for an accurate identification of the event without generating unnecessary reports.

NOTE: Safety improvement recommendations may result from either incident or occurrence investigations.
And that's aborting prior to V1. Must be really professional operators that you deal with.

[john_tullamarine]

It's really all about the need for routinely operating in a disciplined (ie the opposite of a cavalier winging it) way of doing business.

.. abandoned just after V1... Something went 'BANG!'... They stopped. Subsequently discovered that only 'D' hydraulic system remained. 'D' system didn't do very much.

Hardly the basis of a well executed decision process. The history, on this occasion, says "thank heavens for that". However, on any sort of rational risk managed approach to life, the decision probably was grossly flawed if the story is as presented.

The important thing is to compare the historically based probability of successful versus unsuccessful outcomes in the situation where the reject is initiated late.

The common thinking in aviation is to find answers, post crash, and use those answers as a preventative to future similar problems

exactly the situation .. providing that we are working to a probabilistic gameplan rather than generalising from the exception to a rule.

The myopic view of aviation is to look at ..

The SOP view of things is that we should accommodate the average sort of capability. While the superhero pilot (and these folk exist - a frustration to the lesser abilities residing in the rest of us) may well be able to fly after losing both wings, all engines, etc., etc., most of us are just plodders trying to do our best on the day .. and we do better if we load the dice in our favour.

[whenrealityhurts]

John, well maybe because I have command experience, that I can't work on probabilities...a bang in the tail after V1, with 6000 feet ahead gives me the choice of stopping a rolling aircraft with twice my landing distance ahead, or taking it up in the air, and hoping I have a flyable aircraft...

Now if we get to brass tacks and have a big stadium full of pilots discussing this...I would move to exclude all the pilots who don't have 10,000 hours, who work for airlines who push V1 down the runway with Flex and such, for airlines who purposely run around with 30000 hour engines...exclude high time FOs and Flight Engineers that never had the wherewithal to be captain...

Now what are we left with...guys who have command of a ship and say...'what the heck, let's fly it up there and see what the problem is?'

Fat chance.

[john_tullamarine]

Good sir,

One can only suggest that we should agree to disagree.

The whole Industry is based on probabilities - in general, there are few certainties, if any, about aircraft. That's the nature of distribution curves and probabilities of failure.

with 6000 feet ahead gives me the choice of stopping a rolling aircraft with twice my landing distance ahead

Of course it does.

Now, whether such a decision, on a routine basis, is sound or not is a matter for standardisation debate.

As an aside, what do you do in the case where you have, say, 300 - 400ft spare pad in front at V1 with tiger country in the overrun ?

[whenrealityhurts]

Looks like I caught your inexperience John...

Run any Part 25 aircraft you want, your choice...and tell me where you can in any way possible be at V1, using legal balanced field numbers and only have 3-400 feet ahead.

It illustrates my point that you guys are purposefully de-rating the thrusts so far back where your balanced field isn't even on the runway, and extends into the weeds somewhere.

Discussion over.

[mutt]

Your question doesn't make sense, we operate a LOT of FAR25 aircraft, some with a MTOW of 16,000 lbs and others with about 870,000 lbs. Almost all of these use Balanced Field takeoff calculations. It is very easy to get a Balanced Field Length Required which is 300-400 feet less than the Available Runway Length. So what's the issue.

As for the second question, where do you get the idea that your balanced field isn't even on the runway, and extends into the weeds somewhere. Do you understand the concept of DERATE at all? Do you know the difference between calculating a takeoff at 40C OAT or assuming that the temperature is 40C?

You need to jumpseat from somewhere in a 747 classic when it really is Field Length Limited, especially if the clearway is used :):) You might end up having a different perspective on things :ok:

J_T....with tiger country in the overrun ?... So true, I wonder how many pilots know what lies right at the end of the runway, case in point look at Surabaya Indonesia, nothing on the airport charts shows that there are massive drainage ditches off the end of both runways, large enough to take your undercarriage off :{

Mutt

[Brian Abraham]

Looks like I caught your inexperience John...Ignorant little **** isn't he. Post your CV John. :ok:

maybe because I have command experienceIt has been proven time and time again with your numerous aliases that your experience is zip, narda, zilch, nothing.

Posted least anyone should contemplate giving any credence to his ravings.

[bubbers44]

V1 is a very critical speed at balanced field length airports. It means as we all know we can stop before and go at it. If you don't abide by it you get in big trouble or maybe die with your passengers. True, longer runways you can probably still stop but you are still in trouble. If nothing happens and you reverse to lower speed before brakes you still have the explaining to do if it gets reported. Safety is #1 so use that to decide what you are going to do. The AA DC10 at ORD would have been just fine if they hadn't followed company procedures and slowed down to V2. They might have been in trouble but they would have been alive with their passengers. Just a thought.

[Brian Abraham]

They might have been in trouble I very much doubt it bubbers. On one hand you could make the case that their training killed them (slowing to engine out speed schedule), but what the accident highlighted was,

1. The accident scenario had been considered during design, but considered to be so highly improbable as to be not worth worrying about, and the FAA agreed.
2. No instrumentation to inform crew of slat asymmetry

It's all those little holes in the cheese, the crew were blameless.

[whenrealityhurts]

Mutt - You don't get a seat at the table to discuss if at the end of the day, your running de-rated departures, flying around on 30000 engines, and packing the cockpits with kids.

Begs to ask the question how many other areas of safety your cutting corners on.

[mutt]

Looks like I caught your inexperience John... You don't get a seat at the table to discuss if at the end of the day It's appears that you are following the usual cycle, when you can't discuss the technical merits of something, you get personal, then you will usually get abusive and banned from the forum, only to re-invent yourself again and start over......... It's getting kinda boring :{:{

As someone who has read J_T's real resume, I would suggest that you might actually learn something from him, IF you had enough common sense.

your running de-rated departures Very true, all fleets except one :ok: Oh yea, we will also do them on the 787 and 747-8.....

your flying around on 30000 engines, Nope, most of the fleet won't even have 3000 hours on the engines [/QUOTE]:ok:

and packing the cockpits with kids. Nope, haven't you read our local newspapers?

Given that we are certified under FAR91/121/129/135 with ISO Certification, LOSA and IOSA certifications...... why would you think that we are cutting safety corners on aircraft performance?

Mutt

[PLovett]

@whenrealityhurts

Looks like I caught your inexperience John...

No sir, you have been hoisted on your own petard.

What J_T wrote was;

what do you do in the case where you have, say, 300 - 400ft spare pad in front at V1

To which you responded with the derogatory comment above and continued with;

Run any Part 25 aircraft you want, your choice...and tell me where you can in any way possible be at V1, using legal balanced field numbers and only have 3-400 feet ahead.

This shows that you completely misunderstood what you were replying to. If you read it properly, John's hypothetical was postulating the case where there is only 300 to 400 feet IN ADDITION to the distance required to stop the aircraft from V1. The critical word is "spare".

A little more thought and less posturing might have led to you having a better understanding here.

[john_tullamarine]

Aside - for those who might have any concern as to my delicate ego .. have no angst, for I have a thick skin and broad shoulders ...

Inexperienced I may be in many matters .. but in respect of a few I have a passing knowledge. The secret, as most older chaps have come to understand, is to refrain from comment on the former and be prudent in the latter. Occasionally I fail to observe my advice in respect of the former .. there is always the expert who, gently or otherwise, draws my impertinent ignorance to my notice ...

The AA DC10 at ORD would have been just fine if they hadn't followed company procedures and slowed down to V2

While not being at all critical of the poster's observation, it is pertinent to note that, at the time, Industry standard teaching was to fly V2 OEI which the crew did. This was one of those rare out of left field events where the then current rulebook item needed to be ignored .. had the crew had any clue as to the true nature of the failure.

As I recall, it was this mishap, specifically, which led to a revision in thinking to adopt the current approach whereby one holds the present speed at the failure (unless that be excessively high, typically in excess of V2+20-30 or thereabouts).

If you want to play with the big dogs - don't pee like a puppy.

Priceless. Do you claim rights for this observation or may anyone use it on occasion ?

[Slasher]

Looks like I caught your inexperience John...

What an arrogant little 29yo brat you are. I have known John
before you were even a hardon in your old man's pants, and
even back then what he didn't know on the subject did not
bloody matter!

And from what I just read I agree with Unhooked - your lack
of knowledge re reduced thrust TOs stands out like dogs balls.

[Basil]

JT,
Re my story about abandon after V1.
I did not wish to present it as a suggested mode of operation but as an exception.
I'd probably have continued - that captain, on the day, did not. I've mulled that one over for years. Will publish when I come up with an answer.

I would move to exclude all the pilots who don't have 10,000 hours, who work for airlines who push V1 down the runway with Flex
I've met top rate pilots with a LOT less than 10k - and a couple of prats with more.
I'd be excluded because I've never worked for a jet outfit which did not use reduced thrust.

[john_tullamarine]

SOPs are a two-edged sword.

They are sound and desirable to follow on the very great majority of occasions due to the probabilistic nature of our activities.

However, there are few, if any, guarantees in flying.

If/when the ducks are lined up against your interests ... on the rare occasion it may be more sensible to ignore the rule and do something different.

However, these rare exceptions ought not to be generalised into some sort of rule-based behaviour.

Two takeoff instances which come to mind -

(a) post V1 with multiple systems failure which will preclude safe flight .. for instance, I wouldn't envy a pilot with a combined engine failure and total hydraulic loss.

(b) low speed schedule with an uncontrollable yaw post V1 OEI again probably due to a systems failure

While noting that the certification paradigm safeguards against such things - in general - if we find ourselves on the wrong end tail of the distribution curve .. it was a day that we ought to have stayed in bed .. and it is then that the Captain gets to earn his/her salary in a few seconds. No necessary guarantees in many instances that the fallback gameplan will work. However, if it has a significantly higher probability of success, it has to be adopted if the main plan clearly has gone irrecoverably awry.

It is for this sort of reasoning that this type of thread is important. It makes the reader think about things ahead of potentially being confronted with something similar.

I did not wish to present it as a suggested mode of operation but as an exception.

Precisely.

[whenrealityhurts]

JT - I suspect your vision of aviation being so chancy is relative to your ability to mitigate the risk...which in an organization where your told what to do...you can't.

Flying for the airlines is like being a soldier about to hit the beach in Normandy...'isn't there a better way to invade France?'

'Shut up and do what your told'.

[mutt]

'Shut up and do what your told'. Haven't you realised that we are the people who define what others do, if you had given us a sound technical reason to question our modus operandi, we would have listened, but alas you failed miserably. .

Mutt :)

[galaxy flyer]

WRH

Please cite your FAR 121 or similar experience (Military heavy jet, JAA ops, etc.) before you state opinions on subjects you seem to know nothing.

All of certification and operational standards are based on probabilities of success or failure, safety itself is based a probability once one leaves the bed each morning, yet we do and in the die in bed.

Your method of aviation appears based on gut feeling, seat of the pants, Kentucky windage. You seem to think you can experience a failure, take a glance out the windshield and decide to stop or not. Obviously, performance theory and practice is a wasted subject on yourself. Once before, I asked if you always calculated a refusal speed (accelerate-stop speed for the runway) for each take-off you do in whatever flying machine you are trusted with, the reason being, so you would know when you could no longer stop. Never answered that one, did you?

I have known of three cases where the performance in the V1 situation was tested. Two, I personally knew the individuals involved; one I witnessed. All, straggly involved bird strikes right near V1 or in the time between V1 and Vr.

The first two, involved loss of one engine between V1 and Vr, the captains took it airborne, as recommended by the "book" and the performance data. They would have clearly overrun with 60 or more knots. The one I saw happen carried 140,000 pounds of HE for the little dustup in '91. Both had additional problems with a second engine after they got airborne with large vibration moments. Both planes landed successfully, one out of a minimums PAR. The resulting investigations upheld the decisions of the captains, one got a peacetime DFC. The point being planes will deliver the performance specified and nobody ever had a collision with the sky--planes are meant to be there.

The third case was a rejected take-off at NAS Sig, where birds struck the plane just prior to V1. No damage was noted, but the commander, who expressed similar stop orientation as you do, elected to stop. I was in the jump seat and really thought we would go off-roading. We made it with feet to spare--the end of the runway was not visible from the front seats, 34 feet above the ground. All of these incidents were thoroughly investigated, resulted in no changes to the SOP and occurred in planes weighing 600,000 pounds or more.

The point of this dreary tale is that pros do NOT merely "do as they're told", they are learned in performance planning; know that briefed SOP is a far, FAR better response to an emergency and odds are vastly more in everyone's favor if one follows it, rather than inventing responses in the "heat of the battle". If you need proof of this, sit thru some tough sims and watch guys struggle making answers up and crashing.

Mutt J_T

Besides US Mil bases where the clearance standards are exceptionally high (basically 1,000' of surfaced overrun plus level ground 500' either side of centerline and extending beyond the overrun), I have seen many, MANY more airports with very nasty terrain beyond the runway than ones with benign areas. Many have drop-offs greater than 50', highways, etc. The KTEB overrun, where the pilot did a "SSG" rejected take-off, crossed a major highway, critically injuring a motorist and smashed into a bakery. He just got sentenced to 180 days of "3 hits and a cot". SWA overran at KBUR into a gas station "eyeballing" an wildly unstable approach, as they did at KMDW, killing a child in a car. Ignoring the considered wisdom KILLS.

GF

[westhawk]

Hey GF,

I was with ya right up to last paragraph. (see below) I agree with most of what you, John and others are saying with regard to to the proper attitude to take towards stopping beyond V1. DO otherwise at your own, your pax and any innocent bystanders peril. I adopted this attitude early, even before I understood enough to really know why.

But the corners of the statistical bell curve are there and exceptions to the rule do exist. Whether any of us as individuals will recognize that in real time during a real event is the more compelling question. Perhaps it's as postulated by JT and it just wasn't your day to go flying. But it's also possible that people sometimes make correct decisions contrary to policy without a satisfactory explanation as to why. I've seen it and you probably have too. We often call that luck. When good pilots follow procedure to the scene of the crash, we often call it fate. Or a bad day. Bad luck. Seen that too.

So about that last paragraph GF:

The guy sentenced to the pokey in the Challenger overrun at TEB was locked up for falsifying W&B and other records. There's some CFR other than 49 which covers that. I don't think the flight crew faced any criminal charges for being dumb, though I don't know what if any administrative action was taken against the crew by the FAA. They rejected because the nose failed to lift in spite of full up elevator being applied. Had the takeoff been continued, it would have either become airborne or hit the building at V1 plus whatever speed was gained since passing Vr. I don't know which would have happened and neither does anyone else. Obviously there are cases where a 60 kt overrun yields less disastrous results than a 150 kt plus overrun. But maybe anyone careless enough to get themselves into that situation by grossly misloading the aircraft to begin with has problems enough. I wonder if running the pitch trim NU might have helped? I'm glad the crooks at that company got convicted.

Sometime earlier, the exact same thing happened in another Challenger at TEB. They were lighter and had more runway beyond the BFL and so stopped successfully. Lucky dogs!

A very similar thing happened to a Falcon 900 in SBA, but it was loaded properly and the stab trim set within the takeoff range, though not in the ideal position for the CG. They ended up in a grass field with a damaged airplane and no casualties. DA-50/900 pilots have told me they would have run the trim up if that happened to them. I wonder.

SWA BUR: Nothing to do with V1, just an incredibly ill advised approach, poorly executed and completely lacking in airmanship. 182 kts at the threshold. The FO did everything but bust him in face and take the airplane. Maybe he should have.

SWA MDW. Again a landing accident. But not one which was cavalier or off the cuff by any means. The data indicated it was tight, depending on which runway friction value was used. we all know (or should) how well (not!) runway condition or friction reports correlate with actual performance. In any case the performance study indicated they might have stopped had the reversers been deployed in a timely manner. Autobrake was a new procedure and he'd never done it before, so his (the PIC and PF) performance probably suffered as part of executing in an unfamiliar procedure for the first time while facing "the real thing". SWA subsequently added a fair weather familiarization period to get used to A/B landings. Read the full report, it's very interesting.

So other than picking these three examples to fortify your point, I like your post! Sorry to pick on your post like this because I respect your contributions. But I just couldn't let it slide.

My experience is with smaller jets, but it's the same process using smaller numbers.

Hey it's time for Formula one. See ya!

Best regards,

[galaxy flyer]

Westhawk

Enjoy the race!

First, I apologize for the unintended implication that the criminal case resulted from the overrun; it, indeed, was due to other certificate issues. Although, I would submit their casualness about certificate issues drove their casualness about flight ops. Rarely are well-managed, safe flight ops run by dysfunctional or criminal managements.

My point in that last paragraph was related, not to V1 concerns, but to the fact that most runways have very dangerous conditions in VERY close proximity to the EOR. Getting blasé about the possibility of an overrun can be very risky due to the terrain/structures within reach, even in a low speed overrun. I was at a Pacific island airport recently, 75' overrun, followed by a 40' dirt drop- off to the road below. Go off that edge, even at 15 knots, could be fatal.

Our overheated correspondent blows strong against CRM, too. Look at KBUR, were a headstrong captain failed to use the FO's valid concerns--a failure of CRM, not CRM causing an accident.

Lastly, yes, bigger planes, bigger numbers; the basic physics doesn't change, just the magnitudes. For the life of me, I don't understand pilots who get casual with W&B and trim settings. In the USAF, we periodically were given bad data to generate just the situation as at KSBA. Running the trim is often the only situation, but you really need to avoid the situation, in the first place. I had a pilot say, "8 degrees light, 9 degrees heavy", aviation has no room for such casualness.

All that said, as a result of this, and similar discussions, have been considering briefing the "unable to fly" response, especially when large amounts of excess runway exist. The other day at DXB, we had a field length of around 3,900' on 13,123', stopping anytime until actually airborne was reasonable. Every take-off plan in the C-5 included refusal speeds, which gave one an idea what was possible, but what good is a refusal of 170 knots when rotate was 122?

GF

[westhawk]

GF:

Wow, great race!

Vettel continues his domination by winning his 7th race in '11. Weber manages 2nd and Button makes a great drive to take the 3rd podium position. Hamilton crashed out again. Alonso struggled for 4th while Shumie makes an incredible drive from starting dead last to finish 5th just ahead of Rosberg.

Now what were we discussing? Oh, right!

"Dysfunctional and criminal managements".

Well put. My first 135 job was with a somewhat "shady" outfit you might say. Our operating philosophy as pilots was to do the right thing in spite of the company. The owner was just smart enough to stay out of our way and we actually ran a pretty clean op from our end considering. But a year was enough. The next 7 years were thankfully spent somewhat less stressfully in more robust safety cultures with better training, maintenance and standards.

"Go off that edge, even at 15 knots, could be fatal."

Yeah, I saw that happen with my own eyes at KSMO once. They fried in the fire before we could get there. Idiot took off with the gust lock installed in his C-340 and unsuccessfully aborted from 100 plus knots. A drainage culvert at the end cleaned off the gear and opened the tanks. Exit speed was probably less than 40 kts. Really nice guy too, but dead all the same.

As to our friend of strong opinions, I don't know what to say. But you know what they say about opinions...

"For the life of me, I don't understand pilots who get casual with W&B and trim settings."

Yeah. Maybe a selection of NTSB reports should be required reading. Maybe you don't have to repeat the mistakes of the past to learn their lessons. Learning from your own experience is good. Adding the experience of those who came before is a learning multiplier. It bothers me that some pilots seem to think required training is enough learning. This aviation stuff encompasses allot more than any company will teach in a classroom or simulator. Put in a little extra work!

I got to ride up front in a Galaxy once. Just myself, one other space-A pax and the crew repositioning an empty C-5 from Travis AFB to MCAS El Toro on the last leg of my trip home from Germany on MAC flights. That big boy leaped off the runway like an empty Learjet! I'd guess the takeoff on their next leg from El Toro to Clark with a full load of Marines and all their stuff was pretty different. It still amazes me that these things actually fly! And I still don't quite understand how that one got piled up at Dover. I read the report years ago and think I understand the flight dynamics involved, but not the crew actions.

Best,

[galaxy flyer]

west hawk

Yeah, I took off at Kaneohe Bay to Honolulu once with 28K on fuel, empty. One swoop to 9,000', idle, cleared visual; far different story above about 732K gross weight. Not a lot of power out of those 60's vintage GE hair driers. Many, many take-offs required the entire runway, standing take-off and every inch of runway. 0-120 knots was, typically between 33 and 39 seconds.

Speaking of rejected take-offs, reducing your engine choices down to ONE doesn't make it much easier. Last F-100 RTU class, we were lectured by Vietnam vets on th dangers of high speed rejects. The plane took off at about 165 knots, had a drag chute and marginal brakes. The instructors emphasized the dangers and said taking most problems airborne was preferable.

WRT KDOV accident, dysfunctional leadership is in the background, an IP who shouldn't have been made one, poor CRM skills on the IP's part, resignation and fatigue all play role. But the man in the left seat shouldn't have been there and the two other pilots failed badly to correct the situation.

GF

[john_tullamarine]

I suspect your vision of aviation being so chancy is relative to your ability to mitigate the risk

First, I see (scheduled and high end corporate) aviation as having a very high reliability (ie not all that "chancy" as you put it) - the daily successful total of operations provides evidence of that. Caveat - this is not to say that GA has an inherent lack of discipline and safe history - only that it covers a far wider range of activities wherein the less safe taint the statistics of the more safe.

Secondly, if one intends to pursue a strategy other than SOP (and this either can be in respect of managing emergencies or planning non-typical operations), one needs to be able to quantify the risk in order to mitigate it with a reasonable degree of confidence. The necessary safeguard with this approach is that the approval signoff has to be elevated to a level appropriate to the assessed risk - ie often the PIC is not the appropriate level to authorise the non-standard operation (for the planning situation).

In those cases where such quantification is either impractical or time does not permit adequate research

(a) the solution gets progressively closer to the "wing and a prayer" style of management

(b) the SOP approach remains, in all likelihood, the preferred option.

As one who works in a particular environment where "risk mitigation" is a routine buzz phrase, I see many instances of good intentions based on qualitative gut feelings - not quite what the paradigm intends to be the case but better than just winging things on the day.

[whenrealityhurts]

JT - Well your in fine company....

You would have given your seats up like the first three 9/11 crews...

You would have gone through the fuel dump procedure, rather then get it down in Nova Scotia..

You would have continued with a fire light on the Concorde..

You would have sat up there on the phone messing with the trim while jack screw got worse and worse and worse...

Your 'I don't think, I do what I am told' approach to aviation is a credit to all the airline chief pilots who have specifically culled any independent reasoning ability out of it's ranks.

[PLovett]

@whenrealityhurts

I rarely comment on posts such as yours but I can't help myself this time.

Your ignorance regarding the underlying principles of safe aircraft operation are on public display with your last post.

The examples that you have cited in support of your position spits on the memory of the air crew and the passengers that died without offering any positive aspect for your case.

The gratuitous insult that you offer only serves to denigrate yourself and any positive effect (however slight) your posts may have had.

If you really do have the experience that you cite and are actually employed I trust that I never have the misfortune to fly with you as I would be in fear for my life.

[galaxy flyer]

WRH

You really should read those accident reports; not the press reports. You have simplified the chain of events to fit your "point of view", untroubled by real knowledge though it maybe.

All four planes on 9/11 we forcibly taken, not the first three. Flight 93's passengers tried to recover the plane and crashed in the ensuing battle. The hijackers just didn't walk in and ask for the planes and the crews gave their planes to them. To say otherwise is to display your total lack of knowledge of history.

GF

[SFI145]

WRH
I thought John Wayne died some years ago?

[clevlandHD]

WRH, please state who you work for so we can all steer away...
(this guy can't be for real)

[westhawk]

Sometimes even poorly presented and what many would consider to be extreme points of view contain elements of truth hidden beneath the hyperbole and histrionics. I'll attempt to find some nuggets of wisdom in WRH's last post.

You would have given your seats up like the first three 9/11 crews...

Galaxy Flyer addressed this point already, but I'll add that while government and airline policy directives promoted "cooperation" with hijackers right up until that day, not every airline pilot planned to "blindly" comply. Even so, none of these crews had any reason to suspect the hijackers ultimate intent at the time the airplanes were taken. Prior to that, most hijackings were perceived to be for the purpose of hostage taking for some form of ransom. This perception was apparently a key element of the terrorist's plan. Had these crews known what their ultimate plan was, well let's just say they might have reacted differently. They would now.

I find the question asked to be an irrelevancy and a poorly selected example case to use in an argument apparently intended to promote pilot discretion and critical thinking during an abnormal event. Not much wisdom here.

You would have gone through the fuel dump procedure, rather then get it down in Nova Scotia..

Who knows? We weren't there and we're not sure what information would have been available to us if we were. But I'm reasonably sure that in-flight fires and electrical shorts are something most pilots would consider a higher priority than meeting landing weight limitations. Then and now.

This accident does drive home the point that proper prioritization of objectives is a command function. I think it always was.

You would have continued with a fire light on the Concorde..

I don't know enough about the details of what the flightcrew knew at what time to say. But in this airplane especially, a high speed abort from above V1 with failed tires and fuel pouring out doesn't seem likely to have produced a better result.

Again. maybe not the most applicable case to cite.

You would have sat up there on the phone messing with the trim while jack screw got worse and worse and worse...

This one I can find some agreement with in large part. No I would not. Not then, now or ever. But then I am an experienced mechanic in addition to to my piloting background. I've worked on similar stab trim systems and know/knew what this set of symptoms imply. The company mx controllers and others in the company should have too. While the flightcrew thought they were doing the right thing, there was information to the contrary readily available to the mx dept. This information was NOT made available to the crew. For those willing to spend many hours researching this whole affair, the full story is a stinging indictment of a company cost savings plan gone wrong and a series of what I believe to be reprehensible management actions.

Considering what the crew could have reasonably be expected to know and do given their qualification as pilots, the blame rests squarely on the company. Though some individuals like myself had knowledge beyond the scope of what might normally be expected of flightcrew, that does not serve as an indictment of this crew's following of the direction provided to them by their company, who they might well have reasonably believed knew more than they.

Overall, another poor example even though there is some truth in the argument.

Your 'I don't think, I do what I am told' approach to aviation is a credit to all the airline chief pilots who have specifically culled any independent reasoning ability out of it's ranks.

Do I detect a slight hint of contempt for authority figures here? :)

Well that's understandable. Particularly in today's aviation business environment. Still, it's not an attitude one wants to become widely known for. Perhaps many pilots have made a conscious decision that it's better to question authority more quietly, in a way that doesn't needlessly expose them to unwanted managerial scrutiny. Seems kinda spineless? Such is life in the modern corporate machine. Get used to it, cuz it's here to stay. But that doesn't mean one has to do something they know to be wrong. In real conditions of duress, you may find your fellow pilots to be less sheeplike than you seem to believe. However I have to opine that one would be well advised to reserve acting contrary to SOP or accepted policy for situations where the "accepted" or conventional action is either clearly inappropriate or inapplicable to the circumstances. None of the above examples clearly pass the test. Maybe a better example?

So bringing this back to the subject rejecting a takeoff after having accelerated beyond V1.

Of course we can think of circumstances when the potential consequences of aborting beyond V1 might be preferable to the consequences of continuing the takeoff. Under a "system approach" to the problem, statistical analysis will be a large component of any policy promulgated by airlines, manufacturers or regulators. As the commander of an airplane, your obligation is to do whatever is necessary to preserve the safety of your flight. It may come to pass that doing so requires a departure from regs, policies or established procedures. If so, your every move might later come into question. If you're wrong there may be consequences of a professional, legal or mortal nature. This is what you accept every time you sit down in the cockpit. Rules, procedures and policies define the framework for your operations. It is recognized that operating outside the framework may become necessary under certain circumstances. Better make sure you're right when you do.

Just wanted to let you know: We're all counting on you!;)

[Dimlightbulbs]

Reminds of playing football...the coach gives you a play...you call a different one...you throw a touchdown pass..

One coach is mad...another is glad you got the win...

I follow the line of thinking that if I put points on the board...you can whine all you want about how I am a cowboy...the Prom queen is coming home with me. Results count in this business, not how many buddies you keep happy. Not everyone sees it that way though.

Sully put an airbus into the river...it was either that or hit the side of a building...he gets points for no loss of life...if he had been able to do a u turn, dead stick back to his departed field successfully everyone would have whined about how he could have killed everyone..despite saving the plane as well as people.

Seems the gold standard these days is to what is expected, but if you do a little more your reviled for it. I guess it's ok to be good, just not that good.

[galaxy flyer]

He's baaack......

GF

[Pugilistic Animus]

The bewitching hour is upon us once again...:suspect: