Air North Brasilia Crash in Darwin (Merged)
Grandpa Aerotart
Remoak V1 was long thought of/described as decision speed but so many people went off the end of runways rejecting AT V1 that a rethink was in order. Its better to think of V1 as a decision MADE and ACTION TAKEN speed.
At a previous airline we would remove our hands from the thrust levers approx 5 kts before V1. Where I am now uses a wet V1 for ALL departures which amounts to the same thing.
Either way if you lose an engine a fraction of a second after you remove your hand from the thrust levers YOU ARE GOING and you'll be a fraction below the screen height on a performance limited runway - on a typical runway you pass the end of the clearway at hundreds of feet anyway.
If you decide to reject AT V1 by the time you react, slam the thrust levers closed, autobrakes kicks in (or you stand on them) and the reversers deploy and spool up you'll be significantly above V1 by the time you stop accelerating and start to slow down.
Hence V1 is a GO speed.
At a previous airline we would remove our hands from the thrust levers approx 5 kts before V1. Where I am now uses a wet V1 for ALL departures which amounts to the same thing.
Either way if you lose an engine a fraction of a second after you remove your hand from the thrust levers YOU ARE GOING and you'll be a fraction below the screen height on a performance limited runway - on a typical runway you pass the end of the clearway at hundreds of feet anyway.
If you decide to reject AT V1 by the time you react, slam the thrust levers closed, autobrakes kicks in (or you stand on them) and the reversers deploy and spool up you'll be significantly above V1 by the time you stop accelerating and start to slow down.
Hence V1 is a GO speed.
Moderator
The two are inextricably linked. Accelerate, and the yaw departure risk disappears.
I fear that you have the cart before the horse. If a yaw departure has occurred then there is no option for acceleration to get out of the situation for Vmcg and only descent for Vmca ... the very thrust upon which you place your salvation's reliance is the same thrust which is taking you to your accident .... the thrust must be reduced to regain control. Like it or not ... we can't overcome the realities of the physics involved.
Be very aware that this sort of departure is quite rapid and ramps up very quickly over the spread of a few knots. Difficult to appreciate unless you either have been there or watched the aircraft gyrations under someone else's ministrations.
All multi-engine aircraft are Vmcg/Vmca limited.
Again, I fear you miss the point. A multi can be so limited IF the thrust/speed mix is appropriate. At higher speeds for a given thrust, the takeoff will be limited by some other criterion.
There are very few (if any) situations where an aircraft being used for training, with no payload and low-ish fuel (ie very light) NEEDS to be flown at, or anywhere near, limiting speeds.
I would agree. However, if you choose to use the standard min speed schedule .. and if that schedule is Vmcg or Vmca limited (which it often is) then you need to be aware of the potential for excitement in the event of a failure.
they all allow you to maintain an achieved speed ..
I'm afraid you have quite lost me here .. perhaps you might elaborate on your point ?
there is no need to ever go to the place you are describing. It's a theoretical exercise that only needs to be carried out in the sim.
This is not at all a theoretical exercise. Many aircraft schedule takeoff speeds at low weight which put you right in this sort of harm's way if you mishandle the failure during a continued takeoff. I think that it will be useful for the newchums if we continue with this discussion ?
So what is your point, other than semantics?
Philosophy and SOP. From a risk-based approach to things, the OEMs have, for quite some time, recommended such a black and white approach for normal failure situations.
For what it is worth, I always expect to stop until I hear V1, at which point I am absolutely going unless I cannot control the aircraft, or we have an uncontained fire.
The point is that, under the present paradigm, reaching V1 confirms that you are going to continue keeping on going ... ie if you aren't already stopping then it's up, up and away. (Caveat that this is predicated on "normal" failure situations).
I fear that you have the cart before the horse. If a yaw departure has occurred then there is no option for acceleration to get out of the situation for Vmcg and only descent for Vmca ... the very thrust upon which you place your salvation's reliance is the same thrust which is taking you to your accident .... the thrust must be reduced to regain control. Like it or not ... we can't overcome the realities of the physics involved.
Be very aware that this sort of departure is quite rapid and ramps up very quickly over the spread of a few knots. Difficult to appreciate unless you either have been there or watched the aircraft gyrations under someone else's ministrations.
All multi-engine aircraft are Vmcg/Vmca limited.
Again, I fear you miss the point. A multi can be so limited IF the thrust/speed mix is appropriate. At higher speeds for a given thrust, the takeoff will be limited by some other criterion.
There are very few (if any) situations where an aircraft being used for training, with no payload and low-ish fuel (ie very light) NEEDS to be flown at, or anywhere near, limiting speeds.
I would agree. However, if you choose to use the standard min speed schedule .. and if that schedule is Vmcg or Vmca limited (which it often is) then you need to be aware of the potential for excitement in the event of a failure.
they all allow you to maintain an achieved speed ..
I'm afraid you have quite lost me here .. perhaps you might elaborate on your point ?
there is no need to ever go to the place you are describing. It's a theoretical exercise that only needs to be carried out in the sim.
This is not at all a theoretical exercise. Many aircraft schedule takeoff speeds at low weight which put you right in this sort of harm's way if you mishandle the failure during a continued takeoff. I think that it will be useful for the newchums if we continue with this discussion ?
So what is your point, other than semantics?
Philosophy and SOP. From a risk-based approach to things, the OEMs have, for quite some time, recommended such a black and white approach for normal failure situations.
For what it is worth, I always expect to stop until I hear V1, at which point I am absolutely going unless I cannot control the aircraft, or we have an uncontained fire.
The point is that, under the present paradigm, reaching V1 confirms that you are going to continue keeping on going ... ie if you aren't already stopping then it's up, up and away. (Caveat that this is predicated on "normal" failure situations).
Remoak,
My flying career has spanned the period from SFAR 422B to the present certification standards.
What Brian Abrahams and Chimbu Chuckles ( and I) say is correct. It might only be a subtle difference between your views and ours, but believe me, the difference is significant. It is nor just a semantic difference.
I commend to you a careful consideration of the difference.
Tootle pip!!
PS: A Captain being presented with the ANZ problem in Tokyo recently is an unenviable one. It happened in Sydney many years ago. A Pan Am B707-321B had a multiple engine failure, due bird strike, after V1, at max. gross.
My flying career has spanned the period from SFAR 422B to the present certification standards.
What Brian Abrahams and Chimbu Chuckles ( and I) say is correct. It might only be a subtle difference between your views and ours, but believe me, the difference is significant. It is nor just a semantic difference.
I commend to you a careful consideration of the difference.
Tootle pip!!
PS: A Captain being presented with the ANZ problem in Tokyo recently is an unenviable one. It happened in Sydney many years ago. A Pan Am B707-321B had a multiple engine failure, due bird strike, after V1, at max. gross.
Join Date: May 2007
Location: Western Pacific
Posts: 721
Likes: 0
Received 0 Likes
on
0 Posts
Some quotes from the B777 FCTM -
(my emphasis)
And -
And, finally -
The decision should be made when the event occurs & the RTO figures are based on that occuring one second before V1. In terms of speed, one second will differ on each departure depending on the aircraft type, weight, etc. For my operation I'm with Chimbu chuckles & my hand comes off the thrust levers approximately 5 kts before V1.
As the airspeed approaches V1 during a balanced field length takeoff, the effort required to stop can approach the airplane maximum stopping capability. Therefore, the decision to stop must be made before V1.
And -
When the takeoff performance in the AFM is produced, it assumes an engine failure one second before V1.(again, my emphasis) In the runway limited situation, this means the airplane reaches a height of 35 feet at the end of the runway if the decision is to continue the takeoff.
Within reasonable limits, even if the engine failure occurs earlier than the assumed one second before V1, a decision to continue the takeoff will mean that the airplane is lower than the 35 feet at the end of the runway, but it is still flying. For example, if the engine fails 2 seconds before V1 and the decision is made to go, the airplane will reach a height of 15 to 20 feet at the end of the runway.
Within reasonable limits, even if the engine failure occurs earlier than the assumed one second before V1, a decision to continue the takeoff will mean that the airplane is lower than the 35 feet at the end of the runway, but it is still flying. For example, if the engine fails 2 seconds before V1 and the decision is made to go, the airplane will reach a height of 15 to 20 feet at the end of the runway.
What's important to note here is that the majority of past RTO accidents were not engine failure events. Full takeoff power from all engines was available. With normal takeoff power, the airplane should easily reach a height of 150 feet over the end of the runway, and the pilot has the full lenght of the runway to stop the airplane if an air turnback is required.
Join Date: Jul 1999
Location: PLANET ZOG
Posts: 24
Likes: 0
Received 0 Likes
on
0 Posts
I fear that you have the cart before the horse. If a yaw departure has occurred then there is no option for acceleration to get out of the situation for Vmcg and only descent for Vmca ... the very thrust upon which you place your salvation's reliance is the same thrust which is taking you to your accident .... the thrust must be reduced to regain control. Like it or not ... we can't overcome the realities of the physics involved.
JT, I agree with your statement and it reinforces some of my earlier comments about directional control issues that have been experienced.
Remoak, I also think I get your point, if the a/c has accelerated through Vmcg or Vmca (once in the air) and has been stabilised directionally then yes yaw departure risk disappears.
However, if the directional issue hasn’t been stabilised then the acceleration will serve to exacerbate the departure, and as JT said, it can be all over pretty quick unless that thrust is reduced.
Tough choice to make I know, if you’ve got trees rushing up at you....
Join Date: Apr 2008
Location: Richmond Tasmania
Posts: 92
Likes: 0
Received 0 Likes
on
0 Posts
Err!...could I just humbly suggest that you all read the Ops Manual of the airline that you currently work for?
If you do what I say, you will find that it doesn't differ from the airline that you previously worked for!
Do you get my point?
If you do what I say, you will find that it doesn't differ from the airline that you previously worked for!
Do you get my point?
Join Date: May 2005
Location: Here and there.
Posts: 447
Likes: 0
Received 0 Likes
on
0 Posts
I'm not easily drawn into this particular discussion but feel compelled in the interests of safety.
Chimbu Chuckles and JT and many others have posted many very valid, and in my view, technically correct points. I have one to add though I couldn't hold a flame to these guys.
In the event of an aborted take-off, prior to or at V1, depending on the school of thought of the particular airline you work for, and in the absence of auto-brakes, the first action should always be max braking. Start the deceleration, close the throttles etc. etc.
Just my 2 cents from a substantial background in C & T. Not in jets but the theory is the same for mine.
My heartfelt sorrow to all affected.
D.
Chimbu Chuckles and JT and many others have posted many very valid, and in my view, technically correct points. I have one to add though I couldn't hold a flame to these guys.
In the event of an aborted take-off, prior to or at V1, depending on the school of thought of the particular airline you work for, and in the absence of auto-brakes, the first action should always be max braking. Start the deceleration, close the throttles etc. etc.
Just my 2 cents from a substantial background in C & T. Not in jets but the theory is the same for mine.
My heartfelt sorrow to all affected.
D.
Join Date: Jul 1999
Location: PLANET ZOG
Posts: 24
Likes: 0
Received 0 Likes
on
0 Posts
Defenestrator,
For my money (and at all airlines I've worked) the first action is to retard the power levers to max reverse whilst then simultaneously applying max braking...etc etc.
Obviously this action would be dependent on Airline SOP and a/c type operated, I know it’s splitting hairs but brakes against power doesn’t sound like the best way to start the deceleration ....
You could argue that it all happens about the same time, but for me the logic of it would be to initiate with the power levers and call “reject” so the other guy is in the loop, in the time it takes to get your feet up on the brakes and start braking...
I'm not saying you're wrong however, just adding my 5 cents worth
In the event of an aborted take-off, prior to or at V1, depending on the school of thought of the particular airline you work for, and in the absence of auto-brakes, the first action should always be max braking. Start the deceleration, close the throttles etc. etc.
For my money (and at all airlines I've worked) the first action is to retard the power levers to max reverse whilst then simultaneously applying max braking...etc etc.
Obviously this action would be dependent on Airline SOP and a/c type operated, I know it’s splitting hairs but brakes against power doesn’t sound like the best way to start the deceleration ....
You could argue that it all happens about the same time, but for me the logic of it would be to initiate with the power levers and call “reject” so the other guy is in the loop, in the time it takes to get your feet up on the brakes and start braking...
I'm not saying you're wrong however, just adding my 5 cents worth
Join Date: Sep 2006
Location: back of the crew bus
Posts: 1,312
Likes: 0
Received 0 Likes
on
0 Posts
I think we are all basically talking about the same thing.
Nowhere have I said that V1 is a "decision" speed, it is (as others have said) a "must have decided by" speed. So, for example, my takeoff briefs have always, for the last twenty years, been "... at or after V1 we will continue the takeoff..." Note the "at or after".
Now, having said that...
Chimbu Chuckles
Firstly, the certification requirements of the aircraft allow for that (2 second recognition time). Secondly, what is the difference between an abort at V1 minus say, 1/4 second, and V1? Figure it out - if your V1 is 120 kts, we are talking about an additional 15m. Thirdly, deceleration starts as soon as you close the thrust levers - it just isn't at it's maximum until spoilers are out, brakes are applied and reverse is at full noise. If you do exceed V1, it will be by very little. I've never seen anyone take two seconds to figure out it was time to stop with a failure, most folk have the thrust levers retarded within half a second. So figure another 30m or so if your failure happens ever so slightly under V1.
I'm not saying that your point about V1 is wrong, simply that the performance of the aircraft already allows for your scenario.
JT
If Vmcg is controlling, you are on the ground, right? That is what Vmcg means. So in that situation, you control the yaw with asymmetric brake.
Whatever happened to lowering the nose to, at the worst, maintain level flight while you accelerate? It doesn't have to be a descent, not even in the F27 which is marginal at the best of times. The only time I can see that you would be correct is if you had an unfeathered prop or a similar failure. Of course, if you are talking about GA aircraft at high weights, then sure.
Not quite sure what you mean by that...
With the 146 (and the F27 too I think), under JAA-approved manuals, it was permissible to fly the engine-out departure profile at a speed higher than V2 if that speed had been achieved and the minimum climb gradient was being complied with. So, for example, if you were at training weights, it is actually pretty hard to stop the speed running away a bit while still maintaining a reasonable rate of climb (probably initially around 2000'/min at training weights in the 146). The point was that, rather than trying to chase a low V2, allow the aircraft to accelerate a little to aid controllability.
OK, but I can't think of any transport-category aircraft that wouldn't either accelerate quickly through the danger zone you are describing, or allow a power or pitch reduction to regain control while still climbing away quite happily. The reason I say that it is theoretical, is that you never need to get into that position in the first place. Again, using the 146 as an example, if you take off using flex thrust (as you normally would at training weights), there is no requirement to increase thrust to N1ref if you suffer an engine failure. You can if you want, but you don't have to as the flex thrust performance allows for the engine failure case. So for the 146, you have even less of an issue with controllability as the assymetric thrust is lower than it would be with full thrust.
I would be interested to know what aircraft you are thinking of when you mention these difficulties.
Yep been saying that from the beginning...
Obie2
Maybe not in Oz, but I have flown for three 146 operators in Europe with markedly different Ops Manuals and SOPs. One was radically different to the others.
I don't think any of us are fundamentally in disagreement, but we are seeing the problem from our own experience and the instruction that we have had. One's views may well be different if one has operated a type with marginal performance, etc...
Nowhere have I said that V1 is a "decision" speed, it is (as others have said) a "must have decided by" speed. So, for example, my takeoff briefs have always, for the last twenty years, been "... at or after V1 we will continue the takeoff..." Note the "at or after".
Now, having said that...
Chimbu Chuckles
If you decide to reject AT V1 by the time you react, slam the thrust levers closed, autobrakes kicks in (or you stand on them) and the reversers deploy and spool up you'll be significantly above V1 by the time you stop accelerating and start to slow down.
I'm not saying that your point about V1 is wrong, simply that the performance of the aircraft already allows for your scenario.
JT
I fear that you have the cart before the horse. If a yaw departure has occurred then there is no option for acceleration to get out of the situation for Vmcg
and only descent for Vmca ... the very thrust upon which you place your salvation's reliance is the same thrust which is taking you to your accident .... the thrust must be reduced to regain control. Like it or not ... we can't overcome the realities of the physics involved.
A multi can be so limited IF the thrust/speed mix is appropriate.
they all allow you to maintain an achieved speed ..
I'm afraid you have quite lost me here .. perhaps you might elaborate on your point ?
I'm afraid you have quite lost me here .. perhaps you might elaborate on your point ?
This is not at all a theoretical exercise. Many aircraft schedule takeoff speeds at low weight which put you right in this sort of harm's way if you mishandle the failure during a continued takeoff. I think that it will be useful for the newchums if we continue with this discussion ?
I would be interested to know what aircraft you are thinking of when you mention these difficulties.
The point is that, under the present paradigm, reaching V1 confirms that you are going to continue keeping on going
Obie2
Err!...could I just humbly suggest that you all read the Ops Manual of the airline that you currently work for?
If you do what I say, you will find that it doesn't differ from the airline that you previously worked for!
If you do what I say, you will find that it doesn't differ from the airline that you previously worked for!
I don't think any of us are fundamentally in disagreement, but we are seeing the problem from our own experience and the instruction that we have had. One's views may well be different if one has operated a type with marginal performance, etc...
Join Date: Jul 2007
Location: in the classroom of life
Age: 55
Posts: 6,864
Likes: 0
Received 1 Like
on
1 Post
Closer to the original topic...........................
Funeral for Shane W is Wednesday next week.
If you are interested check the local paper for details.
Funeral for Shane W is Wednesday next week.
If you are interested check the local paper for details.
I've never seen anyone take two seconds to figure out it was time to stop with a failure, most folk have the thrust levers retarded within half a second. So figure another 30m or so if your failure happens ever so slightly under V1.
Good god, I hope that isn't the real manual!
A lot of speculation on the operation of the Brasilia prop.
A few pages of the simplified operation can be found at Smart Cockpit. This is dumbed down for pilots so may not tell the whole story, - but I suspect there may be a little more to it than some here appreciate.
SmartCockpit - Airline training guides, Aviation, Operations, Safety
A few pages of the simplified operation can be found at Smart Cockpit. This is dumbed down for pilots so may not tell the whole story, - but I suspect there may be a little more to it than some here appreciate.
SmartCockpit - Airline training guides, Aviation, Operations, Safety
The most fundamental requirement for technical writing is that it should be clear and unambiguous. That is neither.
I really hope that no poor pilot is trying to understand his aircraft by reading that! That material is dangerously bad.
If that is part of the real aircraft documentation, I would hope the ATSB could spare a couple of paragraphs in its report to make a finding on that document.
Join Date: Sep 2006
Location: back of the crew bus
Posts: 1,312
Likes: 0
Received 0 Likes
on
0 Posts
Having observed numerous rejected take off's in the 737 simulator it has been my experience that on almost every occasion the airspeed kept increasing by around seven to ten knots as the thrust levers were in the process of closing. This was regardless of speed of throttle closure. These were ordinary garden-variety pilots - not test pilots.
How an engine keeps on producing enough power to accelerate the aircraft when it's only receiving enough fuel for ground idle escapes me though...
Grandpa Aerotart
How about momentum and inertia?
That the Fischer Price Starlifter gets to V1 at all is a mystery of aviation right up there with sustained flight & Bumblebees
Yes I have flown them
That the Fischer Price Starlifter gets to V1 at all is a mystery of aviation right up there with sustained flight & Bumblebees
Yes I have flown them
Join Date: Sep 2006
Location: back of the crew bus
Posts: 1,312
Likes: 0
Received 0 Likes
on
0 Posts
How about momentum and inertia?
Not really a point worth arguing over though.
You would diss the Queen of the skies?
Interesting that Ron Lawford is prepared to put a price on a pilot's life when he suggests that it is cheaper to do rating renewals and line checks in the aircraft rather than find a sim.
I understand the short term economics for smaller companies but cannot appreciate the big picture "myopia". It is not a matter of "if" so much as a matter of "when" the next accident of this type will occur.
Affordable Safety at work.....all right in the vast majority of cases but not so safe or affordable if you happen to be the exception.
I understand the short term economics for smaller companies but cannot appreciate the big picture "myopia". It is not a matter of "if" so much as a matter of "when" the next accident of this type will occur.
Affordable Safety at work.....all right in the vast majority of cases but not so safe or affordable if you happen to be the exception.
Moderator
What is actually stated is:
I don't think that is exactly putting.....
Appears to be a statement of fact rather than a personal opinion.
RON LAWFORD, VETERAN TERRITORY PILOT, DARWIN: It's a matter of economics where for some people it's cheaper to use the real aeroplane to do the instrument rating renewal, to do the recency checks, than to find a simulator which may be on the other side of the world and fly their pilots to that place to do the, the one or two hours of flying in the simulator.
".....a price on a pilot's life when he suggests that it is cheaper to do rating renewals and line checks in the aircraft rather than find a sim."
Join Date: Aug 2004
Location: asia
Posts: 235
Likes: 0
Received 0 Likes
on
0 Posts
Ron's old school; I think he flew DC3's inthe RAAF a hundred years ago, and from some of the training I saw at the Aero Club in a Partenavia,real heroic stuff ove at D212, I wouldn't put a lot of store in what he says.
What concerned me greatly is that the ABC is prepared to listen to the guy who runs the RMIT flight school at Pt Cook, who is a private pilot. Why don't journalists do just a little research into who they're talking with before putting this crap to air??
I think I know the answer, and it's that 99% of the viewers don't know what they're listening to so it's not all that important. I did think the ABC may have been a little more discriminating though.
I seriously doubt all the following are not qualified to make competent, professional comment:
AIR TRANSPORT SAFETY BUREAU:
MICHAEL BRIDGE, AIRNORTH CEO:
BILL HAMILTON, RETIRED QANTAS PILOT, SYDNEY:
JOHN HARDY, HARDY AVIATION CEO, DARWIN:
RON LAWFORD, VETERAN TERRITORY PILOT, DARWIN:
BOB DUDDINGTON, RMIT, MELBOURNE:
We're not turning this thread into another media bashing thread!
Tail Wheel
What concerned me greatly is that the ABC is prepared to listen to the guy who runs the RMIT flight school at Pt Cook, who is a private pilot. Why don't journalists do just a little research into who they're talking with before putting this crap to air??
I think I know the answer, and it's that 99% of the viewers don't know what they're listening to so it's not all that important. I did think the ABC may have been a little more discriminating though.
I seriously doubt all the following are not qualified to make competent, professional comment:
AIR TRANSPORT SAFETY BUREAU:
MICHAEL BRIDGE, AIRNORTH CEO:
BILL HAMILTON, RETIRED QANTAS PILOT, SYDNEY:
JOHN HARDY, HARDY AVIATION CEO, DARWIN:
RON LAWFORD, VETERAN TERRITORY PILOT, DARWIN:
BOB DUDDINGTON, RMIT, MELBOURNE:
We're not turning this thread into another media bashing thread!
Tail Wheel
There's nothing wrong with what Ron is saying. That it is cheaper for some companies to do their training in an aircraft instead of sending their pilots to a sim somewhere is hardly an earth shattering statement. He's not saying it's right, he's saying that's how many companies see it.