(I am kind of out of the loop in General Aviation now too as 1998 was a long time ago).

Side topic, I know. But why did you stop if I may ask?

 

And much fun on training the +/- V1 stuff. :smile: I think the sim could make it easier than it is, but it's surely nice to have the opportunity, right?

Side topic, I know. But why did you stop if I may ask?

 

Ran out of money back then....When I got money again I just found that Flight Simulation on the Personal Computer became so close to the real thing that I was better off invested into FS2002, FS2004 and then FSX.

 

Now with FSX, Orbx, PMDG and Carenado my money is better value being simulated at this point.

 

I want to go up and rent aircraft again however the price is higher per hour compared to buying three aircraft from Carenado....so I don't anymore.

 

they are asking for around $250 per hour in New Zealand to rent a Cessna......I would rather spent $250 on the Flight Sim community instead.

 

Cheers

Layman question, be gentle...

 

Is it possible for V_rotate to be a lower speed than V₁ (get me with my subscripts!)? If you had a long runway and an aircraft with a short takeoff capability?

Layman question, be gentle...

 

Is it possible for V_rotate to be a lower speed than V₁ (get me with my subscripts!)? If you had a long runway and an aircraft with a short takeoff capability?

Check out this thread from this post down, explains an awful lot about v1 vr v2 vmcg vmca, so no real need to repeat it.

http://forum.avsim.net/topic/353882-two-questions-about-real-world-ops/page__st__25#entry2164102

If you still have questions though I'll answer then either here or on that thread...

 

Regards,

Ró.

Gentlemen really!!! Clearly what I intended was misunderstood. Apologies if so.

...//..

Well, I don't know if you were a pilot in real life or not but I know for sure that you like controversy.

And I don't how you would deal with a rejected take off, but your backtracking on a "rejected thread" is quite good ! :smile:

 

Anyway, thanks for an entertaining (and educative) thread.

 

Bruno

 

PS : Thanks for the last link, Rónán

Layman question, be gentle...

 

Is it possible for V_rotate to be a lower speed than V₁ (get me with my subscripts!)? If you had a long runway and an aircraft with a short takeoff capability?

 

If I rephrase your question into: is it possible for me to stop the aircraft safely when I have already passed the speed at which I should rotate for take-off? Then the answer is yes, in theory this should be possible, given a sufficiently long runway, sufficiently strong tyres and brakes, etc. To give an extreme example I'm pretty sure a Piper Cub could take-off and land again within the length of some of the longest runways in use at big airports. In fact I think there was even a Dash-8 that did this in Canada a while ago when they had an engine fire on take-off, though there was a lot of criticism of that decision by the pilots.

If you ask about specifically V_rotate and V_1 you also need to consider the 'legalese' of how those speeds are defined and you can get into the long arguments that Rónán linked to.

Ran out of money back then....When I got money again I just found that Flight Simulation on the Personal Computer became so close to the real thing that I was better off invested into FS2002, FS2004 and then FSX.

Makes perfect sense on the money aspect. Thanks for answering.

 

Looking at the sim as one of my cheaper hobbies and I'd have to drop the others for making it a rw flying thing. Well, lets talk again in some 3 to 4 years. The sim is nice and easy, you double click and you're in, flying all kinds of cool planes and places.

Layman question, be gentle...

 

Is it possible for V_rotate to be a lower speed than V₁ (get me with my subscripts!)? If you had a long runway and an aircraft with a short takeoff capability?

 

No, V1 will be reset to be the same as Vr in that situation. I use simultaneous V1 andVr speeds on my aircraft normally. However, we have a procedure to look up split v speeds to get a higher max takeoff weight for certain runways. As part of that procedure, one of the last steps when all the counts are in and we know our actual takeoff weight, we recheck the v speeds for that weight and if it is less than the max, we may end up with Vr less than the previously calculated V1. In that case we adjust V1 down to match Vr. It makes absolutely no sense to have a V1 above Vr. You can't start pulling the plane into the air before you decide to pull the plane into the air.

 

I know what you are wondering is whether you can stop the plane after Vr if you have unlimited runway and brakes. The answer is still no. The problem with doing that is you are introducing an element of doubt and confusion to a critical phase of flight that has little leeway for confusion. By introducing an element of doubt about the action to be taken during that phase of a takeoff, you stand a much greater risk of a crash because the pilots fumbled or vacillated at a critical moment. That is why we train the go-nogo decision in stark black and white manner. It is not about the aircraft but rather about human factors.

 

No, V1 will be reset to be the same as Vr in that situation. I use simultaneous V1 andVr speeds on my aircraft normally. However, we have a procedure to look up split v speeds to get a higher max takeoff weight for certain runways. As part of that procedure, one of the last steps when all the counts are in and we know our actual takeoff weight, we recheck the v speeds for that weight and if it is less than the max, we may end up with Vr less than the previously calculated V1. In that case we adjust V1 down to match Vr. It makes absolutely no sense to have a V1 above Vr. You can't start pulling the plane into the air before you decide to pull the plane into the air.

 

I know what you are wondering is whether you can stop the plane after Vr if you have unlimited runway and brakes. The answer is still no. The problem with doing that is you are introducing an element of doubt and confusion to a critical phase of flight that has little leeway for confusion. By introducing an element of doubt about the action to be taken during that phase of a takeoff, you stand a much greater risk of a crash because the pilots fumbled or vacillated at a critical moment. That is why we train the go-nogo decision in stark black and white manner. It is not about the aircraft but rather about human factors.

 

We're talking about an infinite runway and unburstable tyres right? In that case you will never have an overrun, since with an infinite runway you will by definition never run out of runway distance. As long as you keep aligned with the centre line you can drive along at Vr for half an hour while you read through the FCOM and still stop the plane safely (by reducing the throttles to idle and coasting to a stop if need be). In the real world you have to make a decision fast, because every second you're thinking is eating up your remaining runway length. If your runway is infinite that isn't a problem however.

Of course all the above is a theoretical consideration that is only relevant from a physics point of view. In the real world where runways have a finite length indeed the go-nogo decision should be black and white, stop below V1, above V1 go.

 

 

We're talking about an infinite runway and unburstable tyres right? In that case you will never have an overrun, since with an infinite runway you will by definition never run out of runway distance. As long as you keep aligned with the centre line you can drive along at Vr for half an hour while you read through the FCOM and still stop the plane safely (by reducing the throttles to idle and coasting to a stop if need be). In the real world you have to make a decision fast, because every second you're thinking is eating up your remaining runway length. If your runway is infinite that isn't a problem however.

Of course all the above is a theoretical consideration that is only relevant from a physics point of view. In the real world where runways have a finite length indeed the go-nogo decision should be black and white, stop below V1, above V1 go.

 

The point I was making is that there is NO decision to be made. We are not trained to be Steve Canyons anymore. The decision was made long before the takeoff during the takeoff briefing. The only decision to be made is merely whether the abnormality that just occured fit the criteria of the abnormalities that I had briefed that we would abort for. That is all. And if it wasn't one of those things I had briefed we would abort for then there is no abort infinite runway or not.

 

The point I was making is that there is NO decision to be made. We are not trained to be Steve Canyons anymore. The decision was made long before the takeoff during the takeoff briefing. The only decision to be made is merely whether the abnormality that just occured fit the criteria of the abnormalities that I had briefed that we would abort for. That is all. And if it wasn't one of those things I had briefed we would abort for then there is no abort infinite runway or not.

 

Ah ok, that's something I can agree with you on 100%. It's completely disconnected from the question of whether it's physically possible to stop the plane though.

Ah ok, that's something I can agree with you on 100%. It's completely disconnected from the question of whether it's physically possible to stop the plane though.

 

Here's the rub! It's called knowing your a/c and conditions. I can transpose the specs at the beginning of the thread to Heathrow, take the a/c to Vr and still have almost half the rwy in front of me at full stop.

 

Some of the "other" so-called pilots here seem to think that the a/c they fly are the only a/c that fly! They forgot (or didn't read carefully enough) that the example given is of a high performance a/c that would be hundreds of feet in the air by the time it passes the old Heathrow control tower. With regard to emergencies sometimes pilots have to think outside the box and make a decision between a rock and a hard place.

A question asked earlier about whether it is possible for V1 to be higher than Vr is also true as it can be so in terms of the basic calculated numbers. However the Vr would be incremented to be at least the same as V1.

Too many people are too ready to criticise instead of reading more carefully what's written. (If I didn't make myself clear then I accept that. (It was 2130Z here and still 30c!)) They are also too ready to criticise other crew involved in an accident (referring to that of 5X UVA at Addis) who did actually make the right decision. Yes they could have taken-off. But, what would have been the outcome of the landing with burst tyres and the unknown factor of degraded brakes. We can all discuss until the cows come home the do's and don'ts of various actions. But that crew and many others had to make a decision and none of them were sitting in comfortable armchairs at the time the decision had to be made!!

I would suggest that the next time company simulator time is required that said "pilots?" take the opportunity to practice on-rwy emergencies and find out just what the a/c is or is not capable of. Talking of sims as far as I'm aware (I stand corrected if wrong) in both Fs9 and FSX, I haven't yet found an a/c that uses rwy data to calculate V1.

Now here now Mr. Liberista, I won't have my integrity questioned like that, I take offence at being referred to as a "So-Called Pilot" and a "Pilot?". I think I've more that proved both my identity as a pilot and my airmanship/skill to the community over the years. I've contirbuted a wealth of knowledge about the aircraft I fly and their operation and I've met Flight Simmers in my aircraft and had them visit me up front.

 

Secondly, in the case of the Addis Adaba accident, the crew made the WRONG choice. Had they continued and rotated the aircraft and brought the problem into the air, they would not have gone off the end of the runway and there would not have been those fatalities. Bringing a bust tire into the air is far safer than performing a high speed RTO with burst tires, and I don't know how you could see it otherwise.

 

With Regards,

Rónán O Cadhain.

 

Secondly, in the case of the Addis Adaba accident, the crew made the WRONG choice. Had they continued and rotated the aircraft and brought the problem into the air, they would not have gone off the end of the runway and there would not have been those fatalities. Bringing a bust tire into the air is far safer than performing a high speed RTO with burst tires, and I don't know how you could see it otherwise.

 

With Regards,

Rónán O Cadhain.

 

Nor would they have gone off the rwy if the brakes had been correctly re-assembled. The report is quite clear in that respect.

How many accidents have there been due to faulty maintenance? The crew were correct in doing what they did because they didn't know about the faulty brakes. They expected to stop and would have done so otherwise. I'll check the report again re: the burst tyre if it says at what speed it occurred. The Vc10 has a complex braking load balancing system designed for burst tyres etc so I'm sure they were "initially" confident until obviously they realised the brakes weren't working.

Now here now Mr. Liberista, I won't have my integrity questioned like that, I take offence at being referred to as a "So-Called Pilot" and a "Pilot?". I think I've more that proved both my identity as a pilot and my airmanship/skill to the community over the years. I've contirbuted a wealth of knowledge about the aircraft I fly and their operation and I've met Flight Simmers in my aircraft and had them visit me up front.

 

No, I think you are faking it :rolleyes: :P I thank you again for all the information you are able to share on your experiences!

 

With regard to emergencies sometimes pilots have to think outside the box and make a decision between a rock and a hard place.

A question asked earlier about whether it is possible for V1 to be higher than Vr is also true as it can be so in terms of the basic calculated numbers. However the Vr would be incremented to be at least the same as V1.

Too many people are too ready to criticise instead of reading more carefully what's written. (If I didn't make myself clear then I accept that. (It was 2130Z here and still 30c!)) They are also too ready to criticise other crew involved in an accident (referring to that of 5X UVA at Addis) who did actually make the right decision. Yes they could have taken-off. But, what would have been the outcome of the landing with burst tyres and the unknown factor of degraded brakes. We can all discuss until the cows come home the do's and don'ts of various actions. But that crew and many others had to make a decision and none of them were sitting in comfortable armchairs at the time the decision had to be made!!

I would suggest that the next time company simulator time is required that said "pilots?" take the opportunity to practice on-rwy emergencies and find out just what the a/c is or is not capable of. Talking of sims as far as I'm aware (I stand corrected if wrong) in both Fs9 and FSX, I haven't yet found an a/c that uses rwy data to calculate V1.

 

You have to remember if you take it to the air it will give you more time to think and come up with a better solution as well.

 

In the case with the blown tire, if they took it in the air they could have burnt off fuel giving them a lighter weight. Which gives you less mass to have to slow down. The other nice thing is, you will get a full runway to stop in. The situation would have ended at the runway and having your passenger walk off without having to evacuate.