V1 on TOLD CARDS - Limiting Factor (2nd Segment Climb?)

[C150J]

Hi all,

We all know that V1 is contingent upon a multitude of factors (runway length, MELs, braking energy, tire speed, etc.), so what is the limiting factor on the actual weight cards that many of us use? Is it the second segment climb per 121.189's clearance requirements? We obviously adjust these for the given circumstances, but I'm trying to really delve into this and our books are fairly top-level. Thanks!


J.

 

[seagull]

You haven't provided enough information to answer the question. Depends on the location, the type aircraft, the altitude, the runway length, etc...

That said, most of the time you are probably limited by Vr. If V1 and Vr is split, it then depends on a bit on how your company is calculating the stopping distance. I am not sure how second segment climb would come into it, offhand, as you can't rotate earlier than Vr, and V1 cannot exceed Vr, so in either case, the second segment is not affected. Can you clarify?

Hi all,

We all know that V1 is contingent upon a multitude of factors (runway length, MELs, braking energy, tire speed, etc.), so what is the limiting factor on the actual weight cards that many of us use? Is it the second segment climb per 121.189's clearance requirements? We obviously adjust these for the given circumstances, but I'm trying to really delve into this and our books are fairly top-level. Thanks!


J.

 

[C150J]

You haven't provided enough information to answer the question. Depends on the location, the type aircraft, the altitude, the runway length, etc...

That said, most of the time you are probably limited by Vr. If V1 and Vr is split, it then depends on a bit on how your company is calculating the stopping distance. I am not sure how second segment climb would come into it, offhand, as you can't rotate earlier than Vr, and V1 cannot exceed Vr, so in either case, the second segment is not affected. Can you clarify?

Don't know why I was mentioning the second-segment climb, come to think of it. Basically, we all have TOLD cards by weight with given V-speeds on each one. As you said, altitude, runway length, and a number of other factors come into play when calculating max V1 for a given situation. What I'm asking is, since the TOLD cards are only aware of our weight, what V1 is indicated on these laminated sheets? I'm starting to think it's a figure just under V1MBE, as that's the only limiting factor I can think of that would truly limit V1 without knowing runway length, contamination, etc.

Thanks!

 

[seagull]

It is a bit hard to say for sure as we do not do it that way. We enter the data into a performance computer and it includes all runway specific info plus winds, temp, altimeter, etc., and it defaults to V1min. From what you say, it would really have to be V1max, but do you have a split of V1 and Vr normally?

Don't know why I was mentioning the second-segment climb, come to think of it. Basically, we all have TOLD cards by weight with given V-speeds on each one. As you said, altitude, runway length, and a number of other factors come into play when calculating max V1 for a given situation. What I'm asking is, since the TOLD cards are only aware of our weight, what V1 is indicated on these laminated sheets? I'm starting to think it's a figure just under V1MBE, as that's the only limiting factor I can think of that would truly limit V1 without knowing runway length, contamination, etc.

Thanks!

 

[C150J]

It is a bit hard to say for sure as we do not do it that way. We enter the data into a performance computer and it includes all runway specific info plus winds, temp, altimeter, etc., and it defaults to V1min. From what you say, it would really have to be V1max, but do you have a split of V1 and Vr normally?

We do the same thing via ACARS/Aerodata, but we also have weight cards "up" as reference. As far as V1/VR split, we're talking 1-2 knots. Thanks again!

 

[BobDDuck]

Our V1/VR split is normally pretty small (1 or 2 knots) when we use ACARS for data. However, when you start putting in contaminated runways and what not the split will increase. I think I've seen a V1 speed as low as 97 knots with the VR speed up at 130 or so before.

We use the plastic cards when we don't have access to the ACARS. I don't think it actually says anywhere in our manual where that V1 speed comes from for a given weight, but I'd guess it's V1mbe as well. In our TakeOff and Landing Report we have a max V1 listed based on runway conditions, winds, temps and what not. It also lists the limiting factor (obstacle, field, brake or something else I am forgetting right now). Basically, if the Max V1 on the TLR is lower than the V1 on the plastic card, we just use the max allowable V1.

 

[dispatchguy]

Normally, it all depends

Since you use AeroData, their V-speed flip cards are usually based on a maximum V1, since they bias the V1 selection to maximum to permit lifting the maximum possible takeoff weight.

I went to a Boeing Flight Ops Perf Engineering class this past August, and we had a good 4-hr class just on the available range of V1 taught by one of their performance engineers - EXCELLENT class, and all the ramifications of a minimum V1 policy, balanced V1, or maximum V1 policy.

Here is a somewhat dated version of the handout we got in class:

http://www.smartcockpit.com/pdf/flightops/aerodynamics/28

 

[Polar742]

Don't know why I was mentioning the second-segment climb, come to think of it. Basically, we all have TOLD cards by weight with given V-speeds on each one. As you said, altitude, runway length, and a number of other factors come into play when calculating max V1 for a given situation. What I'm asking is, since the TOLD cards are only aware of our weight, what V1 is indicated on these laminated sheets? I'm starting to think it's a figure just under V1MBE, as that's the only limiting factor I can think of that would truly limit V1 without knowing runway length, contamination, etc.

Thanks!

It's been a few years, but IIRC, those numbers are built for BFL at the given weight (the idea being you stop or fly at that point).

Again, that's many malted beverages and 2 kids ago as an end user explination.

Teaching groundschool raises more questions than answers, eh?

 

[C150J]

Thanks guys!!!! Dispatchguy, that's a fantastic presentation, thank you for sharing.


Yes, Polar... I feel like I'm studying for my CFI initial again when it comes to sourcing information!