V2 and the 4 segment climb

[jtrain609]

Ok, so if you're climbing out above the trees, and there's nothing that your immediately worried about hitting, why wouldn't you want some of that extra speed? I mean hell, if you could sustain V2 + 50 in a good climb that satisfies the climb gradient, why wouldn't you want it?

Sorry, didn't want to derail Matt's thread so I made this one down here where it's a much better place to discuss this stuff.

Why not maintain V2 + 50? Because you have no way of determining that you're meeting your climb gradient restrictions. With the way our profile is setup, and I'm sure most are the same, you want to get to acceleration height as soon as possible, which means climbing at V2. Now does V2 plus a few knots (maybe up to 10 I've heard folks say) matter? No, it probably doesn't. But if you start to let that speed get away from you, you're going to end up in a situation where you're not at acceleration height at the proper location, and you may be bumping up against terrain problems.

V2 + 50 in my aircraft is something like 220-230 knots, and at those speeds you're not climbing, you're accelerating. Now don't get me wrong, there's a place for that; acceleration height. After that, climbing at Vfs is what you want to do in order to put distance between you and anything below you that you need to climb above, so you'll take that speed to any MVA or MEA that you want to be at before you start trying to really get down to the business of fixing the aircraft.

An argument against this might be that you could do a VMC climb and accelerate lower while maintaining obstacle clearance. That may be true, but I'm assuming you're in the soup at 100' and you can't see anything. More importantly, sticking to the company profile is important because the numbers you're using for your single engine departure were predicated and you following that profile and not making your own up.

 

[Dugie8]

All good points. But what is a VMC climb?

 

[surreal1221]

I love these arguments.

V+eleventybillion is what I do.

Fly the book, whatever it may be. If you fly the book, on profile, or as close to it with as little positive variance, you're going to reach that acceleration height and be able to continue your climb at Vt earlier than if you decided to keep a lower pitch with a faster airspeed. Thus, potentially, not getting your obstacle clearence. Although, the TERPs are pretty conservative - but OEI is no time to be trying to create your own profile in IMC.

VMC = Visual meteorological conditions. The opposite of IMC, Instrument Meteorological Conditions.

Ok, so if you're climbing out above the trees, and there's nothing that your immediately worried about hitting, why wouldn't you want some of that extra speed? I mean hell, if you could sustain V2 + 50 in a good climb that satisfies the climb gradient, why wouldn't you want it?

Just for my own information, what type jet have you been responsible for? I just can't remember what types you are, or have flown in the past. But I would have figured that someone who has gone through some initial jet training for any jet type would understand the importance of gaining ALTITUDE rather than DISTANCE / AIRSPEED at a low altitude with only one motor.

Climb. On profile. Reach your MEA/MSA whatever, and get your ass back on the ground safely.

 

[dasleben]

Good post jtrain, but I'm just curious: What's the V1 cut profile for the ERJ? I honestly don't remember. If it's V2, then fly V2. Other aircraft with a bit more performance may allow for a larger buffer, say, up to V2+15 while still guaranteeing the climb gradient.

The biggest thing we were talking about in that other thread was slowing back to V2 if you're slow to rotate and a bit faster than V2 (which is normal in a V1 cut anyway). Depending on the aircraft, in order to accomplish that you may need to stand the airplane on its tail; certainly not good form, and really puts you in a tough spot if the decreasing airspeed trend gets away from you. Much more stable to just leave the speed where it's at, within that defined buffer.

 

[Dugie8]

Still good points. Most aircraft "books" allow for V2 plus something. The point is to be within that "something" and not try to slow to V2.

There is no VMC climb, there is just "take off path for large turbine powered aircraft". VMC or IMC you still have to abide by

121.189(d)(2) and 135.379(d)(2) (I assume we are talking relatively current gen transport category aircraft under 121 and 135 ops)

 

[jtrain609]

All good points. But what is a VMC climb?

Visual Meteorological Conditions Climb. Sorry, it's probably a company term.

 

[surreal1221]

Visual Meteorological Conditions Climb. Sorry, it's probably a company term.

VMC and IMC are terms utilized within the aviation meteorology community, to explain basic weather conditions that relate to VFR and IFR flight realms.

 

[jtrain609]

Good post jtrain, but I'm just curious: What's the V1 cut profile for the ERJ? I honestly don't remember. If it's V2, then fly V2. Other aircraft with a bit more performance may allow for a larger buffer, say, up to V2+15 while still guaranteeing the climb gradient.

-Power loss, max thrust.
-Climb at V2 to acceleration height, level off.
-Accelerate to Vfs. At V2+15 raise the flaps to zero.
-At Vfs, mash the speed hold button, climb at Vfs to whatever you want to climb to.

The biggest thing we were talking about in that other thread was slowing back to V2 if you're slow to rotate and a bit faster than V2 (which is normal in a V1 cut anyway). Depending on the aircraft, in order to accomplish that you may need to stand the airplane on its tail; certainly not good form, and really puts you in a tough spot if the decreasing airspeed trend gets away from you. Much more stable to just leave the speed where it's at, within that defined buffer.

We were told during this cycle to slow to V2 if you're above it after rotation, and if you follow the flight guidance you will be, so you'll need to feather that speed back down to V2.

You're correct, don't stand it on the tail, but get to the profile speed. At the same time, though, you say don't let the speed get away from you; isn't that exactly what we're talking about? You can't let the speed get away from you EITHER direction, and frankly neither speed is acceptable. A V1 cut and single engine climb profile is something that you need to demonstrate to a high level because it's one of those things you can't screw up if it actually happens to you.

Also, how do you know what the defined buffer is for the engineering data? We don't have access to that kind of information, though maybe you do at the new company.

 

[jtrain609]

Still good points. Most aircraft "books" allow for V2 plus something. The point is to be within that "something" and not try to slow to V2.

There is no VMC climb, there is just "take off path for large turbine powered aircraft". VMC or IMC you still have to abide by

121.189(d)(2) and 135.379(d)(2) (I assume we are talking relatively current gen transport category aircraft under 121 and 135 ops)

The term "VMC Climb" is something that was in our FOM for a long time. It allowed us to make our turn at 100' AGL after takeoff.

And I agree, you need to follow the profile, I was saying that you CAN'T do a VMC climb, partially because I'm assuming you're in the soup and can't see anything, and partially because it'd be off profile.

 

[Dugie8]

Visual Meteorological Conditions Climb. Sorry, it's probably a company term.

I gotcha, however what IS a VMC climb?

 

[Bandit_Driver]

In the 727 and assuming there isn't a special departure procedure for engine out then it is to maintain a minimum of V2 to V2+10. So if you are V2+10 when you have the engine quit that is what you maintain. Then it is, maintain that speed to 1000' AGL and speed and clean up then we continue climbing out to a reasonable altitude and whip out the QRH. Gross weight is adjusted as necessary.

 

[jtrain609]

I gotcha, however what IS a VMC climb?

heh, our definition was VFR conditions and you could maintain visual separation with anything you may hit.

You can imagine that was fairly liberally applied.

 

[Bandit_Driver]

heh, our definition was VFR conditions and you could maintain visual separation with anything you may hit.

You can imagine that was fairly liberally applied.

Same here and it is brief as such by the Capt in good weather. If we lose 1 we do X, if we lose 2 we do y, and will visually avoid the terrain.

 

[dasleben]

-Power loss, max thrust.
-Climb at V2 to acceleration height, level off.
-Accelerate to Vfs. At V2+15 raise the flaps to zero.
-At Vfs, mash the speed hold button, climb at Vfs to whatever you want to climb to.



We were told during this cycle to slow to V2 if you're above it after rotation, and if you follow the flight guidance you will be, so you'll need to feather that speed back down to V2.

You're correct, don't stand it on the tail, but get to the profile speed. At the same time, though, you say don't let the speed get away from you; isn't that exactly what we're talking about? You can't let the speed get away from you EITHER direction, and frankly neither speed is acceptable. A V1 cut and single engine climb profile is something that you need to demonstrate to a high level because it's one of those things you can't screw up if it actually happens to you.

Also, how do you know what the defined buffer is for the engineering data? We don't have access to that kind of information, though maybe you do at the new company.

Different profiles for different airplanes, I guess. The QRH "maneuvers" section for this airplane says V2 to V2+15, which conveniently is what the flight director will pitch for if it senses the N2 or N3 roll back. Good enough for me.

I'm not sure what you mean by engineering data, though. Are you referring to obstacle clearance and climb gradient requirements for that particular runway?

 

[PositionAndHold]

VMC and IMC are terms utilized within the aviation meteorology community, to explain basic weather conditions that relate to VFR and IFR flight realms.

Vmc is also used in multi engine flying to describe Velocity minimum control. Since we are talking about single engine ops in multi engine A/C, I could see the confusion. <edited>

Which leads me to your respones to ppraggman. I am pretty sure he's done the freight dog piston airplane thing, so he might not know a lot about jet flying. However, the plane I think he SIGNS for now is a Caravan. So I think he was asking a decent question about airspeed, since in piston multi flying airspeed can be your friend. (See Vmc). <edited>

So what A/C do you sign for when you go to work? Last I read you are an FO at a southeast regional? If you've since been upgraded, well then congrats captian. And for clarity I sign for a Lear 45 that I am captian on when i go to work. Are we done measuring yet?

 

[Dugie8]

heh, our definition was VFR conditions and you could maintain visual separation with anything you may hit.

You can imagine that was fairly liberally applied.

I apologize, I was dancing around the bush trying to get you to "say it". Under part 121 and 135 there is no rule that allows for that. Note the regs linked, they don't specify VMC or IMC just, thou shalt...

I would be your GOM or whatever you company calls it states something about takeoff performance and cites the appropriate reg without spelling it out (mine does). I'm not sure where the VMC climb thing came from or why anyone thinks they can "see and avoid" an obstacle that doesn't care if you are in the soup or not.

 

[jtrain609]

Different profiles for different airplanes, I guess. The QRH "maneuvers" section for this airplane says V2 to V2+15, which conveniently is what the flight director will pitch for if it senses the N2 or N3 roll back. Good enough for me.

I'm not sure what you mean by engineering data, though. Are you referring to obstacle clearance and climb gradient requirements for that particular runway?

Exactly. You guys have a speed RANGE to fly, where we have one single speed to fly (as it's trained, I guess I could stop being lazy and double check that we don't have a V2 to V2 + 10 speed range, but I'm guessing it DOESN'T exist because every sim instructor and check airman we saw was on our ass if we were 2-3 knots above V2). Because of that, I have no idea what kind of buffer we're dealing with.

 

[Dugie8]

Exactly. You guys have a speed RANGE to fly, where we have one single speed to fly (as it's trained, I guess I could stop being lazy and double check that we don't have a V2 to V2 + 10 speed range, but I'm guessing it DOESN'T exist because every sim instructor and check airman we saw was on our ass if we were 2-3 knots above V2). Because of that, I have no idea what kind of buffer we're dealing with.

Really? 2 or 3 knots and your "runway data" is broken down into 5 or 10 degree C "chunks"?? Or do you have a takeoff weight for every degree of C from min to max operating OAT?

 

[jtrain609]

Really? 2 or 3 knots and your "runway data" is broken down into 5 or 10 degree C "chunks"?? Or do you have a takeoff weight for every degree of C from min to max operating OAT?

Varies on the temp, sometimes 5, sometimes 10.

I just do what the bossman says to do. We do a few weird things I don't agree with, but I do what they tell me to do. An example is that we have a few profiles (V1 cuts, RNAV approaches) where we don't follow the flight guidance and revert back to raw data, but we keep the flight guidance up on the attitude indicator.

 

[Dugie8]

Varies on the temp, sometimes 5, sometimes 10.

I just do what the bossman says to do. We do a few weird things I don't agree with, but I do what they tell me to do. An example is that we have a few profiles (V1 cuts, RNAV approaches) where we don't follow the flight guidance and revert back to raw data, but we keep the flight guidance up on the attitude indicator.

I can dig that. I'm surprised a check airmen is getting bent out of shape about being within V2+10 but your data that is telling you that V2+10 is based off the "measure with a micrometer, mark with a grease pencil, cut it with a hatchet" mentality.

I think this is a good picture into what is, IMO, one of the biggest problems we have right now.