Pushback Question

[philfab2 3]

I am having trouble with PMDG 777-300 pushback.  Using ORBX scenery for YBBN and selecting gate 78, if I do say, 6 pushbacks using identical settings for the PUSHBACK page, the aircraft ends up at 6 different stopping positions.  Am I asking too much for this to be repeatable and accurate?

[scandinavian13 5,192]

13 hours ago, philfab2 said:

Am I asking too much for this to be repeatable and accurate?

Somewhat, yes. It's meant to be a basic pushback tool that utilizes the underlying SHIFT+P methodology of the sim. It isn't the precision tool that GSX offers.

EDIT:

As a former rampie, you're getting a more realistic experience, honestly. There are some rampies who could work magic with a pushback, but most just got it out into the lane. Centerline, or in a specific spot was simply a bonus.

Edited January 28, 2019 by scandinavian13

[blazer05 15]

Kyle - a good point I have never thought much about - since real pushbacks are not robotic.

Personally I use GSX and am amazed how often I end up exactly centerline.  I do sometimes wonder if they are going to stop, but as long as the nose is pointed the right way, I am happy.

At smaller airports - I have had GSX do some pretty neat driving to get me in the proper place.

Franklin Duncan

 

 

 

Edited January 28, 2019 by blazer05
correction of grammar

[scandinavian13 5,192]

58 minutes ago, blazer05 said:

Kyle - a good point I have never thought much about - since real pushbacks are not robotic.

Thanks. Yeah, I think for us, it's unintended realism, since we're just trying to "time things" using the built in pushback function of FSX/P3D (almost as if you'd hit SHIFT+P, and then SHIFT+P - 1 or SHIFT+P - 2 to turn, and then we're timing the stop). I'm not sure how it was written, but I'd bet that if you'd tracked the frame rate, that's where you'd see the variations in where the plane ended up.

1 hour ago, blazer05 said:

Personally I use GSX and am amazed how often I end up exactly centerline.  I do sometimes wonder if they are going to stop, but as long as the nose is pointed the right way, I am happy.

I took it as a matter of pride to be able to push a plane out and put it right on centerline using a tug and towbar. Even then, I had off days, or would be in a rush, or the ramp tower would call mid-push and say "just stop right there" and the crew would call that down to me. Meanwhile, the plane would be in all sorts of an odd spot.

[BlueStar 323]

2 hours ago, blazer05 said:

Personally I use GSX and am amazed how often I end up exactly centerline.

GSX is only as good as the underlying ADE. 🙂

Grace and Peace, 

[30K 72]

On 1/28/2019 at 3:11 PM, scandinavian13 said:

As a former rampie, you're getting a more realistic experience, honestly.

In DUS Lufthansa Leos does the pushbacks and they always are spot on. I mean exactly on the centerline, isn't that required anyway? We only walk by their side because some airlines don't like single man pbs.

[Captain Kevin 586]

1 hour ago, 30K said:

In DUS Lufthansa Leos does the pushbacks and they always are spot on. I mean exactly on the centerline, isn't that required anyway?

I guess not. See below:

On 1/28/2019 at 11:42 AM, scandinavian13 said:

or the ramp tower would call mid-push and say "just stop right there" and the crew would call that down to me. Meanwhile, the plane would be in all sorts of an odd spot.

 

[ph-cxz 28]

At Amsterdam you are depending on your stand pushed back with a 15 degree offset from the taxi line. Those positions are visible on the satellite image indicated by a White marker.

[scandinavian13 5,192]

4 hours ago, 30K said:

In DUS Lufthansa Leos does the pushbacks and they always are spot on. I mean exactly on the centerline, isn't that required anyway? We only walk by their side because some airlines don't like single man pbs.

You German lot are usually more precise than we are over here. The quality varies pretty significantly.

The first airline I was with allowed a push with a single walker. The last one I was with seemingly wanted you to bring the whole ramp with you, with a lighted wand in each hand, dragging a "safety" cone, and a high-vis vest with flashing lights on it. I pushed an RJ back one day with hand signals (which I'd briefed the crew on to confirm which signals would be used prior to closing the door) one day, and you would've imagined that it was the end of the world when ops found out.

2 hours ago, Captain Kevin said:

I guess not. See below

In his defense, the quality of rampie over in Germany seems to be significantly better - at least from my observations when I've been through MUC and FRA.

[30K 72]

Okay... Well, I knew that in NA the rules are somewhat "guidelines" but o boi, if we screw up, even when it's not really significant, you end up with the marshaller asking you if you have some mental health problems.

The best example is; 

You have 151 bags on the LS, and you loaded an actual of 150, you instruct the captain he says alright and immediately forgets it. We're talking about 20KG +- here. So you don't do an LMC, and this is where the fun begins.

You get into trouble simply because the LIR and LS are not equal and even if it's just this one bag.

Another one:

SWR and AUA have a company procedure which requires the loaders to put the chocks onto the NLDG first then on the Main LDG on the right side, then remove the nose chocks and put them to the other main LDG.  So basically nose -> right -> nose the to left.

You don't keep an eye out for that - you're in deep. It's almost insane how fast you get into trouble here, and I know we keep it tight to the rules but that the difference is so enormous is something I definitely didn't expect.

Edited January 31, 2019 by 30K

[philfab2 3]

Most of the answers are getting right off the subject.  My question is about the variation of the pushback when the setup is identical - same gate, same distance, same turn still ends up at different positions.

[scandinavian13 5,192]

43 minutes ago, philfab2 said:

Most of the answers are getting right off the subject.  My question is about the variation of the pushback when the setup is identical - same gate, same distance, same turn still ends up at different positions.

See my second post:

On 1/28/2019 at 11:42 AM, scandinavian13 said:

I think for us, it's unintended realism, since we're just trying to "time things" using the built in pushback function of FSX/P3D (almost as if you'd hit SHIFT+P, and then SHIFT+P - 1 or SHIFT+P - 2 to turn, and then we're timing the stop). I'm not sure how it was written, but I'd bet that if you'd tracked the frame rate, that's where you'd see the variations in where the plane ended up.

 

 

What you're seeing is a result of variation in the timing of those commands. We're not commanding the sim "move distance X, then begin a turn of radius Y, for arc distance Z, and finish with distance X1."

We're simply hitting SHIFT+P for [Time A]. If there's a turn associated with the push, then we hit SHIFT+P+1/2 for [Time B].

Given the fact that the sim's push function moves at as assumed speed of X, we can give you your requested distance as D = X * [Time A]. So, we find [Time A] by taking your requested distance and dividing by the sim push speed of X. The sim's push speed (more so, the time) is based largely on the frame rate. If this fluctuates (as it's bound to do, particularly on weaker machines), then you will have variation in the actual distance you move. The same can be said for angular distance, since it rotates the plane at a constant degree/sec. As with before, variation creeps in based on the frame rate, so where you end up will be different each time unless all variables can be locked down.

Again, this wasn't put together as a precision pushback sim. It was an additional function to help get people a basic push function to satisfy most people's needs. If you need a more detailed ground services function, there are other add-ons built by devs who simulate the ground functions.