Hi guy's,

I am flying a lot in this fantastic airplane, wich quickly became my very favorite.

Despite that, i have a few things wich IMHO should be improved.

First is the VNAV descent planning in the FMC. It alway's sets the TOD point too close to the arrival airport and that causes a very steep descent (today more than 5.000 ft/min) on wich i still came in to high (and to fast) for the approach.

Flying online with fiends (same route, 30NM distance in between our aircraft) last friday gave this outcome: the Boeings where at the TOD 40 nm earlier then the Maddog, because of this late descent i had to drop my self down as a rocket.

I watched several MD80 cockpit video's on YouTube to learn how the aircraft is flown in Real Life and i saw several crews descending on Vertical Speed mode. But when the TOD is not accurately calculated by the FMC, the problem remains.

What are your experiences guy's?

Second is a known issue, the localizer capture. I saw crews in real life capturing the localizer with HDG Select. When we arm the LOC / GS mode the aircraft is alway's overshooting the localizer (even with a 20 degree intercept angle).

I might be mistaken...but it seems that the VNAV / TOD issue is more worse after the latest update....and the loc intercept issue, wich is suppost to be improved, is still the same IMHO.

What are your experiences? 

Kind regards,

Ben

Edited March 11, 20188 yr by Bentree_

About the late TOD: Do you enter real winds forecast along your descent path before?

Edited March 11, 20188 yr by roland_lfor

Hi Roland,

No, i don't. I did set the average wind for the route in the FMC though.

Do you think that will make a huge difference? Cause in the Boeings i never did and VNAV was alway's accurate.

Regards,

Ben

Edited March 11, 20188 yr by Bentree_

It will make a big difference if you have a strong tailwind of course.

Also you have to enter your SID/Approach waypoints constraints soon enough, especially altitude/speed constraints. It may help to predict a better TOD.

But globally I agree with you: she descends like a rocket and it's a very different aircraft, lot of study required and lot of fun.

It looks like the TOD computation is the very last chance to land without overshooting ;) One should start descent 10-20 NM before.

 

Did you check if the Height x 3 rule applies with the computed TOD?

Edited March 11, 20188 yr by roland_lfor

Before i start to use the TOD rule of thumb, or descent xxNM before TOD given by the FMC, i would like to know how other user experiences are ( am i the only one?).

Maybe even better, let the designers comment on this...how should it be?

Looks like you have kind of the same experience as i have Roland.

regards,

Ben

I did a flight while entering the wind forecast for the descent and that gave a much better outcome.

TOD point was accurate now, i will keep an eye on that in future flights.

Regards,

Ben

TOD is kind of close calculated but on my flights so far I had just one case where I was high and fast on the approach. But this was one of the first flights. In fact,  she is an older lady and VNAV and other fancy avionics where added later on as far as I know. The newer boeings have much better avionics, at least the NGX.

You have to help her on the way down, using VS and propper aviation knowledge. I think that makes it much more fun to fly. 

Edited March 13, 20188 yr by Rhinozherous