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Windshear recovery

Started by Hardy Heinlin, Tue, 6 Jul 2010 19:27

Hardy Heinlin

By the way, I forgot to mention the PLAN mode (similar to MAP mode).

I think that TRK and HDG cannot be mixed and that there is either only a single pin for this programmable -- or several pins; and if the latter is true and some pin programmings disagree with each other there will be a system fault in the IDS (Integrated Display System, i.e. the system of all monitors, interfaces and symbol generators).




Yeesh, TRK UP seems awkward and weird.  I suppose one could adapt, but I'm used to reading the instruments the HDG UP way.
Will /Chicago /USA

Peter Lang

Yes I also prefer HDG UP. Something in my brain is mixed up if the nose of the aircraft does not direct to HDG.
I was really surprised to see how many airlines use TRK UP.



My take on TRK/HDG...

We have both aircrafts with TRK and HDG up in our 737 fleet and I much prefer TRK up. Having the magenta line pointing off to the sides when in cruise and with 50 knots crosswind seems weird. You also get a better use of the display when you can see the route ahead of you as opposed to disappearing off one of the sides of the display.

I see no disadvantages to TRK up. For situational awareness it makes no difference, as we are interested in the ground track. Where the nose precisely is pointing is in theory irrelevant. With HDG up, if flying over a distance with varying winds the magenta line will move about when infact we are navigating a straight track. I prefer a steady indication of a steady situation. The wind correction angle is of course not absolutely irrelevant, hence the " theory". But as we always move the heading bug to match the present heading, we will still have a constant idea of what is happening with the wind and where to look out the window for those Cb's that are displayed from the weather radar on the map.

I don't remember any of my colleagues with whom I talked about this subject who prefers HDG up.

Hardy Heinlin

Some very minor, perhaps irrelevant, disadvantages just came to my mind:

- With extreme crosswinds in TRK UP a noticeable section of the radar image is missing on one side. It may be irrelevant during straight cruise, but a little more relevant during turns. I learned that radar manufacturers try hard to provide radar data up to +/-90 heading angles for even more look-ahead when maneouvering through stormy weather. These efforts are in vain when an outer heading sector is invisible due to TRK UP.

- TRK UP adds a little to the mode complexity in general, especially in polar regions where also TRU/MAG has to be considered, even more so during VOR or ILS approaches in polar regions when one ND is in MAP TRK UP (expanded) and the other one in VOR/ILS HDG UP (expanded).




Hi All

Peter in reading: What your friend tells you is not the discriped windshear escape maneuvre given by Boeing. But the idea is since we dont have computers flying the aircraft then what you can do is set the nose attitude just hight enough to have intermittet stick shacker... flying right there you achive the maximum lift possible...
However that takes some practece since the maneuvre margin/stickshaker activation moves with the G load...
Boeings procedure is however if flying manually to press TOGA then firewall the thrust lever set initially pitch up the 15 deg, then follow the FD since they will follow the follow the windshear recovery logic, wings level and check speedbrakes down and maintain configuration... If flying on autopilot just press TOGA, verify speedbrakes down and monitor the AFDS...

I would at any time choose TRK up... What my HDG is when flying couldnt care less.. Its the track that is the important, especially during approaches and departures...but since the controllers might ask you what our HDG is or gives us radar vectors enroute or during departure/arrival we always set the HDG BUG to match the HDG index on the ND...
For the weather radar problem then we always have it on when we are in areas with CB's so you build up a mental cloud picture over a little time so I have never been affectd by the heavy wind/90 deg turn senario...



Quote from: Hardy HeinlinSome very minor, perhaps irrelevant, disadvantages just came to my mind:

- With extreme crosswinds in TRK UP a noticeable section of the radar image is missing on one side.
I see it the other way around, though you may be technically correct. For example with HDG up and if my track disappears off on the right side of the ND - then I won't be able to see what weather lies ahead on the right side side of my track (because it's off screen). Though now I will be able to a larger section that lies to the left of my nose, but where I will never fly...  8)