View Full Version : why the VOR mode use "Heading" reading instead of "Track" reading?
eagle737
31st Mar 2005, 02:30
on 737, when we choose the VOR mode on EFIS control panel, we get "Heading" reading. but mostly we fly the ILS/MAP mode while we get "Track" reading on the top. i'm wondering why don't boeing design one type of reading on the top 'cause i really think the "track" reading is more convenient.
any opinions will be appreciated.
I'm pretty sure this is a 'pin-selectable' customer choice which your airline may have chosen, and that Boeing has given you all the choices in their system. Have a word with your tech pilots?
Willit Run
31st Mar 2005, 13:13
The CMA-900 FMS units now fitted into our classic 747's has the same set-up. When your flying a sid or star in the map mode, you have a pictorial of the track your supposed to fly anyway, so they give you track to back up with. I like having both to work with , but you have to have your brain engaged. Also, in some parts of the world, we don't have the sids and stars in our data base and then have to go back to the old raw data way of flying.
Old Smokey
1st Apr 2005, 12:28
The basic reasoning is that if you're in VOR (selected) mode, you're back in Raw Data without the LNAV facilities usually available from FMC / FMS / EFIS, i.e. the system has no 'knowledge' of TMG.
Old Smokey
Nor sure which 737 you are flying, eagle, but all the ones I fly (3/4/5/7) display a TMG in 'Expanded VOR' mode. We do not have a 'VOR' button' on the EFIS panel, mind you. We have a 'VOR/LOC' button which does not affect the EFIS display. We also use 'HDG' at the top for all modes. You must have a different system? It can almost certainly be changed by your company, as I said.
eagle737
4th Apr 2005, 07:00
thank u for your replies
BOAC, u see the heading number on the top when u fly the MAP mode? anyway, i'll check with our tech guys.
and i think the answer Old Smokey gave probably is right.
Yep, eagle - and we are not alone! It is, as I said, a customer selectable option. See http://www.b737.org.uk/navigation.htm
Eagle 737 said:
but mostly we fly the ILS/MAP mode while we get "Track" reading on the top.
Old Smokey said:
The basic reasoning is that if you're in VOR (selected) mode, you're back in Raw Data without the LNAV facilities usually available from FMC / FMS / EFIS, i.e. the system has no 'knowledge' of TMG.
Isn't ILS "raw data" also?
Thanks for any insight.
Rgds.
NSEU.
P.S. BTW, what's TMG?
TheOddOne
10th Apr 2005, 12:14
TMG = Track Made Good???
The Odd One