View Full Version : Back Course Localiser Approach

9th Nov 2003, 06:47
Just a quick question about Back Course Localiser Approaches?
I have never had to do one of these approaches before, although fly past a lot of airfields in Northern Canada enroute KLAX-EGLL-KLAX which have LOC BC approaches. I fly a B747-400 and my question is when the LOC BC is entered in the FMC and the LOC is automatically tuned will the LOC respond in the normal sence or the opposite sence? I would assume with this type of modern equipment the sencing will be in the correct direction.
I would appreciate any information on this subject or URL's with information on this subject.
Thanks very much.

9th Nov 2003, 15:03
When I was flying them in the USA, many many years ago - and in equipment far less sophisticated than a 744 - the sensing was reversed. Maybe there's something in the FMC that makes the compensation but, from where I sit, that might have the potential to make it more confusing when flying a BC approach.

9th Nov 2003, 21:00
If I remember well (cause I've looked all the morning thru the books,and I couldn't find it) the sensing will be right provided that you set the ILS course on the MCP course window,not the track course (backcourse) that you are flying.After engaging on ils,the FD bars will not receive commands from the FMS.
But again,I maybe wrong.I'll check my books,I know I've read about this somewhere.


10th Nov 2003, 11:28
The trickiest part on a LOC BC is to remember to read the approach plate and set the FRONT COURSE. Jepp tells you what to set. If you set this in your HSI you'll have no problems. Also select BC then LOC on the MCP, with out refrencing the book, I believe on boeings the order of selection is important.

Anyway, just keep the airplane symbol on the magenta line if you have negligble map shift or GPS. Fly it VNAV if you can.