Hiya. Quick question if I may.And yes, I've RTFM but must say I'm a long way off fully understanding the FM...I'm sure real-world pilots wouldn't want me understanding all this stuff in 20 minutes!! I'm already wondering what they do....though if they can understand the blimmin FMC then they deserve every cent!Anyway, to quote the manual:"Before intercepting the glideslope switch the Autopilot to LOC and then to APP". 1/ What's the difference between the two?2/ At what stage does the APP take over from the LOC?3/ Do I even need to bother with the LOC?Yes, I know I want it "real", but playing Devils Advocate here...Also read in another post about the TCAS. WHAT TCAS?? Is this part of the package, or is it an additional download? Have I got it and just haven't seen it??Thanks in advance.Tim

Hi Tim!1) VOR/LOC establishes the aircraft on a radial of a VOR whether inbound or outbound. If you have the ILS frequency in use, VOR/LOC will intercept the localizer. VOR/LOC does not command pitch, and only deals with the horizontal plain. Another thing to mention is that you have to have the course set in the course window. Also, if you want to intercept a localizer or radial, you can be in heading mode and also press VOR/LOC, so both buttons are lighted on the MCP. What this will do is it will follow the heading that will intercept the localizer or radial, then when it gets closer, go into VOR/LOC mode completely and intercept it.2) You don't need to - you can control your heading via say LNAV, HDG or manual etc, though it generally makes interception of localizers and radials a lot easier.TCAS stands for Traffic Collision Avoidance System. The TCAS is Modelled in the 737-800/900 using the same standards as in real life. When turned on (download special tutorial off precisionmanuals.com download section if having trouble) you are able to see aircraft in conflict (and even aircraft that aren't if you set the option under the PMDG styles menu) on your PND, and eventually if you get too close to another aircraft it will aurally warn you ('TRAFFIC, TRAFFIC!!!') and even tell you how to avoid the potential collision ('CLIMB, CLIMB!!!' or 'DESCEND, DESCEND'), and markers on the PFD pitch bar and VSI will inform you at what rate you should do so.Hope this is all clear!Geoffrey Balean (YSCB) - no sig today, don't think i'm logged in yet :(

Addendum to Geoffrey's post:main difference between APP and VOR/LOC is that APP does the approach fully, while (as Geoffrey said) VOR/LOC only commands the plain on the horizontal plane.Everything you need (well, almost!) is in the manual.Have a look at section 9, there you can find all A/P command modes, and colour meaning, and everything.If you need else feel free to askBRClaudio

Just to add to what has already been stated Tim, The APP button will ARM both for the localizer and G/S (Glide Slope) and appear as white lettering on your pilot's FMA, when the engage the APP light will go out and the white lettering will turn to GREEN. Make sure to ARM the second A/P (:( prior to 800' or you will stay in single channel autoland. Refer to charts for the approach runway to see G/S capture information (Altitude etc). [h4]Best Wishes,Randy J. Smithhttp://www.precisionmanuals.com/images/forum/betaimg.jpgAMD 64 3200+ | ASUS KV8 DELUXE | GFORCE 5700 ULTRA @535/1000 | Maxtor 6Y080M0 SATA 80 GIG | 512 DDR 400 | Windows Xp Pro | Windows Xp Pro 64 |

Great! Thanks guys.T