Why would you need multiple autopilots?And in pictures I've seen of real Boeing 747, 737, 777 autopilots, they have something called VNAV and LNAV holds. Is the FS2004 Nav hold the same as LNAV in real life?PICTURE NOT MINE: Delta 777 MCP. LNAV and VNAV are by the IAS indicatorhttp://www.flickr.com/photos/7702824@N03/3885482426/#/photos/flightblogger/3885482426/lightbox/And pardon the noob question, but what are SIDs and STARs, and what do they do? Are they the same thing as approach plates? Also, what is RNAV?

I'll give a portion of the answer. The VNAV and LNAV and the Auto Pilot work together when the FMC (Flight Management Computer) is used to fly the filed flight plan. The auto Pilot can be used without the FMC by entering the HDG and ALT into the MCP. While the FMC does load a SID or STAR, adjustments are made by the pilot in in the FMC in regard to speed and altitude constraints that are listed on the approach chart. Charts are printed for different departures (SIDs),and approaches(STARs)and RNAVs. GOOGLE RNAV for a lot of education that cannot always be done here. Also you can GOOGLE SIDs & STARs.[Edit] See this post in 2005 at AOPA: http://www.aopa.org/whatsnew/newsitems/2005/050901rnav.htmlThere is also a lot of info here at AVSIM, so do a search. The best education you can recieve is when you do the digging.And Welcome aboard.Jim D.

Why would you need multiple autopilots?

For the simple reason of redundancy. They usually monitor each other and have to be in agreement. Otherwise one may drop out. They are also coupled with the inertial systems. Having more than one AP coupled in this way allowed the development of autoland in the 60's.vololiberista

Interesting. I saw this vid of a guy doing an ILS approach using the Wings of Power B-17G.

This guy was approaching the localizer at a 90deg angle! He seemed to be on the loc heading for no more than 5 seconds before he selected APP. The autopilot still guided him to a smooth landing though.So the prerequisites for selecting APP are: Intercept heading (VOR1 and/or HSI Loc needle centered), and at intercept altitude)?

Neither the LOC nor G/S needs to be active before you select APP. You must be receiving it and you should be on an intercept heading and below G/S before selecting APP. In RW, we usually selected APP when on intercept heading and providing we were below G/S almost always before it became active, (G/S pointer became active). If you have planned and carried out an approach correctly, it is no problem.Maybe your company has different procedures.Colin B