The Radios do not autotune ILS, you are right there , that is for the APP. That has nothing to do with posistion updating during flight which comes from DME data from VOR/DME data, which the FMC autotunes VOR's obtains DME data from 2 differing VOR's and compairs it to the IRS data.The onlt thing I'm unsure of but will find out very soon is whether FMC has it's own dedicated DME channels or not. Which you could be right that there is not autotuning shown on the VOR panel, but not true in the sense that the is not VOR pos update is wrong..The statement that there is no autotuning is untrue, weather or not the NG uses the the pilots NAV radio's for DME updates .11.20.9ILSTwo ILS recivers are installed.The ILS reciver are tuned manually on the VHF navigation control panel. The flight crew must manually tune the ILS for display on the CDS.LOC updating of the FMC occurs only after the ILS is tuned manually.Let me restate what I said before.."Inflight, the FMC position is continually updated from the GPS, Navigation radios and IRS. Updating priority is based on the availability of valid data from the supporting systems. FMC Position updates from Navigation Sensor positions are used in the following priority order:GPStwo or more DME stationsOne VOR with colocated DMEone Localizer and collocated DMEone localizer.11.20.3" FMC logic selcets the position from one of the GPS sensors (two sensor installed that run independent of each other). When GPS position data is available, radio updating can also occur. If all GPS data becomes unavailable, The FMC position will be determinned by radio or inertail (IRS) updating."And this is IF the aircraft has a the option for GPS, if then primary possition updates would come from station tuning.11.20.9(DME)Two frequency scanning DME systems are installed.The FMC autotunes DME recivers as necessary for posistion updating. Durning normal operations, two different DME signals or a single from a collocated VOR/DME pair provide an accurate radio geografical posistion to the FMC.the identifiers of the DMEs currently providing update data to the FMC are displayed on the NAV STATUS page 1/2. The radio position is displayed on the POS REF page 2/3.

It's so great of you to be the sig police and then have a sig with text along the side that takes 3/4 of my screen to display. Thanks. Like I really care about every piece of hardware and software on your system.Lee Hetherington (KBED)

From the Continental 737 manual, section 6.11, page 9, FMC Position Updating:"The navigation radios are automatically tuned by the FMC(s) for the purpose of radio updating (in AUTO, if applicable). The stations to be tuned are selected based upon the best available signals (in terms of geometry and strength) for updating the FMC position, unless a specific station is required by the flight plan. Radio position is usually determined by the intersection of two DME arcs."This manual covers the -300, -500, -700, -800, and -900, and it clearly labels when information is for a particular model, and this paragraph is not labelled such.It sure sounds to me like make a blanket statement that the "737 has no nav autotuning" is false. Maybe it is carrier dependent? It also mentions that GPS is used for updating as well.EDIT: Upon further reading, for the -700, -800, and -900, it appears the nav radios have no auto button. Maybe that does support the non-auto tuning. They likely rely more on GPS than radio for updating.Lee Hetherington (KBED)

The SigWaffenSS wrote:>A friendly reminder, your sig image is out of regulation with>the avsim image sig policies. Does a polite person pull a person off to the side, or does he holler across the room "Hey, mate, YOUR FLY IS OPEN!" ???But the good news, if I publicly berate someone and then put a smiley-face after it, it's all OK. :-)I think private e-mail links still work on avsim...Bob ScottATP IMEL Gulfstream II-III-IV-V"There are people in this world that do not love their fellow man,and I *hate* those people" -T. Lehrer

Yes I agree with you Lee,But even if the carrier selects the GPS option, there is still autoturning, as a secondary there is still DME posistion updating.Boeing 737-NG Operations Manual11.31.5 'Flight Management System Operation"Section 'FMC Position Update:"Inflight, the FMC position is continually updated from the GPS, Navigation radios and IRS. Updating priority is based on the availability of valid data from the supporting systems. FMC Position updates from Navigation Sensor positions are used in the following priority order:GPStwo or more DME stationsOne VOR with colocated DMEone Localizer and collocated DMEone localizer.11.20.3" FMC logic selcets the position from one of the GPS sensors (two sensor installed that run independent of each other). When GPS position data is available, radio updating can also occur. If all GPS data becomes unavailable, The FMC position will be determinned by radio or inertail (IRS) updating."

dismiss my first posti rechecked the manuals and i was wrong ;)it has NAV autotuning, however not all aircrafts are equipped with GPS. this depends on airlinecheers

Lee --I happen to care about my hardware. There is nothing that states that I cannot put large amounts of text into my sig, and avsim has repeatedly stated that they have no policy against text. Anyone can show me said policy indicating that my sig is out of avsim regulations, I will remove the offensive part from my sig.Get over it. Look at Tom Allensworth's sig, just like mine, except avsim related. Perhaps you want to tell him off in a snotty tone?And about my being the sig police, I do like having sigs. If people don't follow the rules, then eventually avsim will alter there policy yet again, and perhaps restrict me even more. I don't want that, and so I ask Martin to politely alter his sig. There is nothing wrong with that Lee, and I find your retort childish and inconsiderate.

Bob --I concede this point. I must'n be a polite person.Oh, and BTW, what I said certainly was not 'beratement', or anything of the sort. I did not call him an ignoramous, and idiot, or anything of the kind. I did not insult him. All of said things would have been out of line. So I take issue with what you said about me 'berateing' him. All I did was point out what was wrong with his sig. I concede that I should have done this in a PM.

@Fredi have reduced the size and should be OK for you too. it was that way since i registered and Tom never complained.but, guys, why you can't do this discussion by mail or pm.this thread is going off topic"NAV Autotuning" remember ;)

"The onlt thing I'm unsure of but will find out very soon is whether FMC has it's own dedicated DME channels or not."Not sure if this is what you are looking for, but....According to our airline's 737-800 maintenance manuals, the FMC tunes the DME Interrogator by sending "up to" 4 autotune commands to the navigation control panel. From here, it goes to the Interrogator. The pilot can add a 5th, manual, tune command using the control panel. If the navigation panels fails, the FMC can send autotune signals directly to the Interrogator.Our manuals basically agree with everything you've said. Definitely autotuning, but not for VOR's or ILS's ;-)Cheers.Ian.

>this thread is going off topic>>"NAV Autotuning" remember ;)exactly. I second Lee

Gents-to clarify this issue once and for all:There's no ILS or VOR autotuning for following a radial or capturing an ILS.There's NAVAID autotuning INTERNAL to the FMC, so that it can have position awareness - it's like signal triangulation, which produces location information.As such, there's no bug or omisssion here. There are others, but this is not one of them!