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pkofman

simple ap control questions for 737

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If i am using the 737-800 or 900 and want to use the ap without using the fms , is it possible to actually simply program the fms and fly without it until cleared of a required "sid". I find it easier to fly without the fms under a vectored departure until cleared enroute. Is it actually the v-nav a l-nav that actually tie together the fms to the flight director.`aslo i find that i have run into a condition where i have programmed the fms and try to engage the aitothrottle but it keeps turning off. I cant find any reference to that situationLastly when you update the nav cycle, what folder should the new nav data be placed in.

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1. All you need is a departure runway.. go for it.2. Make sure engine generators are on line.3. Are you referring to airac or sidstars? Airac data goes in FMCWP/NAVDATA folder under your default FS9 folder. SIDSTARS go in /PMDG/SIDSTARS.


Dan Downs KCRP

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>1. All you need is a departure runway.. go for it.ok so do i simply engage fd, and at, then use heading hold and nav vor. I dont see how vor does simple tracking. If i dial in a vor frq and set the course, I think the thing should simply track the vor, but for some reason it does not always do that, Do you have to engage the lnav. Also does engaging vnav or lnav tie the fms to the fd. >>2. Make sure engine generators are on line.>>3. Are you referring to airac or sidstars? Airac data goes in>FMCWP/NAVDATA folder under your default FS9 folder. SIDSTARS>go in /PMDG/SIDSTARS.>no i was refering to the airac. update. in the init page of the fms it gives the most recent and for some reason the info in that line says 2004 data but i have updated it so tha is wrong. i will check the folder , that is helpful.do you have any idea why the AT will not stay on, and in which condition that happens, that is very frustrating.. thanks for the reply Peter>

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Your questions on how to use systems are covered pretty well in the documentation... also look in the avsim library for PMDG FMC Tutorial, there is plenty available. It takes lots of reading to fly an airplane.


Dan Downs KCRP

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>>>>ok so do i simply engage fd, and at, then use heading hold and nav vor. I dont see how vor does simple tracking. If i dial in a vor frq and set the course, I think the thing should simply track the vor, but for some reason it does not always do that, Do you have to engage the lnav. Also does engaging vnav or lnav tie the fms to the fd.<<<<


Ron Ginsberg
KMSP Minnesota, Land of 10,000 Puddles
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>>>>>ok so do i simply engage fd, and at, then use heading>hold and nav vor. I dont see how vor does simple tracking. If>i dial in a vor frq and set the course, I think the thing>should simply track the vor, but for some reason it does not>always do that, Do you have to engage the lnav. Also does>engaging vnav or lnav tie the fms to the fd.<<<<<>>If you are taking vectors you use HDG and FLCHG with speed.>You can turn on in the EFIS ND control the two VOR switches,>tune them in on the radio panel. Set the COURSE to home a VOR>if you wish. If you press the VOR/LOC button on the MCP the>aircraft will track the VOR1 course displayed on the ND. Do>not engage LNAV for VOR radio tracking under your control.>>When you are ready to use the FMC RNAV functionality, advance>on the LEGS page yopur next waypoint to the top of the list by>LSKing the name of your next way point on whatever page it is.>This puts it in the scratchpad. Then LSK the first waypoint on>page 1 and execute the change and it should plot from your>present position to that new next waypoint. Engage LNAV to>activate that track to couple the AP. VNAV will engage your>vertical profile planning as shown on your LEGS page but if>you are climbing or get an ALT MCP warning you need to>increase your ALT on the MCP panel to your next desired level.>You can do this in steps until you reach your preplanned>cruise level. If you wish to changed your planned TOC cruise>go to the CRZ page, type in your new level and LSK and EXE it,>and then if your MCP ALT is higher the aircraft will climb.>>The same thing happens on descent if you are VNAV. If you have>not reduced your MCP ALT the aircraft will not go below that.>You can start an early descent in VNAV by going to the DES>page and LSKing DES NOW.>>As ATC starts vectoring your arrival and you get low (around>10,000 feet) and you want to slow I find it best to disengage>VNAV and use SPEED, FLCHG, and ALT to follow their>instrctions or manually follow a plate (IAP). As you get to>the ILS merge (NAV tuned and course set on #1 and on standby>on #2 - #2 may be on a nearby VOR for DME info if needed) when>the H indicator on the PFD starts to move toward center crank>HDG toward the inbound course and when close engage LOC or APP>as appropriate. Then tune VOR #2 to the same ILS. When at>about 1500 AFL engage the second CMD for a dual channel>precision autoland under APP if glideslope is present. ALWAYS>CHECK THE IDENT BELOW THE ANNUNCIATOR IN THE PFD TO INSURE YOU>ARE LOCKED ONTO THE CORRECT LOCALIZER. There are some FS>airports with shared frequency localizers at opposite ends of>a runway that until you are close to center beam may give you>the wrong one.>>VOR/LOC and APP disengage LNAV from the AP, by the way.>>>There is more but as Dan stated it is best to read the manual>and prfactice this before getting serious:) . I just gave you>an overview but it sounds more complicated than it is.Very helpful , So i thank you for this explanation, Actually im a 1000 hr pilot in real life but it seems the tie between the ap and fms functionality is what i see as complex ( or new to me). I admit i have not flown a 737 or 747 . I like to know what the aircraft is going to do when i push a button . This is particularly true becuase i fly most of the time online on vatsim and i hate screwing it up. I almost have this deciphered , and I am getting the hang of the fms, Can you explin the situation that causes the AT to continually flip off. It must have something to do with preplanned spds in ths fms. Lastly when flying an interect to track a radial to a vor is there a max angle or distance modeled in l-nav that prohibits the recognition of the intercept or will not engage the approriate funcitionality in the FDthanks Peter Kofman>>

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In RNAV (LNAV control) when you are going to intercept a predetermined track to the next waypoint you do require to be with I think 10 or so degrees of the predicted heading. Mind you, when you engage LNAV the aircraft will turn to merge with the present path (the solid puple line), not toward the next waypoint. If you want to go direct to the next waypoint, on LEGS page 1 you LSK twice the waypoint at the top and a direct path will be created. EXE and it will be activated.For VOR tracking, not LNAV using the FMC, you would home the course and turn inbound within a few degrees and activate VOR/LOC. There is a limitation but I'm not sure what it is.VNAV and AT might disconnect if the aircraft experiences something outside of its performance envelope. Their is an FS9 excentricity known as the Super Stall. It has to do with sudden immediate wind speed shifts, sometimes 180 degrees, that temporarily cause a severe IAS fluctuation. It can be relieved somewhat by a fully registered FSUIPC module. I do not know if the permissions granted by FSUIPC with the included PMDG self-registration allow that feature. It is caused by those using downloaded weather when borders across reporting points are encountered with drastic changes. Those of us who have Active Sky 6 have this smoothing ability as a built in option. (It uses FSUIPC.)There might be other conditions beyond which AT can not compensate and will disco. There are protection mechanisms to prevent excessive N1 and other issues. You might try pausing the flight and checking all your attitude, flaps, and performance instruments to see what might be causing operation outside the aircraft safe service envelope.BTW, I was a long time ago a VFR CPL without over 250 hours in GA in pre GPS days. I know where you are coming from with your concerns about VORs.The FMC includes VORs (seperate receivers) in its nav arsenal and it picks the best nav references available. For approaches a few places allow an RNAV final but in most cases HNAV is done by VOR or LOC.The 747 autotunes the VOR 1 and 2 I believe for navaid procedures. The 737NG does not.


Ron Ginsberg
KMSP Minnesota, Land of 10,000 Puddles
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Support Team

 

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