Sponsor Message:
Aviation Hobby Forum
My Starred Topics | Profile | New Topic | Forum Index | Help | Search 
Lnav And Vnav?  
User currently offlineSPRINGBOK From United Kingdom, joined Jun 2001, 192 posts, RR: 1
Posted (14 years 7 months 2 weeks 6 days 20 hours ago) and read 3593 times:

Still in deep shock, but i have a question "How do the LNAV and VNAV operate with the Autopilot and when are they operated?after purchasing PSS747-400
Any views much appreciated!
P.S RIP to all affected by the attack

5 replies: All unread, jump to last
User currently offlineAJ From Australia, joined Nov 1999, 2406 posts, RR: 24
Reply 1, posted (14 years 7 months 2 weeks 6 days 10 hours ago) and read 3549 times:

Hi Springbok,
LNAV (lateral natigation) and VNAV (vertical navigation) operate using data from the flight management computer.
On a normal B747-400 operation with a SID programmed for departure LNAV and VNAV can be armed for departure.
At 50' TOGA will change to LNAV in the roll mode and the flight director will follow instructions from the FMC to fly the SID. When the autopilot is engaged it will follow these commands. LNAV can remained engaged, follow a programmed STAR right to the destination. Normally it is only disconnected for radar vectors (HDG SEL), weather diversions (HDG SEL) or Localiser intercept (LOC).
At 400' TOGA will change to VNAV in the pitch mode and the flight director will follow instructions from the FMC VNAV page. The first speed commanded is V2+10kts to +25kts depending on current speed. VNAV will then command acceleration for flap retraction at the appropriate altitude and programmed climb speed (VNAV SPD). VNAV will not climb through or leave an MCP entered altitude (VNAV ALT). If cruise altitude on the MCP matches the altitude on the VNAV CRZ page in the FMC you will hav VNAV PTH (path) displayed on the PFD. Approaching TOD calculated by the FMC you will get the message 'Reset MCP altitude'. If the MCP altitude is below the cruise altitude the thrust will reduce to idle and descent will commence in VNAV PTH. VNAV will maintain the path up to 15kts away from the programmed speed. Outside of this VNAV SPD will be displayed and the descent profile will be left. This will normally require speedbrake to resume path with the message 'Drag Required'. VNAV will follow the speed transitions entered in the VNAV DESCENT page, such as 240kts below 10000'. It will also attempt to comply with STAR altitude restrictions. If an intermediate altitude is captured on climb or descent VNAV ALT will be displayed. Once the MCP altitude is reset the selector button must be pushed to resume the climb or descent. VNAV can remain engaged until glideslope (GS/APP) intercept.
I don't want to make this too complicated, I hope this info helps!  Smile/happy/getting dizzy

User currently offlineConcorde1518 From United States of America, joined May 2001, 746 posts, RR: 0
Reply 2, posted (14 years 7 months 2 weeks 5 days 14 hours ago) and read 3540 times:

Basically, the flight planner on MSFS is like programming the FMC, and using the NAV button is like hitting the LNAV. (With a few differences) On real aircraft, the closest thing to the NAV button is the VOR/LOC button which will fly to the airport LOC, or a VOR. Either way, the VOR or LOC frequency must be inputed in the radios.

User currently offlineCoronet-Solo From Sri Lanka, joined Sep 2001, 14 posts, RR: 0
Reply 3, posted (14 years 7 months 2 weeks 5 days 5 hours ago) and read 3530 times:

AJ-thanks for the superb explanation. Very informative-not boring at all! Smile

User currently offlineCoronet-Solo From Sri Lanka, joined Sep 2001, 14 posts, RR: 0
Reply 4, posted (14 years 7 months 2 weeks 5 days 4 hours ago) and read 3531 times:

I already have around 300 cut-away drawings.Would like to have for the following types;
Antonov An-22
Tupolev Tu-16
Anyone with a similar interest,please respond. Smile

User currently offlineSPRINGBOK From United Kingdom, joined Jun 2001, 192 posts, RR: 1
Reply 5, posted (14 years 7 months 2 weeks 4 days 1 hour ago) and read 3530 times:


Top Of Page
Forum Index

Reply To This Topic Lnav And Vnav?
No username? Sign up now!

Forgot Password? Be reminded.
Remember me on this computer (uses cookies)
  • Aviation hobby related posts only.
  • Back all your opinions with facts.
  • No adverts of any kind. This includes web pages.
  • No hostile language or criticizing of others.
  • Do not post copyright protected material.
  • Use relevant and describing topics.
  • Check if your post already been discussed.
  • Check your spelling!
Add Images Add SmiliesPosting Help

Please check your spelling (press "Check Spelling" above)

Similar topics:More similar topics...
FSX And Computer posted Fri Dec 1 2006 03:40:19 by MEACEDAR
Im Unsing Vista And FSX! posted Mon Nov 13 2006 18:58:07 by Qantas744ER
October Trade List--Safety Cards And More posted Mon Oct 30 2006 04:57:58 by SafetyDude
FSx And Vista/XP posted Mon Oct 30 2006 03:51:19 by FURUREFA
Pmdg 737NG Pushback And Turning posted Fri Oct 27 2006 14:28:29 by Treeny
Eyepoint And FSX Works Is Good :) posted Thu Oct 26 2006 20:03:34 by Malaysia
FSX Fuel And Payload posted Sun Oct 22 2006 03:33:55 by Boeing 777-400
Difference Between Deluxe And Standard? posted Fri Oct 20 2006 23:54:25 by Pizzaandplanes
Active Camera And FSX posted Tue Oct 17 2006 11:34:58 by Djw030468
Most Realistic AI (MRAI) Is Up And Running! posted Tue Oct 3 2006 16:55:45 by BAW076

Sponsor Message:
Printer friendly format