Vertical Navigation

[Guest Verran]

v_v Oh man. ... *Crawls under the largest rock he can find*Okay so reference VNAV and step climbs, I basically have to set the ALT MCP to the first cruise alt, then reset it to the next step? She'll then automatically go to that altitude at the proper time, I presume? Or am I giving her to much credit again?

[MarkRey 16]

yup - too much credit :)depeding on what step size you're using (whole 'nother story) but say 2000ft increments, the fmc will compute when the next 2000ft climb should happen, but again you have to manually intervene and command the climb once cleared by ATC (yourself? :) ) so to do.I read the pros saying they use v/s mode a lot to do these small steps - at say 500fpm - once there they engage vnav again.regards,MarkXPHomeSP2/FS9.1/3.2HT/1024mb/X700pro256

[Guest Verran]

So, reference the CDU, should cruise altitude then be set to the flightlevel at which you first level off?

[Guest AlexMcB]

Hi Justin,The Optimum and Maximum Altitudes displays the optimum and maximum cruise altitudes for the aircraft's current gross weight based on FMC performance data (Cost Index, etc). Basically, Cost Index is the balance between fuel and time; we may vary this depending on the load factor and passenger mix on routes. High paying first/business class loads may encourage time having a greater influence than fuel (see 747 example below).Simplistically, you could consider these fields as "information only". If Optimum is FL290, but the FMC cruise level is FL310 and the MCP has FL310 set, the aircraft will climb past optimum to establish in the cruise at FL310. This could be for traffic avoidance or weather, but mainly for Step Climbs. Step Climbs come into play as the aircraft burns off fuel. Obviously for separation purposes we cannot continually drift upwards for fuel efficiency as we get lighter. So we climb initially to around 2000 above optimum and then over a number of hours the optimum "creeps up" and past our current level. Once it is 2000 above us, we intiate a Step Climb (4000ft) so that we are again 2000 above Optimum; this is known as bracketing. Once we're around 200-300 miles from our Top of Descent we wouldn't bother with another Step Climb. We also wouldn't exceed the Maximum Altitude.Of course, with the renewed focus on "green issues" and current fuel prices, prolonged uneconomic flying may result in a chat with the Fleet Chief Pilot or Ops Room :-.It is slightly off topic as I can't reach a T7 manual at the moment but here are a few comments from a ++747-400++ simulator which gives some context to the FMC Optimum calculations and the implications. RegardsAlex ==>>Maximum Range Cruise (MRC) is the cruise speed used when fuel conservation and range is of primary importance. (Cost Index 0). This speed provides the maximum range at optimum altitudes. ==>>Long Range Cruise (LRC) is the recommended speed to minimize trip fuel, generally providing 99% of the maximum fuel mileage but a little faster than MRC.==>>Economy Cruise (ECON) is that cruise speed flown, derived from a valid number in the FMC Cost Index 0-9999. The ECON speed minimises either the cost of fuel or cost of flight time or a balance in between. Cost Index 0 ECON speed will attempt to minimise the use of fuel. If Cost Index 9999 is entered, ECON speed will attempt to minimize the flight time.The best fuel mileage for a given speed is achieved at optimum altitude. The fuel mileage penalty for operation of off-optimum altitudes at Mach .86 is listed below:2000 feet above optimum, fuel penalty 1%2000 feet below optimum, fuel penalty 2%4000 feet below optimum, fuel penalty 6%8000 feet below optimum, fuel penalty 15%12 000 feet below optimum, fuel penalty 25%If operation below optimum altitude is required due to ATC requirements or outside circumstances, operation at LRC cruise speed will minimize excess fuel burn and prevent low arrival fuels. The fuel mileage penalty for LRC:2000 feet above optimum, fuel penalty 1%2000 feet below optimum, fuel penalty 1%4000 feet below optimum, fuel penalty 3%8000 feet below optimum, fuel penalty 7%12 000 feet below optimum, fuel penalty 12%

[MarkRey 16]

Alex,With reference to Justin's last question re initial cruise alt - this is a bit gray for me too. How do I calculate what initial cruise alt to start at given my weight (and I guess general direction of flight - east/west)?edit - I mean while sitting on the ground setting the cdu cuise alt.regards,MarkXPHomeSP2/FS9.1/3.2HT/1024mb/X700pro256

[Guest Verran]

Now obviously you guys understand all this stuff better than I do. Frequently I get chances to hop the atlantic to go see my old man, well, not as frequently as I would like, but I recall the first time I ever left the country, I was on board BAW2226, a B772, from KATL to EGKK. Now, call me whatever you like, but I know this to be true, they took that girl from the floor straight up to 450, and we didn't start coming down until sunrise, just over Ireland. Now what's that all about?

[Guest adameke777]

>Now, call me whatever you>like, but I know this to be true, they took that girl from the>floor straight up to 450, and we didn't start coming down>until sunrise, just over Ireland. Now what's that all about?Did the oxygen masks work ok ?:-xxrotflmao

[Guest DVA2082]

>>Now, call me whatever you>>like, but I know this to be true, they took that girl from>the>>floor straight up to 450, and we didn't start coming down>>until sunrise, just over Ireland. Now what's that all>about?>>Did the oxygen masks work ok ?>:-xxrotflmao I'm dying to know that too..Chris

[Guest Verran]

>>>Now, call me whatever you>>>like, but I know this to be true, they took that girl from>>the>>>floor straight up to 450, and we didn't start coming down>>>until sunrise, just over Ireland. Now what's that all>>about?>>>>Did the oxygen masks work ok ?>>:-xxrotflmao >>>I'm dying to know that too..>>ChrisApproximately 10 minutes ago the aircraft was reset. I found myself at FL310, surrounded by water, with a dead airplane. Leaving 14000 for the floor power was finally restored, however, I'm running entirely on backup systems. Currently I'm approaching cruise altitude again, but, the CDU can't seem to catch up with the aircraft's position, despite my efforts to educate it. Unless the system's restored I don't think I'm finding my way home. Any suggestions?Edit: An FMC message continues to appear every few seconds, Alightment Reinitiated. I clear it out and attempt to align the computer, but, no joy. Good thing I'm not logged on to VATSIM right now. lol.Edit: There's no way for me to align the ADIRU while the plane's moving... is there...? *Cries*

[MarkRey 16]

realign while moving?sure you can :+ just hit the adiru button - and you'll see an fmc message 'wht?'type 'whr m i'you'll see a new moving waypoint pop up on the nd 'u r hr' along with some coords - quickly type in those coords cause they'll fade really quickly...regards,MarkXPHomeSP2/FS9.1/3.2HT/1024mb/X700pro256

[Guest Verran]

... *Grins* I don't believe you. *Chuckles*The FAA would kick my XXX if they knew I was VFR at FL180. In any case. I found Ancorage via Kodiak. That was interesting, considering I'm still No Gyro. Yeah. Navigate that on a magnetic compass. Well. Time to start the descent.

[Guest Verran]

>... *Grins* I don't believe you. *Chuckles*>>The FAA would kick my XXX if they knew I was VFR at FL180. In>any case. I found Ancorage via Kodiak. That was interesting,>considering I'm still No Gyro. Yeah. Navigate that on a>magnetic compass. Well. Time to start the descent.HA! I busted yer fool airplane and I STILL landed it!On a serious note, however, in the setup I have it set to not change the aircraft state when reset, so, why then did the engines, and everything else for that matter, shut down when the aircraft was reset? I'll double check my settings but it's set on "Don't Change"That was hella fun though!

[Johan_Dees 84]

Thats the fun with it!.having non expected difficulties, altough not too many!JohanA LITTLE LESS CONVERSATION, AND A LITTLE MORE ACTION PLEASE!HELP:http://support.microsoft.com/?kbid=238882

[Guest Verran]

So I set the followingStartup Settings>Aircraft status at startup>"Don't Change" and everytime I reset or restart the aircraft, I find her cold and dark. Um. Not cool when I'm at FL310 in he middle of a big body of water. >.< What'd I do wrong this time?

[Guest Verran]

Just a quick question... The Phoenix team took the time to model the winglets on the tips of the T7, but are you guys going to "scale up" the engines to a more realistic size for the GE90-110B1/115B. Just noting it doesn't appear to have a 115in. intake... Let's be honest, that's sort of a defining feature for this girl... them big XXX engines! Woot!