A few questions about 747-400x

[markparslow 2]

Hi all,I've been flying 747 400x for a couple of weeks now mainly doing short flights approximately 1500 2000nm, so it was about time I went long-distance. I have a few questions ?1, I tried to set a cruise altitude of 42000ft but I keep getting an fmc saying Max alt 38200??2, normally when flying under 10,000ft aircraft should stay below 250knots but in the clb page the speed/trans is 265/10000??3, when setting up the fmc the V1 and rotate speeds are in lower case and are not recognized in the cockpit display if I left click on each one then it goes into uppercase and then is shown on the display???thanks for any helpMark

[Guest Scousefox9]

Hey Mark,1.) You're bird is too heavy to fly at FL420 and the FMC is calculating that the MAX altitude that it can fly at that time is FL382. You may have noticed it also gives you an optimum cruise level in the VNAV cruise section. The aim is to fly as close to the optimum level as possible to ensure maximum economy. If you set up step climbs, the aircraft will predict when you should climb to a higher altitude to remain as close to the optimum as possible.2.) This can be changed to 250kts by inputting 250/10000 or something to that effect in the LSK below. I can't remember exactly because I haven't got it infront of me. Again I think this is calculated to be the most economical speed at the time which is why it wants to fly at that speed disregarding the standard 250kts below 10,000 speed restriction. If you're flying online you could always ask for it to be lifted if they haven't declared so already.3.) The speeds are in lowercase initially because it's telling you what it calculated to be the V1, VR and V2 speeds. That itsn't to say you want to accept them. As I understand it, in the real world they are checked against manual calculations from take off performers to ensure that they are sensible and then a decision is made as to which speed to use. By clicking on the corresponding RSK you are confirming and accepting the speed (making it bold) so it puts it into the PFD and the relevant callout is given at that speed.Hope that answers your questions.

[Mats_J 2]

Mark,You already got good answers to 1 and 3. I'll just add a little something to 2.2. The FMC will choose minimum safe speed *or* 250 knots whichever is greater.If you read through the manual and do some of the tutorials you'll learn a whole lot of other useful stuff like this.Hope it helps,

[markparslow 2]

HI LiamThank you for your quick reply and great answers.I am still not sure if i should be flying above 250kt below 10,000ft a thought this was a general restriction of over the world.Thanks againmark

[downscc 1,327]

Not to put words in Mats mouth, but the few places that 744's fly are used to her performance and all that's required is for the crew to let ATC what their requirements are. "Rules are rules," rule number one is to fly safely regardless of the rules and if you need to break them let ATC know.Highly recommend the tutorials too.

[Guest Scousefox9]

>HI Liam>>Thank you for your quick reply and great answers.>>I am still not sure if i should be flying above 250kt below>10,000ft a thought this was a general restriction of over the>world.>>Thanks again>>markHey, I'm not sure where you're from. In the UK, the standard 250 kts restriction below 10,000 ft does NOT apply to:a) flights in Class A and B airspace;:( IFR flights in Class C airspace;c) flights in Class C and D airspace when authorised by an ATC unit;d) test flights in accordance with specified conditions;e) aircraft taking part in flying displays when authorised by the CAA;f) aircraft subject to a written permission granted by the CAA;g) aircraft not subject to the ANO (e.g. military aircraft).The restriction can be lifted by ATC. In London airspace I believe they're trialing the 250/10,000 restriction anyway last time I heared.P.S. If I remember correctly the 250/10,000 cannot be enforced in the event that the aircraft's minimum safe speed is above 250 in the circumstances where the rule would normally apply. Don't quote me on it though!

[markparslow 2]

Thank you all for your help.i now understand more about the 250knots below 10,000ft restriction.You all know a lot more about this than i do.just one other thing,should change the CRZ alt and them dial in optimum cruise level into the MCP or do i just need to change the MCP and the fmc will adjust the optimum cruise level.Thanksmark.

[Guest Mower]

If I remember correctly the 250/10,000 cannot be enforced>in the event that the aircraft's minimum safe speed is above>250 in the circumstances where the rule would normally apply. >Don't quote me on it though!According to the RC4 manual that is correct: the PIC decides what the minimum safe speed is.

[Richard McDonald Woods 168]

Hi Mark,Use the FMC to determine your optimum flight level, and then enter this into the flight level on the MCP, and press the centre button. This will update your flight level in the FMC for you.PS Don't forget to request of ATC your requirement for FL Change if online.Cheers, Richard