Firstly in general I love this aircraft, however after going through tutorial 1 and the "quickstart" guide I have some questions for those of you way more experienced than I am.   Firstly I have spent 99% of my time with the 737NGX. I very much understand that the 777 is a diferent beast entirely, however some things that seem to be very similar to the NGX suddenly behave differently, I'll list them below and please feel free to correct me.  I am not a pilot or a hard core simmer but I do enjoy this as a hobby.

 

1) After planning a route I select VNAV L NAV etc and the aircraft flies it perfectly, with the exception that it never seems to descend at a rate that gets it to the altitude it needs to be at a certain point.  This worked correctly on the tutorial but after following the same process but utilising my own start and end points and a route suppliued by "Route finder" everything works including the Autoland except the decent and I end up either putting a hold on it or having to descend manually much faster than would be healthy.  Any thoughts?

 

2) This questions is a hangover from the NGX, On the NGX I could happily set the Altitude Hold and speed hold through the Autopilot but then take of the Heading hold or even LNAV and fly the aircraft laterally by hand.  On the 777 it seems that the only way of disabling either vertical or Heading from the Autopilot is to completely disconnect the AP, leaving you to 100% fly the aircraft.  Am I missing something here or is this just the way it works on the 777.

 

Thank you for any input you can give in advance.

BEst Wishes for 2014

 

Andy.

 

 

 

 

 

 

Andy Mahaffey.

1. Enter as much info the FMC as possible to help with predictions. Wind data will help to accurately calculate your TOD. If all else fails use the other tools at your disposal to get you on path - FLCH, V/S speed brakes.

 

2. Quite suprised the NG allows you to control the aircraft laterally whilst the A/P is engaged, first I have heard of that? Does it have CWS?

 

Edit - just checked and it does have CWS, you won't find that on the 777

Thanks for your comments.

The NGX does have CWS as far as I am aware and it does allow you to disengage all elements of the AP individually.  As said I'm not a pilot so this may not be possible in reality.

 

As to point 1 Ill have a play again I may have just missed a line in the manual etc.

 

Another question I have that I didn't post originally is to do with Auto Throttle.  After setting 55% N1 and engaging the Autothrottle (via a Saitek throttle quadrant) The aircraft accelerates normally I pull the yoke back at Vr and climb out, the problem I have is that it just keeps accelerating and within 20 seconds I'm at 360 Kts at under 4000 ft and all kinds of overspeed warnings are going off.   The speed hold is set to v2 in the MCP as per tutorial and N1 does not exceed the level set in the Thrust Limit page of the FMC.  It just seems to ignore the MCP entirely.  What have I missed?

 

Many thanks

Andy

Hey Andy,

 

At most weights you are going to find the aircraft overpowered at full rated thrust. Your best option is to use a derate combined with an assumed temperature during take off.

 

TOPCAT should be available soon, this will allow you to calculate your derate/assumed performance safely.

 

Another option is to select FLCH after take off, due to the excess thrust your flight directors will command a high rate of climb that will maintain MCP target speed.

 

Regards

The B777 needs a lot of thrust derate, especially at lower weights. Derate, derate, derate ...

For the purposes of trying out and testing what you have said. I set an assumed temp of about 100 deg ( excessive I know) take off thrust was derated to about 78% N1 Even at this level I still reached 260 knts during initial climb out even with the speed hold on the MCP set to 152. I guess if auto throttle is armed and on Im expecting the engines to auto retard during the climb to maintain the set required speed. Am I expecting wrongly..

I did also try the FLCH but again still overspeed.

Many thanks guys

Andy.

Andy, FLCH uses pitch to maintain speed. Post a video, you are definitely doing something wrong, hopefully the vid will clarify.

 

Btw, an assumed temp and derate are two completely separate things. Setting an assumed temp is not derating the engines.

 

You must derate your take off 'AND' climb thrust.

Ahhhh I dont think I am derating climb thrust. Only take off thrust. Will have to look tomorrow now though. Thank you Rob.

If you derate T/O thrust, climb thrust will be derated as well in the FMC.

 

Pls. post a vid or a pic with your PFD/FMA if you re-encounter this issue.

Also make sure that your throttles are not overriding the AT!

Set "thrust levers override AT.....Never" under PMDG. options in the CDU.

 

That could also cause your VNAV to not work properly as your thrust levers might be overriding the AT in descend, preventing idle thrust to be set by the AT.

 

 

Oh, and it is either AP on or off. Not one mode on and the other off.

You are not supposed to fly the 737 like that either.

Just an update for those that contributed. 

I believe the problem with overspeed at take off is to do with weight. As I have been learning the aircraft and systems I have been flying short routes, as such I have been reducing fuel to just above minimums required.  I guess really I could expect nothing else wjen those engines are designed to power a huge aircraft flying massive distances... :-)

 

As to the point above I changed the options for thrust levers overriding the AT to Never and my next descent appeared to happen flawlessly. 

 

Thanks for all of the input.

 

Andy.