Hi IFC I thought I’d post a topic about a current concern of mine at the moment. I’m flying from Frankfurt, Germany to Rio Dejanerió, Brazil in a Lufthansa Boeing 747-800. Before takeoff I put 16 hours and 45 minutes of fuel for a 12 hour and 20 minute flight just to be safe, as I have had problems with fuel consumption using this aircraft in the past. As you can see under the ETE to Dest it says 11:10 FUEL. I know there has been problems with this aircraft regarding fuel, am I likely to make it to my destination in time? The number for FUEL under ETE is frequently changing (going up and down). Should I be worried, or am I likely to make it to my destination in time with enough fuel?
Currently you are probably too heavy which causes the engines to use extra thrust:
More weight = More thrust
Less weight = Less thrust
This problem should go away as you get lighter and closer to your destination.
Also, do not forget to step climb when you are heavy;
Higher alt = Less air
Less Air = More thrust
Thanks so much for letting me know. If that is the case then hopefully I can make it to Rio with enough fuel of course. 🤞🤞
Or fuel dump as you can’t step climb anymore
Thanks so much this is so helpful. :)
What app do you use to monitor the winds by the way? I need it!!!
I don’t believe that is nessecary at the moment.
Thank you once again I will be using that from now on
Hey there! A great suggestion, is to slowly adjust the trim between 50-70%. It will make a large difference.
Your 'fuel remaining ’ might say anywhere up to 3-4 hours less than the destination once at cruise, but you should be fine
Yes definitely do that! It helps to save fuel :)
I did this route in a 747-400 this morning. All went fine with 70% trim, I usually keep at 60%.
Hi! Thanks for replying, I don’t necessarily use trim that often as I feel that it hasn’t really affected my aircraft when landing or on take off and I don’t fully understand the concept of it. I do know that is that it helps with back pressure on an aircraft but haven’t regularly used it incase I’m doing something wrong. Can I use trim throughout the entire flight? If it’s going to help with fuel consumption I’ll definitely implement it in this flight.
yes you can use trim the entire time!
So 60% to 70% (slowly increasing) should do the job?
yes, I flew from ELLX-SCEL in a 748 last night and the trim helped a lot
Basically trim helps with lifting/pushing down the nose. Positive trim will help you lift the nose, as an example in real life you wouldn’t have to pull back the yoke as much. Negative will do the opposite.
Trim is used in T/O and Landing. Personally I use 15% on T/O and 25% on Landing. However, this is not a rule or anything, you can adjust on how you feel.
Trim is not used IRL during cruise I believe, however because of the 747s bad physics in IF, it does help conserve fuel, a lot.
The Boeing 747 has horribly inaccurate physics (weight to lift and lift to drag ratios) which makes it use much more power and burn much more fuel to maintain speed than how the plane works
I use 10 degrees flaps because it decreases angle of attack and drag therefore reducing required power to maintain speed, try that out. I know it’s not realistic but then again the physics of the plane are even more unrealistic
That makes sense, so when would I use negative trim?
To be honest I do not use negative trim, and I am not sure why and when it is used in real life either.