UA38 Over MTOW

Last week I did UA38 WSSS-KLAX with a B789 and used simbrief. I had 252 passengers and the amount of feul that simbrief gave me and caliculated tge cargo weight.
It was 101% and was over the MTOW
Does someone know if this happens in real life and do they still takeoff with over MTOW weight?

To get accurate weights, you have to configure that in SimBrief according to the models in Infinite Flight. It can be slightly off otherwise.


Roger thanks!
I’ll do that when doing UA37 next week:)

Building off of Seb, I have configured many airframes in SimBrief to match those in Infinite Flight.

Use the aircraft editor to create your own.

Here’s the 787-9 configuration:

Feel free to copy these exact settings for your own airframes. Obviously some of them do not apply to Infinite Flight so just ignore that information and use the defaults.


Thank you :) I’ll this is gonna ve useful:)

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A quote off of SimBreif’s user guide:

The desired number of passengers to transport, used in weight calculations. The system calculates 230 lbs per passenger (175 for the person, 55 for their bags) and adds this weight to the aircraft’s OEW (Empty Weight) to derive the ZFW (Zero Fuel Weight).

So, while SimBreif’s system is extremely accurate and realistic from a simulator standpoint, not all passengers in the real world each weigh exactly 175 lbs and not all bags will equal 55 lbs per person. So there is a little leeway in terms of realism.

So I’d say that if in real life, a UA 789 had this exact config, it would probably not be exactly that same weight, just as Seb said.


So simbrief caliculates the passenger and the bagge wieght at the sametime?
There is a stteing for cargo too so I’m a bit confused.

In real life you will NEVER take off over MTOW. It would be illegal. It is a safety margined physical aircraft restriction.

There are a variety of ways you could achieve the flight with the required safety margins but, predominantly, you would be looking at reducing contingency fuel, considering en-route diversion to reduce diversion fuel, offloading cargo or, as a final resort, passengers.

Don’t forget that you also have a Max Taxy Weight in real life as well so you would also be factoring in your taxy fuel to enable you to start the take off run exactly at MTOW.

In normal operations however it isn’t the MTOW that is normally limiting it’s the TOPL or (Take Off Performance Limit) which is the limit derived from the atmospheric and airport conditions of the day. Usually encountered at high altitude airfields.

Under these conditions you MTOW may well be in excess of your TOPL however the TOPL is restricting and therefore you have to drop weight.



I am not 100% sure about this, but I belive aircraft usually will have additional pallets of cargo along with just passenger bags. Also, they must account for if passengers have more than one checked bag or carry on bag. Passenger bags may also be lost. Also, planes will cary baggage that was not connected correctly on the next flight out via the location, so an aircraft is more likely than not to be carrying more or less a different weight of cargo than just a simple algorithm.

So, as Sim Brief does not simulate to account for all of these circumstances, it generalizes these situations into one simple formula. But it is still somewhat accurate, to reflect a real world weight.

Honestly, I’d say, if your weight was 101% MTOW, you could probably be safe decreasing your cargo load just a little bit, just because the algorithms are generalized.

You actually do not need to worry about pax count and cargo count. All you need to do is enter your Zero Fuel Weight. Your fuel amount will be most accurate thriught that nethid rather than entering your pax and cargo weight.

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