How does the A220-300 have lower fuel capacity and longer range than the -100 variant?

Question

The A220-100 and -300 variants have relevant specs of (respectively)

• fuel capacities of 21,805L and 21,508L
• MTOW of 63T and 71T
• Range of 3450 nmi and 3600 nmi

How is the bigger, heavier variant specified to go further on less fuel?

Answer 1

I assume the numbers you found are from the Wikipedia article. If you look closely at the specifications table, you'll see that the numbers are from two different publications:

1. The Airbus Family Figures Booklet (2019), which lists the following data:

   	A220-100	A220-300
   MTOW	63.1 t	69.9 t
   Fuel Capacity	21 805 l	21 508 l
   Range	3400 NM	3350 NM

2. An article (2021) about improved MTOW and range for the A220-300:

   It will take the MTOW of the -300, the larger of the A220 variants, to 70.9t from the current 69.9t and will provide some 200nm additional range.

So the range of the A220-300 was originally lower than the -100, but was improved due to the higher MTOW. It still has a lower fuel capacity, but range (with payload) is not limited by fuel capacity. It is limited by MTOW as you can see in the payload/range plots:

• A220-100

  

• A220-300

  

As you can see from these plots, the maximum range (ferry range) of the A220-100 is higher than the -300, but the -300 can fly further with 140 passengers than the -100 with 120 passengers due to its higher MTOW, therefore giving it a higher typical range.