I started to collect the backlogs for both aircraft every month to see how the backlog will change over time. With the current or announced future production rates I can then calculate how many orders both aircraft will need.
Of course there are some open questions that will influence the number orders needed to fill the so-called gap:
- How will production rates change until the new aircraft will enter service
- How long will it take until the new aircraft will take over full production
Boeing did not yet announce any production cuts for the B777, staying at a rate of 8.3/month of 100 per year.
As I don't know how long it will take for the new aircraft to take over full production I will only calculate the numbers until EIS of the two aircraft.
Here is what I get for the A330ceo:
Airbus would need another 129 orders until EIS of the A330ceo to keep the production line output at 9 aircraft per month. Airbus already admitted that the rate has to be cut further down but has not yet indicated when and by how much.
And here is what I get for the B777:
To keep output steady until the two new aircraft take over full production a lot more aircraft need to be sold. I highly doubt that this will be possible. Airbus seems to be more open and honest about that.