Does this mean squeezing a quart out of a pint pot by ending segregated mode and rwy alternation at Heathrow and move to permanent all-day (everyday) mixed mode?
This would:
(1) increase available movements by 10-15%(?);
(2) do nothing to address congestion and delays;
(3) end the daily half-day of quiet for those under the flightpath.
The conventional wisdom is that full-time mixed mode would increase capacity by around 60,000 ATMs per year, which equates to 12.5% of the current limit. However we're told that such an increase would be contingent on airspace changes (but see below).
Whether this would or wouldn't reduce congestion and delays is a moot point. We're told that the object of the current mixed mode trials is to improve resilience, i.e. the airport's capability to recover from disruption, so presumably full mixed mode could provide more of the same, depending of course on how much of the increased capacity is absorbed by demand. Obviously if the scheduling limits were increased pro rata to the revised capacity, so that LHR was still operating at 99%, then congestion and delays would continue to be the norm.
But you're missing the point. The Commission, whose 3 or 4 members will be confirmed in the next week or so, will have fulfilled its obligations when it makes its recommendations for those "immediate actions".
It won't have any responsibility for implementing changes, and if any of its recommendations turn out to be infeasible (cf airspace design) or politically unacceptable (cf loss of respite for West London residents) then they will all be consigned to the "too difficult" tray and we'll be back to square one.
In other words, the Commission will have fulfilled its purpose - to give another year or so's breathing space - regardless of what conclusions it reaches.