Answering my own question, I think the following would be the payload/range figures from EDI in a 777-300ER (NB. the figures in brackets below indicate the maximums if there were no PCN or runway length limitations).
Boeing 777-300ER
Max ramp weight at EDI; 595,000lbs (775,000lbs)
Fuel/payload reduction from EDI; 180,000lbs i.e. 49%.
Range from EDI with max payload; 1,350nm (5,700nm).
Range from EDI with 364 pax and no cargo; 2,650nm (6,850nm).
Range from EDI with 364 pax and 30,000lbs of cargo; 1,800nm (5,850nm).
ACN empty; 34. ACN at MTOW; 109 (on rigid pavement with low strength subgrade)
Payload/range from EDI is currently PCN limited; a B773ER only requires 5,920ft runway at this weight (runway is 8,400ft long).
Source data;
Boeing: Commercial Airplanes - Commercial Aviation Services - Flight Operations - Airport Technology - Airplane Characteristics for Airport Planning and
NATS | AIS - Home .
Based on these figures, I can't see any airline being able to operate 777-300ERs on long-range flights from EDI unless the PCNs are significantly upgraded. How much work would that require? Would an extra layer of concrete on top fix the problem or would they have to install a higher strength subgrade first? How could work such as this be carried out without disrupting operations at the airport too much?
I'm still wondering whether the PCNs of Taxiways Lima and Mike at EDI are a further impediment to long range operations. These taxiways are effectively part of runway 12/30 which has a PCN of 31F/C/X/T which is far weaker than the passenger aprons (72R/C/W/T), Taxiway Alpha (74R/C/W/T) and Runway 06/24 (74R/C/W/T). If anyone knows the PCNs for Taxiways Lima and Mike, please let me know. They are not mentioned in the NATS data for EDI. If they are 31F/C/X/T, and given that the only stands capable of taking anything bigger than a 767-300 at EDI need to use these taxiways to reach the SE Apron, then the strength of these taxiways would reduce the payload range figures I calculated above by a significant extent unless the main apron is altered to cater for larger wide-bodied aircraft. The only place I can see where this might be possible would be to create a stand between stands 11 and 14.
Can anyone explain what criteria are used to determine whether a PCN can be exceeded? Block 33 at the SE end of Runway 12/30 is often used for parking widebodies, but perhaps just when they are empty (i.e. when the ACN is much lower)? There is however at least one situation where I know that an ACN has exceeded the PCN of 12/30 by a wide margin. Back in 2001/2 an AN124 at Block 33 was loaded with over 100 tons of drilling equipment and fuel. It was so heavy that it needed to depart at night when the air temp was lower. That must have exceeded the PCN by a wide margin but presumably the multi-wheeled undercarriage was deemed to spread the weight sufficiently that the airfield and aircraft operators deemed that it was acceptable?
Another possibility is that runway 12/30 at EDI is, in reality, much stronger than has been indicated on paper and that the declared PCN has been artificially reduced to limit the size of aircraft that are permitted to takeoff and land on that runway (because of the proximity of housing and related noise considerations). If so, perhaps EDI is quite happy to allow aircraft with a much higher ACN to taxi and park there on a case by case basis? I seem to recall reading that EDI was one of the V-Bomber dispersal airfields during the cold war so runway 12/30 must presumably have been much stronger than 31F/C/X/T back then.