I don't know about an MOU but from the Slate Book Appendix A... copy-paste from a comment I've made before...I have never been able to find it. Have you? I only find references to it, never the actual agreement
Metropolitan Tower Complex – Two (2) or more airport traffic control terminals that provide traffic advisories, spacing, sequencing, and separation services to VFR and IFR aircraft operating in Class B airspace within the vicinity of the airport using a combination of radar and direct observations. These airport traffic control terminals must serve separate Large Hub Airports located in a major metropolitan area and independently be within one (1) facility pay level of each other. Additionally, each airport must be located within fifteen (15) nautical miles (center of airport to center of airport), and have traffic flows that have to be closely coordinated between facilities such that the operational configuration of one (1) airport affects the operational configuration of the other(s).
Traffic Count Index (TCI) – A combined measure of the complexity of the air traffic and the sustained traffic index at each facility. It is the measure used to set facility pay levels. For a Metropolitan Tower Complex, the Traffic Count Index for each airport traffic control terminal facility is calculated independently, and the pay level of the Complex is set based on the highest independently calculated TCI.
JFK is is nine miles from LGA, and LGA is fourteen miles from EWR. However JFK is eighteen miles from EWR. Additionally I know that LGA/JFK runway selection are heavily dependent on each other but I don't know if EWR is affected as much. I would assume yes, though.
So provided JFK and LGA are independently calculated to be within one FPL of each other, each facility's FPL is set to the higher one. Most likely this is true for EWR and LGA as well. For example, this could be true:
- EWR TCI is 10.
- LGA TCI is 11.
- JFK TCI is 10.
- Because EWR is a "metro tower complex" with LGA, and because EWR is within one level of LGA, EWR is set to an 11.
- Because JFK is a "metro tower complex" with LGA, and because JFK is within one level of LGA, JFK is set to an 11.
It does kind of make you wonder why they didn't make the distance requirement 20NM instead of 15NM, though, right? I mean, they had surveying tools and distance calculators back when they negotiated the complexity formula.