Summary

The Emergency Aid site's task is to keep alive a structure or ship for the duration of 10 minutes.

On warp in, a set of NPCs will start attacking a fleet member and occasionally switch target.

About 15 seconds after the first fleet-member enters the site, a group of NPCs arrive and start shooting the objective. Every 2 minutes, additional NPCs arrive and increase the dps pressure on the objective, eventually overwhelming even heavily blinged logistics setups.
Therefor the offending NPCs have to be reduced to an acceptable level.

Due to the spawns being faction specific, strategies and fittings differ.

Upon completion (keeping the objective alive past the 10 minute mark), with 5 participating pilots, each fleet member receives a payout of 15,486,410 isk for a total of 77,432,050 isk. NPC bounties add about 1,300,000 isk per site.