The Hershey Medical Center Heliport has a white-red-green beacon as opposed to a normal heliport white-yellow-green beacon. How is this allowed?
The lighting for private heliports is not regulated by the FAA, but by the individual states. The FAA has an Advisory Circular laying out guidelines for heliports, but it is only a recommendation.
The Federal Aviation Administration (FAA) recommends the specifications
contained in this AC for all applica tions involving development of this natu re. In general, use of this AC is not mandatory.
It is only regulatory when the heliport is built using federal funds. In the AC they recommend the white/green/yellow pattern.
Only a couple of states have adopted the FAA guidelines as regulatory.
The state of Pennsylvania incorporates many of the FAA Advisory Circulars in their state law. For example the ground markings and the lighting for the perimeter of the landing and takeoff area for the heliport are required to adhere to the appropriate FAA AC's. But in regards to the beacon it simply states:
A rotating beacon is recommended to be installed for night operations at public heliports.
It does not even have that recommendation listed for private heliports.
Although it is not in the FAA Advisory Circular some places list the beacon color code for hospital heliports as white/green/red. I can't find anything authoritative on this but examples are at an aviation wiki, on Quora and on airliners.net.
This company that sells heliport beacons indicates that their beacon is "Available in Hospital Heliport version (not FAA certifiable)." It doesn't indicate, but this is likely a white/green/red version. And since it doesn't adhere to the Advisory Circular it isn't FAA certifiable.