Gary
My list published by the company is;
Airport In Alert Available
ACE yes
AGP no
ALC yes
BCN no
FUE yes
GRO yes
IBZ yes
LEI yes
LPA no
MAH no
MJV yes
PMI yes
REU yes
SPC no
TFN no
TFS yes
VLC yes
XRY yes
And the number of aircraft that can have the service at any one time appears to vary from airport to airport, as does availability on various stand positions. Presumably due to access for the firecrews and response time due to distance etc.
Some you can request on the VHF inbound, others when on stand. Hope this helps.
PP
ps In Alert incurs no charge, whereas In Attendance does, that's why our company advocate it's use.