Global SuperTanker Services Approved for Interim Approval of Retardant Delivery System in Boeing 747-400 This memo is in response to the Global SuperTanker Services (GSTS) letter dated March 20, 2020 in requesting interim approval of the retardant delivery system of Boeing 747-400. The Interagency Air Tanker Subcommittee (IABS) has elevated GSTS’s request for a seventh interim approval to the National Interagency Aviation Committee (NIAC), which is the parent committee for IABS. The IABS does not support any further interim approvals without correcting some issues originally identified in the 2009 test of the system that included failure to meet coverage level 3 & 6, retention of retardant in the system after drop, aeration of the retardant causing trail off, and inconsistent flight profiles affecting retardant coverage.