Flame protection seals for gas turbine engines

A gas turbine engine comprising:

• an engine core having a compressor section, a combustor section, and a turbine section;
• an engine casing housing the engine core;
• a transfer tube arranged on an exterior of the engine casing and configured to define a fluid conduit for fluid to be transferred about the engine core;
• a fitting connected to the transfer tube;
• and
• a seal assembly arranged between a surface of the fitting and a surface of the transfer tube, the seal assembly providing a fluid seal between the fluid conduit and an ambient environment at a connection between the fitting and the transfer tube, wherein the seal assembly comprises:
• a primary seal arranged in a gap between the fitting and the transfer tube and configured to provide a fluid seal between the surface of the fitting and the surface of the transfer tube;
• and
• a secondary seal arranged in the gap between the primary seal and an ambient environment, wherein the secondary seal is configured to expand into engagement with the fitting and the transfer tube when exposed to temperatures of at least 800° F.