Flexible support structure for a geared architecture gas turbine engine

A gas turbine engine, comprising:

• a fan shaft driving a fan having fan blades;
• an outer housing surrounding the fan, and a bypass flow path within said outer housing;
• a fan shaft support that supports said fan shaft, said fan shaft support defining a fan shaft support transverse stiffness;
• a gear system connected to said fan shaft, said gear system includes a gear mesh defining a gear mesh lateral stiffness;
• at least one bearing system, a high speed spool including an outer shaft and a low speed spool including an inner shaft, wherein said gear system includes a planet carrier and said fan shaft is mounted to said planet carrier and said inner shaft and outer shaft are concentric and rotate via said at least one bearing system about a longitudinal axis of said engine;
• and
• a flexible support which supports said gear system relative to a static structure and defines a flexible support transverse stiffness and a flexible support lateral stiffness, wherein said flexible support transverse stiffness is less than 11% of said fan shaft support transverse stiffness, and said flexible support lateral stiffness is less than 8% of said gear mesh lateral stiffness.