  Building upon the application of flags to network coding introduced by
Liebhold, Nebe, and Vazquez-Castro, we develop a variant of this coding
technique that uses degenerate flags. The information set is a metric affine
space isometric to the space of upper triangular matrices endowed with the flag
rank metric. This suggests the development of a theory for flag rank metric
codes in analogy to the rank metric codes used in linear subspace coding.
