A　systematic　high-resolution　electron　microscopy　study　of　a　special　type　of　two-dimensional　defects,　phason　planes,　has　been　carried　out　in　the　structurally　complex　metallic　alloys　of　Al–Pd–Mn　and　Al–Ni–Rh.　The　structural　characteristics　of　the　phason　planes　in　these　two　alloys　consist　of　pentagon-banana　pairs　of　polygons　but　with　a　different　arrangement.　Located　on　the　vertex　of　the　polygons　are　pseudo-Mackay　atomic　clusters.　The　detailed　atomic　structures　of　the　phason　planes　in　both　n0-　and　n-phases　of　the　two　alloys　have　been　determined　by　means　of　high-resolution　electron　microscopy　and　theoretical　simulations.　The　possible　ways　of　displacement　of　the　phason　planes　in　the　complex　alloys　are　discussed.