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　xi＇-　and　xi＇-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.