Catalyzes the pyridoxal-phosphate-dependent breakdown of phosphoethanolamine, converting it to ammonia, inorganic phosphate and acetaldehyde. H2O + phosphoethanolamine = acetaldehyde + NH4(+) + phosphate Homotetramer. Belongs to the class-III pyridoxal-phosphate-dependent aminotransferase family. Does not seem to possess aminotransferase activity.