Complex sentence: After comparison tests five YA-19s were redesignated A- 19 and assigned to the 17th Attack Group at March Field in California for a brief period before being transferred to the Panama Canal Zone for utility transport and liaison duties.
Split into simpler sentences: After comparison tests five YA-19s were redesignated A- 19 and assigned to the 17th Attack Group at March Field in California for a brief period. Later were transferred to the Panama Canal Zone for utility transport and liaison duties.