Name the original air date for barnaby southcomb for charlie martin
CREATE TABLE "table1_18335117_5" (
  "no_overall" real,
  "no_in_series" real,
  "title" text,
  "director" text,
  "writer" text,
  "original_air_date" text,
  "production_code" real
);
SELECT "original_air_date" FROM "table1_18335117_5" WHERE "director"='Barnaby Southcomb' AND "writer"='Charlie Martin';