Who wrote when the original airdate is April 5, 1987?
CREATE TABLE "table1_2226817_2" (
  "no_in_series" real,
  "title" text,
  "directed_by" text,
  "written_by" text,
  "original_air_date" text,
  "production_code" text
);
SELECT "written_by" FROM "table1_2226817_2" WHERE "original_air_date"='April 5, 1987';