CREATE TABLE table_204_514 (id DECIMAL, "date" TEXT, "sub" DECIMAL, "flight" TEXT, "dead" DECIMAL, "hurt" DECIMAL, "pax." DECIMAL, "type" TEXT, "perpetrator" TEXT, "description" TEXT)

what is the only attack on an airline to involve grenade and small arms fire ?
SELECT "date" FROM table_204_514 WHERE "type" = 'grenade & small arms fire'
SELECT "date" FROM "table_204_514" WHERE "type" = 'grenade & small arms fire'