 First deliveries began in March 1947 and a flight test program began that month that lasted three years before the major deficiencies identified were fully corrected . Carrier landing trials revealed a structural weakness of the rear fuselage when one aircraft was severed in half during a heavy landing . Severe vibrations in the tail upon engaging the arresting wire were cured by adding a roller bearing to the tailhook to counter the sideways forces placed on the tailhook . Other necessary changes were the addition of spoiler ailerons and an elevator control boost to improve the aircraft 's poor controllability at low speeds . In addition the cockpit layout was unsatisfactory and had to be redesigned . The NATC finally deemed the Mauler acceptable for carrier landings in August 1948 even though aircraft had been issued to one squadron earlier in the year and a new batch of 50 aircraft had been ordered in May . Despite all of the modifications to the aircraft over its short life , it remained a maintenance nightmare , especially the leaky hydraulic systems . 
