The Eastern Air Lines Martin 4-0-4 took off from Indianapolis at 11:05 for a flight to Louisville. The cruising altitude of 5000 feet was maintained somewhat longer to give the stewardess more time in smooth air to remove the luncheon trays. The co-pilot then started to descend to 2000 feet. After turning for finals for runway 11 the captain saw that the aircraft was too high and reduced power further (the throttles were pulled fully back) and the co-pilot lowered the flaps to full down. At about 1000-1500 feet the captain took over control and nosed down sharply, maintaining an airspeed of about 100 knots. Over the threshold, at about 100 feet, the captain tried to flare. The aircraft attained a nose-up attitude, but continued to descend fast. The aircraft struck the runway on its main gear, causing the left wing to separate inboard of the no. 1 engine. The remainder of the aircraft half rolled to an inverted position. Just one passenger was injured seriously. PROBABLE CAUSE: “The captain’s faulty landing approach technique, resulting in an excessively high rate of sink at the instant of touchdown imposing load beyond the design strength of the wing structure.”