Page:CAB Accident Report, Northeast Airlines Flight 715.pdf/7

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been constructed around the shoreline to prevent flooding. This dike is approximately 250 feet from the threshold and stands approximately Six feet above the runway Surface. It has a steel retaining wall painted with red and white crosshatching facing the water.

Runway 31 is 5,965 feet long and 150 feet wide. However, the useable land- ing length was restricted to 5,813 feet due to construction work in progress on the far end of the field inNOIVLHg the use of pile drivers and cranes. This information was contained in issued NOTAMS and was also included in tower trans- m1551ons to landing aircraft.

1 11 Flight Recorder

A flight recorder was not required nor was one installed in this aircraft.

1.12 Wreckage

Investigation revealed that both main landing gear wheels struck the dike about one foot below its top, Wlth the impact points bracketing the extended centerline of the runway. As previously stated, the entire right main landing gear assembly, and the wheel axle, and lower strut components of the left gear Separated from the aircraft at impact. The nose landing gear was intact and locked in the down pOSition.

Initial contact with the runway was made by the shock strut of the left main landing gear 1,16A feet from the threshold. The aft fuselage Section contacted the runway 1,800 feet from the threshold. The aircraft slid down the runway coming to rest Just off the right edge at a distance of 3,400 feet from the thresl hold on a heading of approx1mately 325 degrees. Slash marks made by the No. 4 propeller appeared 1,900 feet from the threshold and 500 feet farther were marks made by the No. 3 propeller There were no marks made by, nor tip damage to Nos. 1 and 2 propellers.

The wing flaps were found in the 20—degree extended position and the cock- pit flap indicator corresponded to this pOSition. The flap selector lever in the cockpit was p051tioned at the full Up setting.

The right Wing flap was tWisted upward and torn outward, the center of the damage being 8 feet 2 inches from the fuselage, almost directly behind the right main landing gear There were tw0 tire marks 1 foot 2 inches upward from the trailing edge of the flap. These marks were 2 feet 11 inches apart, the center-to-center distance between the tWD tires of each main landing gear is 2 feet 11 inches. Both flap actuator rods were straight.

The left flap was relatively intact and was not torn. There were two indentations With tire marks, the most inboard being 3 feet 3 inches from the fuselage This pair of indentations was in back of, and corresponded with, the left main landing gear wheels. The inboard portion of the flap was abraded on the lower trailing edge. The inboard flap cylinder actuator rod had a gradual slightly downward bend, the center of which was seven inches from the rod