Page:Civil Aeronautics Board accident investigation report, National Airlines Flight 2511.pdf/7

 and the tanks aft of the center spars were severely broken apart at impact. The fuel tank compartments in the right inner wing were also severely damaged. The fuel tanks in the wing outboard of the No. 4 engine and the tanks aft of the center spar in the left wing were, however, relatively intact.

Examination of the fuel tank areas showed no fire damage prior to or after ground impact. The fuel tank structure showed no evidence of fuel leakage except that there was evidence of a heavy fuel seep at the No. 4 dump valve manifold fitting at the center spar adjacent to the No. 4 nacelle. Examination of the fuel drain valves, fuel selectors, and crossfeed valves showed no leakage or other malfunction except for impact damage.

At the time of the accident, there was a low pressure area centered in the Gulf of Mexico, with a quasi-stationary front extending eastward from this low across the Florida Peninsula just north of Melbourne and into the Atlantic. A ridge of high pressure existed on the north side of this front extending from the Virginia Capes westward through the Ohio Valley to the central Plains.

Associated with the frontal structure described above, precipitation was falling throughout Virginia, the Carolinas, and Georgia. This precipitation was mostly in the form of rain except for snow in northern and western Virginia and western North Carolina.

The freezing level in the vicinity of the crash was between 10,000 and 12,000 feet, with multiple layers of clouds extending from below 1,000 feet to approximately 18,000 feet. Rain and fog existed at the accident site. Some difficulty with engine icing was reported by aircraft flying in clouds and precipitation several thousand feet below the cruising level of National Flight 2511 (18,000 feet). No difficulties because of icing would have been encountered at 18,000 feet over eastern North Carolina nor were any reported.

In view of the relatively stable upper air conditions over the area, no significant turbulence would have existed at 18,000 feet nor was any reported.

Strong west-southwesterly winds were present over the accident site. At 18,000 feet, the velocity would have been slightly in excess of 100 knots with high velocities (85 knots plus) reported at all altitudes between 18,000 and 12,000 feet. A sizeable reduction in velocity occurred in the level between 12,000 and 10,000 feet (Norfolk reporting 85 knots at 12,000 and 52 knots at 10,000 feet). Thereafter, the wind decreased gradually from 10,000 feet to the surface.

From the passenger manifest it was determined that 29 passengers and a crew of five were aboard the aircraft. Initially, two of the passengers' bodies could not be located. Both of these bodies, however, were found later; one was in the main wreckage area, and the other was recovered from Snow's Marsh on the west side of the Cape Fear River some 16 miles from the main wreckage area.

The local coroner ordered post-mortem examinations of the passengers and crew as deemed necessary to determine the cause of death of each.