Page:NTSB Southern Airways Flight 932 report.pdf/16

 inches m.s.l. The highest ground elevation adjacent to the swath cut was 894.5 feet m.s.l. Tree heights at this point measured 50 feet, which corresponded to a treetop elevation of 944.5 feet m.s.l. The ground elevation near the crest of the hill in the center of the swath cut was 880 feet m.s.l. The break in a poplar tree at this point was 42 feet above the ground (922 feet m.s.l.) However, the U. S. Department of Agriculture Forest Service estimated that the tree was 71 feet (±1 foot) tall before breakage, based on a study of other trees in the area. The MDA was approximately 290 feet above the estimated maximum elevation of the tree top. The swath cut between the initial tree impact and the break in the poplar tree was +2°, measured from the horizontal. The distance between these two trees was approximately 152 feet.

Most of the fuselage was melted or reduced to a powder-like substance; however, several large pieces were scattered throughout the burned area. Examination of the various components indicated that the landing gear and flaps were fully extended at impact. The horizontal stabilizer setting was 5.75 units noseup, which was in the normal range for the weight, and speed, in the approach configuration.

1.13 Fire

A severe ground fire at the main wreckage site followed impact. Firefighting activity at the crash site was limited to containing brush fires in the area. There was no evidence of in-flight fire.

1.14 Survival Aspects

This was a nonsurvivable accident.

1.15 Tests and Research

In reviewing the circumstances of this accident, the safety board again took notice of tests conducted by the Douglas Aircraft Company (DACO) in May 1967. The tests were designed to study the effect of possible water ingestion at the static ports of the aircraft. Several DACO field service reports had indicated that during final descent on ILS approaches, with full flaps and landing gear extended, the altimeter was alternately "pausing" and then "jumping." At each momentary pause and subsequent jump, the instantaneous vertical speed indicator tended toward zero. Most of the "jumps" were between 40 and 60 feet, but several were 80 to 100 feet in magnitude.