-10-
Rubs were conflned prlmarlly to the areas between 3 degrees and 90 degrees and between 176 degrees and 230 degrees, startlng from the top and progre531ng clocku w1se. The rub marks were not truly olrcumferentlal 1n that these between 3 degrees to 90 degrees angled forward about 6 degrees and those between 176 degrees and 230 degrees angled rearward about 3 degrees. The dlrectlons are referenced to the counterclockwlse rotatlon of the compressor rotor.
The 1nternal spllre on the compressor stub shaft and the male epllne of the compressor exten51on shaft showed contact marks on thelr normally loaded eldes. The contact.marks were made durlng the flnal l/B—lnch mesh of the splines as separatlon occurred.
No. l propeller blade angle when recovered was 1n the order of 51 degrees to 56 degrees. The remalnlng propellers were at or near feathered.
Structures
A maJor portlon of the alrcraft structure was shlpped to a Dallas warehouse for further study. All structure was examined for break patterns, f1re damage, stress patterns, exp1051ve damage, and mechanlcal defects, w1th many of the 1ndlv1dual pleces and/or sectlons belng subjected to laboratory examinatlon and evaluatlon. Certaln sectlons of the structure were assembled 1n.mockup form to help deflne fallure, breakup and flre patterns. All of the structural damage was classed as from one or more of the follOW1ng. alrborne dlslntegratlon, ground 1mpact, alrborne flre, and/or ground flre. After a bas1c study of wreckage dlstrlbutlon, 1t became ev1dent that the alrcraft had experlenced alrborne dlslnte— gratlon whlch broke the alrcraft up into a number of major sectlons as outllned under Wreckage Dlstrlbutlon and General Damage.
The left w1ng struck the ground butt—end flrst, rlght Slde up, after pa351ng through trees approximately 50 to 70 feet hlgh. Included w1th the left w1ng were
the left landing 893?, NO- 2 QEC E/unlt and the No. l englne (mlnus propeller, gear‘ box, a1r 1nlet hou51ng and QED structure). The w1ng was subgected to intense grourui flre as a result of the ignltlon of fuel from the No. 1 fuel tank. The ground flre area exiended 150 to 200 feet ahead of and approx1mately 100 feet behlnd the wing, but laterally only a few feet beyond the tlp and the root. Some portlons of the
left wlng 1n the trees showed no ev1dence of fare, whereas others dlrectly over the pranclpal w1ng wreckage showed llght depOSltS of smoke. The starter compressor (magne31um), located normally 1n the rear of the N0. 2 nacelle area, was completelgr consumed by flre and its louvered cover panel lylng under 1t showed elgns of heavy black smoke ex1t1ng through the louvers, however, the adgacent cover panel was fouIni out51de of the ground flre area and showed no ev1dence of ever haV1ng been.sub3ected to flre or heat. The 1n1t1al left wlng separatlon occurred between the W0. 2 nacelle and the center sectlon. Durwng the mockup of thlS area, approx1mately 80 percent
of the lower planklng 1n the No. 2 fuel tank area was acouunted Ior and fltted into place. The upper plank1ng of this area, 1n contrast to LOG lower planklng, had
been shattered 1nto many small fragments. This made 1t dlfflcult and 1n many cases 1mp0351ble to fix the exact locatlon for each plece; some pleces could only be flttec into a general wang statlon area.
2 QEC 18 used hereln for "QUle Englne Coange."
