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descent from approximately 21,200 feet pressure altitude. During the approach descent from 21,200 to 11,000 feet, the change over in the altimeter barometric pressure setting from a standard setting of 29.92 to a m.s.l. setting of 29.65 at the 18,000-foot altitude datum point is reflected in the readout altitude data. No significant variations were indicated by any of the four parameters during the transition to the apparent flareout point at an m.s.l. altitude of approximately 11,150 feet which is recorded at a time point of 22 minutes and 52 seconds before touchdown. Gradual descent to and level flight at 11,000 feet continued until a time point of 21 minutes and 38 seconds before touchdown was reached. At this time point, the acceleration parameter showed that suddenly applied loads were initiated causing the acceleration trace to peak at plus 2.5 "g"[1] while the airspeed trace showed the start of a decrease in speed. The altitude trace remained relatively steady, and small variations are indicated by the heading parameter.
Immediately subsequent to the above aberrations, at a time point of approximately 21 minutes and 32 seconds before touchdown, small variations occurred in all of the parameter traces except the altitude trace. Significant negative acceleration indications began to occur and continued to approximately 21 minutes and 12 seconds before touchdown. Throughout this period, significant changes transpired in the other parameter traces. Acceleration trace variations appeared to stabilize at approximately 21 minutes and 10 seconds before touchdown. The airspeed trace indicated the start of an increase in speed, the altitude trace indicated an increase in altitude, and the heading trace showed the start of an abrupt yaw to the right within one second. All the recorded traces appeared to become normal from the time paint of 21 minutes and 11 seconds until touchdown.
There was no requirement for a flight recorder aboard EA 853 and none was aboard.
1.12 Wreckage
TW 42 showed primary impact damage in three areas: (1) the outer left hand wing panel from the No. 1 nacelle outboard was severed; (2) the No. 1 engine cowl and pylon showed impact abrasions from sliding contact but did not separate from the aircraft; (3) the wing leading edge at wing station 555 just inboard of the No. 1 engine had sustained a deep slash. In addition, secondary structural damage was noted from impact loading and flying debris.
EA 853 crashed on a hillside 4.2 miles north of an area where numerous separated parts from both aircraft ware found. First impact was in a tree which was broken 46 feet above the ground. Nearly 250 feet farther the left wing contacted a large tree and separated from the aircraft. Contact with the ground was made 250 feet beyond the first tree and the aircraft came to rest 700 feet up a 15-percent slope on a magnetic heading of 243 degrees. Portions of the fuselage slewed around to a nearly reciprocal heading. The fuselage was separated into three main pieces which remained in their respective positions but were at varying angles to each other. All engines separated from their nacelles. The flaps and landing gears were in the retracted position at impact.
Upon completion of the structures examination of both aircraft, a three dimensional mockup of TW 42's outer wing panel and EA 853's tail assembly was
- ↑ "g" An acceleration equal to the acceleration of gravity.
