Originally Posted by
Ivor_Bigunn
If the Statement:
"At full nose down (0.25 units), the top of the moving part (ballnut) is within an inch of the upper stop."
is correct, then the photographed screwjack is 80 to 90% Nose Down.
(look at the length of screwjack extending below the ballnut to the lower stop).
Whether this was how it was recovered, or if all the threads were stripped, would reduce the significance of the photo.
Let me add a little more information from the manual here:
0.00 units: ballnut is 0.5 inches from the top = stab leading edge up +2 degrees (full nose down trim with Alternate Trim?)
0.25 units: ballnut is 0.92 inches from the top = stab leading edge up +1.75 degrees. This is the nose down electric trim limit for the column switches with flaps not retracted
0.50 units: ballnut is 3 inches
(?) from the top. This is the nose down electric trim limit for the column switches with the flaps retracted.
2.00 units (neutral): ballnut is 3.84 inches from the top.
12.8 units: ballnut is 22.43 inches from the top. This is the electric nose up limit for column switches. i..e 12.8 units = stab leading edge down minus 11 degrees
14.2 units: ballnut 24.96 inches from the top = stab leading edge down minus 12.5 degrees (full nose up trim for Alternate Trim)
I can't explain the irregularity in the manual with regards to inches versus units. Using up/down column switch limit values, 0.25 units is 0.92 inches and for every unit thereafter, there is an additional (approx) 1.79 inches. However, the 0.5 unit/3 inches value seems to be an aberration. It should be more like 1.3 inches. This 3 inch value is repeated throughout the manual.
For info only.