TM 10-1670-287-23&P  0048 00  (2) Record the span measurement for each cell along with the corresponding cell identifier (i.e.  Cell 1, 2, 3, etc.).  (3) Calculate the average cell span for the canopy. Record this value.  (4) The relevant cell span measurements are:  (5) Any canopy, that has a cell span, that falls below the corresponding lower limit or exceeds  the upper limit, will be deemed unacceptable and will be immediately and permanently  removed from service.  c.  Procedure number 3. Measurement of Top/Bottom Surface Span Differential:  (1) This procedure requires use of a tape measure. In the same manner as above, measure and  record the nose tape span for each cell along the bottom surface of the canopy from loaded  rib to loaded rib.  (2) Calculate the sum of all top surface nose tape span measurements to determine the total top  surface span. Record this value.  (3) Calculate the sum of all bottom surface nose tape span measurements to determine the total  bottom surface span. Record this value.  (4) Subtract the total bottom surface span from the total top surface span to obtain a top/bottom  surface span differential. Record this value.  (5) Top/bottom surface span differentials should fall within the following ranges:  0048 00-3  Change 1  CANOPY MODEL  LOWER LIMIT  DESIRED RANGE  UPPER LIMIT  MC-4 5-inches 6 $^{1}$/$_{8}$ to 17 ½-inches  19-inches  MTl-X 5-inches 6 to15-inches 17-inches MTl-S 3-inches 4 to13-inches 15-inches CELL 1  CELL 5  CELL 4  CELL 3  CELL 2  CELL 6  CELL 7  CELL SPAN TOTAL TOP SURFACE SPAN TOTAL BOTTOM SURFACE SPAN CANOPY MODEL  LOWER LIMIT  DESIRED RANGE  UPPER LIMIT  MC-4  47-inches  48 to 50-inches  50-inches  MTl-X  45-inches  46 to 48-inches  48-inches  MTl-S  47-inches  48 to 50-inches  50-inches 