TB 1-1615-351-23
f. Coating Repair. Local damage to the polyurethane coating can be touched up by brushing
additional coating to the damaged area. Carefully remove the disbonded material. Scuff the damaged
area with 120 grit sandpaper. Wipe clean with MEK. Prime the area with AGC 1201-7 primer if the
blade surface is exposed. Coat the damaged area with sufficient coats of polyurethane coating to
match the thickness of adjacent areas. Application of TASK L-100 polyurethane paint to repair minor
damage on agcoat material is authorized for this procedure.
g. Polyurethane Coating Removal. Saturate coating surface with MEK and scrape coating off with a
plastic scraper while soft. Make a final surface wipe with cloth dampened with MEK.
h. Polyurethane Tape Removal. Slowly peel back over itself. Scrape tape with plastic scraper, if
necessary. Remove adhesion promoter with cloth dampened with toluene.
i. Track and Balance Check. Check track and balance of the main and tail rotors per -23 TM.
j. Inspection of Main Rotor Polyurethane Tape.
(1) Inspect 2-inch tape for wear. No holes allowed.
(2) Inspect 8-inch tape for wear. No more than 1.0 inch-width hole in any spanwise or chordwise
direction allowed on upper or lower side of blade.
(3) Inspect upper and lower trailing edge of tape for disbonding. No more than 0.25 inch
chordwise width for any spanwise length of tape or 0.5 inch chordwise width for 6 inches spanwise
length along a single piece of tape is allowed.
(4) Inspect for board and outboard ends of tape segment for disbonding. No more than 0.5 inch
spanwise or chordwise is allowed.
(5) Inspect for internal disbonding of tape segment. No more than a single disbonding larger than
3.0 inches spanwise and/or 2.0 inches chordwise is allowed. In addition, no more than a total of 6
square inches is allowed for multiple disbonds on a single tape segment. There is no limit to the
number of disbonds per tape segment providing material is not tom.
CAUTION
If damage is discovered and found to be within the above limitations,
do not trim off these damaged areas. Trimming off these damaged areas
creates an increasingly lighter blade and may cause an out of balance
condition.
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