Page 5.48 Chapter 5 Inspections MAY 2015
5-66 Dye Penetrant Inspection of F020-1 Upper Frame
1. Carefully clean all paint, primer, oil, grease, etc from steel tube structure around and
adjacent to four tailcone mounts.
2. Apply epoxy paint remover and allow the softening action to complete (temperature
affects time required).
3. Remove softened paint by hand using a wire brush. Be sure steel structure is perfectly
clean before application of dye penetrant.
4. Carefully check for cracks in and around each weld bead and along each steel
supporting tube for at least two inches away from weld beads. Replace any frame
exhibiting crack indications.
5. If no cracks are found, clean all inspection materials from steel tubing.
6. Prime with good quality zinc chromate or epoxy primer and allow adequate drying
time.
7. Refinish area with gray epoxy top coat or equivalent.
5-67 Corrosion on F020-1 Upper Frame
1. Polish out corrosion on steel frame tube members.
a. Polish out light surface corrosion on frame members using Scotchbrite or 400 grit
wet-or-dry sandpaper. Verify 0.002 inch maximum depth after rework.
b. Polish out corrosion pitting using 320-grit wet-or-dry sandpaper. Verify 0.004 inch
maximum depth and 0.10 inch maximum diameter, after rework.
NOTE
For large areas of corrosion, it may be necessary to remove
entire upper frame from aircraft and strip off paint to adequately
determine extent of damage.
2. Prime bare metal with a good quality zinc chromate or epoxy primer.
3. Refinish area with gray epoxy top coat or equivalent.
5-68 Main Rotor Gearbox Overtemp Illumination
If the gearbox overtemp annunciator segment illuminates, remove main rotor gearbox per
§ 63-20 and return to RHC.
NOTE
Light illuminates at 240±5ºF.
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