if you send me your emailaddress i will send you the page out of the manualMAINTENANCE MANUAL
but for starters
I. Inspection and Rejection Criteria for Bond Line Corrosive Delamination
(1) Main Rotor Blade
Inspect edge of all bond lines for separations, visually and coin tap. If inspection reveals evidence of delamination, depth may be checked on trailing edge and doublers with plastic shim stock .001" in thickness. Do not use shim stock to check spar to leading edge delamination, COIN TAP ONLY.
CAUTION: Do not use anything other than shim stock to check depth of lamination.
(a) Coin tap detectable bond separations at the skin-spar joint in excess of limits in Figure 4-1 and 4-2 are cause for rejection.
(b) Visual or coin tap detectable bond separations at the blade trailing edge of more than 3.00 inches in length or deeper than .25 inch are cause for rejection. (See Figures 4-3 and 4-4)
(c) Any bond separations on the doubler closer than 2.00 inches to the tip, or more than 3.00 inches in length, or greater than .125 inch in depth are cause for rejection.
(2) Tail Rotor Blade
Using the same method as in Part (I) (1), inspect all bond lines.
(a) Bond separations on the trailing edge deeper than .050 inch or more than 2.00 inches in length are cause for rejection.
(b) Any bond separation on the stainless steel cap more than 2.00 inches from the tip or greater in depth than .062 inch is cause for rejection.
(c) Any bond separation on the doublers closer than 2.00 inches to the tip of the doubler under which it appears, or greater than 1.00 inch in length, or deeper than .062 inch in depth is cause for rejection.
NOTE: Delamination as noted in (1) and (2) which are lesser are acceptable, if procedures in paragraph J are performed.
J. Preliminary Repair Procedures for Acceptable Blade Bond Delamination to Arrest Corrosive Action Prior to Refinish
(1) Skin to Spar Bond Sealing Procedure (Main Rotor Blade)
Separations smaller than the limits shown in Figures 4-1 and 4-2 may be sealed using the following procedure.
MM-4-35
i have had 6 enstroms from a f28a to a 480 turbine i found them to be a safe and reliable helicopters ive not had a engine problem or any other major fault and i have over 1000 hrs on enstroms they are also very enconomical to run
there are lots of enstrom engineers out there if in doubt ask one of them
regards steve