Airwolf Aerospace Offers STCd Rotor Blade Tape To Protect
Against Delamination On Robinson Helicopters
FAA-certified (STC) blade tape kits are being marketed by
Airwolf Aerospace LLC as a protective measure against blade skin
delamination on Robinson R22 and R44 helicopter main rotor blades.
The FAA recently issued a second Airworthiness Directive (AD
2011-12-10) on all Robinson helicopters.
In 2007, Robinson Helicopter Co. issued service alerts SB-72 and
SB-103 advising owners that some main rotor blade skins were prone
to debonding at the skin-to-spar joint on the lower surface of the
blade tips, causing the aircraft to compromise its airworthiness.
Debonding can occur when the bond line is exposed due to excessive
erosion of the blade finish, or when corrosion occurs on the
internal aluminium tip cap.
This most recent AD revisits a 2007 directive, which instructs
Robinson R22 and R44 operators to inspect main-rotor blades for
possible defects before each flight. Airwolf addressed this through
its Alternative Method Of Compliance (AMOC), a certified blade tape
that overlaps the skin and leading edge, obviating the need for
recurrent inspections and lap-joint painting.
Airwolf Aerospace Senior Engineer, John Montana said, “
The problem of delamination can be largely avoided if owners
install our easy-to-apply blade tapes, protecting the joint in
question. We look at our tapes as an effective form of insurance
against having to buy new blades which can cost between $25,000 and
$40,000.
Airwolf’s solution, STC- SR02491CH, uses a proprietary
polymer tape which is bonded to the blade. This prevents the
leading-edge skin debonding, which occurs when the bond line is
exposed due to erosion of the blade’s painted finish. The
blade tape covers the outboard section of the rotor blade where
history has shown debonding to occur. It seals the bond line
making penetration by foreign objects impossible, and drastically
reduces the risk of blade skin delamination.
“Pre-flight blade inspections required by the A.D. are now a
breeze as all the pilot has to do is look up and see the blade tape
is still covering the bond line.. It is a great solution to a
problem that affects more than 3,000 helicopters in the US
alone,” adds Montana.
Working with 3M, Airwolf modified 3M’s tape that was
originally designed for use on CH-47 Chinook and S-70 Blackhawk
helicopters, to make it compatible for the smaller, narrower
Robinson rotor blade. Applied as per Airwolf’s detailed
instructions, the tape prevents delamination without causing any
loss in aerodynamic performance.
The current price of the rotor blade protective kit is $1299 for
the R22 and $2499 for the R44. Once the initial kit and STC has
been purchased, Airwolf offers blade tape repair kits costing $500
for the R22 and $1000 for the R44.