80-11-07 ROBINSON HELICOPTER COMPANY: Amendment 39-3834. Applies to Model R22 series helicopters certificated in all categories.
Compliance is required as indicated.
To prevent main rotor blade structural failure, accomplish the following:
(a) Prior to further flight remove from service all main rotor blades Serial numbers 1 through 91 and replace with like serviceable part.
(b) Mark all blades Serial numbers 1 through 91 "UNAIRWORTHY" on the blade upper surface at the approximate mid-span with lettering at least 2 inches high and, using a metal stamp, mark "UNAIRWORTHY" on data plate.
This supersedes Amendment 39-3751, (45 FR 26032), AD 80-08-08.
This amendment becomes effective July 14, 1980, and was effective earlier for all recipients of the telegram T80WE25 dated May 20, 1980.