AD 76-12-09

76-12-09 ROCKWELL INTERNATIONAL: Amendment 39-2645. Applies to Model NA-265-70 airplanes, serial numbers 370-1 through 370-9, and Model NA-265-80 airplanes, serial numbers 380-1 through 380-42 and 380-44.

Compliance required as indicated, unless already accomplished.

To prevent possible in flight flutter due to an improper static balance of the rudder, accomplish the following:

(A) Immediately upon receipt of this AD, notify the flight crewmembers by the most practicable means, of the maximum operating limit speed: 250K/0.8M.

(B) Within the next 10 hours' time in service after receipt of this AD, effect the following operating limitations and install the following placards and markings in clear view of the pilots:

(1) Install a placard adjacent to each airspeed indicator that reads:

"MAXIMUM OPERATING LIMIT SPEED: 250/K0.8M"

(2) Mark the face of each airspeed indicator with a red radial line at 250 knots.

(C) Within 60 days after receiptof this AD accomplish the following:

(1) Remove the rudder from the airplane and measure the rudder's static unbalance about the hinge line using a balance measuring procedure approved by the Chief, Aircraft Engineering Division, FAA Western Region, and

(2) If the static unbalance measured exceeds the limits of 0 to 5 inch-lbs leading edge heavy, before further flight adjust the static balance to be within these limits by a modification approved by the Chief, Aircraft Engineering Division, FAA Western Region.

NOTE: Rockwell International intends to issue Sabreliner Service Bulletin No. 17 to provide the necessary instructions on rebalance.

(D) The operating limitations, placards, and markings required by paragraph (B) may be removed after accomplishment of paragraph (C).

(E) The airplane may be flown in accordance with FAR 21.197 to a base where the placards and markings required by paragraph (B) can be installed or the balance inspection and rebalance procedure of paragraph (C) can be accomplished, provided the operating limitations of paragraph (B) are not exceeded.

This amendment is effective June 23, 1976 for all persons except those to whom it was made effective by airmail letter dated May 21, 1976, which contained this amendment.