52-17-02 CURTISS-WRIGHT: Applies to all Model C-46 Series aircraft.
Compliance required as noted.
As a result of a number of failures the following precautionary measures must be taken:
1. The original compliance date set was not later than December 1, 1952, and at each No. 3 inspection thereafter, however, in order to convert the inspection interval to time in service, the following inspection shall be accomplished within 400 hours' time in service after the effective date of this amendment. Subsequent compliance required at each 400 hours' time in service after initial compliance.
Upon request of the operator, an FAA maintenance inspector, subject to prior approval of the Chief, Engineering and Manufacturing Branch, FAA Southwest Region, may adjust the repetitive inspection intervals specified in this AD to permit compliance at an established inspection period of the operator if the request contains substantiating data to justify the increase for such operator.
Inspect the tail wheel shimmy damper support, P/N 20-360-3108-4, for cracks or damage which might lead to subsequent failure. Particular attention should be paid to the radius formed by the intersection of the vertical and lower horizontal surface on the forward side of the part. A general inspection of the shimmy damper assembly should be made and it should be determined that it is properly adjusted. All cracked or damaged parts must be replaced.
The following method of adjustment of the shimmy damper as outlined in Air Force Technical Order AN 01-25LA-2, section IV, paragraph 8 (f) is quoted below for your convenience:
(a) Position the shimmy damper on the mounting bracket and attach the two 3/8-inch bolts, nuts, and washers, using a 9/16-inch open-end wrench in conjunction with a 9/16- inch socket and a ratchet.
(b) Before installing the link assembly to the shimmy damper arm, the arm must be positioned to allow for maximum travel of the unit in actual operation. This is accomplished by slowly actuating the arm toward the rear of the airplane until the movement stops. From this point reverse the action until the arm has made an arc of 67 degrees. It is now in a neutral position and will assure correct operation when completely installed.
(c) With the arm in neutral and making sure not to move it from this position, attach the link assembly to it with the 5/16-inch bolt, nut, washer and cotter pin using a 1/2-inch open-end wrench, a 1/2-inch socket, and a ratchet.
(d) Make sure that the tail wheel is locked in position. The pin on the centering disc will then be properly set for attaching the eyebolt of the link assembly. If the eyebolt hole does not match with the pin on the centering disc when the tail wheel is locked and the actuating arm is in neutral, adjustment must be made by loosening the locknut on the eyebolt and turning the eyebolt until the proper length is obtained. Be sure to tighten the locknut again.(e) Secure the link assembly to the centering disc by installing the 1 1/8-inch castellated nut and washer drawing up the nut with a crescent wrench. Insert a cotter pin on this nut.
2. Compliance required as noted.
Tail wheel locks for the subject model airplane have been manufactured which do not comply with the material specifications and in some cases physical dimensions of the approved drawings. The approved tail wheel lock P/N 20-360-1033, is a forged steel part of 8740 or N-S- 16 material heat treated to 150,000 pounds per square inch, with a Rockwell harness of C-33 to C-38; however, a cast steel lock complying with the physical dimensions, heat treat and hardness of the approved drawing will also be considered acceptable.
The original compliance date for the following inspection was March 1, 1953; however, in view of a recent accident involving the installation of an unapproved tail wheel lock, it must be ascertained prior to February 15, 1956, that all tailwheel locks meet the stated specifications of an acceptable part. Any tail wheel locks which do not comply with the approved drawing, No. 20-360-1033, in regard to material, heat treat or physical dimensions as mentioned above, must be replaced with an approved part.
It should be noted that some unsatisfactory parts in circulation bear the correct part number, therefore this fact cannot be considered a satisfactory means of determining that an approved part is installed in the airplane.
Revised October 23, 1961.
Revised November 23, 1961.