AD 72-03-05

72-03-05 MCDONNELL DOUGLAS: Amdt. 39-1389 as amended by Amendment 39-1414 is further amended by Amendment 39-1453. Applies to Model DC-9 (-10, -20, -30 and -40 Series and C-9A) airplanes listed in Douglas DC-9 Service Bulletin No. 27-146, Revision 1, dated 20 December 1971, or later FAA-approved revisions.

Compliance required as indicated.

To prevent possible jamming of the elevator and loss of elevator power assist in the down direction in the event of failure of the elevator boost cylinder rod end, accomplish the following:

A. Within the next 300 hours time in service after March 7, 1972, visually inspect the universal fitting, P/N 4918072-1, and rod end assembly, P/N 4918153-1, attaching the elevator power control actuating cylinders to the elevator structure, for proper installation per paragraph 2 of Douglas Service Bulletin 55-4, dated 25 October 1966, or later FAA-approved revisions, or an equivalent inspection approved by the Chief, Aircraft Engineering Division, FAA Western Region. If this inspection reveals an improper installation of the rod end assembly, remove and replace with a new part in accordance with the instructions specified in Service Bulletin 55-4, dated 25 October 1966, or later FAA-approved revisions, prior to further flight.

B. Within the next 300 hours time in service after March 7, 1972, and at intervals not to exceed 300 hours time in service thereafter, visually inspect the left and right hand elevator boost cylinder rod end assemblies, P/N 4918153-1, for cracks or a failed part. If a cracked or failed part is found, replace with a new part prior to further flight.

C. Within 1200 hours time in service after March 7, 1972, unless already accomplished, perform the following inspections and modifications in accordance with the instructions contained in Douglas Service Bulletin 27-146, Revision 1, dated 20 December 1971, or later FAA-approved revisions, or an equivalent inspection and modification approved by the Chief, Aircraft Engineering Division, FAA Western Region.

(1) Inspect the left hand and right hand elevator boost cylinder rod end assembly, P/N 4918153-1, for cracks or a failed part and determine the material hardness of undamaged parts.

If a failed or cracked part is found or if the material hardness is below 32.5 on the Rockwell "C" Scale (145,000 psi ult. tensile strength) or above 43 on the Rockwell "C" scale (200,000 psi ult. tensile strength), replace with a new part.

(2) Modify the left and right hand side of the horizontal stabilizer assembly, left and right hand elevators and hinge eyebolt, P/N YD-211-B or DMD6-9A1-501 and,

(3) Install new elevator boost cylinder rod end assembly retainer, P/N 4911152-1.

D. The requirements of this AD may be discontinued upon accomplishment of the inspections and modifications specified in S.B. 27-146, Revision 1, or later FAA-approved revisions or equivalent inspections and modifications approved by the Chief,Aircraft Engineering Division, FAA Western Region.

Amendment 39-1389 became effective March 7, 1972.

Amendment 39-1414 became effective March 25, 1972.

This amendment 39-1453 becomes effective May 31, 1972.