AD 67-02-01

67-02-01 BOEING: Amdt. 39-335 Part 39 Federal Register January 4, 1967. Applies to Model 727 Series Airplanes Listed in Boeing Service Bulletin No. 55-15.

Compliance required as indicated.

Cracks have occurred on flanges of the trailing edge hinge fittings of the stabilizer ribs at specific stations and on the stabilizer trailing edge beam. These failures have been attributed to high frequency oscillation of the closing panels and the trailing edge beam. In order to correct this problem, accomplish the following or an equivalent approved by the Chief, Aircraft Engineering Division, FAA Western Region:

(a) Within 200 hours' time in service after the effective date of this AD, unless already modified in accordance with (c), and at intervals not to exceed 200 hours' time in service thereafter, comply with either (1) or (2).

(1) Using eddy current methods inspect for cracks in the stabilizer trailing edge lower beam at Elevator Stations 173.21 and 209.96, in the lower flange of the hinge fitting at Elevator Stations 50.50, 99.79, 136.50, and 173.21 and in the upper flange of the hinge fitting at Elevator Station 50.50 at the fastener locations.

(2) Visually inspect for cracks in the stabilizer trailing edge lower beam at Elevator Stations 173.21 and 209.96, in the lower flange of the hinge fitting at Elevator Stations 50.50, 99.79, 136.50, and 173.21 and in the upper flange of the hinge fitting at Elevator Station 50.50 at the fastener locations. Indication of a crack may be confirmed by a dye penetrant inspection.

(b) Repair cracked parts before further flight in accordance with a repair approved by the Chief, Aircraft Engineering Division, FAA Western Region.

(c) When an airplane has been modified in accordance with Paragraph II of Service Bulletin 55-7 and Paragraph II of Service Bulletin 55-15, or FAA-approved revisions to these Service Bulletins, the repetitive inspections specified herein may be discontinued. When an airplane has been modified in accordance with Paragraph II of Service Bulletin 55-7 only, or FAA-approved revision to this Service Bulletin, the repetitive inspections specified herein for Elevator Stations 50.50, 99.79, and 136.50 may be discontinued. Immediately prior to accomplishing any modification, inspect in accordance with either (a)(1) or (a)(2) and if cracks are found, repair in accordance with (b).

This supersedes AD 64-17-02.

This directive effective February 3, 1967.