Airworthiness Directive · Amendment 39-17631 · Stabilizers
The Boeing Company Airplanes
This AD applies to The Boeing Company Model 727, 727C, 727-100, 727 -100C, 727-200, and 727-200F series airplanes, certificated in any category, identified as Group III and Group IV in Boeing Service Bulletin 55-46, dated April 8, 1970.
We are adopting a new airworthiness directive (AD) for certain The Boeing Company Model 727 airplanes. This AD was prompted by certain mandated programs intended to support the airplane reaching its limit of validity (LOV) of the engineering data that support the established structural maintenance program. This AD requires, for certain airplanes, a modification of the web of the horizontal stabilizer center section rear spar. For the other airplanes, this AD requires an inspection for cracks in the web, and repair or modification as applicable. We are issuing this AD to prevent cracking at the upper fastener holes in the riveted web in the horizontal stabilizer center section rear spar, which could result in failure of the spar forging and lead to horizontal stabilizer separation and loss of control of the airplane.
For airplanes identified as Group III in Boeing Service Bulletin 55-46, dated April 8, 1970: At the later of the times specified in paragraphs (g)(1) and (g)(2) of this AD, do an eddy-current inspection for cracks in the web, in accordance with the Accomplishment Instructions of Boeing Service Bulletin 55-46, dated April 8, 1970.
(1) Before the accumulation of 60,000 total flight cycles.
(2) Within 24 months or 2,500 flight cycles after the effective date of this AD, whichever occurs first.
For airplanes identified as Group III in Boeing Service Bulletin 55-46, dated April 8, 1970: After the inspection required by paragraph (g) of this AD, do the applicable actions specified in paragraph (h)(1) or (h)(2) of this AD.
(1) If no crack is found, before further flight, modify the web of the horizontal stabilizer center section rear spar, in accordance with the Accomplishment Instructions of Boeing Service Bulletin 55-46, dated April 8, 1970.
(2) If any crack is found, repair before further flight using a method approved in accordance with the procedures specified in paragraph (j) of this AD.
For airplanes identified as Group IV in Boeing Service Bulletin 55-46, dated April 8, 1970: At the later of the times specified in paragraphs (i)(1) and (i)(2) of this AD, modify the web of the horizontal stabilizer center section rear spar, in accordance with the Accomplishment Instructions of Boeing Service Bulletin 55-46, dated April 8, 1970.
(1) Before the accumulation of 60,000 total flight cycles.
(2) Within 24 months or 2,500 flight cycles after the effective date of this AD, whichever occurs first.
