Airworthiness Directive · Amendment 39-17768 · Wings
The Boeing Company Airplanes
This AD applies to all The Boeing Company Model 727, 727C, 727-100, 727-100C, 727-200, and 727-200F series airplanes, certificated in any category.
We are adopting a new airworthiness directive (AD) for all The Boeing Company Model 727 airplanes. This AD will complete 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 repetitive inspections for cracking of small repairs done on the vertical flange of the rib chord, repetitive inspections for cracking along the upper fillet radius of the rib chord, and a large repair or preventive modification if necessary. Accomplishment of a large repair or preventive modification terminates the actions of this AD. We are issuing this AD to prevent cracks in the rib upper chord, which could result in the inability of the wing structure to support the limit load condition, and consequent loss of structural integrity of the wing.
For any small repair that has been done as specified in Boeing 727 Service Bulletin 57-112; or Part III of the Accomplishment Instructions of Boeing Service Bulletin 727-57-0112: Within 3,500 flight cycles after the small repair was installed or inspected as specified in Boeing Service Bulletin 727-57-0112, or within 18 months after the effective date of this AD, whichever occurs latest, do a high frequency eddy current inspection for cracking of the vertical flange of the rib chord from the inboard side, and do a detailed (close visual) inspection for cracking along the upper fillet radius of the rib chord, in accordance with Part III of the Accomplishment Instructions of Boeing Service Bulletin 727-57-0112, Revision 5, dated July 31, 1997. Repeat the inspections thereafter at intervals not to exceed 3,500 flight cycles until accomplishment of the repair or modification specified in paragraph (i) or (j) of this AD.
Note 1 to paragraph (g) of this AD: Boeing 727 Service Bulletin 57-112 and Boeing Service Bulletin 727-57-0112 are both versions of the same document. The formatting of service bulletins was revised by Boeing following publication of Boeing 727 Service Bulletin 57-112, Revision 1, dated April 23, 1976. Boeing Service Bulletin 727-57-0112, Revision 2, dated May 19, 1988, was published using Boeing's revised formatting.
For the purposes of this AD, a detailed inspection is an intensive examination of a specific item, installation, or assembly to detect damage, failure, or irregularity. Available lighting is normally supplemented with a direct source of good lighting at an intensity deemed appropriate. Inspection aids such as mirror, magnifying lenses, etc., may be necessary. Surface cleaning and elaborate procedures may be required.
If any crack is found during any inspection required by paragraph (g) of this AD, before further flight, do either action specified in paragraph (i)(1) or (i)(2) of this AD. Accomplishment of either action terminates the requirements of paragraph (g) of this AD.
(1) Do a large repair, in accordance with Part IV of the Accomplishment Instructions of Boeing Service Bulletin 727-57-0112, Revision 5, dated July 31, 1997.
(2) Do a preventive modification, in accordance with Part V of the Accomplishment Instructions of Boeing Service Bulletin 727-57-0112, Revision 5, dated July 31, 1997.
Accomplishment of the actions specified in either paragraph (j)(1) or (j)(2) of this AD terminates the requirements of paragraphs (g) and (i) of this AD.
(1) A large repair, in accordance with Part IV of the Accomplishment Instructions of Boeing Service Bulletin 727-57-0112, Revision 5, dated July 31, 1997. Any crack found must be repaired before further flight using a method approved in accordance with the procedures specified in paragraph (l) of this AD.
(2) A preventive modification, in accordance with Part V of the Accomplishment Instructions of Boeing Service Bulletin 727-57-0112, Revision 5, dated July 31, 1997. Any crack found must be repaired before further flight using a method approved in accordance with the procedures specified in paragraph (l) of this AD.
