90-07-05 BOEING: Amendment 39-6548. Docket No. 89-NM-83-AD. \n\n\tApplicability: All Model 727 series airplanes, certificated in any category. \n\n\tCompliance: Required as indicated, unless previously accomplished. \n\tTo prevent separation of an inboard trailing edge flap due to corrosion or cracking of the inboard track, accomplish the following: \n\n\tA.\tFor airplanes with flap tracks that have neither the repair nor the preventative modification installed, as specified in Boeing Service Bulletin 727-57-117, Revision 5, dated January 30, 1981, or earlier revisions, accomplish the following: \n\n\t\t1.\tINSPECTION \n\n\t\t\ta.\tAccomplish the initial inspections required by paragraphs A.1.b., A.1.c, and A.1.d, below, prior to (1) or (2), below, whichever occurs later: \n\n\t\t\t\t(1)\tprior to the accumulation of 7,000 flight cycles or 5 years since manufacture, whichever occurs first; or \n\n\t\t\t\t(2)\twithin the next 1,000 flight cycles or 6 months after the effective date of this AD, whichever occurs first. \n\n\t\t\tb.\tAccomplish either of the following inspections: \n\n\t\t\t\t(1)\tPerform a close visual inspection for cracks and corrosion of the inboard trailing edge flaps inboard track in accordance with the Accomplishment Instructions of Boeing Service Bulletin 727-57-0178, Revision 3, dated December 21, 1989. Repeat this inspection at intervals not to exceed 3,000 flight cycles or 18 months, whichever occurs first.\n \n\t\t\t\t(2)\tRemove the flap track from the airplane, and perform a visual and magnetic particle inspection for cracks and corrosion in the flap track, in accordance with Figure 1 of Boeing Service Bulletin 727-57-0178, Revision 3, dated December 21, 1989. Repeat these inspections at intervals not to exceed 9,000 flight cycles or 6 years, whichever occurs first. \n\n\t\t\tc.\tInspect the inboard trailing edge flaps inboard track for loose mounting bolts. Repeat this inspection at intervals not to exceed 3,000 flight cycles or 18 months, whichever occurs first.d.\tIf the track has a laminated shim installed in accordance with Boeing Service Bulletin 727-57-0178, Revision New, dated May 5, 1988, visually inspect the laminated shim for correct location in accordance with Boeing Service Bulletin 727-57-0178, Revision 3, dated December 21, 1989. Repeat this inspection at intervals not to exceed 3,000 flight cycles or 18 months, whichever occurs first. \n\n\t\t2.\tREPAIR \n\n\t\t\ta.\tIf cracks with or without corrosion are detected as a result of the inspections required by paragraph A.1.b, above, and do not exceed the limits specified in Figures 1 or 3 of Boeing Service Bulletin 727-57-0178, Revision 3, dated December 21, 1989, prior to further flight, repair in accordance with the service bulletin. If the crack extends into the flap track web, inspect the crack using a borescope at intervals not to exceed 3,000 flight cycles or 18 months, whichever occurs first. If crack growth occurs, repair in accordance with this paragraph or A.2.b., below. Ifonly corrosion is detected and it does not exceed the limits specified in Figure 3 of the service bulletin, repair in accordance with the service bulletin within 12 months. If the crack does not extend into the flap track web, repairs made in accordance with this paragraph terminate the repetitive inspections required by paragraph A.1.b., above. \n\n\t\t\tb.\tIf cracks or corrosion are detected which exceed the limits specified in Figures 1 or 3 of Boeing Service Bulletin 727-57-0178, Revision 3, dated December 21, 1989, prior to further flight, replace the flap track. \n\n\t\t\tc.\tIf loose mounting bolts are detected as a result of the inspections required by paragraph A.1.c., above, retorque the bolts in accordance with Boeing Service Bulletin 727-57-0178, Revision 3, dated December 21, 1989, prior to further flight. Modification in accordance with Figure 2 of the service bulletin, terminates the repetitive inspections for loose mounting bolts required in paragraph A.1.c., above. \n\n\t\t\td.\tIf the track is repaired with a splice plate in accordance with Boeing Service Bulletin 727-57-0178, Revision 3, dated December 21, 1989, or earlier revisions, within 12,000 flight cycles since repair or 1,000 flight cycles after the effective date of this AD, whichever occurs later, perform a close visual inspection for cracks of the inboard trailing edge flaps inboard track at the aft splice plate fasteners, in accordance with the Accomplishment Instructions of the service bulletin. Repeat this inspection at intervals not to exceed 3,000 flight cycles or 18 months, whichever occurs first. If cracks are detected, replace the flap track prior to further flight. \n\n\t\t\te.\tIf a mislocated laminated shim is detected as a result of the inspections required by paragraph A.1.d., above, and the mislocation exceeds the limits specified in the Accomplishment Instructions of Boeing Service Bulletin 727-57-0178, Revision 3, dated December 21, 1989, prior to further flight, reinstall the shimor replace the shim in accordance with the service bulletin. Replacement of the shim terminates the repetitive inspections required by paragraph A.1.d., above. \n\n\tB.\tFor airplanes with flap tracks which have the preventative modification installed in accordance with Boeing Service Bulletin 727-57-117, Revision 5, dated January 30, 1981, or earlier revisions, accomplish the following: \n\n\t\t1.\tINSPECTION \n\n\t\t\ta.\tAccomplish the initial inspections required by paragraphs B.1.b. and B.1.c., below, prior to (1) or (2), below, whichever occurs later: \n\n\t\t\t\t(1)\twithin 9,000 flight cycles since modification or 6 years since modification, whichever occurs first; or \n\n\t\t\t\t(2)\twithin the next 1,000 flight cycles or 6 months after the effective date of this AD, whichever occurs first. \n\n\t\t\tb.\tAccomplish either of the following inspections: \n\n\t\t\t\t(1)\tPerform a close visual inspection for cracks and corrosion of the inboard trailing edge flaps inboard track in accordance with the Accomplishment Instructions of Boeing Service Bulletin 727-57-0178, Revision 3, dated December 21, 1989. Repeat this inspection at intervals not to exceed 3,000 flight cycles or 18 months, whichever occurs first. \n\n\t\t\t\t(2)\tRemove the flap track from the airplane, and perform a visual and magnetic particle inspection for cracks and corrosion in the flap track, in accordance with Figure 1 of Boeing Service Bulletin 727-57-0178, Revision 3, dated December 21, 1989. Repeat these inspections at intervals not to exceed 9,000 flight cycles or 6 years, whichever occurs first. \n\n\t\t\tc.\tInspect the inboard trailing edge flaps inboard track for loose mounting bolts. Repeat this inspection at intervals not to exceed 3,000 flight cycles or 18 months, whichever occurs first.\n \n\t\t2.\tREPAIR \n\n\t\t\ta.\tIf cracks with or without corrosion are detected as a result of the inspections required by paragraphs B.1.b., above, and do not exceed the limits specified in Figures 1 or 3 of Boeing Service Bulletin 727-57-0178, Revision 3, dated December 21, 1989, prior to further flight, repair in accordance with the service bulletin. If the crack extends into the flap track web, inspect the crack using a borescope, at intervals not to exceed 3,000 flight cycles or 18 months, whichever occurs first. If crack growth occurs, repair in accordance with this paragraph or B.2.b., below. If only corrosion is detected, and it does not exceed the limits specified in Figure 3 of the service bulletin, repair in accordance with the service bulletin within 12 months. If the crack does not extend into the flap track web, repairs made in accordance with this paragraph terminate the repetitive inspections required by paragraph B.1.b., above. \n\n\t\t\tb.\tIf cracks or corrosion are detected which exceed the limits specified in Figures 1 or 3 of Boeing Service Bulletin 727-57-0178, Revision 3, dated December 21, 1989, prior to further flight, replace the flap track. \n\n\t\t\tc.\tIf loose mounting bolts are detected as a result of the inspections required by paragraph B.1.c., above, prior to further flight, retorque the bolt in accordance with Boeing Service Bulletin 727-57-0178, Revision 3, dated December 21, 1989. Modification in accordance with Figure 2 of the service bulletin, terminates the repetitive inspections for loose mounting bolts required by paragraph B.1.c., above.\n \n\t\t\td.\tIf the track is repaired with a splice plate in accordance with Boeing Service Bulletin 727-57-0178, Revision 3, dated December 21, 1989, within 12,000 flight cycles since repair or 1,000 flight cycles after the effective date of this AD, whichever occurs later, perform a close visual inspection for cracks of the inboard trailing edge flaps inboard track at the aft splice plate fasteners, in accordance with the service bulletin. Repeat this inspection at intervals not to exceed 3,000 flight cycles or 18 months, whichever occurs first. If cracks are detected, replace the flap track prior to further flight.C.\tFor airplanes with flap tracks that have been repaired with the splice plate in accordance with Boeing Service Bulletin 727-57-117, Revision 5, dated January 30, 1981, or earlier revisions, accomplish the following: \n\n\t\t1.\tINSPECTION \n\n\t\t\ta.\tAccomplish the initial inspections required by paragraphs C.1.b., C.1.c., and C.1.d., below, prior to (1) or (2), below, whichever occurs later: \n\n\t\t\t\t(1)\twithin 12,000 flight cycles since repair or 8 years since repair, whichever occurs first; or \n\n\t\t\t\t(2)\twithin the next 1,000 flight cycles or 6 months after the effective date of this AD, whichever occurs first. \n\n\t\t\tb.\tRemove the flap track from the airplane, and perform a visual and magnetic particle inspection for cracks and corrosion in the flap track, in accordance with Figure 1 of Boeing Service Bulletin 727-57-0178, Revision 3, dated December 21, 1989. Repeat these inspections at intervals not to exceed 9,000 flight cycles or 6 years, whichever occurs first. \n\n\t\t\tc.\tInspectthe inboard trailing edge flaps inboard track for loose mounting bolts. Repeat this inspection at intervals not to exceed 3,000 flight cycles or 18 months, whichever occurs first. \n\n\t\t\td.\tPerform a close visual inspection for cracks of the inboard trailing edge flaps inboard track at the aft splice plate fasteners, in accordance with the service bulletin. Repeat this inspection at intervals not to exceed 3,000 flight cycles or 18 months, whichever occurs first. If cracks are detected, replace the flap track prior to further flight. \n\n\t\t2.\tREPAIR \n\n\t\t\ta.\tIf new cracks, crack growth, or corrosion are detected as a result of the inspections required by paragraph C.1.b., above, and do not exceed the limits specified in paragraph C.2.b., below, prior to further flight, repair in accordance with Boeing Service Bulletin 727-57-0178, Revision 3, dated December 21, 1989. If the crack extends into the flap track web, inspect the crack using a borescope at intervals not to exceed 3,000flight cycles or 18 months, whichever occurs first. If crack growth occurs, repair in accordance with this paragraph or C.2.b., below. If the crack does not extend into the flap track web, repairs made in accordance with this paragraph terminate the repetitive inspections required by paragraph C.1.b., above.\n \n\t\t\tb.\tReplace the flap track prior to further flight if any of the following occur: \n\n\t\t\t\t(1)\tThe crack length is within the short limits specified in Figure 1 of Boeing Service Bulletin 727-57-0178, Revision 3, dated December 21, 1989, and the crack runs toward the flap track integral rib. \n\n\t\t\t\t(2)\tThe crack length exceeds the short limits specified in Figure 1 of Boeing Service Bulletin 727-57-0178, Revision 3, dated December 21, 1989. \n\n\t\t\t\t(3)\tThe corrosion exceeds the limits specified in Figure 3 of Boeing Service Bulletin 727-57-0178, Revision 3, dated December 21, 1989. \n\n\t\t\tc.\tIf loose mounting bolts are detected as a result of the inspections required by paragraph C.1.c., above, prior to further flight, retorque the bolts in accordance with the service bulletin. Repair in accordance with Figures 3 or 4 of the service bulletin terminates the repetitive inspections for loose mounting bolts required by paragraph C.1.c., above. \n\n\t\t\td.\tIf the track is repaired with a splice plate in accordance with Boeing Service Bulletin 727-57-0178, Revision 3, dated December 21, 1989, perform a close visual inspection for cracks of the inboard trailing edge flaps inboard track at the aft splice plate fasteners, in accordance with the service bulletin. Repeat this inspection at intervals not to exceed 3,000 flight cycles or 18 months, whichever occurs first. If cracks are detected, replace the flap track prior to further flight. \n\n\tD.\tThe following constitutes terminating action for the inspection requirements of this AD: \n\n\t\t1.\tModification in accordance with Figure 2 of Boeing Service Bulletin 727-57-0178, Revision 3, dated December 21, 1989; or2.\tRepair in accordance with Figure 3 of the service bulletin, if no splice plate is required. \n\n\tE.\tAn alternate means of compliance or adjustment of the compliance time, which provides an acceptable level of safety, may be used when approved by the Manager, Seattle Aircraft Certification Office, FAA, Northwest Mountain Region. \n\n\t\tNOTE: The request should be forwarded through an FAA Principal Maintenance Inspector (PMI), who will either concur or comment, and then send it to the Manager, Seattle Aircraft Certification Office. \n\n\tF.\tSpecial flight permits may be issued in accordance with FAR 21.197 and 21.199 to operate airplanes to a base in order to comply with the requirements of this AD. \n\n\tAll persons affected by this directive who have not already received the appropriate service documents from the manufacturer may obtain copies upon request to Boeing Commercial Airplanes, P.O. Box 3707, Seattle, Washington 98124. These documents may be examined at the FAA, Northwest Mountain Region, Transport Airplane Directorate, 17900 Pacific Highway South, Seattle, Washington, or Seattle Aircraft Certification Office, 9010 East Marginal Way South, Seattle, Washington. \n\n\tThis amendment (39-6548, AD 90-07-05) becomes effective on April 27, 1990.