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71-25-02: 71-25-02 BRITISH AIRCRAFT CORPORATION: Amdt. 39-1349 as amended by Amendment 39-1375. Applies to Model BAC 1-11 200 and 400 series airplanes.
Compliance is required as indicated.
To prevent failures of the flap beam bracket to wing attachments due to loose or failed attachment bolts through the wing lower skin at flap beam locations 2, 3, 4, accomplish the following:
(a) For 200 and 400 series airplanes which do not have parallel shank bolts installed in accordance with paragraph (h)(2) of AD 70-18-1 or do not have BAC Modification PM 3065(b), PM 4407 Part A5 or A6, or PM 4790(c) incorporated, at flap beam locations 2 (both L.H. and R.H.), within the next 50 landings after the effective date of this AD, unless already accomplished within the last 450 landings, and thereafter at intervals not to exceed 500 landings from the last inspection, inspect the six flap beam bracket attachment bolts through the wing lower skin at each affected flap beam location 2 for looseness orfailure in accordance with paragraph (h).
(b) For 200 series airplanes which do not have paralleled shank bolts installed in accordance with paragraph (h)(2) of AD 70-18-1 or do not have BAC Modification PM 3065(d), PM 4407 Part A7 or A8, or PM 4790(c) incorporated, at flap beam locations 3 (both L.H. and R.H.), within the next 50 landings after the effective date of this AD, unless already accomplished within the last 950 landings, and thereafter at intervals not to exceed 1,000 landings from the last inspection, inspect the four flap beam bracket attachment bolts through the wing lower skin at each affected flap beam location 3 for looseness or failure in accordance with paragraph (h).
(c) For 200 series airplanes which do not have paralleled shank bolts installed in accordance with paragraph (h)(2) of AD 70-18-1 or do not have BAC Modification PM 3216, PM 4407 Part A11 or A12, or PM 4790(c) incorporated, at flap beam locations 4 (both L.H. and R.H.), within the next 50 landings after the effective date of this AD, unless already accomplished within the last 950 landings, and thereafter at intervals not to exceed 1,000 landings from the last inspection, inspect the four flap beam bracket attachment bolts through the wing lower skin at each affected flap beam location 4 for looseness or failure in accordance with paragraph (h).
NOTE: An inspection accomplished at a flap beam location in accordance with paragraph (a), (b), or (c) of AD 70-18-1 prior to the effective date of this AD may be considered to meet the initial inspection required by paragraph (a), (b), or (c), respectively, of this AD.
(d) For 200 and 400 series airplanes which have an applicable Part A5, A6, A7, A8, A9, A10, A11, or A12 of BAC Modification PM 4407, or PM 3216 incorporated at a flap beam locations 2, 3, or 4 (both L.H. and R.H.), within the next 50 landings after the effective date of this AD or before the accumulation of 450 landings after incorporating BAC Modification PM 3216 or PM 4407 at an affected flap beam location, whichever occurs later, and thereafter at intervals not to exceed 500 landings from the last inspection, inspect the flap beam bracket attachment bolts through the wing lower skin at each affected flap beam location for looseness or failure in accordance with paragraph (h).
(e) If failed or loose bolts through the wing lower skin are found during an inspection required by paragraph (a), (b), (c), or (d) comply with subparagraph (1), (2), or (3).
(1) If more than one failed or loose bolt are found on any bracket, before further flight, except that the airplane may be flown in accordance with FAR 21.197 to a base where the repairs or modifications can be performed, comply with paragraphs (i), (j), and (k).
(2) If no more than one failed or loose bolt on each bracket at any flap beam location if found, before further flight, except that the airplane may be flown in accordance with FAR 21.197 to a base where the repairs ormodifications can be performed, comply with paragraphs (i) and (j) and either-
(i) Comply with paragraph (k); or
(ii) Replace each failed or loose bolt with a new taper bolt of the same part number or with a parallel shank bolt having a material strength of 140,000 to 165,000 p.s.i. and having a diameter compatible with the maximum diameter of the replaced taper bolt and within the next 300 landings after replacing the failed or loose bolt comply with paragraphs (i), (j), and (k).
(3) If no failed bolt and no more than one loose bolt is found at any flap beam location, before further flight, except that the airplane may be flown in accordance with FAR 21.197 to a base where the repairs or modifications can be performed, comply with paragraphs (i) and (j) and either -
(i) Comply with paragraph (k); or
(ii) Leave the loose bolt in service and within the next 300 landings after finding the loose bolt comply with paragraphs (i), (j), and (k).
(f) For 200 and400 series airplanes which have any parallel shank bolts installed at a flap beam location as a repair for any failed or loose flap beam bracket attachment bolts through the wing lower skin in accordance with paragraph (h)(2) of AD 70-18-1, comply with the following:
(1) At each affected flap beam location inspect all the flap beam bracket attachment bolts through the wing lower skin for failure or looseness in accordance with paragraph (h) as indicated below:
(i) For airplanes with 1,200 or more landings on an affected flap beam location since the installation of the parallel shank bolts, within the next 25 landings after the effective date of this AD unless already accomplished within the last 25 landings, and thereafter at intervals not to exceed 50 landings from the last inspection until paragraph (k) is complied with.
(ii) For airplanes with 900 or more but less than 1,200 landings on an affected flap beam location since the installation of the parallel shank bolts, within the next 50 landings after the effective date of this AD unless already accomplished within the last 50 landings, and thereafter at intervals not to exceed 100 landings from the last inspection until paragraph (k) is complied with.
(iii) For airplanes with less than 900 landings on an affected flap beam location since the installation of the parallel shank bolts, within the next 50 landings after the effective date of this AD unless already accomplished within the last 250 landings, or before the accumulation of 300 landings on the affected flap beam location, whichever occurs later.
(2) If any failed or loose bolts are found during an inspection required by this paragraph before further flight, except that the airplane may be flown in accordance with FAR 21.197 to a base where the repairs or modifications can be performed, comply with paragraphs (i), (j), and (k).
(3) Within the next 300 landings after the effective date of this AD comply with paragraphs (i), (j), and (k) at each affected flap beam location.
(g) For 200 and 400 series airplanes, at those flap beam locations 2, 3, or 4 at which replacement bolts were installed or loose bolts were left in service as provided by paragraphs (d)(1) and (f)(2) of AD 70-18-1, as amended, comply with the following:
(1) For flap beam locations at which a loose bolt or replacement bolt is still in service, before the accumulation of 300 landings on the loose bolt or replacement bolt comply with paragraphs (i), (j), and (k).
(2) For flap beam locations at which a loose bolt or replacement bolt has been removed from service through modifications performed in accordance with paragraph (h) of AD 70-18-1, comply with paragraphs (i) and (j), unless already accomplished at the time of such modifications or subsequent thereto, as indicated below:
(i) For flap beam locations modified in accordance with paragraph (h)(1) of AD 70-18-1, at the first inspection required by paragraph (d).(ii) For flap beam locations modified in accordance with paragraph (h)(2) of AD 70-18-1, at the first inspection required by paragraph (f).
(iii) For flap beam locations modified in accordance with paragraph (h)(3) of AD 70-18-1, within the next 100 landings after the effective date of this AD.
(h) Inspect the flap beam bracket attachment bolts through the wing lower skin for failure or looseness by applying a load to the nut on each bolt to ensure that the bolt has not failed or is not loose.
NOTE: The inspection for security of the taper bolts cannot be adequately carried out at the bolt head because the shallow taper might maintain the bolt shank tight in spite of failure at the thread undercut.
(i) At each affected flap beam location accomplish the following:
(1) Visually inspect the two lower horizontal attachment bolts (one on each side of the flange) which pass through the forward flange of the flap beam attachment bracket and the rear spar lower boom angle for failure or looseness.
(2) Visually inspect the wing structure in the area of the affected flap beam location for damage or fuel leaks.
(3) If any failed or loose horizontal bolts or any damage to the wing structure or any fuel leaks are found during an inspection required by this paragraph, before further flight, except that the airplane may be flown in accordance with FAR 21.197 to a base where the repairs can be performed, replace the failed or loose horizontal bolts, repair the damage to the wing structure, and seal the fuel leaks.
(j) At each affected flap beam location accomplish the following:
(1) Visually inspect both flap beam attachment brackets for cracks in the webs or flanges.
NOTE: Particular attention should be given to Type A and Type B cracks as shown in Figure 1 of British Aircraft Corporation Service Newsletter 57/7, Issue 1, dated April 27, 1970.
(2) If a crack is found during an inspection required by this paragraph, before further flight, except that the airplane may be flown in accordance with FAR 21.197 to a base where the repairs can be performed, comply with ARB-approved instructions from the Service Manager, British Aircraft Corporation, Weybridge, Surrey, England, or an FAA-approved equivalent.
(k) At each affected flap beam location replace all the flap beam bracket attachment bolts through the wing lower skin with new increased diameter BAC Modification PM 4790(c) parallel shank bolts in accordance with Part C of British Aircraft Corporation Model BAC 1-11 Service Bulletin No. 57-PM 4790 dated March 1, 1971, or an FAA-approved equivalent.
(l) The repetitive inspection required by this AD may be discontinued at each flap beam location where the modifications specified by paragraph (k) have been incorporated.
NOTE: These modifications may be accomplished in complying with Amendment 39- 1348.
(m) For the purpose of complying with this AD, subject to acceptance by the assigned FAA maintenance inspector, the number of landings may be determined by dividing each airplane's hours' time in service by the operator's fleet average time from takeoff to landing for BAC 1-11 200 and 400 series airplanes.
(n) Upon request of the operator, an FAA maintenance inspector, subject to prior approval of the Chief, Aircraft Certification Staff, FAA Europe, Africa, and Middle East Region may adjust the repetitive inspection intervals specified in paragraphs (a), (b), (c), and (d) of this AD to permit compliance at an established inspection period of the operator if the request contains substantiating data to justify the increase for that operator.
Amendment 39-1349 superseded Amendment 39-1073 (35 F.R. 13879), AD 70-18-1, as amended by Amendment 39-1184 (36 F.R. 5976).
Amendment 39-1349 became effective November 30, 1971.
This Amendment 39-1375 becomes effective upon publication in the Federal Register.
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