84-23-06 R1 PILATUS BRITTEN-NORMAN LTD.: Amendment 39-10172; Docket No. 84-CE-18-AD; Revises AD 84-23-06, Amendment 39-4942 which superseded AD 83-07-18, Amendment 39-4620.
Applicability: BN-2A MK. 111 Series Airplanes (all serial numbers), certificated in any category.
NOTE 1: This AD applies to each airplane identified in the preceding applicability provision, regardless of whether it has been modified, altered, or repaired in the area subject to the requirements of this AD. For airplanes that have been modified, altered, or repaired so that the performance of the requirements of this AD is affected, the owner/operator must request approval for an alternative method of compliance in accordance with paragraph (d) of this AD. The request should include an assessment of the effect of the modification, alteration, or repair on the unsafe condition addressed by this AD; and, if the unsafe condition has not been eliminated, the request should include specific proposed actions to address it.
NOTE 2: The paragraph structure of this AD is as follows:
Level 1: (a), (b), (c), etc.
Level 2: (1), (2), (3), etc.
Level 3: (i), (ii), (iii), etc.
Level 2 and Level 3 structures are designations of the Level 1 paragraph they immediately follow.
Compliance: Required initially upon the accumulation of 500 hours time-in-service (TIS) or within the next 50 hours TIS after the effective date of this AD, whichever occurs later, unless already accomplished (compliance with AD 84-23-06), and thereafter at intervals not to exceed 500 hours TIS.
To prevent failure of the upper mounting brackets on both wing mounted engines, which could possibly cause structural failure of the airplane, accomplish the following:
(a) Visually inspect the following areas in accordance with paragraphs 1 through 6 of the "Inspection" section of the Pilatus Britten-Norman (Pilatus) Service Bulletin (SB) No. BN- 2/SB.61, Issue 5, dated December 9, 1981:(1) The upper engine to wing mounting brackets for:
(i) Minimum lug bolt hole-to-edge distance, elongation of the bolt holes, distortion, delamination, cracks, flaking, and corrosion;
(ii) The bolts for correct bearing length; and
(iii) Loose and fretted bushings.
(2) Prior to further flight, correct defects in accordance with the following:
(i) If the lug bolt hole-to-edge distance is less than the specified minimum (0.2625-inches), correct in accordance with paragraph 3 of the "Rectification/Modification" section of Pilatus SB No. BN-2/SB.61, Issue 5, dated December 9, 1981;
(ii) If the bolt holes are elongated, or if any bushings are loose or fretted, modify and correct in accordance with paragraph 4 of the "Rectification/Modification" section of Pilatus SB No. BN-2/SB.61, Issue 5, dated December 9, 1981;
(iii) If any mounting bracket is cracked, modify both brackets on the same engine installation (left side engine or right side engine) concurrently (even if only one bracket is defective) in accordance with paragraph 1 of the "Rectification/Modification" section of Pilatus SB No. BN-2/SB.61, Issue 5, dated December 9, 1981;
(iv) If any lug is distorted or delaminated, replace the deficient part in accordance with paragraphs 1 and 2 of the "Rectification/Modification" section of Pilatus SB No. BN-2/SB.61, Issue 5, dated December 9, 1981;
(v) If any inspected part is corroded or flaking, replace the part in accordance paragraph 1 with the "Rectification/Modification" section of Pilatus SB No. BN-2/SB.61, Issue 5, dated December 9, 1981; and
(vi) If any of the bolts are of incorrect length or damaged, replace with new units of the correct length in accordance with paragraphs 1 and 2 of the "Rectification/Modification" section of Pilatus SB No. BN-2/SB.61, Issue 5, dated December 9, 1981.
(b) The intervals between the repetitive inspections required by this AD may be adjusted up to 10 percent of the specified interval to allow for accomplishing these inspections concurrent with the other scheduled maintenance of the airplane.
(c) Special flight permits may be issued in accordance with sections 21.197 and 21.199 of the Federal Aviation Regulations (14 CFR 21.197 and 21.199) to operate the airplane to a location where the requirements of this AD can be accomplished.
(d) An alternative method of compliance or adjustment of the initial or repetitive compliance times that provides an equivalent level of safety may be approved by the Manager, Small Airplane Directorate, Aircraft Certification Service, FAA, 1201 Walnut, suite 900, Kansas City, Missouri 64106. The request shall be forwarded through an appropriate FAA Maintenance Inspector, who may add comments and then send it to the Manager, Small Airplane Directorate.
NOTE 3: Information concerning the existence of approved alternative methods of compliance with this AD, if any, may be obtained from the SmallAirplane Directorate.
(e) The inspections, modifications, and replacements, required by this AD shall be done in accordance with Pilatus Britten-Norman Service Bulletin No. BN-2/SB.61, Issue: 5, Date: December 9, 1981. This incorporation by reference was approved by the Director of the Federal Register in accordance with 5 U.S.C. 552(a) and 1 CFR part 51. Copies may be obtained Pilatus Britten-Norman Limited, Bembridge, Isle of Wight, United Kingdom PO35 5PR. Copies may be inspected at the FAA, Central Region, Office of the Regional Counsel, Room 1558, 601 E. 12th Street, Kansas City, Missouri, or at the Office of the Federal Register, 800 North Capitol Street, NW., suite 700, Washington, DC.
(f) This amendment becomes effective on November 24, 1997.