Airworthiness Directive · Amendment 39-11808 · Saab Model SAAB 2000 Series Airplanes
Saab Model SAAB 2000 Series Airplanes
Superseded. A later AD replaced this one: AD 2004-14-11. Comply with the one in force.
Model SAAB 2000 series airplanes, serial numbers -004 through -063 inclusive; 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.
This amendment adopts a new airworthiness directive (AD), applicable to certain Saab Model SAAB 2000 series airplanes, that requires repetitive detailed visual and dye penetrant inspections of the backup struts in the left and right nacelles to detect discrepancies; and corrective actions, if necessary. This amendment is prompted by issuance of mandatory continuing airworthiness information by a foreign civil airworthiness authority. The actions specified by this AD are intended to prevent failure of the backup struts in the left and right nacelles due to fatigue cracking, which could result in loss of fail-safe redundancy in the design of the nacelle in terms of load capability.
To prevent failure of the backup struts in the left and right nacelles due to fatigue cracking, which could result in loss of fail-safe redundancy in the design of the nacelle in terms of load capability, accomplish the following:
(a) For airplanes on which the dye penetrant inspection of the backup struts in the left and right nacelles specified in Saab Alert Service Bulletin 2000-A54-022, dated October 27, 1999, has not been accomplished prior to the effective date of this AD: Within 200 flight hours after the effective date of this AD, accomplish paragraphs (b)(1) and (b)(2) of this AD in accordance with the Accomplishment Instructions of Saab Service Bulletin 2000-54-023, Revision 02, dated February 23, 2000.
Note 2: Accomplishment of the required actions in accordance with Saab Service Bulletin 2000-54-023, Revision 01, dated January 28, 2000, prior to the effective date of this AD, is acceptable for compliance with this AD.
(b) For airplanes on which the dye penetrant inspection of the backup struts in the left and right nacelle specified in Saab Alert Service Bulletin 2000-A54-022, dated October 27, 1999, has been accomplished prior to the effective date of this AD: Within 450 flight hours after the effective date of this AD, accomplish paragraphs (b)(1) and (b)(2) of this AD in accordance with the Accomplishment Instructions of Saab Service Bulletin 2000-54-023, Revision 02, dated February 23, 2000.
(1) Perform a detailed visual inspection of the upper areas of the backup strut around the welding in the pipe and in the attachment fittings to detect any discrepancy (including fatigue cracking or a failed backup strut) by accomplishing all actions specified in paragraph B.(1) of the Accomplishment Instructions of the service bulletin, in accordance with the service bulletin. Repeat the detailed visual inspection thereafter at intervals not to exceed 450 flight hours.
Note 3: For the purposes of this AD, a detailed visual inspection is defined as: “An intensive visual examination of a specific structural area, system, installation, or assembly to detect damage, failure, or irregularity. Available lighting is normally supplemented with a direct source of good lighting at intensity deemed appropriate by the inspector. Inspection aids (e.g., mirror, magnifying lenses) may be used. Surface cleaning and elaborate access procedures may be required.”
(2) Perform a dye penetrant inspection, using Penetrant Type 1 (fluorescent dye) sensitivity level 2, of the lower areas of the backup strut around the welding in the pipe and in the attachment fittings to detect any discrepancy (including fatigue cracking or a failed backup strut) by accomplishing all actions specified in paragraphs B.(2) and B.(3) of the service bulletin, as applicable, in accordance with the service bulletin.
(i) For airplanes on which all backup struts have accumulated less than 4,500 total flight hours as of the effective date of this AD, repeat the dye penetrant inspection thereafter at intervals not to exceed 1,650 flight hours, until any backup strut on the airplane has accumulated 4,500 total flight hours; then perform the repetitive inspection thereafter at the interval specified by paragraph (b)(2)(ii) of this AD.
(ii) For airplanes on which any backup strut has accumulated 4,500 or more total flight hours as of the effective date of this AD, repeat the dye penetrant inspection thereafter at intervals not to exceed 900 flight hours.
(c) If any discrepancy (including fatigue cracking, a failed backup strut, or damage to the surrounding structure of the engine mount) is detected during any inspection required by this AD: Prior to further flight, accomplish the applicable corrective actions (including performing additional inspections of the engine mount surrounding structure, and replacing any discrepant backup strut in the hydraulic or electrical bay areas with a new backup strut) specified by paragraph C. of the Accomplishment Instructions of Saab Service Bulletin 2000-54-023, Revision 02, dated February 23, 2000, in accordance with the service bulletin. For any repair condition for which the service bulletin specifies to contact the manufacturer for appropriate action: Prior to further flight, repair in accordance with a method approved by either the Manager, International Branch, ANM-116, FAA, Transport Airplane Directorate; or the Luftfartsverket (LFV) (or its delegated agent). For a repair method to be approved by the Manager, International Branch, ANM-116, as required by this paragraph, the Manager's approval letter must specifically reference this AD.
The aircraft, engines and makers this AD names, by the model designations in its text. A model listed here may still be outside the AD's serial ranges.
Aircraft
