Airworthiness Directive · Amendment 39-11524 · British Aerospace (Jetstream) Model 4101 Airplanes
British Aerospace (Jetstream) Model 4101 Airplanes
Jetstream Model 4101 airplanes, on which British Aerospace Modification JM41384 has not been accomplished, certificated in any category.
Note 1: This AD applies to each airplane identified in the preceding applicability provision, regardless of whether it has been otherwise 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 supersedes an existing airworthiness directive (AD), applicable to certain British Aerospace (Jetstream) Model 4101 airplanes, that currently requires repetitive detailed visual inspections to detect cracking or other damage of certain diaphragm support structures of the forward equipment compartment; and repair, if necessary. This amendment continues to require repetitive inspections, but also requires replacement of cracked or damaged diaphragm support structures with improved parts, which terminates the requirement for repetitive inspections. This amendment also adds airplanes to the applicability of the AD. This amendment is prompted by the development of improved diaphragms. The actions specified by this AD are intended to prevent failure of the two diaphragms that support the upper structure of the forward equipment compartment, which could accelerate fatigue damage in adjacent structure and result in reduced structural integrity of the airframe.
To detect and correct failure of the two diaphragms that support the upper structure of the forward equipment compartment, which could accelerate fatigue damage in adjacent structure and result in reduced structural integrity of the airframe, accomplish the following:
(a) For airplanes having constructors numbers 41004 through 41098 inclusive: Prior to the accumulation of 4,500 total landings, or within 300 landings after December 23, 1998 (the effective date of AD 98-24-01, amendment 39-10888), whichever occurs later: Perform a detailed visual inspection to detect cracking or other damage of the diaphragms installed between station 4 and station 8 of the forward fuselage, in accordance with Jetstream Alert Service Bulletin J41-A53-023, dated December 2, 1996, or Revision 1, dated July 30, 1999.
Note 2: 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 such as mirror, magnifying lenses, etc., may be used. Surface cleaning and elaborate access procedures may be required.”
(1) If no cracking or other damage is detected, repeat the inspection thereafter at intervals not to exceed 3,000 landings.
(2) If any cracking or other damage is detected, prior to further flight, accomplish the actions required by either paragraph (a)(2)(i) or (a)(2)(ii). After the effective date of this AD, only replacement of the diaphragms in accordance with paragraph (a)(2)(ii) of this AD is acceptable for compliance with the repair requirements of this paragraph.
(i) Repair the diaphragm in accordance with a method approved by the Manager, International Branch, ANM-116, FAA, Transport Airplane Directorate. Thereafter, repeat the inspection at intervals not to exceed 3,000 landings.
(ii) Replace both diaphragms with new, improved diaphragms, in accordance with Part 2 of the Accomplishment Instructions of Jetstream Alert Service Bulletin J41-A53-023, Revision 1, dated July 30, 1999. Such replacement constitutes terminating action for the repetitive inspections required by this AD.
(b) For airplanes other than those listed in paragraph (a) of this AD: Prior to the accumulation of 4,500 total landings, or within 300 landings after the effective date of this AD, whichever occurs later, perform a detailed visual inspection to detect cracking or other damage of the diaphragms installed between station 4 and station 8 of the forward fuselage, in accordance with Jetstream Alert Service Bulletin J41-A53-023, Revision 1, dated July 30, 1999.
(1) If no cracking or other damage is detected, repeat the inspection thereafter at intervals not to exceed 3,000 landings.
(2) If any cracking or other damage is detected, prior to further flight, replace both diaphragms with new, improved diaphragms, in accordance with Part 2 of the Accomplishment Instructions of Jetstream Alert Service Bulletin J41-A53-023, Revision 1, dated July 30, 1999. Such replacement constitutes terminating action for the repetitive inspections required by this AD.
(c) Replacement of diaphragms with new, improved diaphragms, in accordance with Part 2 of the Accomplishment Instructions of Jetstream Alert Service Bulletin J41-A53-023, Revision 1, dated July 30, 1999, constitutes terminating action for the requirements of this AD.
