AD 97-02-18

Active

Antenna Mounting Reinforcing Plates

Key Information
97-02-18
Active
March 04, 1997
Not specified
95-NM-160-AD
39-9903
Applicability
["Aircraft"]
["Large Airplane"]
BAE Systems (Operations) Limited
ATP
Summary

This amendment adopts a new airworthiness directive (AD), applicable to certain Jetstream Model BAe ATP airplanes, that requires repetitive inspections to detect damage of the antenna mounting reinforcing plates and surrounding fuselage skin. If any damage is detected, the AD requires replacement of the reinforcing plate with a new reinforcing plate and/or repair of the surrounding fuselage skin, which would terminate the repetitive inspection requirements. This amendment is prompted by reports of corrosion found at the antenna reinforcing plates, which was caused by the ingress of water at the plates. The actions specified by this AD are intended to prevent such corrosion, which could result in reduced structural integrity of the fuselage pressure vessel.

Action Required

Final rule

Regulatory Text

97-02-18 JETSTREAM AIRCRAFT LIMITED (Formerly British Aerospace Commercial Aircraft Limited): Amendment 39-9903. Docket 95-NM-160-AD.
Applicability: Model BAe ATP airplanes having constructor s numbers 2002 through 2063, 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 (c) 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.

Compliance: Required as indicated, unless accomplished previously.

To prevent corrosion of the antenna mounting reinforcing plates and surrounding skin, which could result in reduced structural integrity of the fuselage pressure vessel, accomplish the following:

(a) Within 6 months after the effective date of this AD, perform a detailed external visual inspection to detect damage (i.e., corrosion, cracks, pillowing, and rivet pulling) of the antenna mounting reinforcing plates and surrounding fuselage skin in accordance with Part A of the Accomplishment Instructions of Jetstream Service Bulletin ATP-53-31, Revision 1, dated December 5, 1995.

NOTE 2: Inspections of the areas specified in Jetstream Service Bulletin ATP-53-31, dated July 1, 1995, that have been accomplished prior to the effective date of this AD and in accordance with that service bulletin, are considered acceptable for compliance with the inspections of those areas as required by paragraph(a) of this AD. (It should be noted, however, that Revision 1 of Service Bulletin ATP-53-31 specifies procedures for inspection of two additional ADF antenna locations.)

(1) If no damage is detected, repeat the inspection thereafter at intervals not to exceed 2 years.

(2) If any damage is detected, replace the reinforcing plate with a new reinforcing plate and/or repair the surrounding fuselage skin at the applicable times specified in Figure 4 of the service bulletin, and in accordance with Part B of the Accomplishment Instructions of the service bulletin. Accomplishment of this replacement/repair constitutes terminating action for the repetitive inspection requirements of paragraph (a)(1) of this AD.

(b) Accomplishment of the replacement/repair procedures specified in Part B of the Accomplishment Instructions of Jetstream Service Bulletin ATP-53-31, Revision 1, dated December 5, 1995, constitutes terminating action for the requirements of this AD.

(c) An alternative method of compliance or adjustment of the compliance time that provides an acceptable level of safety may be used if approved by the Manager, Standardization Branch, ANM-113, FAA, Transport Airplane Directorate. Operators shall submit their requests through an appropriate FAA Principal Maintenance Inspector, who may add comments and then send it to the Manager, Standardization Branch, ANM-113.

NOTE 3: Information concerning the existence of approved alternative methods of compliance with this AD, if any, may be obtained from the Standardization Branch, ANM-113.

(d) 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.

(e) The inspections, replacement, and repair shall be done in accordance with Jetstream Service Bulletin ATP-53-31, Revision 1, dated December 5, 1995. 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 from Jetstream Aircraft, Inc., P.O. Box 16029, Dulles International Airport, Washington, DC 20041-6029. Copies may be inspected at the FAA, Transport Airplane Directorate, 1601 Lind Avenue, SW., Renton, Washington; or at the Office of the Federal Register, 800 North Capitol Street, NW., suite 700, Washington, DC.

(f) This amendment becomes effective on March 4, 1997.

Supplementary Information

A proposal to amend part 39 of the Federal Aviation Regulations (14 CFR part 39) to include an airworthiness directive (AD) that is applicable to certain Jetstream Model BAe ATP airplanes was published as a supplemental notice of proposed rulemaking (NPRM) in the Federal Register on November 8, 1996 (61 FR 57830). That action proposed to require repetitive detailed external visual inspections to detect damage (i.e., corrosion, cracks, pillowing, and rivet pulling) of the antenna mounting reinforcing plates and surrounding fuselage skin. For cases where any damage is detected during the inspection, that action also proposed to require replacement of the reinforcing plate with a new reinforcing plate and/or repair of the surrounding fuselage skin; this replacement/repair would constitute terminating action for the repetitive inspection requirements.

Interested persons have been afforded an opportunity to participate in the making of this amendment. Due consideration has been given to the comments received.

Support for the Proposal
One commenter supports the proposed rule.

Request for Extension of Repetitive Inspection Interval
One commenter requests that the proposal be revised to extend the repetitive inspection interval (when no corrosion is detected) from the proposed 1 year to 2 years. The commenter states that both the manufacturer and the Civil Aviation Authority (CAA) of the United Kingdom have determined that a 2-year repeat interval is a conservative figure, during which time any corrosion forming at the antenna reinforcing plates cannot progress to a state that would create a hazard. Additionally, the service bulletin referenced in the proposal recommends a 2-year repetitive inspection interval.

Based on the data presented, the FAA concurs. Paragraph (a)(1) of the final rule has been revised accordingly.

Conclusion
After careful review of the available data, including the comments noted above, the FAAhas determined that air safety and the public interest require the adoption of the rule with the change previously described. The FAA has determined that this change will neither increase the economic burden on any operator nor increase the scope of the AD.

Cost Impact
The FAA estimates that 10 airplanes of U.S. registry will be affected by this AD, that it will take approximately 2 work hours per airplane to accomplish the required actions, and that the average labor rate is $60 per work hour. Based on these figures, the cost impact of the AD on U.S. operators is estimated to be $1,200, or $120 per airplane, per inspection cycle.

The cost impact figure discussed above is based on assumptions that no operator has yet accomplished any of the requirements of this AD action, and that no operator would accomplish those actions in the future if this AD were not adopted.

Regulatory Impact
The regulations adopted herein will not have substantial direct effects on the States, on the relationship between the national government and the States, or on the distribution of power and responsibilities among the various levels of government. Therefore, in accordance with Executive Order 12612, it is determined that this final rule does not have sufficient federalism implications to warrant the preparation of a Federalism Assessment.

For the reasons discussed above, I certify that this action (1) is not a "significant regulatory action" under Executive Order 12866; (2) is not a "significant rule" under DOT Regulatory Policies and Procedures (44 FR 11034, February 26, 1979); and (3) will not have a significant economic impact, positive or negative, on a substantial number of small entities under the criteria of the Regulatory Flexibility Act. A final evaluation has been prepared for this action and it is contained in the Rules Docket. A copy of it may be obtained from the Rules Docket at the location provided under the caption "ADDRESSES."

List of Subjectsin 14 CFR Part 39
Air transportation, Aircraft, Aviation safety, Incorporation by reference, Safety.

Adoption of the Amendment
Accordingly, pursuant to the authority delegated to me by the Administrator, the Federal Aviation Administration amends part 39 of the Federal Aviation Regulations (14 CFR part 39) as follows:

PART 39 - AIRWORTHINESS DIRECTIVES
1. The authority citation for part 39 continues to read as follows:
Authority: 49 U.S.C. 106(g), 40113, 44701.

39.13 - [Amended]
2. Section 39.13 is amended by adding the following new airworthiness directive:

AD Assistant

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Contact Information

William Schroeder, Aerospace Engineer, Standardization Branch, ANM-113, FAA, Transport Airplane Directorate, 1601 Lind Avenue, SW., Renton, Washington 98055-4056; telephone (206) 227-2141; fax (206) 227-1149.

References
This information is not available.
--- - Part 39 [62 FR 3996 NO. 18 01/28/97]
FAA Documents