AD 2008-03-21

We are adopting a new airworthiness directive (AD) for the products listed above. This AD results from mandatory continuing airworthiness information (MCAI) originated by an aviation authority of another country to identify and correct an unsafe condition on an aviation product. The MCAI describes the unsafe condition as:

* * * * *

Recently, it was discovered that the inspection procedure as described by Fokker 50 Non-Destructive Testing Manual (NDTM), Part 6, Chapter 53-30-02, which is referenced by Fokker 50 Maintenance Review Board (MRB) Tasks Number 530000-00-04 and 530000-00-08 [currently required per AD (BLA) 2002-061], did not show the correct inspection areas. In addition to the existing procedure, the area at the kink in the bottom fuselage skin, the actual chine line, must be inspected. Investigation revealed that a number of aircraft have already passed the relevant inspection thresholds of 20,000 and 45,000 flight cycles by a considerable margin. As a result, it may be possible that cracks have developed and remained undetected. * *
*
* * * * *

The unsafe condition is cracking and subsequent failure of the fuselage bottom skin, which could result in reduced structural integrity of the fuselage. This AD requires actions that are intended to address the unsafe condition described in the MCAI.

Final rule; request for comments.

2008-03-21 Fokker Services B.V: Amendment 39-15372. Docket No. FAA- 2008-0153; Directorate Identifier 2007-NM-243-AD.

Effective Date

(a) This airworthiness directive (AD) becomes effective February 26, 2008.

Affected ADs

(b) None.

Applicability

(c) This AD applies to Fokker Model F.27 Mark 050 airplanes, certificated in any category; serial numbers 20103 through 20172 inclusive.

Subject

(d) Air Transport Association (ATA) of America Code 53: Fuselage.

Reason

(e) The mandatory continued airworthiness information (MCAI) states:
* * * * *

Recently, it was discovered that the inspection procedure as described by Fokker 50 Non-Destructive Testing Manual (NDTM), Part 6, Chapter 53-30-02, which is referenced by Fokker 50 Maintenance Review Board (MRB) Tasks Number 530000-00-04 and 530000-00-08 [currently required per AD (BLA) 2002-061], did not show the correct inspection areas. In addition to the existing procedure, the area at the kink inthe bottom fuselage skin, the actual chine line, must be inspected. Investigation revealed that a number of aircraft have already passed the relevant inspection thresholds of 20,000 and 45,000 flight cycles by a considerable margin. As a result, it may be possible that cracks have developed and remained undetected. To prevent future use of the incorrect procedure in NDTM, Part 6, chapter 53-30-02, Fokker Services has removed this procedure from the NDTM and replaced by chapter 53-30-03 (refer to NDTM Temporary Revisions No. 53-004 and 53-005 dated September 15, 2006). Furthermore the Fokker 50/60 Maintenance Planning Document (refer to MPD Temporary Revision No. 53-009 dated August 15, 2006) has been revised to delete references to the incorrect procedure and to include references to the correct procedure of NDTM, Part 6, chapter 53-30-03. This condition, if not corrected, could result in failure of the fuselage bottom skin. Since an unsafe condition has been identified that is likelyto exist or develop on aircraft of this type design, CAA-NL has originally published AD NL-2006-009, which is now replaced by NL- 2006-009 R1.
This directive requires a one-time inspection of the fuselage bottom skin at the chine line, of the area not covered by the procedure of NDTM, Part 6, chapter 53-30-02. This one-time inspection consists of two parts:

--A detailed visual inspection. The visual inspection is described in Fokker Services Service Bulletin SBF50-53-058 (dated June 30, 2006).
--An eddy-current inspection. The eddy-current inspection is described in Fokker Services Service Bulletin SBF50-53-059 (dated August 24, 2006).

The unsafe condition is cracking and subsequent failure of the fuselage bottom skin, which could result in reduced structural integrity of the fuselage. Corrective actions include repairing any cracking.

Actions and Compliance

(f) Unless already done, do the following actions.
(1) Before the accumulation of 20,000 total flight cycles, or within 3 weeks after the effective date of this AD, whichever occurs later, perform a detailed visual inspection for cracks of the fuselage bottom skin chine line between fuselage station (STA) 6675 and STA 15375 in accordance with Part 3, Steps A. and B., of the Accomplishment Instructions of Fokker Service Bulletin SBF50-53-058, dated June 30, 2006. If any crack is found appearing through the paint layer, before further flight, remove the paint to determine the extent of the cracking and repair in accordance with the instructions in the service bulletin.
(2) Before the accumulation of 45,000 total flight cycles, or within 3 weeks after the effective date of this AD, whichever occurs later, perform a detailed visual inspection for cracks of the fuselage bottom skin chine line between STA 1320 and STA 3100 in accordance with Part 3, Steps C. and D., of the Accomplishment Instructions of Fokker Service Bulletin SBF50-53-058, dated June 30, 2006. If any crack is found appearing through the paint layer, before further flight remove the paint to determine the extent of the cracking and repair in accordance with the instructions in the service bulletin.
(3) In all cases, whether or not cracks were found and repaired in accordance with the requirements in paragraphs (f)(1) and (f)(2) of this AD: Within 1,000 flight cycles after the visual inspections required by paragraphs (f)(1) and (f)(2) of this AD or within 1,000 flight cycles after the effective date of this AD, whichever occurs later, do an eddy current inspection of the fuselage bottom skin chine line (between the same fuselage stations as covered by the visual inspection) in accordance with Part 3 of the Accomplishment Instructions of Fokker Service Bulletin SBF50-53-059, dated August 24, 2006. If any crack is found during any eddy-current inspection, repair before further flight in accordance with the instructions in the service bulletin.
(4) If any crack is found as a result of any inspectionrequirement of this directive, within 30 days after the inspection or 30 days after the effective date of this AD, whichever occurs later, report all findings to the Type Certificate holder at the following address: Fokker Services B.V., Technical Services Dept., P.O. Box 231, 2150 AE Nieuw-Vennep, the Netherlands.

FAA AD Differences

Note: This AD differs from the MCAI and/or service information as follows: Although the MCAI or service information allows flight with cracks of different lengths on the fuselage bottom skin chine line between certain fuselage stations, this AD requires accomplishing the applicable repair before further flight if any crack is found.

Other FAA AD Provisions

(g) The following provisions also apply to this AD:
(1) Alternative Methods of Compliance (AMOCs): The Manager, International Branch, ANM-116, has the authority to approve AMOCs for this AD, if requested using the procedures found in 14 CFR 39.19. Send information to ATTN: Tom Rodriguez, Aerospace Engineer, International Branch, ANM-116, Transport Airplane Directorate, FAA, 1601 Lind Avenue, SW., Renton, Washington 98057-3356; telephone (425) 227-1137; fax (425) 227-1149. Before using any approved AMOC on any airplane to which the AMOC applies, notify your appropriate principal inspector (PI) in the FAA Flight Standards District Office (FSDO), or lacking a PI, your local FSDO.
(2) Airworthy Product: For any requirement in this AD to obtain corrective actions from a manufacturer or other source, use these actions if they are FAA-approved. Corrective actions are considered FAA-approved if they are approved by the State of Design Authority (or their delegated agent). You are required to assure the product is airworthy before it is returned to service.
(3) Reporting Requirements: For any reporting requirement in this AD, under the provisions of the Paperwork Reduction Act, the Office of Management and Budget (OMB) has approved the information collection requirements and has assigned OMB Control Number 2120- 0056.

Related Information

(h) Refer to Mandatory Continuing Airworthiness Information (MCAI) CAA-NL Dutch Airworthiness Directive NL-2006-009 R1 dated September 28, 2006; and Fokker Service Bulletins SBF50-53-058, dated June 30, 2006, and SBF50-53-059, dated August 24, 2006; for related information.

Material Incorporated by Reference

(i) You must use Fokker Service Bulletin SBF50-53-058, dated June 30, 2006; and Fokker Service Bulletin SBF50-53-059, dated August 24, 2006; as applicable, to do the actions required by this AD, unless the AD specifies otherwise. Fokker Service Bulletin SBF50-53-059 contains the following effective pages:

Page Nos.
Revision level shown on page
Date shown on page
1, 3, 5, 7, 9, 11, 13, 15
2, 4, 6, 8, 10, 12, 14, 16
Original
Original
August 24, 2006
August 21, 2006

(1) The Director of the Federal Register approved the incorporation by reference of this service information under 5 U.S.C. 552(a) and 1 CFR part 51.
(2) For service information identified in this AD, contact Fokker Services B.V., Technical Services Dept., P.O. Box 231, 2150 AE Nieuw-Vennep, the Netherlands.
(3) You may review copies at the FAA, Transport Airplane Directorate, 1601 Lind Avenue, SW., Renton, Washington; or at the National Archives and Records Administration (NARA). For information on the availability of this material at NARA, call (202) 741-6030, or go to: http://www.archives.gov/federal-register/cfr/ibr-locations.html .

Discussion

The Civil Aviation Authority--The Netherlands (CAA-NL), which is the aviation authority for the Netherlands, has issued Dutch Airworthiness Directive NL-2006-009 R1 dated September 28, 2006 (referred to after this as ``the MCAI''), to correct an unsafe condition for the specified products. The MCAI states:

* * * * *

Recently, it was discovered that the inspection procedure as described by Fokker 50 Non-Destructive Testing Manual (NDTM), Part 6, Chapter 53-30-02, which is referenced by Fokker 50 Maintenance Review Board (MRB) Tasks Number 530000-00-04 and 530000-00-08 [currently required per AD (BLA) 2002-061], did not show the correct inspection areas. In addition to the existing procedure, the area at the kink in the bottom fuselage skin, the actual chine line, must be inspected. Investigation revealed that a number of aircraft have already passed the relevant inspection thresholds of 20,000 and 45,000 flight cycles by a considerable margin. As a result, it may be possible that cracks have developed and remained undetected. To prevent future use of the incorrect procedure in NDTM, Part 6, chapter 53-30-02, Fokker Services has removed this procedure from the NDTM and replaced by chapter 53-30-03 (refer to NDTM Temporary Revisions No. 53-004 and 53-005 dated September 15, 2006). Furthermore the Fokker 50/60 Maintenance Planning Document (refer to MPD Temporary Revision No. 53-009 dated August 15, 2006) has been revised to delete references to the incorrect procedure and to include references to the correct procedure of NDTM, Part 6, chapter 53-30-03. This condition, if not corrected, could result in failure of the fuselage bottom skin. Since an unsafe condition has been identified that is likely to exist or develop on aircraft of this type design, CAA-NL has originally published AD NL-2006-009, which is now replaced by NL-2006-009 R1.
This directive requires a one-time inspection of the fuselage bottom skin atthe chine line, of the area not covered by the procedure of NDTM, Part 6, chapter 53-30-02. This one-time inspection consists of two parts:

--A detailed visual inspection. The visual inspection is described in Fokker Services Service Bulletin SBF50-53-058 (dated June 30, 2006).
--An eddy-current inspection. The eddy-current inspection is described in Fokker Services Service Bulletin SBF50-53-059 (dated August 24, 2006).

The unsafe condition is cracking and subsequent failure of the fuselage bottom skin, which could result in reduced structural integrity of the fuselage. Corrective actions include repairing any cracking. You may obtain further information by examining the MCAI in the AD docket.

Relevant Service Information

Fokker Services B.V. has issued Service Bulletins SBF50-53-058, dated June 30, 2006, and SBF50-53-059, dated August 24, 2006. The actions described in this service information are intended to correct the unsafe condition identified in the MCAI.FAA's Determination and Requirements of This AD

This product has been approved by the aviation authority of another country, and is approved for operation in the United States. Pursuant to our bilateral agreement with the State of Design Authority, we have been notified of the unsafe condition described in the MCAI and service information referenced above. We are issuing this AD because we evaluated all pertinent information and determined the unsafe condition exists and is likely to exist or develop on other products of the same type design.
There are no products of this type currently registered in the United States. However, this rule is necessary to ensure that the described unsafe condition is addressed if any of these products are placed on the U.S. Register in the future.

Differences Between the AD and the MCAI or Service Information

We have reviewed the MCAI and related service information and, in general, agree with their substance. But we might have found it necessary to use different words from those in the MCAI to ensure the AD is clear for U.S. operators and is enforceable. In making these changes, we do not intend to differ substantively from the information provided in the MCAI and related service information.
We might also have required different actions in this AD from those in the MCAI in order to follow FAA policies. Any such differences are highlighted in a Note within the AD.

FAA's Determination of the Effective Date

Since there are currently no domestic operators of this product, notice and opportunity for public comment before issuing this AD are unnecessary.

Comments Invited

This AD is a final rule that involves requirements affecting flight safety, and we did not precede it by notice and opportunity for public comment. We invite you to send any written relevant data, views, or arguments about this AD. Send your comments to an address listed under the ADDRESSES section. Include ``Docket No. FAA-2008-0153; Directorate Identifier 2007-NM-243-AD'' at the beginning of your comments. We specifically invite comments on the overall regulatory, economic, environmental, and energy aspects of this AD. We will consider all comments received by the closing date and may amend this AD because of those comments.
We will post all comments we receive, without change, to http://www.regulations.gov , including any personal information you provide. We will also post a report summarizing each substantive verbal contact we receive about this AD.

Authority for This Rulemaking

Title 49 of the United States Code specifies the FAA's authority to issue rules on aviation safety. Subtitle I, section 106, describes the authority of the FAA Administrator. ``Subtitle VII: Aviation Programs,'' describes in more detail the scope of the Agency's authority.
We are issuing this rulemaking under the authority described in ``Subtitle VII, Part A, Subpart III, Section 44701: General requirements.'' Under that section, Congress charges the FAA with promoting safe flight of civil aircraft in air commerce by prescribing regulations for practices, methods, and procedures the Administrator finds necessary for safety in air commerce. This regulation is within the scope of that authority because it addresses an unsafe condition that is likely to exist or develop on products identified in this rulemaking action.

Regulatory Findings

We determined that this AD will not have federalism implications under Executive Order 13132. This AD will not have a substantial direct effect 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.
For the reasons discussed above, I certify this AD:
1. Is not a ``significant regulatory action'' under Executive Order 12866;
2. Is not a ``significant rule'' under the 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.
We prepared a regulatory evaluation of the estimated costs to comply with this AD and placed it in the AD docket.

List of Subjects in 14 CFR Part 39

Air transportation, Aircraft, Aviation safety, Incorporation by reference, Safety.

Adoption of the Amendment

Accordingly, under the authority delegated to me by the Administrator, the FAA amends 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.

Sec. 39.13 [Amended]

2. The FAA amends Sec. 39.13 by adding the following new AD: