AD 99-09-18

This amendment supersedes an existing airworthiness directive (AD), applicable to certain Fokker Model F.28 Mark 0070 and Mark 0100 series airplanes, that currently requires a one-time inspection for heat damage of the fuselage skin and stubwing structure; either repetitive tests of certain seals or repair of heat damage, as necessary; and eventual replacement of corrujoint seals with new, improved seals. This amendment adds a requirement for repetitive inspections for heat damage of the subject area, and provides for a new optional terminating action for the repetitive inspections. This action 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 leakage of hot air from the corrujoint seals of certain valves in the stubwings, and subsequent heat damage of the fuselage skin and stubwing structure, which could result in reduced structural integrity of theairplane.

The incorporation by reference of certain publications listed in the regulations is approved by the Director of the Federal Register as of June 8, 1999.

The incorporation by reference of certain other publications as listed in the regulations, was approved previously by the Director of the Federal Register as of May 14, 1998 (63 FR 17318, April 9, 1998).

Final rule

99-09-18 FOKKER SERVICES B.V.: Amendment 39-11151. Docket 98-NM-202-AD. Supersedes AD 98-08-01, Amendment 39-10450.

Applicability: Model F.28 Mark 0070 and Mark 0100 series airplanes equipped with any corrujoint seal having part number (P/N) BE20061 (Rolls-Royce P/N 3405891) or on which Fokker Proforma Service Bulletin SBF100-36-027, including Appendix I, both dated March 21, 1997, 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 (i)(1) of this AD. The request should include an assessment of the effect of themodification, 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 leakage of hot air from the corrujoint seals of the low- and high-pressure check valves located in the stubwings, and subsequent heat damage of fuselage skin and stubwing structure adjacent to bleed air system components in the stubwings, which could result in reduced structural integrity of the airplane, accomplish the following:

Restatement of Requirements of AD 98-08-01, Amendment 39-10450:
(a) For Model F28 Mark 0070 and Mark 0100 series airplanes as listed in Fokker Service Bulletin SFB100-53-084, dated July 6, 1996; if equipped with any corrujoint seal having P/N BE20061 (Rolls-Royce P/N 3405891): Within 3,000 flight hours or 12 months after May 14, 1998 (the effective date of AD 98-08-01, amendment 39-10450), whichever occurs first, perform a one-time visual inspection of the fuselage skin in the left- and right-hand stubwings to detect heat damage; in accordance with Part 2 of the Accomplishment Instructions of Fokker Service Bulletin SFB100-53-084, dated July 6, 1996.

(b) If no heat damage is found during the inspection required by paragraph (a) of this AD, prior to further flight, accomplish either paragraph (b)(1) or (b)(2) of this AD.

(1) Replace all corrujoint seals having P/N BE20061 (Rolls-Royce P/N 3405891) at the 7th stage low-pressure and 12th stage high-pressure check valves of the left- and right-hand bleed air systems with new, improved corrujoint seals having P/N EU15969, in accordance with the Accomplishment Instructions of Fokker Service Bulletin SBF100-36-026, Revision 1, dated July 6, 1996.

(2) Perform a leak test of each corrujoint seal at the 7th stage low-pressure and 12th stage high-pressure check valves of the left- and right-hand bleed air systems, in accordance with Part 3 of the Accomplishment Instructions of Fokker Service Bulletin SBF100-53-084, dated July 6, 1996.

(i) If any leakage is found at a seal, prior to further flight, replace that seal with a new, improved seal having part number EU15969, in accordance with the Accomplishment Instructions of Fokker Service Bulletin SBF100-36-026, Revision 1, dated July 6, 1996.

(ii) If no leakage is found at a seal, perform an additional leak test of that seal within 250 flight hours after the initial test.

(A) If no leakage is found during the additional test of the seal, within 3,000 flight hours after the additional test, replace the seal with an improved seal having P/N EU15969, in accordance with the Accomplishment Instructions of Fokker Service Bulletin SBF100-36-026, Revision 1, dated July 6, 1996.

(B) If any leakage is found during the additional test of the seal, prior to further flight, replace the seal with a new,improved seal having P/N EU15969, in accordance with the Accomplishment Instructions of Fokker Service Bulletin SBF100-36-026, Revision 1, dated July 6, 1996; and inspect the fuselage skin in the applicable left- or right-hand stubwing to detect heat damage, in accordance with Part 2 of the Accomplishment Instructions of Fokker Service Bulletin SBF100-53-084, dated July 6, 1996.

(c) If any heat damage is found during the inspection required by paragraph (a) or paragraph (b)(2)(ii)(B) of this AD, prior to further flight, perform a detailed inspection of the fuselage skin and stubwing structure to detect the extent of heat damage, in accordance with Parts 4 and 5 of the Accomplishment Instructions of Fokker Service Bulletin SBF100-53-084, dated July 6, 1996; and accomplish paragraphs (c)(1) and (c)(2) of this AD.

(1) Except as provided by paragraph (g) of this AD: Repair the affected structure in accordance with Part 6 of the Accomplishment Instructions of Fokker Service Bulletin SBF100-53-084, dated July 6, 1996. And

(2) Replace all corrujoint seals having P/N BE20061 (Rolls-Royce P/N 3405891) at the 7th stage low-pressure and 12th stage high-pressure check valves of the left- and right-hand bleed air systems with new, improved corrujoint seals having P/N EU15969, in accordance with the Accomplishment Instructions of Fokker Service Bulletin SBF100-36-026, Revision 1, dated July 6, 1996.

(d) As of May 14, 1998, no person shall install a corrujoint seal having P/N BE20061 (Rolls-Royce P/N 3405891) on any airplane.

New Requirements for This AD:
(e) For Model F.28 Mark 0070 and Mark 0100 series airplanes on which Fokker Proforma Service Bulletin SBF100-36-027, including Appendix I, both dated March 21, 1997, has not been accomplished: Perform a visual inspection of the fuselage skin in the left- and right-hand stubwings to detect heat damage, in accordance with the Accomplishment Instructions of Fokker Service Bulletin SBF100-53-087, datedNovember 17, 1997, at the latest of the times specified in paragraphs (e)(1), (e)(2), and (e)(3) of this AD, as applicable. Repeat the inspection required by paragraph (e) of this AD thereafter at intervals not to exceed 6,000 landings.

(1) Within 6,000 landings after the effective date of this AD.

(2) Within 6 months after the effective date of this AD.

(3) Within 6,000 landings after accomplishment of the inspection required by paragraph (a) of this AD.

(f) If any heat damage is detected during any inspection required by paragraph (e) of this AD, prior to further flight, perform a detailed visual inspection to determine the extent of heat damage, in accordance with paragraph 2.B.(2) of the Accomplishment Instructions of Fokker Service Bulletin SBF100-53-087, dated November 17, 1997. Except as provided by paragraph (g) of this AD, prior to further flight, repair in accordance with the service bulletin.

NOTE 2: Fokker Service Bulletin SBF100-53-087, dated November 17, 1997, refers to Fokker Service Bulletin SBF100-53-084, dated July 6, 1996, as an additional source of service information for the detailed inspection procedures, repair limits, and repair procedures.

(g) If any damage is found during accomplishment of any action specified by paragraph (c)(1) or (f) of this AD, and Fokker Service Bulletin SBF100-53-084, dated July 6, 1996, or Fokker Service Bulletin SBF100-53-087, dated November 17, 1997, specifies to contact the manufacturer for an appropriate action: Prior to further flight, repair in accordance with a method approved by the Manager, International Branch, ANM-116, FAA, Transport Airplane Directorate; or the RLD (or its delegated agent).

(h) Installation of new heat shields, relocation of the aft bay overheat switch, and replacement of the insulation blankets of the bleed air ducts with new, improved insulation blankets, in accordance with Fokker Proforma Service Bulletin SBF100-36-027, including Appendix I, both dated March 21, 1997, constitutes terminating action for the repetitive inspection requirements of paragraph (e) of this AD.

Alternative Method of Compliance
(i) (1) 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, International Branch, ANM-116. Operators shall submit their requests through an appropriate FAA Principal Maintenance Inspector, who may add comments and then send it to the Manager, International Branch, ANM-116.

(2) Alternative methods of compliance, approved previously in accordance with AD 98-08-01, amendment 39-10450, are approved as alternative methods of compliance with paragraphs (a), (b), and (c) of this AD.

(3) Airplanes repaired in accordance with alternative methods of compliance, approved previously in accordance with AD 98-08-01, amendment 39-10450, are not considered exempt from the repetitive inspection requirements of paragraph(e) of this AD.

NOTE 3: Information concerning the existence of approved alternative methods of compliance with this AD, if any, may be obtained from the International Branch, ANM-116.

Special Flight Permits
(j) 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.

Incorporation by Reference
(k) Except for the actions specified in paragraphs (g) and (h) of this AD, the actions shall be done in accordance with Fokker Service Bulletin SBF100-53-084, dated July 6, 1996; Fokker Service Bulletin SBF100-36-026, Revision 1, dated July 6, 1996; or Fokker Service Bulletin SBF100-53-087, dated November 17, 1997. The terminating action specified in paragraph (h) of this AD, if accomplished, shall be accomplished in accordance with Fokker Proforma Service Bulletin SBF100-36-027, including Appendix I, both dated March 21, 1997.

(1) The incorporation by reference of Fokker Service Bulletin SBF100-53-087, dated November 17, 1997; and Fokker Proforma Service Bulletin SBF100-36-027, including Apprendix I, both dated March 21, 1997; is approved by the Director of the Federal Register in accordance with 5 U.S.C. 552(a) and 1 CFR part 51.

(2) The incorporation by reference of Fokker Service Bulletin SBF100-53-084, dated July 6, 1996; and Fokker Service Bulletin SBF100-36-026, Revision 1, dated July 6, 1996; was approved previously by the Director of the Federal Register as of May 14, 1998 (63 FR 17318, April 9, 1998).

(3) Copies may be obtained from Fokker Services B.V., Technical Support Department, P.O. Box 75047, 1117 ZN Schiphol Airport, the Netherlands. 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.NOTE 4: The subject of this AD is addressed in Dutch airworthiness directive 1995-076/3 (A), dated November 28, 1997.

(l) This amendment becomes effective on June 8, 1999.

A proposal to amend part 39 of the Federal Aviation Regulations (14 CFR part 39) by superseding AD 98-08-01, amendment 39 -10450 (63 FR 17318, April 9, 1998), which is applicable to certain Fokker Model F.28 Mark 0070 and Mark 0100 series airplanes, was published in the Federal Register on November 10, 1998 (63 FR 62970). The action proposed to continue to require a one-time visual inspection to detect heat damage of the fuselage skin and stubwing structure; either repetitive leak tests of the seals of the bleed air system or repair of any heat-damaged structure, as necessary; and replacement of corrujoint seals with new, improved seals. Additionally, that action proposed to require repetitive inspections of the fuselage skin and stubwing connection angles to detect heat damage, and an additional detailed inspection of the fuselage and stubwing structure and repair when heat damage is detected. That action also proposed to provide for a new optional terminating action for the repetitive inspections.

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 proposal.

Request to Delay Requiring Repetitive Testing
One commenter, an airline operator, requests that data derived from the initial inspection mandated by AD 98-08-01, which has a May 1999 compliance time, be analyzed before a decision is made in regard to the need for additional testing.

The commenter states that it has no objection to accomplishing the repetitive inspections specified in the proposal, if they are required. However, the commenter contends that mandating those repetitive inspections at this time would be acting prematurely, since all data from the initial inspections are not available to analyze.

The FAA does not concur with the commenter's request to delay requiring repetitive inspections. The Rijksluchtvaartdienst (RLD), which is the airworthiness authority for the Netherlands, advised the FAA that a sufficient number of operators have already accomplished the one-time inspection described in Fokker Service Bulletin SBF100-53-084, dated July 6, 1996 (the referenced source of service information in the proposal and AD 98-08-01). Consequently, the RLD included requirements for repetitive inspections in Revision 3 of the Dutch airworthiness directive BLA 1995-076/3 (A), dated November 28, 1997, to ensure continued airworthiness. That revision is referenced in this AD.

Therefore, the FAA has determined that the repetitive inspections required by this AD are necessary in order to adequately address the identified unsafe condition. However, as specified in paragraph (h) of this AD, operators have the option of modifying the airplane in accordance with Fokker Proforma Service Bulletin F100-36-027, dated March 21, 1997, which would provide terminating actionfor the repetitive inspection requirements of this AD.

Conclusion
After careful review of the available data, including the comments noted above, the FAA has determined that air safety and the public interest require the adoption of the rule as proposed.

Cost Impact
There are approximately 141 Fokker Model F.28 Mark 0070 and Mark 0100 series airplanes of U.S. registry that will be affected by this AD.

The one-time visual inspection that is currently required by AD 98-08-01, and retained in this AD, takes approximately 3 work hours per airplane to accomplish, at an average labor rate of $60 per work hour. Based on these figures, the cost impact of the one-time inspection requirement of this AD on U.S. operators is estimated to be $180 per airplane.

The seal replacement that is currently required by AD 98-08-01, and retained in this AD, takes approximately 7 work hours per airplane to accomplish, at an average labor rate of $60 per work hour. Required parts costapproximately $80 per airplane. Based on these figures, the cost impact of the seal replacement requirement of this AD on U.S. operators is estimated to be $500 per airplane.

The new actions that are required by this new AD will take approximately 3 work hours per airplane to accomplish, at an average labor rate of $60 per work hour. Based on these figures, the cost impact of the new requirements of this AD on U.S. operators is estimated to be $25,380, or $180 per airplane, per inspection cycle.

The cost impact figures discussed above are 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 Subjects in 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 removing amendment 39-10450 (63 FR 17318, April 9, 1998), and by adding a new airworthiness directive (AD), amendment 39-11151, to read as follows: