Airworthiness directives: Fokker,

[Federal Register: November 10, 1998 (Volume 63, Number 217)]

[Proposed Rules]

[Page 62970-62973]

From the Federal Register Online via GPO Access [wais.access.gpo.gov]

[DOCID:fr10no98-27]

DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 98-NM-202-AD]

RIN 2120-AA64

Airworthiness Directives; Fokker Model F.28 Mark 0070 and Mark 0100 Series Airplanes

AGENCY: Federal Aviation Administration, DOT.

ACTION: Notice of proposed rulemaking (NPRM).

SUMMARY: This document proposes the supersedure of 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 action would add a requirement for repetitive inspections for heat damage of the subject area, and would provide for a new optional terminating action for the repetitive inspections. This proposal is prompted by issuance of mandatory continuing airworthiness information by a foreign civil airworthiness authority. The actions specified by the proposed 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 the airplane.

DATES: Comments must be received by December 10, 1998.

ADDRESSES: Submit comments in triplicate to the Federal Aviation Administration (FAA), Transport Airplane Directorate, ANM-114, Attention: Rules Docket No. 98-NM-202-AD, 1601 Lind Avenue, SW., Renton, Washington 98055-4056. Comments may be inspected at this location between 9:00 a.m. and 3:00 p.m., Monday through Friday, except Federal holidays.

The service information referenced in the proposed rule may be obtained from Fokker Services B.V., Technical Support Department, P.O. Box 75047, 1117 ZN Schiphol Airport, the Netherlands. This information may be examined at the FAA, Transport Airplane Directorate, 1601 Lind Avenue, SW., Renton, Washington.

FOR FURTHER INFORMATION CONTACT: Norman B. Martenson, Manager, International Branch, ANM-116, FAA, Transport Airplane Directorate, 1601 Lind Avenue, SW., Renton, Washington 98055-4056; telephone (425) 227-2110; fax (425) 227-1149.

SUPPLEMENTARY INFORMATION:

Comments Invited

Interested persons are invited to participate in the making of the proposed rule by submitting such written data, views, or arguments as they may desire. Communications shall identify the Rules Docket number and be submitted in triplicate to the address specified above. All communications received on or before the closing date for comments, specified above, will be considered before taking action on the proposed rule. The proposals contained in this notice may be changed in light of the comments received.

Comments are specifically invited on the overall regulatory, economic, environmental, and energy aspects of the proposed rule. All comments submitted will be available, both before and after the closing date for comments, in the Rules Docket for examination by interested persons. A report summarizing each FAA-public contact concerned with the substance of this proposal will be filedin the Rules Docket.

Commenters wishing the FAA to acknowledge receipt of their comments submitted in response to this notice must submit a self-addressed, stamped postcard on which the following statement is made: ``Comments to

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Docket Number 98-NM-202-AD.'' The postcard will be date stamped and returned to the commenter.

Availability of NPRMs

Any person may obtain a copy of this NPRM by submitting a request to the FAA, Transport Airplane Directorate, ANM-114, Attention: Rules Docket No. 98-NM-202-AD, 1601 Lind Avenue, SW., Renton, Washington 98055-4056.

Discussion

On March 31, 1998, the FAA issued AD 98-08-01, amendment 39-10450 (63 FR 17318, April 9, 1998), applicable to certain Fokker Model F.28 Mark 0070 and Mark 0100 series airplanes. That AD requires 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 eventual replacement of corrujoint seals with new, improved seals. That action was prompted by the issuance of mandatory continuing airworthiness information by a foreign civil airworthiness authority. The requirements of that AD are intended to prevent the leakage of hot air from the corrujoint seals of the low- and high-pressure check valves located in the stubwings, which could result in heat damage to the fuselage skin and stubwing structure, and consequent reduced structural integrity of the airplane.

Actions Since Issuance of Previous Rule

Since the issuance of that AD, the Rijksluchtvaartdienst (RLD), which is the airworthiness authority for the Netherlands, has advised the FAA that the unsafe condition addressed in AD 98-08-01 may exist or develop on certain Fokker Model F.28 Mark 0070 and Mark 0100 series airplanes despite compliance with the requirements of that AD. Based on the results of the one-time visual inspection (required by AD 98-08- 01), the manufacturer has recommended, and the RLD has mandated, that a visual inspection be repeated at specified intervals to detect heat damage of the fuselage skin and stubwing connection angles in the stubwing area.

Explanation of Relevant Service Information

Fokker has issued Service Bulletin SBF100-53-087, dated November 17, 1997, which describes procedures for repetitive visual inspections to detect heat damage of the fuselage skin and stubwing connection angles in the stubwing area. This service bulletin also describes procedures for an additional detailed inspection of the fuselage skin and stubwing structure, and repair when overheat damage is detected. Accomplishment of the actions specified in Fokker Service Bulletin SBF100-53-087 is intended to adequately address the identified unsafe condition. The RLD classified Fokker Service Bulletin SBF100-53-087 as mandatory and issued Dutch airworthiness directive 1995-076/3 (A), dated November 28, 1997, in order to assure the continued airworthiness of these airplanes in the Netherlands.

Fokker also has issued Proforma Service Bulletin SBF100-36-027, including Appendix I, both dated March 21, 1997, which describes procedures for modification of the fuselage skin and stubwing structure to improve heat protection. The modification involves installing new heat shields on the fuselage skin, relocating the aft bay overheat switch, and replacing insulation blankets of the bleed air ducts with new, improved insulation blankets. This service bulletin specifies that accomplishment of the modification would eliminate the need for the repetitive inspections described in Fokker Service Bulletin SBF100-53- 087. The RLD has approved Fokker Service Bulletin SBF100-36-027 and classified it as optional.

FAA's Conclusions

These airplane models are manufactured in the Netherlands and are type certificated for operation in the United States under the provisions of section 21.29 of the Federal Aviation Regulations (14 CFR 21.29) and the applicable bilateral airworthiness agreement. Pursuant to this bilateral airworthiness agreement, the RLD has kept the FAA informed of the situation described above. The FAA has examined the findings of the RLD, reviewed all available information, and determined that AD action is necessary for products of this type design that are certificated for operation in the United States.

Explanation of Requirements of Proposed Rule

Since an unsafe condition has been identified that is likely to exist or develop on other airplanes of the same type design registered in the United States, the proposed AD would supersede AD 98-08-01, amendment 39-10450 (63 FR 17318, April 9, 1998), 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, this proposal would 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. This proposal also would provide for a new optional terminating action for the repetitive inspections.

FAA's Determination

Operators should note that, in consonance with the findings of the RLD, the FAA has determined that the repetitive inspections proposed by this AD can be allowed to continue in lieu of accomplishment of a terminating action. In making this determination, the FAA considers that, in this case, long-term continued operational safety will be adequately assured by accomplishing the repetitive inspections to detect heat damage to the fuselage skin and stubwing structure before the damage represents a hazard to the airplane.

Difference Between Proposed Rule and Relevant Service Information

Operators should note that Fokker Service Bulletin SBF100-53-087 specifies that heat damage of the fuselage skin should be repaired in accordance with Fokker Service Bulletin SBF100-53-084, dated July 6, 1996, which describes procedures for certain repairs of heat damage, and recommends that the manufacturer may be contacted for disposition of other repairs. This proposal would require such other repairs to be accomplished in accordance with a method approved by either the FAA or the RLD (or its delegated agent). In light of the type of repair that would be required to address the identified unsafe condition, and in consonance with existing bilateral airworthiness agreements, the FAA has determined that, for this proposed AD, a repair approved by either the FAA or the RLD would be acceptable for compliance with this proposed AD.

Explanation of Changes Made to Applicability

Operators should note that the applicability of the proposed AD differs from the applicability of AD 98-08-01 in that it excludes those airplanes on which Fokker Proforma Service Bulletin SBF100-36-027 has been accomplished. The FAA has determined that accomplishment of the actions described in that service bulletin would terminate the requirements of the new repetitive visual inspections of the

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fuselage skin in the left- and right-hand stubwings.

Cost Impact

The FAA estimates that 141 airplanes of U.S. registry would be affected by this proposed AD.

The one-time visual inspection that was previously 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 was previously 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 cost approximately $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 repetitive inspections proposed by this AD would 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 repetitive inspections proposed by 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 current or proposed 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 proposed herein would 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 proposal would not have sufficient federalism implications to warrant the preparation of a Federalism Assessment.

For the reasons discussed above, I certify that this proposed regulation (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) if promulgated, 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 copy of the draft regulatory evaluation prepared for this action is contained in the Rules Docket. A copy of it may be obtained by contacting the Rules Docket at the location provided under the caption ADDRESSES.

List of Subjects in 14 CFR Part 39

Air transportation, Aircraft, Aviation safety, Safety.

The Proposed Amendment

Accordingly, pursuant to the authority delegated to me by the Administrator, the Federal Aviation Administration proposes to amend 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.

    Sec. 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), to read as follows:

    Fokker Services B.V.: 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 1, 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 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 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

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    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 1, 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, dated November 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.

    (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.

    (i)(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.

    (i)(3) Airplanes repaired in accordance with alternative methods of compliance, approved previously in accordance with AD 98-08-01, 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.

    (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.

    Note 4: The subject of this AD is addressed in Dutch airworthiness directive 1995-076/3 (A), dated November 28, 1997.

    Issued in Renton, Washington, on November 3, 1998. Vi L. Lipski, Acting Manager, Transport Airplane Directorate, Aircraft Certification Service.

    [FR Doc. 98-30052Filed11-9-98; 8:45 am]

    BILLING CODE 4910-13-P

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