AD 94-05-02

This amendment adopts a new airworthiness directive (AD), applicable to certain Fokker Model F-28 series airplanes, that requires the implementation of a corrosion prevention and control program either by accomplishing specific tasks or by revising the maintenance inspection program to include such a program. This amendment is prompted by reports of incidents involving corrosion and fatigue cracking in transport category airplanes that are approaching or have exceeded their economic design goal; these incidents have jeopardized the airworthiness of the affected airplanes. The actions specified by this AD are intended to prevent degradation of the structural capabilities of the airplane due to the problems associated with corrosion.

Final rule

94-05-02 FOKKER: Amendment 39-8840. Docket 93-NM-77-AD.
Applicability: Model F-28 Mark 1000, MK 2000, MK 3000, and MK 4000 series airplanes (does not include
Model MK 0100 series airplanes), certificated in any category.

Compliance: Required as indicated, unless accomplished previously.

NOTE 1: This AD references Fokker Document SE-253, "F-28 Corrosion Control Program," including all revisions through September 15, 1992, (hereafter referred to as "the Document"), for basic tasks, definitions of corrosion levels, compliance times, and reporting requirements. In addition, this AD specifies inspection and reporting requirements beyond those included in the Document. Where there are differences between the AD and the Document, the AD prevails.

NOTE 2: As used throughout this AD, the term "the FAA" is defined differently for different operators, as follows: For those operators complying with paragraph (a) of this AD, "the FAA" is defined as "the Manager of the Standardization Branch, ANM-113, FAA, Transport Airplane Directorate." For those operators operating under Federal Aviation Regulation (FAR) Part 121 or 129, and complying with paragraph (b) of this AD, "the FAA" is defined as "the cognizant Principal Maintenance Inspector (PMI)." For those operators operating under FAR Part 91 or 125, and complying with paragraph (b) of this AD, "the FAA" is defined as "the cognizant Maintenance Inspector at the appropriate FAA Flight Standards office."

NOTE 3: The FAA recommends that priority for implementing the corrosion prevention and control program, specified in this AD, be given to older aircraft and areas requiring a significant upgrade of previous maintenance procedures to meet the program requirements.

To preclude degradation of the structural capabilities of the airplane due to the problems associated with corrosion, accomplish the following:

(a) Except as provided in paragraph (b) of this AD, complete each of the basictasks specified in Section 2.4 of the Document in accordance with the procedures of the Document and the schedule specified in paragraphs (a)(1) and (a)(2) of this AD.

NOTE 4: A "basic task," as defined in Section 2.4 of the Document, includes inspections; procedures for a corrective action, including repairs, under identified circumstances; application of sealants or corrosion inhibitors; and other follow-on actions.

NOTE 5: Airplane "areas" are those items listed in columnar form in the "ACTION" statement of each task, as listed in the Document.

NOTE 6: Basic tasks completed in accordance with the Document before the effective date of this AD may be credited for compliance with the initial basic task requirements of paragraph (a)(1) of this AD.

NOTE 7: Where non-destructive inspection (NDI) methods are employed, in accordance with Section 2.4 of the Document, the standards and procedures used must be acceptable to the Administrator in accordance with FAR Section 43.13.

(1) Complete the initial basic task of each aircraft zone specified in Section 2.4 of the Document as follows:

(i) For airplane areas that have not yet exceeded the "Initial Inspection Time (IIT)" for a basic task as of one year after the effective date of this AD: Initial compliance must occur no later than the IIT, or no later than one Repeat Inspection Time (RIT) interval measured from a date one year after the effective date of this AD, whichever occurs later.

(ii) For airplane areas that have exceeded the IIT for a particular basic task as of one year after the effective date of this AD: Initial compliance must occur within one RIT interval for that task, or within 6 years, measured from a date one year after the effective date of this AD, whichever occurs first.

(iii) Notwithstanding paragraphs (a)(1)(i) and (a)(1)(ii) of this AD, accomplish the initial basic task, for each area that exceeds the IIT for that area, at a minimum rate of one such area every two years, beginning one year after the effective date of this AD.

NOTE 8: This paragraph does not require inspection of any area that has not exceeded the IIT for that area.

NOTE 9: This minimum rate requirement may cause an undue hardship on some small operators. In those circumstances, requests for adjustments to the implementation rate will be evaluated on a case-by-case basis under the provisions of paragraph (h) of this AD.

(2) Repeat each basic task at a time interval not to exceed the RIT interval specified in the Document for that task.

(b) As an alternative to the requirements of paragraph (a) of this AD: Prior to one year after the effective date of this AD, revise the FAA-approved maintenance/inspection program to include the corrosion control program specified in the Document; or to include an equivalent program that is approved by the FAA. In all cases, the initial basic task for each airplane area must be completed in accordance with the compliance schedule specified in paragraph (a)(1) of this AD.

(1) Any operator complying with paragraph (b) of this AD may use an alternative recordkeeping method to that otherwise required by FAR Section 91.417 or Section 121.380 for the actions required by this AD, provided it is approved by the FAA and is included in a revision to the FAA-approved maintenance/inspection program.

(2) Subsequent to the accomplishment of the initial basic task, extensions of RIT intervals specified in the Document must be approved by the FAA.

(c) To accommodate unanticipated scheduling requirements, it is acceptable for an RIT interval to be increased by up to 10%, but not to exceed 6 months. The FAA must be informed, in writing, of any such extension within 30 days after such adjustment of the schedule.

(d)(1) If, as a result of any inspection conducted in accordance with paragraphs (a) or (b) of this AD, Level 3 corrosion is determined to exist in any airplane area, accomplish either paragraph (d)(1)(i) or (d)(1)(ii) within 7 days after such determination:

(i) Submit a report of that determination to the FAA and complete the basic task in the affected aircraft zones on all Model F-28 series airplanes in the operator's fleet; or

(ii) Submit to the FAA for approval one of the following:
(A) A proposed schedule for performing the basic tasks in the affected aircraft zones on the remaining Model F-28 series airplanes in the operator's fleet, which is adequate to ensure that any other Level 3 corrosion is detected in a timely manner, along with substantiating data for that schedule; or

(B) Data substantiating that the Level 3 corrosion found is an isolated occurrence.

NOTE 10: Notwithstanding the provisions of Section 2.1 of the Document, which would permit corrosion that otherwise meets the definition of Level 3 corrosion (i.e., which is determined to be a potentially urgent airworthiness concern requiring expeditious action) to be treated as Level 1 if the operator finds that it "can be attributed to an event not typical of the operator's usage of other airplanes in the same fleet," this paragraph requires that data substantiating any such finding be submitted to the FAA (ref. NOTE 2 of this AD) for approval.

(2) The FAA may impose schedules other than those proposed, upon finding that such changes are necessary to ensure that any other Level 3 corrosion is detected in a timely manner.

(3) Within the time schedule approved under paragraph (d)(1) or (d)(2) of this AD, accomplish the basic tasks in the affected aircraft zones of the remaining Model F-28 series airplanes in the operator's fleet.

(e) If, as a result of any inspection after the initial inspection conducted in accordance with paragraphs (a) or (b) of this AD, it is determined that corrosion findings exceed Level 1 in any area, within 60 days after such determination, implement a means, approved by the FAA, to reduce futurefindings of corrosion in that area to Level 1 or better.

(f) Before any operator places into service any airplane subject to the requirements of this AD, a schedule for the accomplishment of basic tasks required by this AD must be established in accordance with paragraph (f)(1) or (f)(2) of this AD, as applicable:

(1) For airplanes previously maintained in accordance with this AD, the first basic task in each aircraft zone to be performed by the new operator must be accomplished in accordance with the previous operator's schedule or with the new operator's schedule, whichever would result in the earlier accomplishment date for that task. After each basic task has been performed once, each subsequent task must be performed in
accordance with the new operator's schedule.

(2) For airplanes that have not been previously maintained in accordance with this AD, the first basic task for each aircraft zone to be performed by the new operator must be accomplished prior to further flight or in accordance with a schedule approved by the FAA.

(g) Within 7 days after the date of detection of any Level 3 corrosion, and within 3 months after the date of detection of any Level 2 corrosion, submit a report to Fokker of such findings, in accordance with Section 2.5 of the Document.

NOTE 11: Reporting to the FAA of Level 2 and Level 3 corrosion found as a result of any opportunity inspections is highly desirable.

(h) An alternative method of compliance or adjustment of the compliance time, which provides an acceptable level of safety, may be used when approved by the Manager, Standardization Branch, ANM-113, FAA, Transport Airplane Directorate. Operators shall submit their requests through the cognizant Maintenance Inspector at the appropriate FAA Flight
Standards office, who may concur or comment and then send it to the Manager, Standardization Branch, ANM-113.

NOTE 12: Information concerning the existence of approved alternative methods ofcompliance with this AD, if any, may be obtained from the Standardization Branch, ANM-113.

(i) Special flight permits may be issued in accordance with FAR 21.197 and 21.199 to operate airplanes to a base in order to comply with the requirements of this AD.

(j) Reports of inspection results required by this AD have been approved by the Office of Management and Budget (OMB) under the provisions of the Paperwork Reduction Act of 1980 (44 U.S.C. 3501 et seq.) and have been assigned OMB Control Number 2120-0056.

(k) The basic tasks shall be done in accordance with Fokker Document SE-253 "F28 Corrosion Control Program," revised through September 15, 1992, which contains the following list of effective pages:

Task Number

Page Number
Revision Level
Shown on Page
Date Shown on Page

INTRODUCTION
--
1-2, 5-8,
3
January 1, 1992

10-15, 17-19,

--
3-4, 9, 16,

20, 25
3-1
September 15, 1992
--
21-24, 26
1
January 1, 1992

CORROSION INSPECTIONS
010-00
010/01
3
January 1, 1992
020-00
020/01

030-00
030/01

040-00
040/01

050-00
050/01

100-00
100/01

110-00
110/01

120-00
120/01

120-01
120/02

130-00
130/01

130-01
130/02

140-00
140/01

140-01
140/02

150-00
150/01

160-00
160/01

200-00
200/01

250-00
250/01

250-01
250/02

250-02
250/03

250-03
250/04

270-00
270/01

280-00
280/01

290-00
290/01

290-01
290/02

290-02
290/03

290-03
290/04

290-04
290/05

300-00
300/01

300-01 Cont.
300/03

300-02
300/04

400-00
400/01

410-00
410/01

420-00
420/01

520-00
520/01

520-01
520/02
3
January 1, 1992
520-02
520/03

Task Number

Page Number
Revision Level
Shown on Page
Date Shown on Page
530-00
530/01

537-00
537/01

537-01
537/02

537-02
537/03

538-00
538/01

538-01
538/02

538-02
538/03

540-00
540/01

556-00
556/01

560-00
560/01

570-00
570/01

570-01
570/02

570-02
570/03

570-03
570/04

700-00
700/01

710-00
710/01

720-00
720/01

730-00
730/01

740-00
740/01

750-00
750/01

760-00
760/01

800-00
800/01

810-00
810/01

810-01
810/02

820-00
820/01

910-00
910/01

910-02
910/03

920-00
920/01

920-01
920/02

930-00
930/01

940-00
940/01

950-00
950/01

980-00
980/01

300-01
300/02
3-1
September 15, 1992
300-03
300/05

560-01
560/02

820-01
820/02

910-01
910/02

920-02
920/03

940-01
940/02

980-01
980/02

APPENDIX A

1-11
3
January 1, 1992
Task Number

Page Number
Revision Level
Shown on Page
Date Shown on Page

APPENDIX B

1
3-1
September15, 1992

APPENDIX C

1-3
3
January 1, 1992

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 Fokker Aircraft USA, Inc., 1199 North Fairfax Street, Alexandria, Virginia 22314. 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.

(l) This amendment becomes effective on April 7, 1994.

A proposal to amend part 39 of the Federal Aviation Regulations to include an airworthiness directive (AD) that is applicable to certain Fokker Model F-28 series airplanes was published as a supplemental notice of proposed rulemaking (NPRM) in the Federal Register on November 9, 1993 (58 FR 59418). That action proposed to require the implementation of a corrosion prevention and control program either by accomplishing specific tasks or by revising the maintenance inspection program to include such a program.

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

Both commenters support the proposed rule.

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.

The FAA estimates that 46 airplanes ofU.S. registry will be affected by this AD, that it will take an average of approximately 7 work hours per basic task to accomplish the 77 basic tasks called out in the Fokker Corrosion Prevention and Control Program (CPCP) Document; this represents a total average of 539 work hours (this figure includes not only inspection time, but access and closure time as well). The average labor rate is $55 per work hour. Based on these figures, the total cost impact of the AD on U.S. operators for the 4-year average inspection cycle is estimated to be $1,363,670, or $29,645 per airplane.

The total 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.

The FAA recognizes that the obligation to maintain aircraft in an airworthy condition is vital, but sometimes expensive. Because AD's require specific actionsto address specific unsafe conditions, they appear to impose costs that would not otherwise be borne by operators. However, because of the general obligation of operators to maintain aircraft in an airworthy condition, this appearance is deceptive. Attributing those costs solely to the issuance of this AD is unrealistic because, in the interest of maintaining safe aircraft, most prudent operators would accomplish the required actions even if they were not required to do so by the AD.

A full cost-benefit analysis has not been accomplished for this AD. As a matter of law, in order to be airworthy, an aircraft must conform to its type design and be in a condition for safe operation. The type design is approved only after the FAA makes a determination that it complies with all applicable airworthiness requirements. In adopting and maintaining those requirements, the FAA has already made the determination that they establish a level of safety that is cost- beneficial. When the FAA, as in this AD, makes a finding of an unsafe condition, this means that this cost-beneficial level of safety is no longer being achieved and that the required actions are necessary to restore that level of safety. Because this level of safety has already been determined to be cost-beneficial, a full cost-benefit analysis for this AD would be redundant and unnecessary.

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" underDOT 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 14 CFR part 39 of the Federal Aviation Regulations as follows:

PART 39 - AIRWORTHINESS DIRECTIVES
1. The authority citation for part 39 continues to read as follows:
Authority: 49 U.S.C. App. 1354(a), 1421 and 1423; 49 U.S.C. 106(g); and 14 CFR 11.89.

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