E6-8897. Airworthiness Directives; Fokker Model F.28 Mark 0070 and 0100 Airplanes

AGENCY:

Federal Aviation Administration (FAA), Department of Transportation (DOT).

ACTION:

Notice of proposed rulemaking (NPRM).

SUMMARY:

The FAA proposes to adopt a new airworthiness directive (AD) for all Fokker Model F.28 Mark 0070 and 0100 airplanes. This proposed AD would require a one-time detailed inspection to detect corrosion on the wing rear spar lower girder, and related investigative and applicable corrective actions if necessary. This proposed AD results from reports of corrosion of the wing rear spar lower girder between wing station (STA) 8700 and wing STA 9200. We are proposing this AD to detect and correct corrosion of the wing rear spar lower girder, which could result in reduced structural integrity of the wing rear spar.

DATES:

We must receive comments on this proposed AD by July 10, 2006.

ADDRESSES:

Use one of the following addresses to submit comments on this proposed AD.

• DOT Docket Web site: Go to http://dms.dot.gov and follow the instructions for sending your comments electronically.
• Government-wide rulemaking Web site: Go to http://www.regulations.gov and follow the instructions for sending your comments electronically.
• Mail: Docket Management Facility, U.S. Department of Transportation, 400 Seventh Street, SW., Nassif Building, room PL-401, Washington, DC 20590.
• Fax: [phone].
• Hand Delivery: Room PL-401 on the plaza level of the Nassif Building, 400 Seventh Street, SW., Washington, DC, between 9 a.m. and 5 p.m., Monday through Friday, except Federal holidays.

Contact Fokker Services B.V., Technical Services Dept., P.O. Box 231, 2150 AE Nieuw-Vennep, the Netherlands, for service information identified in this proposed AD.

FOR FURTHER INFORMATION CONTACT:

Tom Rodriguez, Aerospace Engineer, International Branch, ANM-116, Transport Airplane Directorate, FAA, 1601 Lind Avenue SW., Renton, WA 98055-4056; telephone [phone]; fax [phone].

SUPPLEMENTARY INFORMATION:

Comments Invited

We invite you to submit any relevant written data, views, or arguments regarding this proposed AD. Send your comments to an address listed in the ADDRESSES section. Include the docket number “FAA-2006-24959; Directorate Identifier 2005-NM-258-AD” at the beginning of your comments. We specifically invite comments on the overall regulatory, economic, environmental, and energy aspects of the proposed AD. We will consider all comments received by the closing date and may amend the proposed AD in light of those comments.

We will post all comments we receive, without change, to http://dms.dot.gov,, including any personal information you provide. We will also post a report summarizing each substantive verbal contact with FAA personnel concerning this proposed AD. Using the search function of that Web site, anyone can find and read the comments in any of our dockets, including the name of the individual who sent the comment (or signed the comment on behalf of an association, business, labor union, etc.). You may review the DOT's complete Privacy Act Statement in the Federal Register published on April 11, 2000 (65 FR 19477-78), or you may visit http://dms.dot.gov.

Examining the Docket

You may examine the AD docket on the Internet at http://dms.dot.gov,, or in person at the Docket Management Facility office between 9 a.m. and 5 p.m., Monday through Friday, except Federal holidays. The Docket Management Facility office (telephone [phone]) is located on the plaza level of the Nassif Building at the DOT street address stated in the ADDRESSES section. Comments will be available in the AD docket shortly after the Docket Management System receives them.

Discussion

The Civil Aviation Authority—The Netherlands (CAA-NL), which is the airworthiness authority for the Netherlands, notified us that an unsafe condition may exist on all Fokker Model F.28 Mark 0070 and 0100 airplanes. The CAA-NL advises that it has received reports of corrosion of the wing rear spar lower girder between wing station (STA) 8700 and wing STA 9200 on several Fokker Model F.28 Mark 0100 airplanes. The exfoliation corrosion was found when the aileron pulley assembly was removed from the airplane. In at least one case, replacement of a section of the rear spar lower girder was necessary to return the airplane back to service. This particular part of the wing is visible only through a narrow slot between the aileron pulley assembly and the rear spar, and through small lightening holes in the aileron pulley attachment bracket. Therefore, it is possible that any corrosion in this area could remain undetected during routine inspections of fuselage zones 536 and 636 done in accordance with Tasks 062505-00-01 and 062605-00-01 of the Fokker 70/100 Maintenance Review Board Document. The cause of the corrosion is unknown. Corrosion of the wing rear spar lower girder, if not corrected, could result in corrosion remaining undetected, resulting in reduced structural integrity of the wing rear spar.

The design of the wing rear spar lower girder on Fokker Model F.28 Mark 0070 airplanes is the same as on Model F.28 Mark 0100 airplanes; therefore, the unsafe condition could exist on all of these airplanes.

Relevant Service Information

Fokker Services B.V. has issued Service Bulletin SBF100-57-038, dated April 15, 2005. The service bulletin describes procedures for doing a one-time detailed inspection of the wing rear spar lower girder between STA 8700 and STA 9200 for corrosion, and related investigative and applicable corrective actions if necessary. If corrosion is found, the related investigative actions include removing the aileron pulley assembly, removing the corrosion from the wing rear spar lower girder, and measuring the depth of the damaged spots. The corrective actions include repairing the wing rear spar lower girder if the damage is outside of specified limits and repairing the surface treatment. The service bulletin also describes procedures for reporting inspection and damage findings to the manufacturer. The CAA-NL mandated the service information and issued Dutch airworthiness directive NL-2005-006, dated April 29, 2005, to ensure the continued airworthiness of these airplanes in the Netherlands.

FAA's Determination and Requirements of the Proposed AD

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 CAA-NL has kept the FAA informed of the situation described above. We have examined the CAA-NL's findings, evaluated all pertinent information, and determined that we need to issue an AD for airplanes of this type design that are certificated for operation in the United States.

Therefore, we are proposing this AD, which would require accomplishing the actions specified in the service information described previously, except as discussed under “Differences Among the Proposed AD, the Dutch Airworthiness Directive, and the Service Bulletin.” The proposed AD would also require sending the inspection results to the FAA.

Differences Among the Proposed AD, the Dutch Airworthiness Directive, and the Service Bulletin

The service bulletin specifies to contact the manufacturer for instructions on how to repair certain conditions, but this proposed AD would require repairing those conditions using a method that we or the European Aviation Safety Agency (EASA) (or its delegated agent) approve. In light of the type of repair that would be required to address the unsafe condition, and consistent with existing bilateral airworthiness agreements, we have determined that, for this proposed AD, a repair we or the EASA approve would be acceptable for compliance with this proposed AD.

The service bulletin specifies procedures to take when the damage is more than 1.3 millimeters (mm) deep and when the remaining material of the rear spar lower girder is less than 2.1 mm thick, but it does not specify what to do if the depth is exactly 1.3 mm and the thickness is exactly 2.1 mm. We have determined that, for this proposed AD, any damage found that measures more than or equal to 1.3 mm deep or when the remaining material of the rear spar lower girder is less than or equal to 2.1 mm thick, must be repaired in accordance with a method approved by us; or the EASA (or its delegated agent).

Clarification of Inspection Type

The Dutch airworthiness directive refers only to an “inspection” for corrosion of the wing rear spar lower girder. We have determined that the procedures in the service bulletin should be described—as they are in the service bulletin—as a “detailed inspection.” We have included Note 1 in this proposed AD to define this type of inspection.

Interim Action

This proposed AD is considered to be interim action. The inspection reports that would be required by this proposed AD would enable the manufacturer to obtain better insight into the nature, cause, and extent of the corrosion, and eventually to develop final action to address the unsafe condition. Once final action has been identified, we may consider further rulemaking.

Costs of Compliance

The following table provides the estimated costs for U.S. operators to comply with this proposed AD.

Estimated Costs

Action	Work hours	Average labor rate per hour	Parts	Cost per airplane	Number of U.S.-registered airplanes	Fleet cost
Inspection of wing rear spar lower girder	2	$80	$0	$160	44	$7,040

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 have determined that this proposed AD would not have federalism implications under Executive Order 13132. This proposed AD would 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 that the 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. 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 proposed AD and placed it in the AD docket. See the ADDRESSES section for a location to examine the regulatory evaluation.

List of Subjects in 14 CFR Part 39

• Air transportation
• Aircraft
• Aviation safety
• Safety

The Proposed Amendment

Accordingly, under the authority delegated to me by the Administrator, the FAA proposes to amend 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. The Federal Aviation Administration (FAA) amends § 39.13 by adding the following new airworthiness directive (AD):

Fokker Services B.V.: Docket No. FAA-2006-24959; Directorate Identifier 2005-NM-258-AD.

Comments Due Date

(a) The FAA must receive comments on this AD action by July 10, 2006.

Affected ADs

(b) None.

Applicability

(c) This AD applies to all Fokker Model F.28 Mark 0070 and 0100 airplanes, certificated in any category.

Unsafe Condition

(d) This AD results from reports of corrosion of the wing rear spar lower girder between wing station (STA) 8700 and wing STA 9200. We are issuing this AD to detect and correct corrosion of the wing rear spar lower girder, which, if not detected, could result in reduced structural integrity of the wing rear spar.

Compliance

(e) You are responsible for having the actions required by this AD performed within the compliance times specified, unless the actions have already been done.

Wing Rear Spar Lower Girder Inspection/Related Investigative/Corrective Actions

(f) Within 4,000 flight hours or 21 months after the effective date of this AD, whichever occurs first: Do a detailed inspection to detect corrosion on the wing rear spar lower girder between wing STA 8700 and wing STA 9200, and do all related investigative and applicable corrective actions by accomplishing all the actions specified in the Accomplishment Instructions of Fokker Service Bulletin SBF100-57-038, dated April 15, 2005, except as provided by paragraphs (g) and (h) of this AD. Do all related investigative and corrective actions before further flight. If any damage found that measures more than or equal to 1.3 millimeters (mm) deep, or if the thickness of the remaining material of the rear spar lower girder is less than or equal to 2.1 mm thick, repair in accordance with a method approved by the Manager, International Branch, ANM-116, Transport Airplane Directorate, FAA; or the European Aviation Safety Agency (EASA) (or its delegated agent).

Note 1:

For the purposes of this AD, a detailed inspection is: “An intensive examination of a specific item, installation, or assembly to detect damage, failure, or irregularity. Available lighting is normally supplemented with a direct source of good lighting at an intensity deemed appropriate. Inspection aids such as mirror, magnifying lenses, etc., may be necessary. Surface cleaning and elaborate procedures may be required.”

(g) If, during the accomplishment of the corrective actions required by paragraph (f) of this AD, the service bulletin specifies contacting the manufacturer for certain repair instructions: Before further flight, repair in accordance with a method approved by the Manager, International Branch, ANM-116; or the EASA (or its delegated agent).

Reporting Inspection and Damage Results

(h) Submit a report of the findings (both positive and negative) of the inspection required by paragraph (f) of this AD to Fokker Services B.V., Technical Services Dept., P.O. Box 231, 2150 AE Nieuw-Vennep, the Netherlands; fax [phone]; e-mail [e-mail]; at the applicable time specified in paragraph (h)(1) or (h)(2) of this AD. Use the reporting forms in Figures 3 and 4 of Fokker Service Bulletin SBF100-57-038, dated April 15, 2005. Under the provisions of the Paperwork Reduction Act of 1980 (44 U.S.C. 3501 et seq.), the Office of Management and Budget (OMB) has approved the information collection requirements contained in this AD and has assigned OMB Control Number 2120-0056.

(1) If the inspection was done after the effective date of this AD: Submit the report within 30 days after the inspection.

(2) If the inspection was done before the effective date of this AD: Submit the report within 30 days after the effective date of this AD.

Alternative Methods of Compliance (AMOCs)

(i)(1) The Manager, International Branch, ANM-116, has the authority to approve AMOCs for this AD, if requested in accordance with the procedures found in 14 CFR 39.19.

(2) Before using any AMOC approved in accordance with § 39.19 on any airplane to which the AMOC applies, notify the appropriate principal inspector in the FAA Flight Standards Certificate Holding District Office.

Related Information

(j) Dutch airworthiness directive NL-2005-006, dated April 29, 2005, also addresses the subject of this AD.

Issued in Renton, Washington, on May 30, 2006.

Jeffrey E. Duven,

Acting Manager, Transport Airplane Directorate, Aircraft Certification Service.