Airworthiness directives: Fokker,

[Federal Register: August 13, 1998 (Volume 63, Number 156)]

[Proposed Rules]

[Page 43342-43345]

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

[DOCID:fr13au98-24]

DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 98-NM-92-AD]

RIN 2120-AA64

Airworthiness Directives; Fokker Model F27 Mark 050, 100, 200, 300, 400, 500, 600, and 700 Rough Field Version (RFV) Series Airplanes

AGENCY: Federal Aviation Administration, DOT.

ACTION: Notice of proposed rulemaking (NPRM).

[[Page 43343]]

SUMMARY: This document proposes the supersedure of an existing airworthiness directive (AD), applicable to certain Fokker Model F27 Mark 100, 200, 300, 400, 500, 600, and 700 Rough Field Version (RFV) series airplanes, that currently requires inspection of the main landing gear (MLG) legs to determine if parts are missing or damaged, and modification, if necessary; and periodic measurements of the extension of each MLG shock absorber sliding member. That AD also provides for the accomplishment of a certain modification as optional terminating action for the periodic measurements. This action would require accomplishment of the previously optional terminating action. This action also would revise the applicability of the existing AD to add an airplane model. 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 loss of the MLG sliding member, which could result in reduced structural integrity of the MLG.

DATES: Comments must be received by September 14, 1998.

ADDRESSES: Submit comments in triplicate to the Federal Aviation Administration (FAA), Transport Airplane Directorate, ANM-114, Attention: Rules Docket No. 98-NM-92-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 Docket Number 98-NM-92-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-92-AD, 1601 Lind Avenue, SW., Renton, Washington 98055-4056.

Discussion

On October 28, 1993, the FAA issued AD 93-22-02, amendment 39-8727 (58 FR 60370, November 16, 1993), applicable to certain Fokker Model F27 Mark 100, 200, 300, 400, 500, 600, and 700 Rough Field Version (RFV) series airplanes, to require inspection of the main landing gear (MLG) legs to determine if parts are missing or damaged, and modification, if necessary; and periodic measurements of the extension of each MLG shock absorber sliding member. That AD also provides for the accomplishment of a certain modification as optional terminating action for the periodic measurements. That AD was prompted by reports of overextension of the MLG sliding member due to missing parts in the MLG leg assembly. The requirements of that AD are intended to prevent loss of the MLG sliding member, which could result in reduced structural integrity of the MLG.

Actions Since Issuance of Previous Rule

Since the issuance of that AD, the Rijksluchtvaartdienst (RLD), which is the airworthiness authority for the Netherlands, notified the FAA that it received a report indicating that, during routine maintenance on an in-service Fokker Model F27 Mark 050 series airplane, maintenance personnel discovered a dowel and a castellation missing from an MLG assembly. Further investigation revealed that the inspections of the MLG legs to determine if parts are missing or damaged, as specified in Fokker Service Bulletin F50-32-025 (Messier- Dowty Service Bulletin F50-32-48), had been accomplished previously on the airplane.

Further, the RLD advised the FAA that modification of the MLG assembly should be accomplished to ensure correct assembly of the piston rod. Therefore, the FAA has determined that this modification (which was specified as optional in AD 93-22-02) is necessary in order to positively address the identified unsafe condition..

Additionally, in AD 93-22-02, the FAA referenced the applicability as ``Fokker Model F27 Rough Field Version (RFV) series airplanes, excluding Model F27 Mark 050 series airplanes.'' However, the FAA has determined that the applicability of the existing AD should be clarified by specifying that it applies to Fokker Model F27 Mark 100, 200, 300, 400, 500, 600, and 700 Rough Field Version (RFV) series airplanes. In addition, the FAA finds that Fokker Model F27 Mark 050 series airplanes also are subject to the identified unsafe condition; therefore, those airplanes are specified in the applicability of this proposed AD.

Explanation of Relevant Service Information

The manufacturer of the landing gear has issued Messier-Dowty Service Bulletin F50-32-48, Revision 4, dated June 21, 1995 (for Model F27 Mark 050 series airplanes), which describes detailed procedures for inspecting the MLG piston rod and adapter to confirm the correct installation of the stepped pin and dowel. It also describes procedures for periodic measurements of the extension of the MLG sliding member when the landing gear is fully extended.

The manufacturer of the landing gear also has issued Dowty Aerospace Landing Gear Service Bulletin F50-32-27, Revision 4, dated December 18, 1992 (for Model F27 Mark 050 series airplanes), which describes procedures for modification of the MLG piston rod assembly. This modification involves the installation of a shim between the contact face of the piston rod and adapter, and the installation of a pin in lieu of the currently installed dowel to secure the castellated nut to the adapter.

[[Page 43344]]

Accomplishment of the modification would eliminate the need for inspections and periodic measurements of the extension of the MLG shock absorber sliding member.

For Model F27 Mark 100, 200, 300, 400, 500, 600, and 700 series airplanes, Fokker has issued Service Bulletin F27-32-165, Revision 1, dated April 28, 1993; and the manufacture of the landing gear has issued Dowty Aerospace Landing Gear Service Bulletin 32-81W, Revision 2, dated February 3, 1993, and Dowty Aerospace Landing Gear Service Bulletin 32-77W, Revision 4, dated February 3, 1993. As described in AD 93-22-02, these service bulletins inspection of the MLG legs to determine if parts are missing or damaged, and modification, if necessary; and periodic measurements of each MLG shock absorber sliding member. Further, Dowty Aerospace Landing Gear Service Bulletin 32-77W describes procedures for modification of the MLG assembly, which would eliminate the need for the inspections and periodic measurements discussed previously.

Accomplishment of the actions specified in the service bulletins is intended to adequately address the identified unsafe condition. The RLD classified these service bulletins as mandatory and issued Dutch airworthiness directive 1996-159/2 (A), dated July 31, 1997, in order to assure the continued airworthiness of these airplanes in the Netherlands.

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 93-22-02 to continue to require inspection of the MLG legs to determine if parts are missing or damaged, and modification, if necessary; and periodic measurements of the extension of each MLG shock absorber sliding member. In addition, this proposed AD also would require accomplishment of the previously optional terminating action and would revise the applicability of the existing AD to add an airplane model.

The actions would be required to be accomplished in accordance with the service bulletins described previously.

Cost Impact

There are approximately 34 Fokker Model F27 Mark 100, 200, 300, 400, 500, 600, and 700 RFV series airplanes, and no Fokker Model F27 Mark 050 series airplanes, of U.S. registry that would be affected by this proposed AD.

The actions that are currently required by AD 93-22-02, and retained in this proposed 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 currently required inspections on U.S. operators is estimated to be $6,120, or $180 per airplane, per inspection cycle.

The new modification that is proposed in this AD action would take approximately 2 work hours per airplane to accomplish, at an average labor rate of $60 per work hour. Required parts would be supplied by the manufacturer at no cost to the operators. Based on these figures, the cost impact of the modification proposed by this AD on U.S. operators is estimated to be $4,080, or $120 per airplane.

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 39-8727 (58 FR 60370, November 16, 1993), and by adding a new airworthiness directive (AD), to read as follows:

   Fokker Services B.V.: Docket 98-NM-92-AD. Supersedes AD 93-22-02, Amendment 39-8727.

   Applicability: Model F27 Mark 050, 100, 200, 300, 400, 500, 600, and 700 Rough Field Version (RFV) series airplanes, equipped with Dowty Aerospace MLG Legs, part and serial numbers as listed in Dowty Aerospace Landing Gear Service Bulletin 32-77W, Revision 4, dated February 3, 1993, or Dowty Aerospace Landing Gear Service Bulletin F50-32-27, Revision 4, dated December 18, 1992; certificated in any category.

   Note 1: This AD applies to each airplane identified in the preceding applicability provision, regardless of whether it has been 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 (g) 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 loss of the MLG sliding member, which could result in reduced

   [[Page 43345]]

   structural integrity of the MLG, accomplish the following:

   Restatement of Requirements of AD 93-22-02

   (a) For Model F27 Mark 100, 200, 300, 400, 500, 600, and 700 RFV series airplanes, equipped with Dowty Aerospace MLG, part numbers 200563001, 200679001, 200679002, 200679003, or 200679004: Within 30 days after December 16, 1993 (the effective date of AD 93-22-02, amendment 39-8727), inspect the MLG legs to confirm the correct installation of the sliding member out-stop installation, in accordance with Fokker Service Bulletin F27-32-165, Revision 1, dated April 28, 1993, and paragraph 2.C. (``Part A Procedure'') of Dowty Aerospace Landing Gear Service Bulletin 32-81W, Revision 2, dated February 3, 1993. If any parts are determined to be missing or damaged, prior to further flight, modify the MLG assembly, in accordance with Dowty Aerospace Landing Gear Service Bulletin 32- 77W, Revision 4, dated February 3, 1993.

   (b) For Model F27 Mark 100, 200, 300, 400, 500, 600, and 700 RFV series airplanes, equipped with Dowty Aerospace MLG, part numbers 200563001, 200679001, 200679002, 200679003, or 200679004: Within 30 days after December 16, 1993, measure and record the extension of the MLG sliding member when the landing gear is fully extended, in accordance with paragraph 2.D. (``Part B Procedure'') of Dowty Aerospace Landing Gear Service Bulletin 32-81W, Revision 2, dated February 3, 1993.

   (1) If the extension dimension exceeds 410.2 mm (16.15 inches), prior to further flight, modify the MLG assembly in accordance with Dowty Aerospace Landing Gear Service Bulletin 32-77W, Revision 4, dated February 3, 1993.

   (2) If the extension dimension is equal to or less than 410.2 mm (16.15 inches), repeat the measurement thereafter at intervals not to exceed 500 flight cycles.

   (3) If the extension dimension increases by more than 1.0 mm (0.40 inch) above the initially recorded dimension during any measurement required by this paragraph, prior to further flight, inspect the MLG in accordance with paragraph (a) of this AD.

   New Requirements of This AD

   (c) For airplanes other than those identified in paragraph (a) of this AD: Within 30 days after the effective date of this AD, inspect the MLG legs to confirm the correct installation of the sliding member out-stop installation, in accordance with paragraph 2.C. (``Part A Procedure'') of Messier-Dowty Service Bulletin F50- 32-48, Revision 4, dated June 21, 1995. If any parts are determined to be missing or damaged, prior to further flight, modify the MLG assembly, in accordance with Dowty Aerospace Landing Gear Service Bulletin F50-32-27, Revision 4, dated December 18, 1992.

   (d) For airplanes other than those identified in paragraph (a) of this AD: Within 30 days after the effective date of this AD, measure and record the extension of the MLG sliding member when the landing gear is fully extended, in accordance with paragraph 2.D. (``Part B Procedure'') of Messier-Dowty Service Bulletin F50-32-48, Revision 4, dated June 21, 1995.

   (1) If the extension dimension exceeds 410.2 mm (16.15 inches), prior to further flight, modify the MLG assembly in accordance with Dowty Aerospace Landing Gear Service Bulletin F50-32-27, Revision 4, dated December 18, 1992.

   (2) If the extension dimension is equal to or less than 410.2 mm (16.15 inches), repeat the measurement thereafter at intervals not to exceed 500 flight cycles.

   (3) If the extension dimension increases by more than 1.0 mm (0.40 inch) above the initially recorded dimension during any measurement required by this paragraph, prior to further flight, inspect the MLG in accordance with paragraph (c) of this AD.

   (e) For all airplanes: Within 5,000 flight cycles or 24 months after the effective date of this AD, whichever occurs earlier, modify the MLG piston rod assembly, in accordance with Dowty Aerospace Landing Gear Service Bulletin 32-77W, Revision 4, dated February 3, 1993 (for Model F27 Mark 100, 200, 300, 400, 500, 600, and 700 series airplanes), or Dowty Aerospace Landing Gear Service Bulletin F50-32-27, Revision 4, dated December 18, 1992 (for Model F27 Mark 050 series airplanes), as applicable. Accomplishment of this modification constitutes terminating action for the repetitive actions required by this AD.

   (f) As of the effective date of this AD, no person shall install on any airplane, an MLG piston rod assembly, unless it has been modified in accordance with Dowty Aerospace Landing Gear Service Bulletin 32-77W, Revision 4, dated February 3, 1993 (for Model F27 Mark 100, 200, 300, 400, 500, 600, and 700 series airplanes), or Dowty Aerospace Landing Gear Service Bulletin F50-32-27, Revision 4, dated December 18, 1992 (for Model F27 Mark 050 series airplanes), as applicable.

   (g) 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, FAA, Transport Airplane Directorate. 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.

   Note 2: Information concerning the existence of approved alternative methods of compliance with this AD, if any, may be obtained from the International Branch, ANM-116.

   (h) 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 3: The subject of this AD is addressed in Dutch airworthiness directive 1996-159/2 (A), dated July 31, 1997.

   Issued in Renton, Washington, on August 7, 1998. Darrell M. Pederson, Acting Manager, Transport Airplane Directorate, Aircraft Certification Service.

   [FR Doc. 98-21718Filed8-12-98; 8:45 am]

   BILLING CODE 4910-13-P