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###### Department of Transportation

###### Federal Aviation Administration 

          - 14 CFR Part 39 
          - [Docket No. 2000-NM-179-AD] 
          - RIN 2120-AA64 

# AGENCY:

Federal Aviation Administration, DOT. 

# ACTION:

Supplemental notice of proposed rulemaking; reopening of comment period.

# SUMMARY:

This document revises an earlier proposed airworthiness directive (AD), applicable to all BAe Systems (Operations) Limited Model BAe 146 and Model Avro 146-RJ series airplanes, that would have superseded an existing AD that currently requires a one-time inspection for “drill marks” and corrosion on the underside of the wing top skin, and corrective actions, if necessary. The proposed AD would have required a one-time inspection for “drill marks” and corrosion, and corrective actions, if necessary, per new procedures. For certain airplanes, the proposed AD would have added a requirement for one-time detailed visual and borescopic inspections of the fuel tank, pump, and stringers for paint debris and inadequacy of the existing protective treatment coating; and corrective actions, if necessary. This new action revises the proposed rule by requiring repetitive inspections for “drill marks” and corrosion on the underside of the wing top skin, and corrective actions, if necessary, until all corrective actions and protective treatment actions are done. The actions specified by this new proposed AD are intended to prevent corrosion from developing on the underside of the top skin of the center wing, which could result in reduced structural integrity of the airplane. 

# DATES:

Comments must be received by March 19, 2001. 

# ADDRESSES:

Submit comments in triplicate to the Federal Aviation Administration (FAA), Transport Airplane Directorate, ANM-114, Attention: Rules Docket No. 2000-NM-179-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. Comments may be submitted via fax to (425) 227-1232. Comments may also be sent via the Internet using the following address: 9-anm-nprmcomment@faa.gov. Comments sent via fax or the Internet must contain “Docket No. 2000-NM-179-AD” in the subject line and need not be submitted in triplicate. Comments sent via the Internet as attached electronic files must be formatted in Microsoft Word 97 for Windows or ASCII text. 

The service information referenced in the proposed rule may be obtained from British Aerospace Regional Aircraft American Support, 13850 Mclearen Road, Herndon, Virginia 20171. 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 action may be changed in light of the comments received. 

Submit comments using the following format: 
    - Organize comments issue-by-issue. For example, discuss a request to change the compliance time and a request to change the service bulletin reference as two separate issues.
    - For each issue, state what specific change to the proposed AD is being requested.
    - Include justification (e.g., reasons or data) for each request.

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 filed in the Rules Docket. 

Commenters wishing the FAA to acknowledge receipt of their comments submitted in response to this action must submit a self-addressed, stamped postcard on which the following statement is made: “Comments to Docket Number 2000-NM-179-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. 2000-NM-179-AD, 1601 Lind Avenue, SW., Renton, Washington 98055-4056.                           ( print page 10977)    

## Discussion 

                    A proposal to amend part 39 of the Federal Aviation Regulations (14 CFR part 39) to add an airworthiness directive (AD), applicable to all British Aerospace Model BAe 146 and Model Avro 146-RJ series airplanes, was published as a notice of proposed rulemaking (NPRM) in the                     **Federal Register**                     on July 27, 2000 (65 FR 46119). That NPRM:                 
    - Proposed to supersede AD 98-16-24, amendment 39-10701 ( 63 FR 42220 , August 7, 1998), which is applicable to all British Aerospace Model BAe 146 and certain Model Avro 146-RJ series airplanes. 
    - Would have continued to require a one-time inspection for “drill marks” and corrosion on the underside of the wing top skin, and corrective actions, if necessary.
    - Would have added a requirement for one-time detailed visual and borescopic inspections of the fuel tank, pump, and stringers for paint debris and inadequacy of the existing protective treatment coating; and corrective actions, if necessary.
    - Was prompted by issuance of mandatory continuing airworthiness information by a foreign civil airworthiness authority.
    - Was intended to prevent corrosion from developing on the underside of the top skin of the center wing, which could result in reduced structural integrity of the airplane.

## Actions Since Issuance of Previous Proposal 

Due consideration has been given to the comments received in response to the NPRM. 

## Request to Revise the Inspection and Corrective Action Requirements 

One commenter, BAe Systems, requests adding a corrective action to paragraph (a)(1) of the original NPRM, and specifying repetitive inspections until the corrective action is accomplished. The commenter states that inspections of the underside of the wing top skin should continue until the corrective action is accomplished, regardless of whether any discrepancies (drill marks or corrosion) are found. These changes are necessary because operators cannot be sure that the proposed [one-time intrascopic] inspection will identify slight damage that, in the long run, could result in corrosion. The commenter points out that it could take a minimum of 4 years for slight damage (due to “drill marks” in the protective coating) to reach a level that could be detected by an inspection. In addition, the commenter has reported the following findings: 
    - On a number of production airplanes, during assembly of Stringer Crown Dagger fittings at Ribs 0 and 2, “drill marks” were produced on the underside of the wing top skin. These small marks impaired the protective treatment in that area.
    - The terminating action specified in British Aerospace Service Bulletin SB.57-50 was to restore the surface protection per Repair Instruction Leaflet (R.I.L.) HC573H9014. However, following the closing action specified in that R.I.L, paint debris was found in the fuel tanks.

The FAA concurs with the commenter's request to revise the proposed NPRM to require certain corrective actions even if no “drill mark” or corrosion is detected. After considering the information provided by the manufacturer, we have made the following determinations: 
    - For airplanes on which protective treatment coating has NOT been applied per British Aerospace Service Bulletin SB.57-50, and for airplanes on which the inspection required by AD 98-16-24, amendment 39-10701, has NOT been done, if no “drill mark” or corrosion is detected, paragraph (a)(1) of this AD requires operators to repeat the intrascopic inspection required by paragraph (a) of this AD thereafter at intervals not to exceed 4 years, until the protective treatment coating is applied, which is terminating action.
    - For airplanes on which the protective coating HAS been applied prior to the effective date of this AD per Service Bulletin SB.57-50, paragraph (b) of this AD requires operators to do one-time detailed visual and borescopic inspections of the fuel tank, pump, and stringers to detect discrepancies (including paint debris and inadequacy of existing protective treatment coating) at the next scheduled maintenance inspection (“C-check”) or within 6 months after the effective date of this AD, whichever occurs first.

We consider that the option to either continue inspections or do the terminating action will avoid placing an undue burden on some operators, while still ensuring an adequate level of safety for the fleet. In addition, we have determined that a shorter compliance time and more detailed inspections are necessary for airplanes on which the protective treatment coating has been applied per Service Bulletin SB.57-50. Paragraphs (a), (a)(1), and (a)(2) of this AD have been revised accordingly. 

## Request To Revise Company Name 

That same commenter requests that we change the name of the company responsible for the Model BAe Avro 146 type certificate from British Aerospace Regional Aircraft American Support to BAe Systems (Operations) Limited in the proposed AD. 

The FAA concurs with the commenter's request to change the name of the company to BAe Systems (Operations) Limited. We point out that this name was changed in the Type Certificate Data Sheet, and we have revised the company name throughout this AD accordingly. 

## Clarification of Service Information 

                    The FAA has revised                     **Note 3**                     of this proposed AD to further clarify a reference for an additional source of service information for accomplishing the inspection action, and to add a reference for an additional source of information for accomplishing the protective treatment actions.                 

## Conclusion 

Since these changes expand the scope of the originally proposed rule, the FAA has determined that it is necessary to reopen the comment period to provide additional opportunity for public comment. 

## Cost Impact 

There are approximately 39 Model BAe 146 and Model Avro 146-RJ series airplanes of U.S. registry that would be affected by this proposed AD. 

The inspection for “drill marks” and corrosion that is proposed in this AD action would take approximately 10 work hours per airplane (including access and close) to accomplish, at an average labor rate of $60 per work hour. Based on these figures, the cost impact of the proposed AD on U.S. operators is estimated to be $600 per airplane, per inspection cycle. 

The inspection for paint debris and inadequacy of the existing protective treatment coating that is proposed in this AD action would take approximately 8 work hours per airplane (including access and close) to accomplish, at an average labor rate of $60 per work hour. Based on these figures, the cost impact of the proposed inspection on U.S. operators is estimated to be $480 per airplane. 

                    The cost impact figures discussed above are based on assumptions that no operator has yet accomplished any of the proposed requirements of this AD action, and that no operator would accomplish those actions in the future if this AD were not adopted.                           ( print page 10978)    

## Regulatory Impact 

The regulations proposed herein 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. Therefore, it is determined that this proposal would not have federalism implications under Executive Order 13132. 

                    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. 

§ 39.13 

2. Section 39.13 is amended by adding the following new airworthiness directive: 

**BAe Systems (Operations) Limited (Formerly British Aerospace Regional Aircraft):**                                 Docket 2000-NM-179-AD.                            

*Applicability:*                                 All Model BAe 146 series airplanes; and Model Avro 146-RJ airplanes, as listed in British Aerospace Inspection Service Bulletin ISB.57-57, dated February 25, 2000; 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 per paragraph (d) 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 corrosion from developing on the underside of the top skin of the center wing, which could result in reduced structural integrity of the airplane, accomplish the following: 

## Intrascopic Inspection: “Drill Marks” and Corrosion 

(a) For airplanes on which protective treatment coating has NOT been applied per British Aerospace Service Bulletin SB.57-50 [reference Repair Instruction Leaflet (R.I.L.) HC573H9014], and for airplanes on which the inspection required by AD 98-16-24, amendment 39-10701, has not been accomplished as of the effective date of this AD: Within 6 months after the effective date of this AD, perform an intrascopic inspection for “drill marks” and corrosion on the underside of the wing top skin, per British Aerospace Inspection Service Bulletin ISB.57-57, dated February 25, 2000. 

(1) If no “drill mark” or corrosion is detected, repeat the intrascopic inspection required by paragraph (a) of this AD thereafter at intervals not to exceed 4 years, until the terminating action required by paragraph (c) of this AD is done. 

(2) If any corrosion is detected, prior to further flight, repair per a method approved by either the Manager, International Branch, ANM-116, FAA, Transport Directorate; or the Civil Aviation Authority (CAA) of the United Kingdom (or its delegated agent). 

(3) If any “drill mark” is detected, or if any corrosion is detected and repaired, prior to further flight, do the terminating action required by paragraph (c) of this AD. 

# Note 2:

Accomplishment of an intrascopic inspection for “drill marks” and corrosion prior to the effective date of this AD, per British Aerospace Service Bulletin SB.57-50, Revision 2, dated March 20, 1997, is acceptable for compliance with the inspection requirements of paragraph (a) of this AD.

## Detailed Visual and Borescopic Inspections: Paint Debris and Inadequate Protective Treatment Coating 

(b) For airplanes on which protective treatment coating HAS been applied prior to the effective date of this AD per British Aerospace Service Bulletin SB.57-50 (reference R.I.L. HC573H9014): At the next scheduled maintenance inspection (“C-check”) or within 6 months after the effective date of this AD, whichever occurs first, do one-time detailed visual and borescopic inspections of the fuel tank, pump, and stringers to detect discrepancies (including paint debris and inadequacy of existing protective treatment coating); per Paragraph D. of the Accomplishment Instructions of British Aerospace Inspection Service Bulletin ISB.57-57, dated February 25, 2000. 

(1) If no discrepancy is found, no further action is required by this AD. 

(2) If any discrepancy is found, prior to further flight, do all applicable corrective actions (including removal of paint debris and testing of paint adhesion), and the terminating action required by paragraph (c) of this AD, per British Aerospace Inspection Service Bulletin ISB.57-57, dated February 25, 2000. 

# Note 3:

Paragraph B. of the Accomplishment Instructions of British Aerospace Inspection Service Bulletin ISB.57-57, dated February 25, 2000, references R.I.L. HC573H9024 as an additional source of service information for accomplishing the intrascopic inspection. Paragraph C. of the Accomplishment Instructions of the service bulletin references R.I.L. HC573H9032 as an additional source of service information for applying the protective treatment coating.

# Note 4:

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

## Terminating Action 

(c) Application of the protective treatment coating, per Paragraph C. of the Accomplishment Instructions of British Aerospace Inspection Service Bulletin ISB.57-57, dated February 25, 2000, constitutes terminating action for the requirements of this AD. 

## Alternative Methods of Compliance 

(d) 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. 

# Note 5:

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 

(e) Special flight permits may be issued per §§ 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.

      ( print page 10979)    
Issued in Renton, Washington, on February 13, 2001. 

Vi L. Lipski, 

Manager, Transport Airplane Directorate, Aircraft Certification Service.

[FR Doc. 01-4218 Filed 2-20-01; 8:45 am] 

BILLING CODE 4910-13-U