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###### Department of Transportation

###### Federal Aviation Administration 

          - 14 CFR Part 39 
          - [Docket No. 2000-NM-212-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 certain Raytheon Model BAe.125, Hawker 800 (U-125A military) and Hawker 800XP series airplanes that would have required removal of existing clamps, bedding tapes, and rubber connecting sleeves at the ends of the turbine air discharge duct and the water separator, and replacement of the clamps and rubber connecting sleeves with new, improved components. This new action revises the proposed rule by adding airplanes to the applicability; and, for certain airplanes, adding a new requirement to remove aluminum bedding strips that are installed under the existing clamps. The actions specified by this new proposed AD are intended to prevent the turbine air discharge duct or water separator outlet duct from disconnecting from the cold air unit turbine or from the water separator, resulting in the loss of air supply to maintain adequate cabin pressure. Loss of adequate cabin pressure at high altitude would require emergency procedures, such as use of oxygen, auxiliary pressurization, or emergency descent. 

# DATES:

Comments must be received by March 12, 2001. 

# ADDRESSES:

                        Submit comments in triplicate to the Federal Aviation Administration (FAA), Transport Airplane Directorate, ANM-114, Attention: Rules Docket No. 2000-NM-212-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                               ( print page 10237)                            sent via fax or the Internet must contain “Docket No. 2000-NM-212-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 Raytheon Aircraft Company, Manager, Service Engineering, Product Support Department (62), P.O. Box 85, Wichita, Kansas 67201-0085. This information may be examined at the FAA, Transport Airplane Directorate, 1601 Lind Avenue, SW., Renton, Washington; or at the FAA, Wichita Aircraft Certification Office, 1801 Airport Road, Room 100, Mid-Continent Airport, Wichita, Kansas. 

# FOR FURTHER INFORMATION CONTACT:

Paul C. DeVore, Aerospace Engineer, Systems and Propulsion Branch, ACE-116W, FAA, Wichita Aircraft Certification Office, 1801 Airport Road, Room 100, Mid-Continent Airport, Wichita, Kansas 67209; telephone (316) 946-4142; fax (316) 946-4407. 

# 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-212-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-212-AD, 1601 Lind Avenue, SW., Renton, Washington 98055-4056. 

## Discussion 

                    A proposal to amend part 39 of the Federal Aviation Regulations (14 CFR part 39) to add an airworthiness directive (AD), applicable to certain Raytheon Model BAe.125, Hawker 800 (U-125A), and Hawker 800XP series airplanes, was published as a notice of proposed rulemaking (NPRM) in the                     **Federal Register**                     on August 14, 2000 (65 FR 49523). That NPRM would have required removal of existing clamps, bedding tapes, and rubber connecting sleeves at the ends of the turbine air discharge duct and the water separator, and replacement of the clamps and rubber connecting sleeves with new, improved components.                 

## Actions Since Issuance of Previous Proposal 

Since the issuance of that NPRM, the FAA has received reports indicating that aluminum bedding strips may inhibit proper torquing of the clamp. Such improper torquing of the clamp may allow separation of the turbine air discharge duct or water separator outlet duct from the cold air unit turbine or from the water separator, which could result in the loss of air supply to maintain adequate cabin pressure. Loss of adequate cabin pressure at high altitude would require emergency procedures, such as use of oxygen, auxiliary pressurization, or emergency descent. 

## Issuance of a New Service Bulletin 

The FAA has reviewed and approved Raytheon Service Bulletin SB 21-3414, Revision 1, dated July 2000, that describes procedures for removing certain aluminum bedding strips on the air conditioning duct sleeves attached to both ends of the turbine air discharge duct and at the outlet end of the water separator. That service bulletin also specifies additional airplane models to the effectivity specified in Raytheon Service Bulletin SB 21-3377, Revision 1, dated July 2000, which was specified as the appropriate service information in the original NPRM. 

## Conclusion 

Since this change expands 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 270 Model BAe.125 series 800A (C-29A and U-125 military), 1000A, and 1000B airplanes, Hawker 800 (U-125A military) airplanes, and Hawker 800XP and 1000 series airplanes of the affected design in the worldwide fleet. 

The FAA estimates that 154 airplanes of U.S. registry would be affected by paragraph (a) of this proposed AD. We estimate that the actions required by paragraph (a) of this AD would take approximately 8 work hours per airplane to accomplish, and that the average labor rate is $60 per work hour. Required parts would cost approximately $492 per airplane. Based on these figures, the cost impact of the proposed AD on U.S. operators is estimated to be $149,688, or $972 per airplane. 

The FAA estimates that an additional 36 airplanes of U.S. registry would be affected by paragraph (b) of this proposed AD. We estimate that the actions required by paragraph (b) of this AD would take approximately 2 hours per airplane to accomplish the proposed actions, and that the average labor rate is $60 per work hour. There is no cost for required parts. Based on these figures, the cost impact of paragraph (b) of the proposed AD on U.S. operators is estimated to be $4,320, or $120 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. The cost impact figures discussed in AD rulemaking actions represent only the time necessary to perform the specific actions actually required by the AD. These figures typically do not include incidental costs, such as the time required to gain access and close up, planning time, or time necessitated by other administrative actions. 

## Regulatory Impact 

                    The regulations proposed herein would not have a substantial direct effect on the States, on the relationship                           ( print page 10238)                        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: 

**Raytheon Aircraft Company:**                                 Docket 2000-NM-212-AD.                             

*Applicability:*                                 Model BAe.125 series 800A (C-29A and U-125 military), 1000A, and 1000B airplanes, Hawker 800 (U-125A military) airplanes; up to and including serial number 258406; and Hawker 800XP series airplanes, up to and including serial number 258483 and 1000 series airplanes; 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 (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 the turbine air discharge duct or water separator outlet duct from disconnecting from the cold air unit turbine or from the water separator, resulting in the loss of air supply to maintain adequate cabin pressure, accomplish the following: 

## Replacement 

(a) For Model BAe.125 series 800A (C-29A and U-125 military) series airplanes, Hawker 800 (U-125A military) airplanes up to and including serial number 258406, and Hawker 800XP series airplanes up to and including serial number 258459: Remove the clamps, bedding tapes, and rubber connecting sleeves at the ends of the air turbine discharge duct and the water separator, and replace the clamps and rubber connecting sleeves with new, improved components, in accordance with the Accomplishment Instructions of Raytheon Service Bulletin SB 21-3377, Revision 1, dated July 2000, at the earliest of the times specified in paragraphs (a)(1), (a)(2), and (a)(3) of this AD. 

(1) Prior to any extended over-water operation. 

(2) Within the next 300 hours time-in-service after the effective date of this AD. 

(3) Within the next six months after the effective date of this AD. 

# Note 2:

An extended over-water operation is defined in 14 CFR 1.1 as “ * * * an operation over water at a horizontal distance of more than 50 nautical miles from the nearest shoreline. * * * ”

(b) For Model Hawker 800XP series airplanes having serial numbers 258460 through 258483, Model BAe.125 series 1000A/1000B airplanes, and Hawker 1000 series airplanes: Remove the aluminum bedding strips from the air conditioning duct sleeves attached to both ends of the turbine air discharge duct and at the outlet end of the water separator, in accordance with the Accomplishment Instructions of Raytheon Service Bulletin SB 21-3414, Revision 1, dated July 2000, at the earliest of the times specified in paragraphs (b)(1), (b)(2), and (b)(3) of this AD. 

(1) Prior to any extended over-water operation. 

(2) Within the next 300 hours time-in-service after the effective date of this AD. 

(3) Within the next six months after the effective date of this AD. 

## Actions Accomplished Previously and Terminating Actions 

(c) For certain airplanes, actions described in the original issuance of Raytheon Service Bulletin SB 21-3377, may have been accomplished prior to the effective date of this AD. On those airplanes, those actions are not required to be repeated, as allowed by the phrase, “unless accomplished previously.” However, any action described in Raytheon Service Bulletin SB 21-3377, Revision 1, dated July 2000, or Raytheon Service Bulletin SB 21-3414, Revision 1, dated July 2000, that has not been accomplished on those airplanes must be accomplished in accordance with this AD. Accomplishment of the actions specified in both Raytheon Service Bulletin SB 21-3377, Revision 1, dated July 2000, and Raytheon Service Bulletin SB 21-3414, Revision 1, dated July 2000, is considered to be 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, Wichita Aircraft Certification Office (ACO), FAA. Operators shall submit their requests through an appropriate FAA Principal Maintenance Inspector, who may add comments and then send it to the Manager, Wichita ACO. 

# Note 3:

Information concerning the existence of approved alternative methods of compliance with this AD, if any, may be obtained from the Wichita ACO.

## Special Flight Permits 

(e) 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. 

Issued in Renton, Washington, on February 7, 2001. 

Donald L. Riggin, 

Acting Manager,, Transport Airplane Directorate, Aircraft Certification Service. 

[FR Doc. 01-3675 Filed 2-13-01; 8:45 am] 

BILLING CODE 4910-13-P