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###### Department of Transportation

###### Federal Aviation Administration 

          - 14 CFR Part 39 
          - [Docket No. 2000-NM-373-AD] 
          - RIN 2120-AA64 

# AGENCY:

Federal Aviation Administration, DOT. 

# ACTION:

Notice of proposed rulemaking (NPRM). 

# SUMMARY:

This document proposes the adoption of a new airworthiness directive (AD) that is applicable to certain Raytheon Model DH.125, HS.125, BH.125, and BAe 125 (U-125 and C-29A) series airplanes, and Hawker 800, Hawker 800 (U-125A), Hawker 800XP, and Hawker 1000 airplanes. This proposed AD would require an inspection for cracking or corrosion of the cylinder head lugs of the main landing gear (MLG) actuator and follow-on/corrective actions. This proposed AD is prompted by reports of attachment lugs cracking at the actuator cylinder head. This action is necessary to prevent separation of the cylinder head lugs, which could prevent the MLG from extending and result in a partial gear-up landing. This action is intended to address the identified unsafe condition. 

# DATES:

Comments must be received by July 20, 2001. 

# ADDRESSES:

Submit comments in triplicate to the Federal Aviation Administration (FAA), Transport Airplane Directorate, ANM-114, Attention: Rules Docket No. 2000-NM-373-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-373-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, 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, Wichita, Kansas. 

# FOR FURTHER INFORMATION CONTACT:

David Ostrodka, Aerospace Engineer, Airframe Branch, ACE-118W, FAA, Wichita Aircraft Certification Office, 1801 Airport Road, Room 100, Wichita, Kansas 67209; telephone (316) 946-4129; fax (316) 946-4407. 

#                     SUPPLEMENTARY INFORMATION:                          ( print page 30108)    

## 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-373-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-373-AD, 1601 Lind Avenue, SW., Renton, Washington 98055-4056. 

## Discussion 

The FAA has received reports of cracking of the cylinder head lugs of the main landing gear (MLG) actuator. Such cracking of the cylinder heads could result in separation of the cylinder head lugs, which could prevent the MLG from extending. This condition, if not corrected, could result in a partial gear-up landing. 

## Explanation of Relevant Service Information 

The FAA has reviewed and approved Raytheon Service Bulletin (SB) 32-3391, dated August 2000. The service bulletin describes procedures for performing a one-time eddy current inspection to detect cracking or corrosion of the cylinder head lugs of the MLG and follow-on/corrective actions. The follow-on/corrective actions include “vibro-etching” the MLG actuator data plate, painting a blue stripe on the actuator cylinder head, and replacing bushings; applying corrosion protection to the lug bores; and replacing the actuator with a new or overhauled actuator or replacement of the actuator cylinder head with a new cylinder head, as applicable. 

## Additional Source of Service Information 

The Raytheon service bulletin references Precision Hydraulics Cylinder Maintenance Manual 32-30-1105 for additional service information regarding the replacement of the actuator cylinder head with a new cylinder head. 

## Explanation of Requirements of Proposed Rule 

Since an unsafe condition has been identified that is likely to exist or develop on other products of this same type design, the proposed AD would require doing the actions specified in the Raytheon service bulletin described previously. The actions would be required to be accomplished in accordance with the Raytheon service bulletin described previously. 

## Cost Impact 

There are approximately 1,000 airplanes of the affected design in the worldwide fleet. The FAA estimates that this proposed AD would affect 650 airplanes of U.S. registry. The proposed inspection would take approximately 20 work hours per airplane, at an average labor rate of $60 per work hour. Based on these figures, we estimate the cost of the proposed AD on U.S. operators to be $780,000, or $1,200 per airplane. 

The cost impact figure discussed above is 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 proposed 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 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-373-AD.                            

*Applicability:*                                 Model DH.125, HS.125, BH.125, and BAe 125 (U-125 and C-29A) series airplanes, and Hawker 800, Hawker 800 (U-125A), Hawker 800XP, and Hawker 1000 airplanes, as listed in Raytheon Service Bulletin SB 32-3391, dated August 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                                           ( print page 30109)                                        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 separation of the cylinder head lugs, which could prevent the main landing gear (MLG) from extending and result in a partial gear-up landing, do the following: 

## Inspection 

(a) Perform an eddy current inspection of the actuator cylinder head lugs for cracking or corrosion per Raytheon Service Bulletin SB 32-3391, dated August 2000, at the time specified in paragraph (a)(1), (a)(2), (a)(3), or (a)(4) of this AD, as applicable. 

(1) For actuator cylinder heads that have 3,000 or less total landings as of the effective date of this AD: Perform the eddy current inspection within 24 months after the effective date of this AD. 

(2) For actuator cylinder heads that have 3,001 to 4,000 total landings as of the effective date of this AD: Perform the eddy current inspection within 6 months after the effective date of this AD. 

(3) For actuator cylinder heads that have been in service for more than 7 years as of the effective date of this AD: Perform the eddy current inspection within 6 months of the effective date of this AD. 

(4) For actuator cylinder heads that have 4,001 or more total landings as of the effective date of this AD: Perform the eddy current inspection within 10 landings after the effective date of this AD. 

## If No Cracking or Corrosion 

                                (b) If no cracking or corrosion is found during the inspection required by paragraph (a) of this AD, before further flight, accomplish the follow-on actions (e.g., “vibro-etching” the MLG actuator data plate, painting a blue stripe on the actuator cylinder head to indicate                                 1/32                                 inch oversize bushings, replacing bushings, and applying corrosion protection to the lug bores), per Raytheon Service Bulletin SB 32-3391, dated August 2000.                             

## If Any Cracking or Corrosion 

(c) If any cracking or corrosion is found during the inspection required by paragraph (a) of this AD, before further flight, accomplish either of the actions specified in paragraph (c)(1) or (c)(2) of this AD, per Raytheon Service Bulletin SB 32-3391, dated August 2000. 

(1) Replace the actuator of the MLG with a new or serviceable actuator, or 

(2) Replace the actuator cylinder head with a new cylinder head. 

# Note 2:

Raytheon Service Bulletin SB 32-3391, dated August 2000, references Precision Hydraulics Cylinder Maintenance Manual (CMM) 32-30-1105 as an additional source of service information.

## 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 Permit 

(e) Special flight permits may be issued in accordance with §§ 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 May 30, 2001. 

Vi L. Lipski, 

Manager, Transport Airplane Directorate, Aircraft Certification Service. 

[FR Doc. 01-14044 Filed 6-4-01; 8:45 am] 

BILLING CODE 4910-13-P