# AGENCY: 

Federal Aviation Administration, DOT. 

# ACTION: 

Notice of proposed rulemaking (NPRM).

# SUMMARY: 

This document proposes the supersedure of an existing airworthiness directive (AD), applicable to certain Raytheon Model BAe 125-800A, Model Hawker 800, and Model Hawker 800XP series airplanes, that currently requires the filling of two tooling holes on the firewalls of the left and right engine pylons with firewall sealant. This action would require the sealing of all unused (open) tooling holes on the firewalls of the left and right engine pylons, and would expand the applicability to include additional airplanes. This proposal is prompted by reports of additional unused (open) tooling holes, found at locations other than those currently addressed. The actions specified by the proposed AD are intended to prevent an engine fire from moving to the fuselage and to the lines that carry flammable fluid that are located inboard of the firewall. 

# DATES: 

Comments must be received by February 23, 2000. 

# ADDRESSES: 

Submit comments in triplicate to the Federal Aviation Administration (FAA), Transport Airplane Directorate, ANM-114, Attention: Rules Docket No. 99-NM-13-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 Raytheon Aircraft Company, Manager Service Engineering, Hawker Customer Support Department, 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, Small Airplane Directorate, Wichita Aircraft Certification Office, 1801 Airport Road, Room 100, Mid-Continent Airport, Wichita, Kansas. 

# FOR FURTHER INFORMATION CONTACT: 

Jeffrey A. Pretz, Aerospace Engineer, Systems and Propulsion Branch, ACE-116W, FAA, Small Airplane Directorate, Wichita Aircraft Certification Office, 1801 Airport Road, Room 100, Mid-Continent Airport, Wichita, Kansas 67209; telephone (316) 946-4153; 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 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 filed in 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 99-NM-13-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. 99-NM-13-AD, 1601 Lind Avenue, SW., Renton, Washington 98055-4056. 

## Discussion 

On November 22, 1996, the FAA issued AD 96-24-16, amendment 39-9840 (61 FR 66878, December 19, 1996), applicable to certain Raytheon Model BAe 125-800A, Model Hawker 800, and Model Hawker 800XP series airplanes, to require the filling of two tooling holes on the firewalls of the left and right engine pylons with firewall sealant. That action was prompted by notification from the manufacturer that these holes were not sealed during production. The requirements of that AD are intended to prevent an engine fire from moving to the fuselage and to the lines that carry flammable fluid that are located inboard of the firewall. 

## Actions Since Issuance of Previous Rule 

                    Since the issuance of that AD, reports have been received of airplanes with additional unused tooling holes, at locations other than those addressed in AD 96-24-16, on the left and right engine pylon firewalls, which may permit the passage of flames to the                     Start Printed Page 3620                    structure and flammable fluids inboard of the engine pylon firewall.                 

## Explanation of Relevant Service Information 

Raytheon has issued Service Bulletin SB.54-1-3815B, Revision 1, dated May 1998, which describes procedures for the sealing of all unused tooling holes on the firewalls of the left and right engine pylons. Revision 1 of the service bulletin was issued to address additional unused engine pylon firewall tooling holes at locations other than those indicated in the original service bulletin, dated March 26, 1996. Accomplishment of the actions specified in Raytheon Service Bulletin SB.54-1-3815B, Revision 1, is intended to adequately address the identified unsafe condition. 

## 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, the proposed AD would supersede AD 96-24-16 to require the sealing of all unused tooling holes on the firewalls of the left and right engine pylons. The actions would be required to be accomplished in accordance with Raytheon Service Bulletin SB.54-1-3815B, Revision 1, described previously. 

## Expanded Applicability 

The applicability of the proposed AD has been expanded to include Model BAe 125-800B series airplanes, which have received FAA type certification and have a similar design to airplanes subject to the requirements of AD 96-24-16. 

## Cost Impact 

There are approximately 340 Model BAe 125-800A and BAe 125-800B, Model Hawker 800, and Model Hawker 800XP series airplanes of the affected design in the worldwide fleet. The FAA estimates that 221 airplanes of U.S. registry would be affected by this proposed AD. 

The actions that are currently required by AD 96-24-16, and retained in this AD, take approximately 2 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 actions on U.S. operators is estimated to be $120 per airplane. 

The new actions that are 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. Based on these figures, the cost impact of the proposed requirements of this AD on U.S. operators is estimated to be $26,520, 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 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 removing amendment 39-9840 ( 61 FR 66878, December 19, 1996), and by adding a new airworthiness directive (AD), to read as follows: 

**Raytheon Aircraft Co. (Formerly Beech):**                         Docket 99-NM-13-AD. Supersedes AD 96-24-16, Amendment 39-9840.                     

*Applicability:*                         Model BAe 125-800A and BAe 125-800B, Model Hawker 800, and Model Hawker 800XP series airplanes; as listed in Raytheon Service Bulletin SB.54-1-3815B, Revision 1, dated May 1998; 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 (c) 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 an engine fire from moving to the fuselage and to the lines that carry flammable fluid that are located inboard of the firewall, accomplish the following: 

## Restatement of Requirements of AD 96-24-16 

(a) For airplanes identified in AD 96-24-16, amendment 39-9840: Within 6 months after January 27, 1997 (the effective date of AD 96-24-16), fill the two, unused tooling holes in the firewalls of the left and right engine pylons, in accordance with Raytheon Service Bulletin SB.54-1-3815B, dated March 26, 1996, or Raytheon Service Bulletin SB.54-1-3815B, Revision 1, dated May 1998. After the effective date of this AD, only Revision 1 of this service bulletin shall be used. 

## New Requirements of This AD 

(b) For all airplanes: Within 6 months after the effective date of this AD, fill all unused tooling holes in the left and right engine pylon firewalls with firewall sealant, in accordance with Raytheon Service Bulletin SB.54-1-3815B, Revision 1, dated May 1998. 

## Alternative Methods of Compliance 

(c) 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), ACE-116W, FAA, Small 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, Wichita ACO. 

# Note 2: 

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 

                        (d) Special flight permits may be issued in accordance with sections §§ 21.197 and                         Start Printed Page 3621                        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 January 18, 2000. 

Donald L. Riggin, 

Acting Manager, Transport Airplane Directorate, Aircraft Certification Service. 

[FR Doc. 00-1597 Filed 1-21-00; 8:45 am] 

BILLING CODE 4910-13-U