AD 98-11-13

This amendment adopts a new airworthiness directive (AD) that is applicable to certain Raytheon Model Hawker 800XP series airplanes and Hawker 800 (U-125A military derivative) airplanes. This action requires removal of the sealant from the firewall mounting flanges and mounting points of the fire extinguisher assemblies; removal of sealant obstructing the discharge tubes of the fire extinguisher assemblies; cleaning and flushing of the mounting flanges, mounting points, and discharge tubes with solvent; and installation of new gaskets on the firewall mounting flanges and mounting points. This amendment is prompted by reports of excessive sealant applied during manufacture of the firewall mounting flanges and mounting points of the fire extinguisher assemblies, which subsequently entered and obstructed the discharge tubes. The actions specified in this AD are intended to prevent obstructions of the discharge tubes of the fire extinguisher assemblies, which could result in improper distribution of the fire extinguishing agent within the nacelle in the event of a fire.

Final rule; request for comments.

98-11-13 RAYTHEON AIRCRAFT COMPANY (Formerly Beech): Amendment 39-10540. Docket 98-NM-165-AD.

Applicability: Model Hawker 800XP series airplanes and Hawker 800 (U-125A military derivative) airplanes, as listed in Raytheon Service Bulletin SB.26-3197, dated April 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 (b) 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 shouldinclude specific proposed actions to address it.

Compliance: Required as indicated, unless accomplished previously.

To prevent obstructions of the discharge tubes of the fire extinguisher assemblies, which could result in improper distribution of the fire extinguishing agent within the nacelle in the event of a fire, accomplish the following:

(a) Within 25 days after the effective date of this AD, accomplish paragraphs (a)(1), (a)(2), (a)(3), and (a)(4) of this AD, in accordance with Raytheon Service Bulletin SB.26-3197, dated April 1998.

(1) Remove the sealant from the firewall mounting flanges and mounting points of the fire extinguisher assemblies;

(2) Remove all sealant obstructing the discharge tubes of the fire extinguisher assemblies;

(3) Clean and flush the mounting flanges, mounting points, and discharge tubes with solvent; and

(4) Install new gaskets on the firewall mounting flanges and mounting points.

(b) An alternative method ofcompliance 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, 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.

(c) 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.

(d) The actions shall be done in accordance with Raytheon Service Bulletin SB.26-3197, dated April 1998. This incorporation by reference was approved by the Director of the Federal Register in accordance with 5 U.S.C. 552(a) and 1 CFR part 51. Copies may be obtained from Raytheon Aircraft Company, Manager Service Engineering, Hawker Customer Support Department, P.O. Box 85, Wichita, Kansas 67201-0085. Copies may be inspected 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; or at the Office of the Federal Register, 800 North Capitol Street, NW., suite 700, Washington, DC.

(e) This amendment becomes effective on June 8, 1998.

The FAA has received a report indicating that, during manufacture testing of the fire suppression system on a Raytheon Model Hawker 800XP series airplane, the system failed to operate properly. Investigation has revealed that the discharge tubes of the fire extinguisher assemblies were obstructed. Testing of other Model Hawker 800XP series airplanes and a Hawker 800 (U-125A military derivative) airplane revealed similar obstructions of the discharge tubes of the fire extinguisher assemblies. The cause of the obstructions has been attributed to excessive sealant applied during manufacture of the firewall mounting flanges and mounting points of the fire extinguisher assemblies, which subsequently entered and obstructed the discharge tubes. This condition, if not corrected, could result in improper distribution of the fire extinguishing agent within the nacelle in the event of a fire.

Explanation of Relevant Service Information
The FAA has reviewed and approved Raytheon Service Bulletin SB.26-3197, dated April 1998, which describes procedures for removal of the sealant from the firewall mounting flanges and mounting points of the fire extinguisher assemblies; removal of sealant obstructing the discharge tubes of the fire extinguisher assemblies; cleaning and flushing of the mounting flanges, mounting points, and discharge tubes with solvent; and installation of new gaskets on the firewall mounting flanges and mounting points. Accomplishment of the actions specified in the service bulletin is intended to adequately address the identified unsafe condition.

Explanation of the Requirements of the Rule
Since an unsafe condition has been identified that is likely to exist or develop on other airplanes of the same type design, this AD is being issued to prevent obstructions of the discharge tubes of the fire extinguisher assemblies, which could result in improper distribution of the fire extinguishing agent within the nacelle inthe event of a fire. This AD requires removal of the sealant from the firewall mounting flanges and mounting points of the fire extinguisher assemblies; removal of sealant obstructing the discharge tubes of the fire extinguisher assemblies; cleaning and flushing of the mounting flanges, mounting points, and discharge tubes with solvent; and installation of new gaskets on the firewall mounting flanges and mounting points.

Determination of Rule's Effective Date
Since a situation exists that requires the immediate adoption of this regulation, it is found that notice and opportunity for prior public comment hereon are impracticable, and that good cause exists for making this amendment effective in less than 30 days.

Comments Invited
Although this action is in the form of a final rule that involves requirements affecting flight safety and, thus, was not preceded by notice and an opportunity for public comment, comments are invited on this rule. Interested persons are invitedto comment on this 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 under the caption "ADDRESSES." All communications received on or before the closing date for comments will be considered, and this rule may be amended in light of the comments received. Factual information that supports the commenter's ideas and suggestions is extremely helpful in evaluating the effectiveness of the AD action and determining whether additional rulemaking action would be needed.

Comments are specifically invited on the overall regulatory, economic, environmental, and energy aspects of the rule that might suggest a need to modify the 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 that summarizes each FAA-public contact concerned with thesubstance of this AD will be filed in the Rules Docket.

Commenters wishing the FAA to acknowledge receipt of their comments submitted in response to this rule must submit a self-addressed, stamped postcard on which the following statement is made: "Comments to Docket Number 98-NM-165-AD." The postcard will be date stamped and returned to the commenter.

Regulatory Impact
The regulations adopted herein will 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 final rule does not have sufficient federalism implications to warrant the preparation of a Federalism Assessment.

The FAA has determined that this regulation is an emergency regulation that must be issued immediately to correct an unsafe condition in aircraft, and that it is not a "significant regulatory action" under Executive Order 12866. It has been determined further that this action involves an emergency regulation under DOT Regulatory Policies and Procedures (44 FR 11034, February 26, 1979). If it is determined that this emergency regulation otherwise would be significant under DOT Regulatory Policies and Procedures, a final regulatory evaluation will be prepared and placed in the Rules Docket. A copy of it, if filed, may be obtained from the Rules Docket at the location provided under the caption "ADDRESSES."

List of Subjects in 14 CFR Part 39
Air transportation, Aircraft, Aviation safety, Incorporation by reference, Safety.

Adoption of the Amendment
Accordingly, pursuant to the authority delegated to me by the Administrator, the Federal Aviation Administration amends 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 [Amended]
2. Section 39.13 is amended by adding the following new airworthiness directive: