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CFR Citation: 14 CFR Part 39

Docket ID: [Docket No. FAA-2004-18660; Directorate Identifier 2003-NM-161-AD]

RIN ID: RIN 2120-AA64

NOTICE: PROPOSED RULES

ACTION: Airworthiness directives:

DOCUMENT ACTION: Notice of proposed rulemaking (NPRM).

SUBJECT CATEGORY: Airworthiness Directives; Raytheon (Beech) Model MU-300-10, 400, 400A, and 400T Series Airplanes; and Raytheon (Mitsubishi) Model Beech MU-300 Airplanes

DATES: We must receive comments on this proposed AD by September 7, 2004.

DOCUMENT SUMMARY: The FAA proposes to adopt a new airworthiness directive (AD) for certain Raytheon (Beech) Model MU30010, 400, 400A, and 400T series airplanes; and certain Raytheon (Mitsubishi) Model Beech MU300 airplanes. This proposed AD would require a onetime inspection of certain panels in the spoiler mixer bay for the presence of drain holes, and the addition of at least one new drain hole; and a onetime inspection for discrepancies of the sealant on the relief cutout on the aft pressure bulkhead, and on certain baffles; and corrective actions [[Page 43784]]
if necessary. This proposed AD is prompted by a report of fuel leaking from components in the spoiler mixer bay of several Raytheon (Beech) Model 400A series airplanes. We are proposing this AD to prevent the accumulation of fuel and/or fuel vapor in the spoiler mixer bay and/or the aft fuselage compartment, which could result in a fire in the airplane.

SUMMARY: Raytheon,

SUPPLEMENTAL INFORMATION

The FAA has implemented new procedures for maintaining AD dockets electronically. As of May 17, 2004, new AD actions are posted on DMS and assigned a docket number. We track each action and assign a corresponding directorate identifier. The DMS AD docket number is in the form ``Docket No. FAA200499999.'' The Transport Airplane Directorate identifier is in the form ``Directorate Identifier 2004NM 999AD.'' Each DMS AD docket also lists the directorate identifier (``Old Docket Number'') as a crossreference for searching purposes. Comments Invited

We invite you to submit any written relevant data, views, or arguments regarding this proposed AD. Send your comments to an address listed under ADDRESSES. Include ``Docket No. FAA200418660; Directorate Identifier 2003NM161AD'' in the subject line of your comments. We specifically invite comments on the overall regulatory, economic, environmental, and energy aspects of the proposed AD. We will consider all comments submitted by the closing date and may amend the proposed AD in light of those comments.

We will post all comments we receive, without change, to http://dms.dot.gov , including any personal information you provide. We will
also post a report summarizing each substantive verbal contact with FAA personnel concerning this proposed AD. Using the search function of that website, anyone can find and read the comments in any of our dockets, including the name of the individual who sent the comment (or signed the comment on behalf of an association, business, labor union, etc.). You can review DOT's complete Privacy Act Statement in the Federal Register published on April 11, 2000 (65 FR 1947778), or you can visit http://dms.dot.gov.

We are reviewing the writing style we currently use in regulatory documents. We are interested in your comments on whether the style of this document is clear, and your suggestions to improve the clarity of our communications that affect you. You can get more information about plain language at http://www.plainlanguage.gov.Examining the Docket

You can examine the AD docket in person at the Docket Management Facility office between 9 a.m. and 5 p.m., Monday through Friday, except Federal holidays. The Docket Management Facility office (telephone (800) 6475227) is located on the plaza level of the Nassif Building at the DOT street address stated in the ADDRESSES section. Comments will be available in the AD docket shortly after the DMS receives them.

Discussion

We have received a report indicating that fuel leaked from components in the spoiler mixer bay of several Raytheon (Beech) Model 400A series airplanes. On one occasion, fuel migrated into the aft fuselage, resulting in fuel odor in the aft baggage compartment. Further investigation by the manufacturer showed that both the left and right spoiler bay mixer panels of certain Raytheon airplane models lacked the drain holes required by the type design. If there is a fuel leak, and the mixer panels do not have the requisite drain holes, fuel could pool in the spoiler mixer bay. Fuel could also migrate from the mixer bay into the aft fuselage if the sealant is missing from the bulkhead between the mixer bay and the aft fuselage compartment. This condition, if not corrected, could result in the accumulation of fuel and/or fuel vapor in the spoiler mixer bay and/or the aft fuselage compartment, which could result in a fire in the airplane.

Raytheon (Beech) Model 400 and 400T series airplanes, and Raytheon (Beech) Model MU300 airplanes, are similar in design to the Raytheon (Beech) Model 400A series airplanes that had the fuel leaks. Therefore, all of these airplanes could have the same unsafe condition, and all are subject to the requirements of this proposed AD.

Relevant Service Information

We have reviewed Raytheon Service Bulletin SB 533486, dated June 2003. The service bulletin describes procedures for a onetime inspection of the spoiler mixer bay panels to determine if there are the correct number of drain holes; and a onetime inspection for discrepancies of the sealant on the relief cutout on the aft pressure bulkhead, and the baffles at left butt line (BL) 19.13 and right BL 10.43; and corrective actions, if necessary. Discrepancies include missing sealant, or inadequate sealant, which is defined as sealant not adhering properly, flaking, peeling, or having voids, gaps, or pinholes. The service bulletin also describes procedures for corrective actions. The corrective actions include drilling at least one new drain hole, and any additional drain holes needed to make a total of five at specified places in each mixer bay panel; and applying sealant, if necessary, to repair discrepancies. We have determined that accomplishing the actions specified in the service bulletin will adequately address the unsafe condition.

FAA's Determination and Requirements of the Proposed AD

We have evaluated all pertinent information and identified an unsafe condition that is likely to exist or develop on other airplanes of this same type design. Therefore, we are proposing this AD, which would require a onetime inspection of the spoiler
[[Page 43785]]
mixer bay panels to determine if there are the correct number of drain holes; and a onetime inspection of the sealant on the relief cutout on the aft pressure bulkhead, and the baffles at left butt line (BL) 19.13 and right BL 10.43 for discrepancies; and corrective actions, if necessary. The proposed AD would require you to use the service information described previously to perform these actions.

Clarification of Inspection Language

Although the service bulletin does not define the type of inspection required for the drain holes and the sealant, this proposed AD would classify the inspection as a ``general visual inspection.'' Note 1 of this proposed AD defines this inspection.

Costs of Compliance

This proposed AD would affect about 673 airplanes worldwide. The following table provides the estimated costs for U.S. operators to comply with this proposed AD.
Estimated Costs Average Number of Work labor Cost per U.S. Action hours rate per Parts airplane registered Fleet cost hour airplanes Inspections.................... 1 $65 None.............. $65 610 $39,650 Drilling one drain hole........ 3 $65 None.............. $195 610 $118,950 Regulatory Findings

We have determined that this proposed AD would not have federalism implications under Executive Order 13132. This proposed AD 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.

For the reasons discussed above, I certify that the 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. 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.

We prepared a regulatory evaluation of the estimated costs to comply with this proposed AD. See the ADDRESSES section for a location to examine the regulatory evaluation.

List of Subjects in 14 CFR Part 39

Air transportation, Aircraft, Aviation safety, Safety. The Proposed Amendment

Accordingly, under the authority delegated to me by the Administrator, the FAA proposes to amend 14 CFR part 39 as follows: PART 39AIRWORTHINESS DIRECTIVES

1. The authority citation for part 39 continues to read as follows:

Authority: 49 U.S.C. 106(g), 40113, 44701.

Sec. 39.13 [Amended]

2. The FAA amends Sec. 39.13 by adding the following new airworthiness directive (AD):
Raytheon Aircraft Company (Formerly Beech): Docket No. FAA2004 18660; Directorate Identifier 2003NM161AD.
Comments Due Date
(a) The Federal Aviation Administration (FAA) must receive comments on this AD action by September 7, 2004.
Affected ADs
(b) None.
Applicability
(c) This AD applies to Raytheon (Beech) Model MU30010, 400, 400A, and 400T series airplanes; and Raytheon (Mitsubishi) Model Beech MU300 airplanes; certificated in any category; as listed in Raytheon Service Bulletin SB 533486, dated June 2003.
Unsafe Condition
(d) This AD was prompted by a report of fuel leaking from components in the spoiler mixer bay of several Raytheon (Beech) Model 400A series airplanes. We are issuing this AD to prevent the accumulation of fuel and/or fuel vapor in the spoiler mixer bay and/ or the aft fuselage compartment, which could result in a fire in the airplane.
Compliance
(e) You are responsible for having the actions required by this AD performed within the compliance times specified, unless the actions have already been done.
Inspections and Corrective Actions
(f) Within 400 flight hours or 12 months after the effective date of this AD, whichever occurs first, do the actions in paragraphs (a)(1) and (a)(2) of this AD. Do all actions in accordance with the Accomplishment Instructions of Raytheon Service Bulletin SB 533486, dated June 2003.
(1) Do a onetime general visual inspection of the spoiler mixer bay panels to determine the presence of drain holes. Before further flight after doing this inspection, drill at least one new drain hole, and any additional drain holes needed to make a total of five, at the places in each mixer bay panel specified in the service bulletin.
(2) Do a onetime general visual inspection for discrepancies of the sealant on the relief cutout on the aft pressure bulkhead, and of the small triangularshaped baffles at left butt line (BL) 19.13 and right BL 10.43. Before further flight after doing this inspection, do any applicable corrective actions.

Note 1: For the purposes of this AD, a general visual inspection is: ``A visual examination of an interior or exterior area, installation, or assembly to detect obvious damage, failure, or irregularity. This level of inspection is made from within touching distance unless otherwise specified. A mirror may be necessary to enhance visual access to all exposed surfaces in the inspection area. This level of inspection is made under normally available lighting conditions such as daylight, hangar lighting, flashlight, or droplight and may require removal or opening of access panels or doors. Stands, ladders, or platforms may be required to gain proximity to the area being checked.''
Parts Installation
(g) As of the effective date of this AD, no person may install on any airplane a spoiler mixer bay panel that has a part number listed in paragraph 3.B., ``Spares,'' of the Accomplishment Instructions of Raytheon Service Bulletin SB 533486, dated June 2003, unless the panel has been inspected and modified in accordance with paragraph (f)(1) of this AD.
Alternative Methods of Compliance (AMOCs)
(h) The Manager, Wichita Aircraft Certification Office (ACO), FAA, has the authority to approve AMOCs for this AD, if requested in accordance with the procedures found in 14 CFR 39.19.

Issued in Renton, Washington, on July 9, 2004.
Kevin M. Mullin,
Acting Manager, Transport Airplane Directorate, Aircraft Certification Service.
[FR Doc. 0416684 Filed 72104; 8:45 am]
BILLING CODE 491013P

FOR FURTHER INFORMATION CONTACT Jeff Pretz, Aerospace Engineer, Airframe Branch, ACE118W, FAA, Wichita Aircraft Certification Office, 1801 Airport Road, Propulsion 100, MidContinent Airport, Wichita, Kansas 67209; telephone (316) 9464153; fax (316) 9464107.