Airworthiness Directives; Raytheon Model DH.125, HS.125, and BH.125 Series Airplanes; BAe.125 Series 800A (C-29A and U-125) and 800B Airplanes; and Hawker 800 (Including Variant U-125A) and 800XP Airplanes; Equipped With TFE731 Engines

AGENCY:

Federal Aviation Administration (FAA), DOT.

ACTION:

Notice of proposed rulemaking (NPRM).

SUMMARY:

The FAA proposes to adopt a new airworthiness directive (AD) for certain Raytheon Model DH.125, HS.125, and BH.125 series airplanes; BAe.125 series 800A (C-29A and U-125) and 800B airplanes; and Hawker 800 (including variant U-125A) and 800XP airplanes. This proposed AD would require installing insulating blankets on the engine compartment firewall and the wire harness passing through the firewall fairlead. This proposed AD is prompted by a report indicating that insulation on the wire harness passing through the firewall fairlead ignited on the fuselage side of the firewall. We are proposing this AD to prevent a fire in the engine compartment from causing possible ignition of outgassing wire insulation on the fuselage side of the firewall, which could lead to an uncontrollable fire in the fuselage.

DATES:

We must receive comments on this proposed AD by December 27, 2004.

ADDRESSES:

Use one of the following addresses to submit comments on this proposed AD.

• DOT Docket Web site: Go to http://dms.dot.gov and follow the instructions for sending your comments electronically.
• Government-wide rulemaking web site: Go to http://www.regulations.gov and follow the instructions for sending your comments electronically.
• Mail: Docket Management Facility, U.S. Department of Transportation, 400 Seventh Street SW., Nassif Building, room PL-401, Washington, DC 20590.
• By fax: (202) 493-2251.
• Hand Delivery: Room PL-401 on the plaza level of the Nassif Building, 400 Seventh Street SW., Washington, DC, between 9 a.m. and 5 p.m., Monday through Friday, except Federal holidays.

For service information identified in this proposed AD, contact Raytheon Aircraft Company, Department 62, PO Box 85, Wichita, Kansas 67201-0085.

You can examine the contents of this AD docket on the Internet at http://dms.dot.gov,, or in person at the Docket Management Facility, U.S. Department of Transportation, 400 Seventh Street SW., room PL-401, on the plaza level of the Nassif Building, Washington, DC. This docket number is FAA-2004-19561; the directorate identifier for this docket is 2004-NM-50-AD.

FOR FURTHER INFORMATION CONTACT:

Technical information: Jeff Pretz, Aerospace Engineer, Airframe Branch, ACE-118W, FAA, Wichita Aircraft Certification Office, 1801 Airport Road, room 100, Mid-Continent Airport, Wichita, Kansas 67209; telephone (316) 946-4153; fax (316) 946-4407.

Plain language information: Marcia Walters, marcia.walters@faa.gov.

SUPPLEMENTARY INFORMATION:

Docket Management System (DMS)

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. FAA-2004-99999.” The Transport Airplane Directorate identifier is in the form “Directorate Identifier 2004-NM-999-AD.” Each DMS AD docket also lists the directorate identifier (“Old Docket Number”) as a cross-reference for searching purposes.

Comments Invited

We invite you to submit any relevant written data, views, or arguments regarding this proposed AD. Send your comments to an address listed under ADDRESSES. Include “Docket No. FAA-2004-19561; Directorate Identifier 2004-NM-50-AD” 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 19477-78), 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.faa.gov/language and http://www.plainlanguage.gov.

Examining the Docket

You can examine the AD docket on the Internet at http://dms.dot.gov,, or 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) 647-5227) 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 during certification testing of a new firewall fairlead material, insulation on the wire harness passing through the laboratory test firewall fairlead ignited on the fuselage side of the firewall. The configuration of the test firewall and wire harness was similar to the configuration of the firewall and wire harness found on certain Raytheon Model DH.125, HS.125, and BH.125 series airplanes; BAe.125 series 800A (C-29A and U-125), and 800B airplanes; and Hawker 800 (including variant U-125A) and 800XP airplanes; equipped with TFE731 engines. This condition, if not corrected, could result in a fire in the engine compartment causing possible ignition of outgassing wire insulation on the fuselage side of the firewall, which could lead to an uncontrollable fire in the fuselage.

Relevant Service Information

We have reviewed Raytheon Service Bulletin SB 26-3496, dated November 2003. The service bulletin describes procedures for installing insulating blankets on the engine compartment firewall and the wire harness passing through the firewall fairlead. Accomplishing the actions specified in the service information is intended to 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 accomplishing the actions specified in the service information described previously, except as discussed under “Differences Between the Proposed AD and Service Bulletin.”

Differences Between the Proposed AD and Service Bulletin

The service bulletin describes procedures for reporting accomplishment of the service bulletin to the manufacturer; however, this proposed AD would not require that action.

Costs of Compliance

There are about 804 airplanes of the affected design in the worldwide fleet. This proposed AD would affect about 530 airplanes of U.S. registry. The proposed actions would take about 8 work hours per airplane, at an average labor rate of $65 per work hour. Required parts would cost about $1,784 per airplane. Based on these figures, the estimated cost of the proposed AD for U.S. operators is $1,221,120, or $2,304 per airplane.

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 39—AIRWORTHINESS DIRECTIVES

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

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