Airworthiness Directives; BAE Systems (Operations) Limited Model BAe 146 Series Airplanes

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 BAE Systems (Operations) Limited Model BAe 146 series airplanes. This proposal would require repetitive detailed inspections for heat damage to any in-line splice in the auxiliary power unit (APU) and integrated drive generator (IDG) feeder cable circuits, and corrective action if necessary. This proposed AD also would provide for optional terminating action for the repetitive inspections. This action is necessary to prevent overheating of the in-line splices of the APU and IDG feeder cables, which can lead to smoke, fumes, and possible fire in the flight deck and cabin. This action is intended to address the identified unsafe condition.

DATES:

Comments must be received by April 16, 2004.

ADDRESSES:

Submit comments in triplicate to the Federal Aviation Administration (FAA), Transport Airplane Directorate, ANM-114, Attention: Rules Docket No. 2003-NM-171-AD, 1601 Lind Avenue, SW., Renton, Washington 98055-4056. Comments may be inspected at this location between 9 a.m. and 3 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. 2003-NM-171-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 or 2000 or ASCII text.

The service information referenced in the proposed rule may be obtained from British Aerospace Regional Aircraft American Support, 13850 Mclearen Road, Herndon, Virginia 20171. This information may be examined at the FAA, Transport Airplane Directorate, 1601 Lind Avenue, SW., Renton, Washington.

FOR FURTHER INFORMATION CONTACT:

Todd Thompson, Aerospace Engineer, International Branch, ANM-116, FAA, Transport Airplane Directorate, 1601 Lind Avenue, SW., Renton, Washington 98055-4056; telephone (425) 227-1175; fax (425) 227-1149.

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 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 2003-NM-171-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. 2003-NM-171-AD, 1601 Lind Avenue, SW., Renton, Washington 98055-4056.

Discussion

The Civil Aviation Authority (CAA), which is the airworthiness authority for the United Kingdom, notified the FAA that an unsafe condition may exist on certain BAE Systems (Operations) Limited Model BAe 146 series airplanes. The CAA advises that it received reports of in-line splices in the auxiliary power unit (APU) feeder cables being damaged by overheating. The CAA considers that splices in the integrated drive generator (IDG) feeder cables could also be subject to overheating. Poor joint splicing of electrical cables can lead to overheating that involves conductor melting. These failures can result in open APU generator or IDG circuits, followed by the associated generator tripping off-line. Overheating of the in-line splices of the APU or IDG feeder cables, if not corrected, can lead to smoke, fumes, and possible fire in the flight deck and cabin.

Explanation of Relevant Service Information

BAE Systems (Operations) Limited has issued Inspection Service Bulletin ISB.24-139, dated April 2, 2003, which describes procedures for repetitive detailed inspections for heat damage to any in-line splice in the APU and IDG feeder cable circuits, and corrective action if necessary. The service bulletin refers to additional service bulletins for corrective and terminating actions, as follows:

• BAE Systems (Operations) Limited Modification Service Bulletin SB.24-82-36097A&B, Revision No. 2, dated September 23, 1992, which describes procedures for modification of the APU feeders involving installation of an improved splice, and installation of continuous size 6 cables without splices.
• BAE Systems (Operations) Limited Modification Service Bulletin SB.24-85-01253A, Revision No. 1, dated March 15, 1991, which describes procedures for modification of the IDG feeders involving installation of an improved splice.
• BAE Systems (Operations) Limited Modification Service Bulletin SB.24-98-01253B, dated October 30, 1992, which describes procedures for modification of the IDG feeders involving installation of continuous size 6 cables without splices.
• BAE Systems (Operations) Limited Modification Service Bulletin SB.24-92-01203C, Revision 1, dated August 27, 2002, which describes procedures for modification of the IDG feeders involving installation of size 4 cables that have terminal blocks instead of splices.

Per BAE Systems (Operations) Limited Inspection Service Bulletin ISB.24-139, dated April 2, 2003, accomplishment of any of the modifications described previously eliminates the need for the repetitive inspections of the APU or IDG feeders, as applicable.

Accomplishment of the actions specified in the service bulletins is intended to adequately address the identified unsafe condition. The CAA classified BAE Systems (Operations) Limited Inspection Service Bulletin ISB.24-139, dated April 2, 2003, as mandatory and issued British airworthiness directive 005-04-2003 to ensure the continued airworthiness of these airplanes in the United Kingdom.

FAA's Conclusions

This airplane model is manufactured in the United Kingdom and is type certificated for operation in the United States under the provisions of section 21.29 of the Federal Aviation Regulations (14 CFR 21.29) and the applicable bilateral airworthiness agreement. Pursuant to this bilateral airworthiness agreement, the CAA has kept the FAA informed of the situation described above. The FAA has examined the findings of the CAA, reviewed all available information, and determined that AD action is necessary for products of this type design that are certificated for operation in the United States.

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 registered in the United States, the proposed AD would require accomplishment of the actions specified in BAE Systems (Operations) Limited Inspection Service Bulletin ISB.24-139, dated April 2, 2003, except as discussed below under “Difference Between Proposed Rule and Certain Referenced Service Bulletin.”

This proposed AD also would provide for optional terminating action for the repetitive inspections. Consistent with the findings of the CAA, the proposed AD would allow repetitive inspections to continue in lieu of the terminating action. In making this determination, we considered that long-term continued operational safety in this case will be adequately ensured by repetitive inspections of in-line splices in the APU and IDG feeder cables to detect heat damage before it represents a hazard to the airplane.

Difference Between Proposed Rule and Certain Referenced Service Bulletin

Operators should note that, although the Accomplishment Instructions of BAE Systems (Operations) Limited Inspection Service Bulletin ISB.24-139, dated April 2, 2003, describes procedures for reporting inspection findings to the airplane manufacturer, this proposed AD would not require that action.

Cost Impact

The FAA estimates that 17 airplanes of U.S. registry would be affected by this proposed AD, that it would take approximately 6 work hours per airplane to accomplish the proposed inspections, and that the average labor rate is $65 per work hour. Based on these figures, the cost impact of the proposed AD on U.S. operators is estimated to be $6,630, or $390 per airplane, per inspection cycle.

The optional terminating action, if done, would take approximately between 5 and 30 work hours per airplane, at an average labor rate of $65 per work hour. Required parts would cost approximately between $744 and $1,379 per airplane. Based on these figures, we estimate the cost of the optional terminating action to be between $1,069 and $2,847 per airplane.

The cost impact figures discussed above are 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 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.