05-24247. Airworthiness Directives; McDonnell Douglas Model MD-90-30 Airplanes

AGENCY:

Federal Aviation Administration (FAA), Department of Transportation (DOT).

ACTION:

Supplemental notice of proposed rulemaking; reopening of comment period.

SUMMARY:

This document revises an earlier proposed airworthiness directive (AD), applicable to certain McDonnell Douglas Model MD-90-30 airplanes, that would have required repetitive inspections and functional tests of the static port heater assemblies, an inspection of the static port heaters and insulators, and corrective actions if necessary. This new action revises the proposed AD by adding repetitive inspections of the static port heaters and insulators and revising the functional test of the static port heater assemblies. The actions specified by this new proposed AD are intended to prevent an electrical short of the static port heater from sparking and igniting the insulation blanket adjacent to the static port heater, which could result in smoke and/or fire in the cabin area. This action is intended to address the identified unsafe condition.

DATES:

Comments must be received by January 17, 2006.

ADDRESSES:

Submit comments in triplicate to the Federal Aviation Administration (FAA), Transport Airplane Directorate, ANM-114, Attention: Rules Docket No. 2003-NM-194-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 [phone]. Comments may also be sent via the Internet using the following address: [e-mail]. Comments sent via fax or the Internet must contain “Docket No. 2003-NM-194-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 AD may be obtained from Boeing Commercial Airplanes, Long Beach Division, 3855 Lakewood Boulevard, Long Beach, California 90846, Attention: Data and Service Management, Dept. C1-L5A (D800-0024). This information may be examined at the FAA, Transport Airplane Directorate, 1601 Lind Avenue, SW., Renton, Washington; or at the FAA, Los Angeles Aircraft Certification Office, 3960 Paramount Boulevard, Lakewood, California.

FOR FURTHER INFORMATION CONTACT:

Elvin Wheeler, Aerospace Engineer, Systems and Equipment Branch, ANM-130L, FAA, Los Angeles Aircraft Certification Office, 3960 Paramount Boulevard, Lakewood, California 90712-4137; telephone [phone]; fax [phone].

SUPPLEMENTARY INFORMATION:

Comments Invited

Interested persons are invited to participate in the making of the proposed AD 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 AD. 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 AD. 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-194-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-194-AD, 1601 Lind Avenue, SW., Renton, Washington 98055-4056.

Discussion

A proposal to amend part 39 of the Federal Aviation Regulations (14 CFR part 39) to add an airworthiness directive (AD), applicable to certain McDonnell Douglas Model MD-90-30 airplanes, was published as a notice of proposed rulemaking (NPRM) in the Federal Register on March 8, 2004 (69 FR 10638). That NPRM would have required repetitive inspections and functional tests of the static port heater assemblies, an inspection of the static port heaters and insulators, and corrective actions if necessary. That NPRM was prompted by studies that revealed that the wiring of the static port heater assembly may be damaged. That condition, if not corrected, could result in an electrical short of the static port heater and consequent sparking and ignition of the insulation blanket adjacent to the static port heater, which could result in smoke and/or fire in the cabin area.

Actions Since Issuance of Previous Proposal

The airplane manufacturer informed the FAA that the functional test of the left and right primary and alternate static port heater assemblies must be revised to prevent damaging the aircraft fuselage skin. An operator informed the airplane manufacturer that performing the current functional test will overheat and damage the aircraft fuselage skin. Therefore, the airplane manufacturer has revised the functional test and issued Boeing Service Bulletin MD90-30-026, Revision 1, dated May 27, 2005, which references the revised functional test (Boeing Service Bulletin MD90-30-026, dated February 15, 2002, is cited as the appropriate source of service information for doing functional tests specified in the original NPRM). We have revised the supplemental NPRM to reference Revision 1 of Boeing Service Bulletin MD90-30-026 as the appropriate source of service information for accomplishing certain proposed inspections, replacements, and functional tests.

We have also considered the following comments we received in response to the original NPRM:

Request To Add Repetitive Inspections

The National Transportation Safety Board (NTSB) requests that the inspection for incorrect stacking specified in paragraph (b)(2) of the NPRM be changed from a one-time inspection to a repetitive inspection. The NTSB is concerned that, after the one-time inspection specified in the NPRM, incorrect stacking may still occur. The NTSB states that repetitive inspections would address any incorrect stacking that may occur in the future. The NTSB also states that the repetitive inspection interval could be the same as the one for the inspection specified in paragraph (b)(1) of the NPRM, and therefore would not place an undue burden on operators.

We agree with the NTSB that the inspection required in paragraph (b)(2) of the supplemental NPRM be changed to repetitive inspections. Incorrect stacking of the heater and insulator will cause higher-than-normal operating temperature locally in the insulation blanket, which would lead to quicker deterioration and aging of the rubber, causing it to crack and lead to electrical shorting or arcing. In consideration of this unsafe condition and the potential for incorrect stacking, we have determined that repetitive inspections of the heater and insulator for incorrect stacking is necessary. We have revised paragraph (b) of the supplemental NPRM accordingly.

Request To Withdraw the NPRM

One commenter, the airplane manufacturer, requests that the NPRM be withdrawn. The commenter contends that the unsafe condition no longer exists. The commenter states that the unsafe condition was addressed by Boeing Alert Service Bulletin MD90-30A023, including Appendix, dated March 14, 2001 (for Model MD-90-30 airplanes), which was mandated by AD 2001-10-11, amendment 39-12237 (66 FR 28651, May 24, 2001), and by Boeing Alert Service Bulletin MD80-30A092, including Appendix, dated March 14, 2001 (for Model DC-9-81, -82, -83, and -87 airplanes, and Model MD-88 airplanes), which was mandated by AD 2001-10-10, amendment 39-12236 (66 FR 28643, May 24, 2001). The commenter states that those ADs require inspecting the wiring of the primary and alternate static port heaters, determining if the type of insulation blanket installed is metallized Mylar, and modifying the insulation blankets if necessary.

The commenter also states that a review of operator's reports indicates only two events resulted in smoke in the cabin, both on one operator's MD-88 airplanes. One event resulted in the issuance of the service bulletins described previously, and the other event report stated a smoke smell was “evident.” The commenter notes that “in the three years since the release of these service bulletins and the related ADs, no other static port heater smoke/fire events have been reported from the entire MD-80/90 fleet.”

The commenter concludes that the unsafe condition no longer exists, and that the actions in the NPRM are purely an enhancement. Therefore, the commenter requests that the NPRM be withdrawn.

We do not agree with the commenter's request to withdraw the NPRM. Although no other static port heater smoke/fire events have been reported since we issued ADs 2001-10-10 and 2001-10-11, the potential for sparks from an electrical short of the static port heater to ignite the insulation blanket adjacent to the static port heater and result in smoke and/or fire in the cabin area still exists. While ADs 2001-10-10 and 2001-10-11 require only a one-time inspection of the wiring of the static port heaters, this supplemental NPRM would require repetitive functional tests and inspections of the static port heater assemblies and wiring. The proposed repetitive inspections are required to identify and remove marginal static port heaters before they fail and generate sparks. Therefore, we have not withdrawn this supplemental NPRM.

Request To Revise Airplane Maintenance Manual (AMM)

One commenter requests that AMM 30-32-00 be revised to include the procedures to check the insulator for proper installation.

We partially agree with the commenter's request. Operators should note that the procedures to check the insulator for proper installation are located in Boeing Model MD-90-30 AMM 30-32-01, which is a subparagraph of AMM 30-32-00. We have revised the reference to the AMM in paragraph (b)(2) of this supplemental NPRM accordingly.

Request To Revise Service Bulletin

The same commenter requests that Boeing Service Bulletin MD90-30-026, dated February 15, 2002 (cited as the appropriate source of service information for the NPRM), be revised to include the inspection for proper installation as required by the NPRM. The commenter notes that the service bulletin does not include an inspection for proper installation.

We do not agree with the commenter's request. We have consulted with the manufacturer and have concluded that the AMM provides the necessary information to properly complete the inspection. Therefore, there is limited value in revising the service bulletin to include this information. No change is made to the supplemental NPRM in this regard.

Clarification of Alternative Method of Compliance (AMOC) Paragraph

We have revised this supplemental NPRM to clarify the appropriate procedure for notifying the principal inspector before using any approved AMOC on any airplane to which the AMOC applies.

Conclusion

Since certain changes described above expand the scope of the original NPRM, the FAA has determined that it is necessary to reopen the comment period to provide additional opportunity for public comment.

Cost Impact

There are approximately 116 airplanes of the affected design in the worldwide fleet. The FAA estimates that 22 airplanes of U.S. registry would be affected by this proposed AD.

It would take approximately 1 work hour per airplane to accomplish the proposed general visual inspection for wire damage and functional test, at an average labor rate of $65 per work hour. Based on these figures, the cost impact of the proposed inspection for wire damage and functional test on U.S. operators is estimated to be $1,430, or $65 per airplane, per inspection cycle.

It would also take approximately 1 work hour per airplane to accomplish the proposed general visual inspection for proper installation, at an average labor rate of $65 per work hour. Based on these figures, the cost impact of the proposed inspection for proper installation on U.S. operators is estimated to be $1,430, or $65 per airplane, per inspection cycle.

The cost impact figure discussed above is 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.

Authority for This Rulemaking

Title 49 of the United States Code specifies the FAA's authority to issue rules on aviation safety. Subtitle I, Section 106, describes the authority of the FAA Administrator. Subtitle VII, Aviation Programs, describes in more detail the scope of the Agency's authority.

We are issuing this rulemaking under the authority described in Subtitle VII, Part A, Subpart III, Section 44701, “General requirements.” Under that section, Congress charges the FAA with promoting safe flight of civil aircraft in air commerce by prescribing regulations for practices, methods, and procedures the Administrator finds necessary for safety in air commerce. This regulation is within the scope of that authority because it addresses an unsafe condition that is likely to exist or develop on products identified in this rulemaking action.

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

[Amended]

2. Section 39.13 is amended by adding the following new airworthiness directive:

McDonnell Douglas: Docket 2003-NM-194-AD.

Applicability: Model MD-90-30 airplanes, certificated in any category, as identified in Boeing Service Bulletin MD90-30-026, Revision 1, dated May 27, 2005.

Compliance: Required as indicated, unless accomplished previously.

To prevent an electrical short of the static port heater from sparking and igniting the insulation blanket adjacent to the static port heater, which could result in smoke and/or fire in the cabin area, accomplish the following:

Service Bulletin References

(a) The term “service bulletin,” as used in this AD, means the Accomplishment Instructions of Boeing Service Bulletin MD90-30-026, Revision 1, dated May 27, 2005.

Inspection and Functional Test

(b) Within 18 months after the effective date of this AD, do the actions in paragraphs (b)(1) and (b)(2) of this AD. Repeat the actions thereafter at intervals not to exceed 48 months.

(1) Perform a general visual inspection of the left and right primary and alternate static port heater assemblies for wire damage; and perform a functional test of the left and right primary and alternate static port heater assemblies; in accordance with the service bulletin.

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 ensure visual access to all surfaces in the inspection area. This level of inspection is made under normal available lighting conditions such as daylight, hangar lighting, flashlight or drop-light 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.”

(2) Perform a general visual inspection of the left and right primary and alternate static port heater and insulator for proper installation in accordance with a method approved by the Manager, Los Angeles Aircraft Certification Office (ACO). Inspecting for proper installation in accordance with “Static Port Heaters—Maintenance Practices” of McDonnell Douglas MD-90-30 Airplane Maintenance Manual (AMM) 30-32-01 is one approved method. Before further flight, correct any improper installation in accordance with a method approved by the Manager, Los Angeles ACO. Correcting improper installation in accordance with “Static Port Heaters—Maintenance Practices” of AMM 30-32-01 is one approved method. For an inspection method or corrective method to be approved by the Manager, Los Angeles ACO, as required by this paragraph, the Manager's approval letter must specifically refer to this AD.

Wire Damage or Heater Failures

(c) If wire damage is found and/or the heater assembly fails the functional test during the general visual inspection and functional test required by paragraph (b)(1) of this AD: Before further flight, replace the damaged or inoperative static port heater assembly with a new or serviceable static port heater assembly in accordance with the service bulletin.

Actions Accomplished According to Previous Issue of Service Bulletin

(d) Actions accomplished before the effective date of this AD according to Boeing Service Bulletin MD90-30-026, dated February 15, 2002, are considered acceptable for compliance with the corresponding actions specified in this AD.

Alternative Methods of Compliance

(e)(1) In accordance with 14 CFR 39.19, the Manager, Los Angeles ACO, FAA, is authorized to approve alternative methods of compliance for this AD.

(2) Before using any AMOC approved in accordance with 14 CFR 39.19 on any airplane to which the AMOC applies, notify the appropriate principal inspector in the FAA Flight Standards Certificate Holding District Office.

Issued in Renton, Washington, on December 12, 2005.

Ali Bahrami,

Manager, Transport Airplane Directorate, Aircraft Certification Service.