2010-15652. Airworthiness Directives; McDonnell Douglas Corporation Model MD-90-30 Airplanes

AGENCY:

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

ACTION:

Notice of proposed rulemaking (NPRM).

SUMMARY:

The FAA proposes to supersede an existing airworthiness directive (AD) that applies to certain Model MD-90-30 airplanes. The existing AD currently requires modifying the auxiliary hydraulic power system (including doing all applicable related investigative and corrective actions). This proposed AD would require these same actions, using corrected service information. This proposed AD results from fuel system reviews conducted by the manufacturer, as well as reports of electrically shorted wires in the right wheel well and evidence of arcing on the auxiliary hydraulic pump power cables, which are routed within the tire burst area. We are proposing this AD to prevent electrically shorted wires or arcing at the auxiliary hydraulic pump power cables, which could result in a fire in the wheel well. We are also proposing this AD to reduce the potential of an ignition source adjacent to the fuel tanks, which, in combination with flammable fuel vapors, could result in a fuel tank explosion and consequent loss of the airplane.

DATES:

We must receive comments on this proposed AD by August 12, 2010.

ADDRESSES:

You may send comments by any of the following methods:

• Federal eRulemaking Portal: Go to http://www.regulations.gov. Follow the instructions for submitting comments.
• Fax: [phone].
• Mail: U.S. Department of Transportation, Docket Operations, M-30, West Building Ground Floor, Room W12-140, 1200 New Jersey Avenue, SE., Washington, DC 20590.
• Hand Delivery: U.S. Department of Transportation, Docket Operations, M-30, West Building Ground Floor, Room W12-140, 1200 New Jersey Avenue, SE., Washington, DC 20590, between 9 a.m. and 5 p.m., Monday through Friday, except Federal holidays.

For service information identified in this proposed AD, contact Boeing Commercial Airplanes, Attention: Data & Services Management, 3855 Lakewood Boulevard, MC D800-0019, Long Beach, California 90846-0001; telephone [phone], extension 2; fax [phone]; e-mail [e-mail]; Internet https://www.myboeingfleet.com. You may review copies of the referenced service information at the FAA, Transport Airplane Directorate, 1601 Lind Avenue, SW., Renton, Washington. For information on the availability of this material at the FAA, call 425-227-1221.

Examining the AD Docket

You may examine the AD docket on the Internet at http://www.regulations.gov;​; or in person at the Docket Management Facility between 9 a.m. and 5 p.m., Monday through Friday, except Federal holidays. The AD docket contains this proposed AD, the regulatory evaluation, any comments received, and other information. The street address for the Docket Office (telephone [phone]) is in the ADDRESSES section. Comments will be available in the AD docket shortly after receipt.

FOR FURTHER INFORMATION CONTACT:

Ken Sujishi, Aerospace Engineer, Cabin Safety/Mechanical and Environmental Systems Branch, ANM-150L, FAA, Los Angeles Aircraft Certification Office, 3960 Paramount Boulevard, Lakewood, California 90712-4137; telephone [phone]; fax [phone].

SUPPLEMENTARY INFORMATION:

Comments Invited

We invite you to send any written relevant data, views, or arguments about this proposed AD. Send your comments to an address listed under the ADDRESSES section. Include “Docket No. FAA-2010-0554; Directorate Identifier 2010-NM-082-AD” at the beginning of your comments. We specifically invite comments on the overall regulatory, economic, environmental, and energy aspects of this proposed AD. We will consider all comments received by the closing date and may amend this proposed AD because of those comments.

We will post all comments we receive, without change, to http://www.regulations.gov,, including any personal information you provide. We will also post a report summarizing each substantive verbal contact we receive about this proposed AD.

Discussion

On March 18, 2009, we issued AD 2009-07-04, Amendment 39-15863 (74 FR 14460, March 31, 2009), for certain Model MD-90-30 airplanes. That AD requires modifying the auxiliary hydraulic power system (including doing all applicable related investigative and corrective actions). That AD resulted from fuel system reviews conducted by the manufacturer, as well as reports of shorted wires in the right wheel well and evidence of arcing on the power cables of the auxiliary hydraulic pump. Boeing analysis determined that the existing auxiliary hydraulic pump wire harness assembly is routed within the tire burst area and that installing and routing a new and longer auxiliary hydraulic pump wire harness assembly outside the tire burst area will minimize the possibility of chafing and electrical wire arcing damage. We issued that AD to prevent shorted wires or electrical arcing at the auxiliary hydraulic pump, which could result in a fire in the wheel well; and to reduce the potential of an ignition source adjacent to the fuel tanks, which, in combination with flammable fuel vapors, could result in a fuel tank explosion and consequent loss of the airplane.

Actions Since Existing AD Was Issued

Since we issued AD 2009-07-04, we have been advised that the Work Instructions of Boeing Alert Service Bulletin MD90-29A021, Revision 1, dated August 29, 2008 (the service bulletin referenced in AD 2009-07-04), are inadequate in that some wire support clamp orientations would present a riding condition with surrounding structure or existing hydraulic lines.

Relevant Service Information

Boeing has issued Alert Service Bulletin MD90-29A021, Revision 2, dated March 16, 2010, which includes additional work (e.g., checking electrical resistance and doing a general visual inspection of the wire harness protective sleeving dimensions, which are related investigative actions; and installing new sleeving, adding tie tape, installing a new wire harness assembly, and installing new clamps, which are corrective actions).

FAA's Determination and Requirements of the Proposed AD

We have evaluated all pertinent information and identified an unsafe condition that is likely to develop on other airplanes of the same type design. For this reason, we are proposing this AD, which would supersede AD 2009-07-04 but would not retain the requirements of the existing AD. This proposed AD would require accomplishing the actions specified in Boeing Alert Service Bulletin MD90-29A021, Revision 2, dated March 16, 2010, as described previously.

Costs of Compliance

There are about 109 airplanes of the affected design in the worldwide fleet. The following table provides the estimated costs for U.S. operators to comply with this proposed AD.

Estimated Costs

Action	Work hours	Average labor rate per hour	Parts	Cost per airplane	Number of U.S.- registered airplanes	Fleet cost
Modification	Between 4 and 11	$85	Up to $4,870	Between $5,210 and $5,805	21	Between $109,410 and $121,905.

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 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 and placed it in the AD docket. 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
• Incorporation by reference
• 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.

§ 39.13

[Amended]

2. The FAA amends § 39.13 by removing Amendment 39-15863 (74 FR 14460, March 31, 2009) and adding the following new AD:

McDonnell Douglas Corporation: Docket No. FAA-2010-0554; Directorate Identifier 2010-NM-082-AD.

Comments Due Date

(a) The FAA must receive comments on this AD action by August 12, 2010.

Affected ADs

(b) This AD supersedes AD 2009-07-04, Amendment 39-15863.

Applicability

(c) This AD applies to McDonnell Douglas Corporation Model MD-90-30 airplanes, certificated in any category; as identified in Boeing Alert Service Bulletin MD90-29A021, Revision 2, dated March 16, 2010.

Subject

(d) Air Transport Association (ATA) of America Code 29: Hydraulic Power.

Unsafe Condition

(e) This AD results from fuel system reviews conducted by the manufacturer, as well as reports of electrically shorted wires in the right wheel well and evidence of arcing on the auxiliary hydraulic pump power cables, which are routed within the tire burst area. The Federal Aviation Administration is proposing this AD to prevent electrically shorted wires or arcing at the auxiliary hydraulic pump power cables, which could result in a fire in the wheel well. We are also proposing this AD to reduce the potential of an ignition source adjacent to the fuel tanks, which, in combination with flammable fuel vapors, could result in a fuel tank explosion and consequent loss of the airplane.

Compliance

(f) You are responsible for having the actions required by this AD performed within the compliance times specified, unless the actions have already been done.

Replacement

(g) Within 18 months after the effective date of this AD, modify the auxiliary hydraulic power system, and do all applicable related investigative and corrective actions, in accordance with the Accomplishment Instructions of Boeing Alert Service Bulletin MD90-29A021, Revision 2, dated March 16, 2010. Do all applicable related investigative and corrective actions before further flight.

Alternative Methods of Compliance (AMOCs)

(h)(1) The Manager, Los Angeles Aircraft Certification Office, FAA, has the authority to approve AMOCs for this AD, if requested using the procedures found in 14 CFR 39.19. Send information to ATTN: Ken Sujishi, Aerospace Engineer, Cabin Safety/Mechanical and Environmental Systems Branch, ANM-150L, FAA, Los Angeles Aircraft Certification Office, 3960 Paramount Boulevard, Lakewood, California 90712-4137; telephone [phone]; fax [phone].

(2) To request a different method of compliance or a different compliance time for this AD, follow the procedures in 14 CFR 39.19. Before using any approved AMOC on any airplane to which the AMOC applies, notify your principal maintenance inspector (PMI) or principal avionics inspector (PAI), as appropriate, or lacking a principal inspector, your local Flight Standards District Office. The AMOC approval letter must specifically reference this AD.

Issued in Renton, Washington, on June 17, 2010.

Robert D. Breneman,

Acting Manager, Transport Airplane Directorate, Aircraft Certification Service.