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Federal Aviation Administration (FAA), Department of Transportation (DOT).
Notice of proposed rulemaking (NPRM).
The FAA proposes to adopt a new airworthiness directive (AD) for all transport category airplanes listed above. This proposed AD would require repetitive inspections for cracks of the main landing gear (MLG) shock strut cylinder, and related investigative and corrective actions if necessary. This proposed AD is prompted by two reports of a collapsed MLG and a report of cracks in two MLG cylinders. We are proposing this AD to detect and correct fatigue cracks in the shock strut cylinder of the MLG, which could result in a collapsed MLG during takeoff or landing, and possible reduced structural integrity of the airplane.
We must receive comments on this proposed AD by June 23, 2005.
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 Boeing Commercial Airplanes, Long Beach Division, 3855 Lakewood Boulevard, Long Beach, California 90846, Attention: Data and Service Management, Dept. C1-L5A (D800-0024).
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-2005-21140; the directorate identifier for this docket is 2004-NM-274-AD.Start Further Info
FOR FURTHER INFORMATION CONTACT:
Wahib Mina, Aerospace Engineer, Airframe Branch, ANM-120L, FAA, Los Angeles Aircraft Certification Office, 3960 Paramount Boulevard, Lakewood, California 90712-4137; telephone (562) 627-5324; fax (562) 627-5210.End Further Info End Preamble Start Supplemental Information
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-2005-21140; Directorate Identifier 2004-NM-274-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.
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.
We have received a report of two incidents of a collapsed main landing gear (MLG) on one McDonnell Douglas Model DC-9-32 airplane and one Model DC-9-31 airplane. These incidents happened when the MLG cylinder cracked and failed. The cracks and failures were caused by fatigue stresses from inclusions in high-stress areas, which caused sub-surface fatigue cracks to propagate to the surface of the MLG cylinder. After the two failures, the airplane operator started an inspection program and found cracks in two additional cylinders before the cracks Start Printed Page 24339grew large enough to cause an MLG failure. These additional cracks were found on one McDonnell Douglas Model DC-9-14 airplane and one Model DC-9-15 airplane. Laboratory testing and failure analysis confirmed that inclusions and sub-surface fatigue cracks were present in all four cases, at the same location. This condition, if not corrected, could result in a collapsed MLG during takeoff or landing, and possible reduced structural integrity of the airplane.
Relevant Service Information
We have reviewed Boeing Alert Service Bulletin DC9-32A350, dated December 3, 2004. The service bulletin gives procedures for verifying the number of landings on the MLG shock strut cylinder by examining each airplane's service history. For airplanes that have less than 60,000 landings on the MLG, the service bulletin states that no further action is required until the MLG reaches the 60,000-landing threshold.
The service bulletin also gives procedures for reviewing the maintenance records to determine if the MLG shock strut cylinders on airplanes identified in the service bulletin as Group 3 have always been on Group 3 airplanes.
The service bulletin gives two inspection options:
- Option 1: Fluorescent dye penetrant inspection combined with fluorescent magnetic particle inspection.
- Option 2: Phased array ultrasonic inspection.
For MLG shock strut cylinders on which no crack indication is found, the service bulletin gives procedures for repeating the inspections.
For MLG shock strut cylinders on which any crack indication is found during any inspection, the service bulletin recommends related investigative and corrective actions. The related investigative and corrective actions vary according to the inspection option and are described in the table below.
|Inspect to confirm crack indication—||If crack indication confirmed—||If crack indication not confirmed—|
|Option 1||Remove the cadmium plating and repeat the Option 1 inspection to confirm the crack||Replace the shock strut cylinder and repeat either the Option 1 or Option 2 inspection at the applicable interval indicated in the service bulletin||Apply the primer and topcoat, and repeat either the Option 1 or Option 2 inspection at the applicable interval indicated in the service bulletin.|
|Option 2||Remove the primer and topcoat and repeat the Option 2 inspection to confirm the crack||Remove the cadmium plating and repeat the Option 2 inspection to re-confirm the crack indication If the crack indication is re-confirmed, replace the shock strut cylinder and repeat either the Option 1 or Option 2 inspection at the applicable interval indicated in the service bulletin||Apply the primer and topcoat and repeat either the Option 1 or Option 2 inspection at the applicable interval indicated in the service bulletin.|
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 bulletin described previously.
Costs of Compliance
There are about 644 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.
|Action||Work hours||Average labor rate per hour||Parts||Cost per airplane||Number of U.S.-registered airplanes||Fleet cost|
|Inspection, per inspection cycle||4 to 6||$65||None||$260 to 390||426||$110,760 to $166,140, per inspection cycle.|
Explanation of Change to Applicability
We have specified model designations in the applicability of this proposed AD as published in the most recent type certificate data sheet for the affected models. These model designations do not include the DC-9-10 and DC-9-33, which are listed in paragraph 1.A. “Effectivity,” of the referenced service bulletin.
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. Start Printed Page 24340
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.Start List of Subjects
List of Subjects in 14 CFR Part 39
- Air transportation
- Aviation 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:Start Part
PART 39—AIRWORTHINESS DIRECTIVES
1. The authority citation for part 39 continues to read as follows:
2. The FAA amends § 39.13 by adding the following new airworthiness directive (AD):
McDonnell Douglas: Docket No. FAA-2005-21140; Directorate Identifier 2004-NM-274-AD.
Comments Due Date
(a) The Federal Aviation Administration (FAA) must receive comments on this AD action by June 23, 2005.
(c) This AD applies to all McDonnell Douglas Model DC-9-14, DC-9-15, and DC-9-15F airplanes; Model DC-9-21 airplanes; Model DC-9-31, DC-9-32, DC-9-32 (VC-9C), DC-9-32F, DC-9-33F, DC-9-34, DC-9-34F, and DC-9-32F (C-9A, C-9B) airplanes; Model DC-9-41 airplanes; and Model DC-9-51 airplanes; certificated in any category.
(d) This AD was prompted by two reports of a collapsed main landing gear (MLG) and a report of cracks in two MLG cylinders. We are issuing this AD to detect and correct fatigue cracks in the shock strut cylinder of the MLG, which could result in a collapsed MLG during takeoff or landing, and possible reduced structural integrity of the airplane.
(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.
Service Bulletin Reference Paragraph
(f) The term “service bulletin,” as used in this AD, means the Accomplishment Instructions of Boeing Alert Service Bulletin DC9-32A350, dated December 3, 2004.
(g) Before the applicable compliance time specified in paragraph (h) or Table 1 of this AD, as applicable, do the applicable actions in paragraphs (g)(1) and (g)(2) of this AD.
(1) For all airplane groups: Review the airplane maintenance records of the MLG to determine its service history and the number of landings on the MLG shock strut cylinder.
(2) For Group 3 airplanes identified in the service bulletin: Review the maintenance records to determine if the MLG cylinder on each Group 3 airplane has always been on a Group 3 airplane, and do the actions in paragraph (k) of this AD.
(h) Inspect the MLG shock strut cylinders for cracks using the Option 1 or Option 2 non-destructive testing inspection described in the service bulletin. Inspect in accordance with the Accomplishment Instructions of the service bulletin. Do the detailed inspection before the accumulation of 60,000 total landings on the MLG, or at the applicable grace period specified in Table 1 of this AD, whichever occurs later, except as provided by paragraph (k) of this AD. If the review of maintenance records is not sufficient to conclusively determine the service history and number of landings on the MLG shock strut cylinder, perform the initial inspection at the applicable grace period specified in Table 1 of this AD.
|Airplanes identified in the service bulletin as group||Grace period||Repetitive interval|
|1||Within 18 months or 650 landings after the effective date of this AD, whichever occurs first||Intervals not to exceed 650 landings.|
|2||Within 18 months or 500 landings after the effective date of this AD, whichever occurs first||Intervals not to exceed 500 landings.|
|3, except as provided by paragraph (k) of this AD||Within 18 months or 2,500 landings after the effective date of this AD, whichever occurs first||Intervals not to exceed 2,500 landings.|
|4||Within 18 months or 2,100 landings after the effective date of this AD, whichever occurs first||Intervals not to exceed 2,100 landings.|
No Crack Indication Found
(i) If no crack indication is found during the inspection required by paragraph (h) of this AD, repeat the inspection at the applicable interval specified in Table 1 of this AD.
Related Investigative and Corrective Actions
(j) If any crack indication is found during any inspection required by paragraph (h) or (i) of this AD, before further flight: Confirm the crack indication by doing all applicable related investigative actions and doing the applicable corrective actions in accordance with the service bulletin. Repeat the inspection at the applicable threshold and interval specified in paragraph (h) of this AD.
MLG Cylinder Previously Installed on Group 4 Airplanes
(k) For MLG cylinders on Group 3 airplanes as identified in the service bulletin: If the MLG cylinder was previously installed on a Group 4 airplane, as identified in the service bulletin, or if the service history and number of landings cannot be determined, the MLG cylinder must be inspected at the grace period and repetitive interval that applies to Group 4 airplanes, as specified in Table 1 of this AD.
Alternative Methods of Compliance (AMOCs)
(l) The Manager, Los Angeles Aircraft Certification Office, 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 April 29, 2005.
Manager, Transport Airplane Directorate, Aircraft Certification Service.
[FR Doc. 05-9188 Filed 5-6-05; 8:45 am]
BILLING CODE 4910-13-P