Federal Aviation Administration, DOT.
Notice of proposed rulemaking (NPRM).
This document proposes the adoption of a new airworthiness directive (AD) that is applicable to certain Boeing Model 747-200B and -200F series airplanes powered by Pratt & Whitney JT9D-70 series engines. This proposal would require repetitive detailed inspections of the pylon skin and internal structure of the nacelle struts adjacent to and aft of the precooler exhaust vent for heat damage (discoloration), wrinkling, and cracking; and corrective action, if necessary. This action is necessary to find and fix such damage, which could result in cracking Start Printed Page 70876or fracture of the nacelle struts, and consequent reduced structural integrity and possible separation of the strut and engine from the airplane. This action is intended to address the identified unsafe condition.
Comments must be received by January 13, 2003.
Submit comments in triplicate to the Federal Aviation Administration (FAA), Transport Airplane Directorate, ANM-114, Attention: Rules Docket No. 2002-NM-23-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: firstname.lastname@example.org. Comments sent via fax or the Internet must contain “Docket No. 2002-NM-23-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 for Windows or ASCII text.
The service information referenced in the proposed rule may be obtained from Boeing Commercial Airplane Group, P.O. Box 3707, Seattle, Washington 98124-2207. This information may be examined at the FAA, Transport Airplane Directorate, 1601 Lind Avenue, SW., Renton, Washington.Start Further Info
FOR FURTHER INFORMATION CONTACT:
Tamara L. Anderson, Aerospace Engineer, Airframe Branch, ANM-120S, FAA, Seattle Aircraft Certification Office, 1601 Lind Avenue, SW., Renton, Washington 98055-4056; telephone (425) 227-2771; fax (425) 227-1181.End Further Info End Preamble Start Supplemental Information
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 2002-NM-23-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. 2002-NM-23-AD, 1601 Lind Avenue, SW., Renton, Washington 98055-4056.
The FAA has received reports from three operators who found heat damage (discoloration) and cracking adjacent to and aft of the precooler exhaust vent on the nacelle struts of three Boeing Model 747 series airplanes powered by Pratt & Whitney JT9D-70 series engines. Investigation revealed that high temperature exhaust air from the precooler vent caused the heat damage. Such damage to the structure could result in cracking or fracture of the nacelle struts, and consequent reduced structural integrity and possible separation of the strut and engine from the airplane.
Explanation of Relevant Service Information
We have reviewed and approved Boeing Special Attention Service Bulletin 747-54-2210, dated December 19, 2001, which describes procedures for repetitive detailed inspections of the pylon skin and internal structure of the nacelle struts adjacent to and aft of the precooler exhaust vent for heat discoloration, wrinkling, and cracking; and corrective action, if necessary. The corrective action includes the following:
- If heat discoloration but no wrinkling is found, do a conductivity test of the damaged area(s). If the conductivity test is within specified limits, do a penetrant or high frequency eddy current (HFEC) inspection of the heat discolored areas for cracking. If no cracking is found, repeat the detailed inspection.
- If wrinkling is found, do a penetrant inspection for cracking of the wrinkled area(s). An optional HFEC inspection can also be done for such damage. The service bulletin specifies contacting the manufacturer for additional instructions if wrinkling is found.
- If cracking is found, or the conductivity readings are not within the limits specified in the service bulletin, the service bulletin specifies contacting the manufacturer for additional instructions.
Accomplishment of the actions specified in the service bulletin is intended to adequately address the identified unsafe condition.
Explanation of Requirements of Proposed Rule
Since an unsafe condition has been identified that is likely to exist or develop on other products of this same type design, the proposed AD would require accomplishment of the actions specified in the service bulletin described previously, except as discussed below.
Difference Between Proposed Rule and Service Bulletin
Although the service bulletin specifies that the manufacturer may be contacted for disposition of certain repair conditions, this proposal would require the repair of those conditions to be accomplished per a method approved by the FAA, or per data meeting the type certification basis of the airplane approved by a Boeing Company Designated Engineering Representative who has been authorized by the FAA to make such findings.
There are approximately 7 airplanes of the affected design in the worldwide fleet. The FAA estimates that 6 airplanes of U.S. registry would be affected by this proposed AD, that it would take approximately 8 work hours per airplane to accomplish the proposed inspection, and that the average labor rate is $60 per work hour. Based on these figures, the cost impact of the proposed AD on U.S. operators is estimated to be $2,880, or $480 per airplane, per inspection cycle.
The cost impact figure discussed above is based on assumptions that no Start Printed Page 70877operator 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 proposed 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.
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.Start List of Subjects
List of Subjects in 14 CFR Part 39
- Air transportation
- Aviation 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:Start Part
PART 39—AIRWORTHINESS DIRECTIVES
1. The authority citation for part 39 continues to read as follows:
2. Section 39.13 is amended by adding the following new airworthiness directive:
Boeing: Docket 2002-NM-23-AD.
Applicability: Model 747-200B and -200F series airplanes powered by Pratt & Whitney JT9D-70 series engines, certificated in any category; as listed in Boeing Special Attention Service Bulletin 747-54-2210, dated December 19, 2001.
This AD applies to each airplane identified in the preceding applicability provision, regardless of whether it has been modified, altered, or repaired in the area subject to the requirements of this AD. For airplanes that have been modified, altered, or repaired so that the performance of the requirements of this AD is affected, the owner/operator must request approval for an alternative method of compliance in accordance with paragraph (c) of this AD. The request should include an assessment of the effect of the modification, alteration, or repair on the unsafe condition addressed by this AD; and, if the unsafe condition has not been eliminated, the request should include specific proposed actions to address it.
Compliance: Required as indicated, unless accomplished previously.
To find and fix heat damage of the pylon skin and internal structure of the nacelle struts, which could result in cracking or fracture of the struts, and consequent reduced structural integrity and possible separation of the strut and engine from the airplane; accomplish the following:
Repetitive Inspections/Corrective Action
(a) Within 6 months after the effective date of this AD: Do a detailed inspection of the pylon skin and internal structure of the nacelle struts adjacent to and aft of the precooler exhaust vent for heat discoloration, wrinkling, and cracking, per the Work Instructions of Boeing Special Attention Service Bulletin 747-54-2210, dated December 19, 2001. Repeat the inspection at least every 18 months.
For the purposes of this AD, a detailed inspection is defined as: “An intensive visual examination of a specific structural area, system, installation, or assembly to detect damage, failure, or irregularity. Available lighting is normally supplemented with a direct source of good lighting at intensity deemed appropriate by the inspector. Inspection aids such as mirror, magnifying lenses, etc., may be used. Surface cleaning and elaborate access procedures may be required.”
(1) If any sign of heat discoloration is found, but there is no wrinkling: Before further flight, do a conductivity test of the discolored area(s) per the service bulletin. If the conductivity test is within the limits specified in Figures 3 and 4, as applicable, of the Work Instructions of the service bulletin, and no cracking is found, before further flight, do a penetrant or high frequency eddy current (HFEC) inspection for cracking.
(2) If any sign of wrinkling is found: Before further flight, do a penetrant or HFEC inspection of the wrinkled area(s) for cracking, per the service bulletin.
(3) If any sign of cracking is found, before further flight, do the corrective action required by paragraph (b) of this AD.
(b) If, during any inspection or test done by this AD, any wrinkling or cracking is found, or the conductivity limits exceed the limits specified in Figures 3 and 4, as applicable, of the Work Instructions of the service bulletin: Before further flight, repair per a method approved by the Manager, Seattle Aircraft Certification Office (ACO), FAA; or per data meeting the type certification basis of the airplane approved by a Boeing Company Designated Engineering Representative who has been authorized by the Manager, Seattle ACO, to make such findings. For a repair method to be approved, the approval must specifically reference this AD.
Alternative Methods of Compliance
(c) An alternative method of compliance or adjustment of the compliance time that provides an acceptable level of safety may be used if approved by the Manager, Seattle ACO. Operators shall submit their requests through an appropriate FAA Principal Maintenance Inspector, who may add comments and then send it to the Manager, Seattle ACO.
Information concerning the existence of approved alternative methods of compliance with this AD, if any, may be obtained from the Seattle ACO.
Special Flight Permit
(d) Special flight permits may be issued in accordance with sections 21.197 and 21.199 of the Federal Aviation Regulations (14 CFR 21.197 and 21.199) to operate the airplane to a location where the requirements of this AD can be accomplished.
Issued in Renton, Washington, on November 19, 2002.
Vi L. Lipski,
Manager, Transport Airplane Directorate, Aircraft Certification Service.
[FR Doc. 02-30027 Filed 11-26-02; 8:45 am]
BILLING CODE 4910-13-P