AD 2001-17-09 R1 ACTIVE

This amendment rescinds Airworthiness Directive (AD) 2000-17-09, which is applicable to certain McDonnell Douglas Model MD-11 series airplanes. That AD requires an inspection of the upper avionics circuit breaker panel at the main observer's station to detect damage of the wires and to verify the correct routing of the wire bundles; corrective actions, if necessary; and installation of a new clamp, spacer, and sta-straps. The requirements of that AD were intended to prevent chafing in the upper avionics circuit breaker panel of the main observer's station, which could result in arcing and consequent smoke and/or fire in the cockpit. Since the issuance of that AD, the FAA has determined that the improper procedures specified by the service bulletin referenced in that AD could lead to wiring pre-load conditions and consequent wire damage, and arcing in the upper avionics circuit breaker panel. Such conditions could result in arcing and consequent smoke and/or fire in the cockpit.

Final rule; rescission

2001-17-09 R1 McDonnell Douglas: Amendment 39-12451. Docket No. 2001-NM-299-AD. Rescinds AD 2001-17-09, Amendment 39-12400.\n\n\tApplicability: Model MD-11 series airplanes, as listed in Boeing Alert Service Bulletin MD11-24A179, Revision 01, dated October 31, 2000; certificated in any category.\n\n This rescission is effective September 27, 2001.

On August 14, 2001, the Federal Aviation Administration (FAA) issued AD 2001-17-09, amendment 39-12400 (66 FR 44041, August 22, 2001), applicable to certain McDonnell Douglas Model MD-11 series airplanes. That AD requires an inspection of the upper avionics circuit breaker panel at the main observer's station to detect damage of the wires and to verify the correct routing of the wire bundles; corrective actions, if necessary; and installation of a new clamp, spacer, and sta-straps. Chafing in the upper avionics circuit breaker panel of the main observer's station, could result in arcing and consequent smoke and/or fire in the cockpit. \n\nBackground \n\n\tDuring the comment period preceding the issuance of AD 2001-17-09, an operator submitted a letter stating its concern about the validity of the wiring procedures specified by Boeing Alert Service Bulletin MD11-24A179, Revision 01, dated October 31, 2000, which was cited in that AD. In response to that concern, the FAA consulted with the airplane manufacturer and was informed that the wiring procedures in the service bulletin were workable, and that the specified wire lengths were adequate. In light of this information, we determined that no change to the wire routing requirements of paragraph (a)(1)(ii) in the final rule was necessary. \n\nActions Since Issuance of Previous AD \n\n\tFollowing the issuance of AD 2001-17-09, the same operator contacted the FAA, informing us that the wiring procedures required by the AD per the Boeing service bulletin could cause wiring pre-load conditions. In response, we again consulted with Boeing to re-confirm their previous assessment. Boeing informed us that it had re-evaluated the procedures specified in the service bulletin and determined that, contrary to its original assessment, those procedures could actually cause wiring pre-load conditions and chafing. \n\n\tIn light of this information, the FAA has determined that the procedures in the previouslyreferenced Boeing service bulletin could lead to wiring pre-load conditions and consequent wire damage, and arcing in the upper avionics circuit breaker panel. Such conditions could result in arcing and consequent smoke and/or fire in the cockpit. \n\nFAA's Determination \n\n\tSince accomplishment of the requirements of AD 2001-17-09 could cause conditions that may contribute to the identified unsafe condition, the FAA has determined that it is necessary to rescind that AD to prevent operators from performing the procedures included in the previously referenced Boeing service bulletin, which was cited in that \nAD. The FAA may consider further rulemaking to correct the original unsafe condition that prompted AD 2001-17-09.\n\n\tSince this action rescinds a requirement to perform improper procedures, it has no adverse economic impact and imposes no additional burden on any person. Therefore, notice and public procedures hereon are unnecessary and the rescission may be made effective uponpublication in the Federal Register.\n\nThe Rescission\n\n\tAccordingly, pursuant to the authority delegated to me by the Administrator, the Federal Aviation Administration amends part 39 of the Federal Aviation Regulations (14 CFR part 39) as follows:\n\nPART 39--AIRWORTHINESS DIRECTIVES\n\n\t1. The authority citation for part 39 continues to read as follows:\n\n\tAuthority: 49 U.S.C. 106(g), 40113, 44701.\n\nSec. 39.13 (Amended)\n\n\t2. Section 39.13 is amended by adding an AD which removes amendment 39-12400, to read as follows:

Brett Portwood, Aerospace Engineer, Systems and Equipment Branch, ANM-130L, FAA, Los Angeles Aircraft Certification Office, 3960 Paramount Boulevard, Lakewood, California\n90712-4137; telephone (562) 627-5350; fax (562) 627-5210.