AD 94-11-06 SUPERSEDED

This amendment adopts a new airworthiness directive (AD) that is applicable to certain McDonnell Douglas Model MD-11 and MD-11F series airplanes. This action requires modification of the external power feeder cable clamping installation. This amendment is prompted by reports of damage to the external power feeder cables located under the forward cargo compartment floor, which was caused by excessive cable length and/or maintenance personnel stepping on the cables. The actions specified in this AD are intended to prevent arcing from occurring under the forward cargo compartment floor as a result of damaged external power feeder cables, a situation that could lead to a fire at this location.

Final rule; request for comments.

94-11-06 McDONNELL DOUGLAS: Amendment 39-8922. Docket 94-NM-64-AD. \n\n\tApplicability: Model MD-11 and MD-11F series airplanes, as listed in McDonnell Douglas Service Bulletin 24-78, dated May 10, 1994, certificated in any category. \n\n\tCompliance: Required as indicated, unless accomplished previously. \n\n\tTo prevent arcing from occurring under the forward cargo compartment floor as a result of damaged external power feeder cables, a situation that could lead to a fire at this location, accomplish the following: \n\n\t(a)\tWithin 90 days after the effective date of this AD, modify the external power feeder cable clamping installation in accordance with McDonnell Douglas Service Bulletin 24-78, dated May 10, 1994. \n\n\t(b)\tAn 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, Los Angeles Aircraft Certification Office (ACO), FAA, Transport Airplane Directorate. Operators shall submit their requests through an appropriate FAA Principal Maintenance Inspector, who may add comments and then send it to the Manager, Los Angeles ACO. \n\n\tNOTE: Information concerning the existence of approved alternative methods of compliance with this AD, if any, may be obtained from the Los Angeles ACO. \n\n\t(c)\tSpecial 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. \n\n\t(d)\tThe modification shall be done in accordance with McDonnell Douglas Service Bulletin 24-78, dated May 10, 1994. This incorporation by reference was approved by the Director of the Federal Register in accordance with 5 U.S.C. 552(a) and 1 CFR Part 51. Copies may be obtained from McDonnell Douglas Corporation, P.O. Box 1771, Long Beach, California 90801-1771, Attention: Business Unit Manager, Technical Administrative support, Dept. L51, M.C. 2-98. Copies may be inspected at the FAA, Transport Airplane Directorate, 1601 Lind Avenue, SW., Renton, Washington; or at the FAA, Los Angeles Aircraft Certification Office, Transport Airplane Directorate, 3229 East Spring Street, Long Beach, California; or at the Office of the Federal Register, 800 North Capitol Street, NW., suite 700, Washington, DC. \n\n\t(e)\tThis amendment becomes effective on June 15, 1994.

One operator of McDonnell Douglas Model MD-11 series airplanes recently reported that, during fueling and loading of cargo, smoke was observed in the forward lower cargo compartment of one airplane. The forward cargo door was open and no cargo compartment smoke warning was noted in the cockpit. Maintenance personnel directed a fire extinguisher into the cargo compartment air outlet at approximately station Y=635. The airport fire department was notified and assisted in extinguishing all smoke. No injuries were reported. Investigation of this incident revealed heat damage under the cargo floor from station Y=602 to station Y=695, between longerons 48 left-hand side to 43 right-hand side. Insulation blankets at these locations were replaced. Vertical supports, part numbers (P/N) ADA0033-2, suffered possible heat damage and were replaced. Certain wiring located near the aircraft centerline, station Y=602 to Y=615, was discolored and replaced. Paint on the lower fuselage in three locations was slightly darkened. The airplane was repaired prior to return to service. \n\n\tApproximately one month later, a second incident occurred on this same airplane in which, prior to flight, a burning smell was noticed in the First Class passenger seating area at about the same time that electrical power was being applied to the airplane. Subsequently, the airplane would not accept external power. Investigation revealed that the external power cables had chafed and arced to the fuselage frame at station Y=655. The metalized covering of one blanket at this location from the airplane centerline to one yard left of centerline was missing, and the blanket insulation had burn spots. The cables and blankets were replaced on this airplane. \n\n\tInvestigation of these incidents by McDonnell Douglas revealed that the damage to the external power feeder cables located under the forward cargo compartment floor could have been caused by excessive cable length and/or maintenance personnel stepping on the cable. Damage to the cables, such as chafing, can lead to arcing at the subject location. This condition, if not corrected, could result in a fire under the forward cargo compartment floor. \n\n\tThe FAA has reviewed and approved McDonnell Douglas Service Bulletin 24-78, dated May 10, 1994, that describes procedures for replacing one cable clamp support (standoff) with a new bracket at station Y=655, and replacing six nylon cable clamps with new metal clamps having rubber cushions at station Y=635. Modifying the external power feeder cable clamping installation will minimize the possibility of damage and chafing of the cables, and thereby minimize the possibility of arcing and potential resultant fire. The manufacturer has advised that this installation will be incorporated prior to delivery on airplanes having manufacturer's serial numbers 559, 560, 562, and subsequent. \n\n\tSince an unsafe condition has been identified that is likelyto exist or develop on other Model MD-11 and MD-11F series airplanes of the same type design, this AD is being issued to prevent arcing from occurring under the forward cargo compartment floor as a result of damaged external power feeder cables, a situation that could lead to a fire at this location. This AD requires modification of the external power feeder cable clamping installation. The actions are required to be accomplished in accordance with the service bulletin described previously. \n\n\tSince a situation exists that requires the immediate adoption of this regulation, it is found that notice and opportunity for prior public comment hereon are impracticable, and that good cause exists for making this amendment effective in less than 30 days. \n\nComments Invited \n\n\tAlthough this action is in the form of a final rule that involves requirements affecting flight safety and, thus, was not preceded by notice and an opportunity for public comment, comments are invited on this rule. Interested persons are invited to comment on this 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 under the caption "ADDRESSES." All communications received on or before the closing date for comments will be considered, and this rule may be amended in light of the comments received. Factual information that supports the commenter's ideas and suggestions is extremely helpful in evaluating the effectiveness of the AD action and determining whether additional rulemaking action would be needed. \n\n\tComments are specifically invited on the overall regulatory, economic, environmental, and energy aspects of the rule that might suggest a need to modify the 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 that summarizes each FAA-public contact concerned with the substance of this AD will be filed in the Rules Docket. \n\n\tCommenters wishing the FAA to acknowledge receipt of their comments submitted in response to this notice must submit a self-addressed, stamped postcard on which the following statement is made: "Comments to Docket Number 94-NM-64-AD." The postcard will be date stamped and returned to the commenter. \n\n\tThe regulations adopted herein will not have substantial direct effects 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, in accordance with Executive Order 12612, it is determined that this final rule does not have sufficient federalism implications to warrant the preparation of a Federalism Assessment. \n\n\tThe FAA has determined that this regulation is an emergency regulation that must be issued immediately to correct an unsafe condition in aircraft, and is not a "significant regulatory action" under Executive Order 12866. It has been determined further that this action involves an emergency regulation under DOT Regulatory Policies and Procedures (44 FR 11034, February 26, 1979). If it is determined that this emergency regulation otherwise would be significant under DOT Regulatory Policies and Procedures, a final regulatory evaluation will be prepared and placed in the Rules Docket. A copy of it, if filed, may be obtained from the Rules Docket at the location provided under the caption "ADDRESSES." \n\nList of Subjects in 14 CFR Part 39 \n\n\tAir transportation, Aircraft, Aviation safety, Incorporation by reference, Safety. \n\nAdoption of the Amendment \n\n\tAccordingly, pursuant to the authority delegated to me by the Administrator, the Federal Aviation Administration amends 14 CFR part 39 of the Federal Aviation Regulations as follows: \n\nPART 39 - AIRWORTHINESS DIRECTIVES \n\n\t1.\tThe authority citation for part 39 continues toread as follows: \n\nAuthority: 49 U.S.C. App. 1354(a), 1421 and 1423; 49 U.S.C. 106(g); and 14 CFR 11.89. \n\n§ 39.13 - (Amended) \n\n\t2.\tSection 39.13 is amended by adding the following new airworthiness directive:

Submit comments in triplicate to the Federal Aviation Administration (FAA), Transport Airplane Directorate, ANM-103, Attention: Rules Docket No. 94-NM-64-AD, 1601 Lind Avenue, SW., Renton, Washington 98055-4056.\n\n\tThe service information referenced in this AD may be obtained from McDonnell Douglas Corporation, P.O. Box 1771, Long Beach, California 90801-1771, Attention: Business Unit Manager, Technical Administrative support, Dept. L51, M.C. 2-98. 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, Transport Airplane Directorate, 3229 East Spring Street, Long Beach, California; or at the Office of the Federal Register, 800 North Capitol Street, NW., suite 700, Washington, DC.

Brett Portwood, Aerospace Engineer, Systems & Equipment Branch, ANM-130L, Los Angeles Aircraft Certification Office, FAA, Transport Airplane Directorate, 3229 East Spring Street, Long Beach, California 90806-2425; telephone (310) 988-5347; fax (310) 988-5210.