AD 94-10-03 ACTIVE

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 deactivation of the Visual Omnidirectional Receiver/Localizer (VOR/LOC) option by revising the program pin wiring for the Flight Management Computer/Flight Control Computer (FMC/FCC). This amendment is prompted by reports of uncommanded roll mode changes on these airplanes during takeoff and landing due to incorrect initialization of VOR/LOC logic within the FMC. The actions specified in this AD are intended to prevent the airplane from deviating from its intended flight path due to an uncommanded change in the course of direction.

Final rule; request for comments.

94-10-03 McDONNELL DOUGLAS: Amendment 39-8910. Docket 94-NM-57-AD. \n\n\tApplicability: Model MD-11 and MD-11F series airplanes; equipped with Honeywell Flight Management Computers having part numbers 4059050-907 or 4059050-908; certificated in any category. \n\n\tCompliance: Required as indicated, unless accomplished previously. \n\n\tTo prevent the airplane from deviating from its intended flight path due to an uncommanded change in the course of direction, accomplish the following: \n\n\t(a)\tWithin 30 days after the effective date of this AD, deactivate the Visual Omnidirectional Receiver/Localizer (VOR/LOC) option by removing the VOR/LOC pin from the Flight Management Computer/Flight Control Computer (FMC/FCC) configuration plug on the main avionics rack, in accordance with McDonnell Douglas MD-11 Alert Service Bulletin A34-55, dated April 22, 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). Operators shall submit their requests through an appropriate FAA Principal Avionics 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 deactivation procedure shall be done in accordance with McDonnell Douglas MD-11 Alert Service Bulletin A34-55, dated April 22, 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 May 23, 1994.

The FAA has received reports of uncommanded roll mode changes that have occurred on McDonnell Douglas Model MD-11 series airplanes during takeoff and landing. The airplanes involved in these incidents have been equipped with Honeywell Flight Management Computers (FMC) having part numbers 4059050-907 and 4059050-908. The incidents occurred when these FMC's were operating with the Visual Omnidirectional Receiver/Localizer (VOR/LOC) option selected. \n\n\tInvestigation revealed that these incidents of uncommanded roll mode changes were caused by one of the two FMC's not automatically resetting or clearing all VOR mode logic upon landing. If the VOR mode was selected on the previous inbound flight, and if this VOR mode is not automatically cleared after the airplane lands, the VOR logic may remain valid (in operation) in one of the two FMC's onboard the airplane. If, during a subsequent flight, the autoflight system is engaged to the FMC that still has the valid VOR logic (either by disconnecting the autopilot (AP) or by swapping autopilots (AP1 to AP2, or vice versa) with the "AUTOFLIGHT" switch), that FMC will automatically command the airplane into a VOR roll mode. The airplane will then follow this VOR mode logic guidance and fly in a direction not planned by the flight crew. Such an uncommanded change in course direction, if not corrected, could result in the airplane deviating from its intended flight path. \n\n\tThe FAA has reviewed and approved McDonnell Douglas MD-11 Alert Service Bulletin A34-55, dated April 22, 1994, that describes procedures for deactivating the VOR/LOC option on the subject Honeywell FMC's by removing the VOR/LOC pin from the Flight Management Computer/Flight Control Computer (FMC/FCC) configuration plug on the main avionics rack. This procedure will minimize the possibility of uncommanded roll mode changes. \n\n\tSince an unsafe condition has been identified that is likely to 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 the airplane from deviating from its intended flight path due to an uncommanded change in the course of direction. This AD requires deactivating the VOR/LOC option on certain Honeywell FMC's by removing the VOR/LOC pin from the FMC/FCC configuration plug on the main avionics rack. 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 contactconcerned 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-57-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 to read as follows:\n\n Authority: 49 U.S.C. App. 1354(a), 1421 and 1423; 49 U.S.C. 106(g); and 14 CFR 11.89. § 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-57-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.

Natalie Phan-Tran, 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) 988-5343; fax (310) 988-5210.