AD 95-16-01

This amendment supersedes an existing airworthiness directive (AD), applicable to all McDonnell Douglas Model MD-11 series airplanes, that currently requires a revision to the Airplane Flight Manual (AFM) that prohibits autoland operation below 100 feet above ground level, and installation of flight control computer software. It also provides for an optional terminating action for the AFM revision. This amendment provides for a new optional terminating action for the AFM revision. This amendment is prompted by reports of erroneous central aural warning system altitude callouts and erroneous radio altimeter indications during autoland approaches due to radio frequency leakage (RF) on airplanes on which the optional terminating action had been accomplished. The actions specified in this AD are intended to prevent radio altimeter antenna/coaxial cable RF leakage, which could result in early and/or abnormal flare (pitch) control during autoland operation and potential degradation of the landing capability of the airplane.

Final rule; request for comments.

95-16-01 MCDONNELL DOUGLAS: Amendment 39-9320. Docket 95-NM-126-AD. Supersedes AD 94-26-51, Amendment 39-9120. \n\n\tApplicability: All Model MD-11 series airplanes, certificated in any category. \n\n\tNOTE 1: 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 use the authority provided in paragraph (e) of this AD to request approval from the FAA. This approval may address either no action, if the current configuration eliminates the unsafe condition; or different actions necessary to address the unsafe condition described in this AD. Such a request should include an assessment of the effect of the changed configuration on the unsafe condition addressed by this AD. In no case does the presence of any modification, alteration, or repair remove any airplane from the applicability of this AD. \n\n\tCompliance: Required as indicated, unless accomplished previously. \n\n\tTo prevent degradation of the landing capability of the airplane, accomplish the following: \n\n\t(a)\tWithin 24 hours after February 6, 1995 (the effective date of AD 94-26-51, amendment 39-9120), revise the Limitations Section of the FAA-approved MD-11 Airplane Flight Manual (AFM), page 5-3, Flight Guidance, Automatic Landing Section, to include the following restriction. This may be accomplished by inserting a copy of this AD in the AFM. \n\n\t"Autoland operation below 100 feet above ground level (AGL) is prohibited. The autopilot must be disconnected prior to descent below 100 feet AGL." \n\n\t(b)\tFor airplanes on which the inspections and tests specified in paragraph (b) of AD 94-26-51, amendment 39-9120, (and reiterated below) have been initiated prior to the effective date of this AD: Accomplishment of the inspections and tests specified in paragraphs (b)(1) and (b)(2) of this AD, in accordance with McDonnell Douglas MD-11 Alert Service Bulletin A34-57, dated December 19, 1994, temporarily terminates the AFM revision required by paragraph (a) of this AD. These inspections and tests must be repeated at intervals not to exceed 500 hours time-in-service. As of 60 days after the effective date of this AD, however, those actions no longer constitute terminating action for paragraph (a) of this AD. As of 60 days after the effective date of this AD, only the actions specified in paragraph (c) of this AD constitute such terminating action. \n\n\t\t(1)\tPerform an inspection to determine if the connector nut of the four coaxial connectors on the back of the radio altimeter receiver/transmitter is loose. \n\n\t\t\t(i)\tIf no loose nut is found, prior to further flight, loosen the nut until finger tight, retorque the nut to 10 to 15 inch pounds, and mark the nut with a torque stripe.NOTE 2: Retorque is not necessary during repetitive inspections if the torque stripe is in line, as specified in the alert service bulletin. \n\n\t\t(2)\tPerform a leakage indication test to verify the integrity of the radio altimeter antenna system. Prior to further flight, correct any discrepancy found. \n\n\t(c)\tAccomplishment of the actions specified in paragraphs (c)(1), (c)(2), and (c)(3) of this AD, as applicable, constitutes terminating action for the AFM revision required by paragraph (a) of this AD, and for the repetitive inspections and tests specified in paragraph (b) of this AD. Following accomplishment of the actions specified in this paragraph, the AFM revision may be removed from the AFM. \n\n\t\t(1)\tFor airplanes equipped with Allied Signal radio altimeters: Replace radio altimeters 1 and 2 located in the center accessory compartment with modified radio altimeters, in accordance with McDonnell Douglas Service Bulletin MD11-34-063, dated July 10, 1995. The requirementsof this paragraph must be accomplished prior to or in conjunction with paragraph (c)(3) of this AD. \n\n\t\t(2)\tFor all airplanes: Perform an inspection to identify the part number (P/N) of the coaxial cables of the radio altimeter in accordance with McDonnell Douglas Service Bulletin MD11-34-060, Revision 3, dated July 14, 1995. The requirements of this paragraph must be accomplished prior to or in conjunction with paragraph (c)(3) of this AD. \n\n\t\t\t(i)\tFor Group 1, 2, and 4 airplanes: Prior to further flight, accomplish either paragraph (c)(2)(i)(A) or (c)(2)(i)(B) of this AD, as applicable, in accordance with the service bulletin. \n\n\t\t\t\t(A)\tIf the cables are identified as P/N AE11532-1, -2, -3, or -4, install new clamps, replace the cables with new cables, and perform an inspection to verify if lockwashers having P/N MS51848-45 are installed on the coaxial contacts. \n\n\t\t\t\t\t(1)\tIf no lockwasher is installed, prior to further flight, install a lockwasher having P/N MS51848-45 and install the coaxial contact, in accordance with the service bulletin. \n\n\t\t\t\t\t(2)\tIf a lockwasher having P/N MS51848-45 is installed, prior to further flight, install the coaxial contact in accordance with the service bulletin. \n\n\t\t\t\t(B)\tIf the cables are identified as P/N AE11919-1, -2, -3, or -4, install the new clamps. \n\n\t\t\t(ii)\tFor Group 3 airplanes: Prior to further flight, accomplish either paragraph (c)(2)(ii)(A) or (c)(2)(ii)(B) of this AD, as applicable, in accordance with the service bulletin. \n\n\t\t\t\t(A)\tIf the cables are identified as P/N AE11532-1, -2, -3 or -4, install the new clamps, replace the cables with new cables, perform an inspection to verify if lockwashers having P/N MS51848-45 are installed on the coaxial contacts, and replace the brackets of the terminal grounding block with a new bracket and relocate them, in accordance with the service bulletin. \n\n\t\t\t\t\t(1)\tIf no lockwasher is installed, prior to further flight, install a lockwasher having P/N MS51848-45 and install the coaxial contact, in accordance with the service bulletin. \n\n\t\t\t\t\t(2)\tIf a lockwasher having P/N MS51848-45 is installed, prior to further flight, install the coaxial contact in accordance with the service bulletin. \n\n\t\t\t\t(B)\tIf the cables are identified as P/N AE11919-1, -2, -3, or -4, install the new clamps, and replace the brackets of the terminal ground block with new brackets and relocate them, in accordance with the service bulletin. \n\n\t\t(3)\tFor all airplanes: Update the software of the two flight control computers (FCC) having part number (P/N) 4059001-904 or -905, and reidentify them as P/N 4059001-906, in accordance with McDonnell Douglas Service Bulletin MD11-22-015, dated July 3, 1995. The requirements of paragraphs (c)(1) and/or (c)(2), as applicable, must be accomplished prior to or in conjunction with this paragraph. \n\n\t(d)\tWithin 10 days after accomplishing the inspection required by paragraph (b)(2) of this AD, submit a report of the inspection results (both positive and negative findings) to the Manager, Los Angeles Aircraft Certification Office (ACO), 3960 Paramount Boulevard, Lakewood, California 90712; fax (310) 627-5210. Information collection requirements contained in this regulation have been approved by the Office of Management and Budget (OMB) under the provisions of the Paperwork Reduction Act of 1980 (44 U.S.C. 3501 et seq.) and have been assigned OMB Control Number 2120-0056. \n\n\t(e)\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 ACO. 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 3: 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(f)\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(g)\tThe actions shall be done in accordance with McDonnell Douglas MD-11 Alert Service Bulletin A34-57, dated December 19, 1994; McDonnell Douglas Service Bulletin MD11-34-063, dated July 10, 1995; McDonnell Douglas Service Bulletin MD11-34-060, Revision 3, dated July 14, 1995; and McDonnell Douglas Service Bulletin MD11-22-015, dated July 3, 1995. The incorporation by reference of McDonnell Douglas MD-11 Alert Service Bulletin A34-57, dated December 19, 1994, was approved previously by the Director of the Federal Register in accordance with 5 U.S.C. 552(a) and 1 CFR part 51 as of February 6, 1995 (60 FR 4076, January 20, 1995). The incorporation by reference of the remainder of the service documents listed above 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, 3855 Lakewood Boulevard, Long Beach, California 90846, Attention: Technical Publications Business Administration, Dept. C1-L51 (2-60). Copies may be inspected at the FAA, Transport Airplane Directorate, 1601 Lind Avenue, SW., Renton, Washington; or at FAA, Transport Airplane Directorate, Los Angeles Aircraft Certification Office, 3960 Paramount Boulevard, Lakewood, California; or at the Office of the Federal Register, 800 North Capitol Street, NW., suite 700, Washington, DC. \n\n\t(h)\tThis amendment becomes effective on August 18, 1995.

On January 6, 1995, the FAA issued AD 94-26-51, amendment 39-9120 (60 FR 4076, January 20, 1995), applicable to all McDonnell Douglas Model MD-11 series airplanes. It requires a revision to the Limitations Section of the FAA-approved Airplane Flight Manual (AFM) to prohibit autoland operation below 100 feet above ground level (AGL), and installation of -905 flight control computer (FCC) software. It also provides for an optional terminating action for the AFM revision, consisting of certain inspections and tests. That action was prompted by reports of a loose nut on a coaxial connector on a radio altimeter receiver/transmitter rack, and the transmittal of erroneous altitude data to the FCC while the airplane was below 100 feet AGL, which resulted in abnormal flare (pitch) control during autoland operation. The actions required by that AD are intended to prevent abnormal flare (pitch) control, which could result in degradation of the landing capability ofthe airplane. \n\n\tSince the issuance of that AD, the FAA has received several reports of erroneous central aural warning system (CAWS) altitude callouts and erroneous radio altimeter indications during autoland approaches on Model MD-11 series airplanes. Investigation has revealed that these incidents occurred on these airplanes following accomplishment of the optional terminating action (inspections and tests) and the installation of the -905 FCC software, as specified in AD 94-26-51. In light of these incidents, the FAA has determined that those provisions of AD 94-26-51 do not adequately preclude radio frequency (RF) leakage of the radio altimeter antenna/coaxial cable. That condition could result in abnormal flare (pitch) control during autoland operation and potential degradation of the landing capability of the airplane. \n\n\tAdditionally, since the issuance of AD 94-26-51, McDonnell Douglas has developed a new, improved modification to the FCC software for Model MD-11 seriesairplanes. Further, Allied Signal has developed a new, improved modification to the radio altimeter. \n\n\tThe FAA has reviewed and approved McDonnell Douglas Service Bulletin MD11-34-063, dated July 10, 1995, which describes procedures for replacement of the radio altimeters 1 and 2 located in the center accessory compartment with modified radio altimeters, for certain airplanes. The modified radio altimeters are less susceptible to influence by antenna/coaxial system RF leakage. \n\n\tThe FAA has also reviewed and approved McDonnell Douglas Service Bulletin MD11-34-060, Revision 3, dated July 14, 1995, which describes procedures for: \n\n\t1. Performing an inspection to identify the part number (P/N) of the coaxial cables of the radio altimeter; \n\n\t2. Installing new clamps, replacing the cables with new cables, performing an inspection to verify if lockwashers having P/N MS51848-45 are installed on the coaxial contacts, and various follow-on actions; and \n\n\t3. Installing new clamps on certain airplanes, and replacing and relocating the brackets of the terminal grounding block on certain other airplanes, if any cable is identified as P/N AE11919-1, -2, -3, or -4. \n\n\tThese procedures will minimize the possibility of RF signal leakage. The service bulletin specifies that these actions be accomplished within 7 months. \n\n\tAdditionally, the FAA has reviewed and approved McDonnell Douglas Service Bulletin MD11-22-015, dated July 3, 1995, which describes procedures for updating the software of two flight control computers (FCC) having part number (P/N) 4059001-904 or -905 and reidentifying them as P/N 4059001-906. This update will minimize the effects of radio altimeter signal leakage. Accomplishment of the update and reidentification constitutes terminating action for the AFM revision. \n\n\tSince an unsafe condition has been identified that is likely to exist or develop on other airplanes of this same type design, this AD supersedes AD 94-26-51 to continue torequire a revision to the Limitations Section of the FAA-approved AFM to prohibit autoland operation below 100 feet AGL. However, this AD provides for a new optional terminating action, which would constitute terminating action for the AFM revision and the temporary optional terminating action (repetitive inspections and tests, which have been retained from AD 94-26-51). Operators electing to accomplish the new terminating action will be required to perform it in accordance with procedures described in the service bulletins described previously. This AD also requires that operators report results of inspection findings, positive or negative, to the FAA. \n\n\tOperators who currently are accomplishing the terminating action specified in AD 94-26-51 should note that, although McDonnell Douglas Service Bulletin MD11-34-060 recommends accomplishment of the described procedures within 7 months, this AD requires their accomplishment within 60 days. The FAA finds that continuing to performthe previous terminating actions for a period of 7 months would not address the identified unsafe condition in a timely manner. In developing an appropriate compliance time for this AD, the FAA considered not only the degree of urgency associated with addressing the subject unsafe condition, but the upcoming inclement weather conditions and the maximum interval of time allowable for all affected airplanes to continue to operate without compromising safety. The FAA finds 60 days to be an appropriate compliance time for initiating these new terminating actions. \n\n\tAs a result of recent communications with the Air Transport Association (ATA) of America, the FAA has learned that, in general, some operators may misunderstand the legal effect of AD's on airplanes that are identified in the applicability provision of the AD, but that have been altered or repaired in the area addressed by the AD. The FAA points out that all airplanes identified in the applicability provision of an AD arelegally subject to the AD. If an airplane has been altered or repaired in the affected area in such a way as to affect compliance with the AD, the owner or operator is required to obtain FAA approval for an alternative method of compliance with the AD, in accordance with the paragraph of each AD that provides for such approvals. A note has been included in this rule to clarify this long-standing requirement. \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 rule must submit a self-addressed, stamped postcard on which the following statement is made: "Comments to Docket Number 95-NM-126-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 that it is not a "significant regulatory action" under Executive Order 12866. Ithas 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 part 39 of the Federal Aviation Regulations (14 CFR part 39) as follows:\n\nPART 39 - AIRWORTHINESS DIRECTIVES \n\n\t1.\tThe authority citation for part 39 continues to read 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 removing amendment 39-9120 (60 FR 4076, January 20, 1995), and by adding a new airworthiness directive (AD), amendment 39-9320, to read as follows: