AD 99-06-08

This amendment adopts a new airworthiness directive (AD), applicable to certain McDonnell Douglas Model DC-10 and MD-11 series airplanes, and KC-10 (military) series airplanes, that requires a one-time inspection for blockage of the lubrication holes on the forward trunnion spacer assembly, and a one-time inspection of the forward trunnion bolt on the left and right main landing gear (MLG) to detect discrepancies; and repair, if necessary. This amendment is prompted by reports of blockage by opposing bushings of the lubrication holes on the forward trunnion spacer assembly, and reports of flaking, galling, and corrosion of the forward trunnion bolt. The actions specified by this AD are intended to detect and correct such flaking, galling, and corrosion of the forward trunnion bolt, which could result in premature failure of the forward trunnion bolt and could lead to separation of the MLG from the wing during takeoff and landing.

Final rule.

99-06-08 MCDONNELL DOUGLAS: Amendment 39-11072. Docket 98-NM-55-AD.\n\n\tApplicability: Model DC-10 and MD-11 series airplanes, and KC-10 (military) series airplanes; as listed in McDonnell Douglas Service Bulletin DC10-32-248, dated December 17, 1997, and in McDonnell Douglas Service Bulletin MD11-32-074, dated December 15, 1997; 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 request approval for an alternative method of compliance in accordance with paragraph (f) 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. \n\n\tCompliance: Required as indicated, unless accomplished previously. \n\n\tTo detect and correct flaking, galling, and corrosion of the forward trunnion bolt as a result of installation of a suspected unapproved part (SUP), and consequent premature failure of the forward trunnion bolt and separation of the main landing gear (MLG) from the wing during takeoff and landing, accomplish the following: \n\n\t(a)\tFor airplanes listed in McDonnell Douglas Service Bulletin MD11-32-074, dated December 15, 1997: Except as provided by paragraphs (c) of this AD, within 24 months after the effective date of this AD, perform a one-time visual inspection of the lubrication holes on the forward trunnion spacer assembly on the MLG for blockage by opposing bushings, and perform a one-time visual inspection of the forward trunnion bolt on the left and right MLG for chrome flaking, galling, and corrosion in the grooves; in accordance with the service bulletin. \n\n\t\t(1)\tCondition 1. If the lubrication holes on the forward trunnion spacer assembly are not blocked by opposing bushings, and the forward trunnion bolt does not reveal chrome flaking or galling, and exhibits no corrosion in the grooves, no further work is required by this AD.\n\n\t\t(2)\tCondition 2. If the lubrication holes on the forward trunnion spacer assembly are blocked by opposing bushings, and the forward trunnion bolt does not reveal chrome flaking or galling, and exhibits no corrosion in the grooves: Prior to further flight, replace the forward trunnion spacer assembly with a new part in accordance with the service bulletin, or with a part that has been reworked in accordance with Chapter 32-10-01 of Douglas Aircraft Company Component Maintenance Manual.\n\n\t\t(3)\tCondition 3. If the lubrication holes on the forward trunnion spacer assembly are blocked by opposing bushings, and the forward trunnion bolt reveals chrome flaking, galling, or corrosion in the grooves, accomplish either paragraph (a)(3)(i) or (a)(3)(ii) of this AD: \n\n\t\t\t(i)\tOption 1. Prior to further flight, replace the forward trunnion spacer assembly with a new part in accordance with the service bulletin, or with a part that has been reworked in accordance with Chapter 32-10-01 of Douglas Aircraft Company Component Maintenance Manual; and replace the forward trunnion bolt with a new part in accordance with the service bulletin. Or\n\n\t\t\t(ii)\tOption 2. Prior to further flight, replace the forward trunnion spacer assembly with a new part in accordance with the service bulletin, or with a part that has been reworked in accordance with Chapter 32-10-01 of Douglas Aircraft Company Component Maintenance Manual; and rework the forward trunnion bolt in accordance with the service bulletin.\n\n\t(b)\tFor airplanes listed in McDonnell Douglas Service Bulletin DC10-32-248, dated December 17, 1997: Except as provided by paragraphs (d) and (e) of this AD, within 24 months after the effective date of this AD, perform a one-time visual inspection of the lubrication holes on the forward trunnion spacer assembly on the MLG for blockage by opposing bushings, and perform a one-time visual inspection of the forward trunnion bolt on the left and right MLG for chrome flaking, galling, and corrosion in the grooves; in accordance with the service bulletin. \n\n\t\t(1)\tCondition 1. If the lubrication holes on the forward trunnion spacer assembly are not blocked by opposing bushings, and the forward trunnion bolt does not reveal chrome flaking, or galling, and exhibits no corrosion in the grooves, no further work is required by this AD.\n\n\t\t(2)\tCondition 2. If the lubrication holes on the forward trunnion spacer assembly are blocked by opposing bushings, and the forward trunnion bolt does not reveal chrome flaking or galling, and exhibits no corrosion in the grooves: Prior to further flight, replace the forward trunnion spacer assembly with a new part in accordance with the service bulletin, or with a part that has been reworked in accordance with Chapter 32-10-01 of Douglas Aircraft Company Component Maintenance Manual.\n\n\t\t(3)\tCondition 3. If the lubrication holes on the forward trunnion spacer assembly are blocked by opposing bushings, and the forward trunnion bolt reveals chrome flaking, galling, or corrosion in the grooves, accomplish either paragraph (b)(3)(i) or (b)(3)(ii) of this AD: \n\n\t\t\t(i)\tOption 1. Prior to further flight, replace the forward trunnion spacer assembly with a new part in accordance with the service bulletin, or with a part that has been reworked in accordance with Chapter 32-10-01 of Douglas Aircraft Company Component Maintenance Manual; and replace the forward trunnion bolt with a new part in accordance with the service bulletin. Or\n\n\t\t\t(ii)\tOption 2. Prior to further flight, replace the forward trunnion spacer assembly with a new part in accordance with the service bulletin, or with a part that has been reworked in accordance with Chapter 32-10-01 of Douglas Aircraft Company Component Maintenance Manual; and rework the forward trunnion bolt in accordance with the service bulletin.\n\n\t(c)\tFor Model MD-11 series airplanes on which the requirements specified in either paragraph (a)(2) or (b) of AD 96-03-05, amendment 39-9502, have been accomplished: Within 48 months after the effective date of this AD, accomplish the requirements specified in paragraph (a) of this AD.\n\n\t(d)\tFor Model DC-10-30, DC-10-40, and KC-10A (military) series airplanes on which the requirements specified in either paragraph (c)(1)(i) or (c)(2)(ii) of AD 96-03-05, amendment 39-9502, have been accomplished: Within 48 months after the effective date of this AD, accomplish the requirements specified in paragraph (b) of this AD.\n\n\t(e)\tFor Model DC-10-10 and DC-10-15 series airplanes, on which the requirements specified in paragraph (a)(1)(i), (a)(2)(ii), (b)(2)(i), or (b)(2)(ii) of AD 96-16-01, amendment 39-9701, have been accomplished: Within 48 months after the effective date of this AD, accomplish the requirements specified in paragraph (b) of this AD.\n\n\t(f)\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 2: 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(g)\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(h)\tThe inspections and replacements shall be done in accordance with McDonnell Douglas Service Bulletin MD11-32-074, dated December 15, 1997; or McDonnell Douglas Service Bulletin DC10-32-248, dated December 17, 1997; as applicable. 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 The Boeing Company, Douglas Products Division, 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 the 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(i)\tThis amendment becomes effectiveon April 16, 1999.

A proposal to amend part 39 of the Federal Aviation Regulations (14 CFR part 39) to include an airworthiness directive (AD) that is applicable to certain McDonnell Douglas Model DC-10 and MD-11 series airplanes, and KC-10 (military) series airplanes was published in the Federal Register on March 27, 1998 (63 FR 14851). That action proposed to require a one-time inspection for blockage of the lubrication holes on the forward trunnion spacer assembly, and a one-time inspection of the forward trunnion bolt on the left and right main landing gear (MLG) to detect discrepancies; and repair, if necessary. \n\n\tInterested persons have been afforded an opportunity to participate in the making of this amendment. Due consideration has been given to the comments received. \n\nRequest to Extend Compliance Time for Initial Inspections\n\n\tSeveral commenters request that the proposed compliance time be revised from 18 to 24 months (for Model DC-10 series airplanes) andfrom 15 to 24 months (for Model MD-11 series airplanes). In support of this request, the commenters state that the time required to accomplish the inspection is actually 18 or more work hours, not 1 work hour, as estimated in the proposed rule. The commenters add that the referenced service bulletins recommend a compliance time of 24 months. \n\n\tThe commenters also note that many of the affected airplanes were inspected for chrome flaking of the trunnion bolt in accordance with two existing AD's, and any corrosion would have been discovered at that time. (The two existing AD's are: AD 96-03-05, amendment 39-9502 (61 FR 5281, February 12, 1996); and AD 96-16-01, amendment 39-9701 (61 FR 39312, July 29, 1996), which affect Model MD-11 series airplanes and DC-10-30, DC-10-40, and KC-10A (military) airplanes, and Model DC-10-10 and -15 series airplanes, respectively.) \n\n\tOne commenter indicates that in cases where discrepant spacers were found, the airplanes had been in service for five to eight years, and that it is not uncommon to find corrosion on the trunnion bolts during overhaul (after eight years of service). The commenters estimate an eight- to nine-month lead time for replacement parts if discrepant spacers are found during accomplishment of the proposed inspection.\n\n\tThe FAA concurs with the commenter's request to extend the compliance time. Although the FAA determined that a 24-month compliance time would not address the identified unsafe condition in a timely manner, as was described in the preamble to the notice, the FAA has reconsidered its position in light of the commenters' remarks.\n\n\tThe FAA finds that the requirements of AD's 96-16-01 and 96-03-05 are similar to those required in this AD. Therefore, the exposure of corrosion as the result of chrome flaking on the trunnion bolts is much less than if the trunnion bolts had not been inspected. In addition, service history does indicate that discrepant spacers were found on airplanes withfive to eight years of service.\n\n\tIn the preamble of the notice, the FAA indicated that it would take less than one work hour to perform the inspections by discounting the time to access the subject inspection area. In many cases during maintenance, operators have access to an inspection area; however, this is not true of the subject inspection area of this AD. The FAA finds that, as suggested by the commenters, it will take approximately 18 work hours to accomplish the required inspections. This work hour estimate is in consonance with that specified in the referenced service bulletin.\n\n\tIn light of these findings, the FAA finds that extending the compliance time by 6 (for Model DC-10 series airplanes) and 9 (for Model MD-11 series airplanes) additional months will not adversely affect safety. Therefore, the FAA has revised paragraphs (a) and (b) of the final rule to specify a compliance time of 24 months. In addition, the FAA has revised the cost impact information, below,to include the updated work hours for the required inspections.\n\nRequest to Revise Cost Estimate\n\n\tSeveral commenters request that the FAA revise the estimated number of work hours required to accomplish the proposed actions. The commenters note that only one work hour was specified in the proposed AD; however, access time is estimated to be at least 17 work hours. The commenters indicate that this type of action would not normally be addressed during regularly scheduled maintenance. One commenter estimates that the proposed action would require 50 work hours and 25 elapsed hours. Another commenter estimates a total of 80 work hours.\n\n\tThe FAA concurs with the commenters' request to revise the estimated number of work hours. However, as discussed previously, the FAA finds that it will take approximately 18 work hours, as specified in the referenced service bulletin, to accomplish the required inspections. The final rule has been revised accordingly.\n\nRequest to Extend Compliance Time for Certain Airplanes\n\n\tOne commenter requests that the FAA allow a 48-month compliance time for airplanes on which the requirements of AD 96-03-05 have been accomplished. The commenter indicates that, during accomplishment of that AD, any corrosion would have been discovered. In addition, if chrome flaking was discovered, the trunnion bolts would have been replaced with new bolts having the most corrosion resistant properties provided on those parts.\n\n\tThe FAA concurs partially. As discussed previously, the FAA notes that AD 96-03-05 and AD 96-16-01 both address chrome flaking of the trunnion bolt. If corrosion were found and the bolts replaced in accordance with either of these AD's, the lubrication blockage addressed in this AD could have been a cause of that corrosion. Therefore, only specific conditions from AD 96-03-05 and AD 96-16-01 would be applicable and, in some cases, it would be necessary for the operator to have kept records that corrosion was not discovered. Therefore, the FAA has added paragraphs (c), (d), and (e) to this final rule to allow operators that accomplished certain paragraphs of those AD's to accomplish the required one-time visual inspection within 48 months.\n\nRequest to Allow Time to Obtain Parts\n\n\tOne commenter requests that if a discrepant spacer assembly is found, the FAA should allow time to obtain a new part instead of requiring repair before further flight. The commenter states that two techniques are being developed by Douglas Products Division (DPD), which would allow for an inspection of the discrepant spacer without disassembly. In addition, the commenter indicates that an airplane was flown without failure for eight years with a discrepant spacer.\n\n\tThe FAA does not concur with the commenter's request. The blocked lubrication holes do not allow lubrication to reach the trunnion bolt. This condition can accelerate corrosion damage to the bolt, which could lead to the identified unsafe condition. An airplane that was in service for eight years may not have been subjected to loads that could contribute to failure of the bolt. However, another airplane may be in service for an even shorter period of time and yet experience loads that could lead to failure of a corroded bolt. Therefore, the FAA finds that repair of any discrepant spacer assembly prior to further flight is warranted.\n\nRequest for Alternate Inspection Procedure\n\n\tOne commenter requests that the FAA allow the use of a newly developed x-ray inspection technique that would allow for an inspection without disassembly of the structure. The commenter indicates that this would reduce operator time and effort without jeopardizing safety.\n\n\tThe FAA does not concur with the commenter's request. The FAA is aware that DPD is attempting to develop alternative inspection procedures. However, since those procedures have not been provided to the FAA, it cannot approve the alternative inspection technique at this time.\n\nRequest to Allow Replacement of Spacers with Reworked Spacers\n\n\tOne commenter requests that the FAA allow discrepant spacers to be reworked in accordance with Chapter 32-10-01 of Douglas Aircraft Company Component Maintenance Manual. The commenter contends that allowing rework of the spacers to an acceptable condition would reduce the economic impact on the fleet. The FAA concurs. The FAA has revised paragraphs (a)(2), (a)(3)(i), (a)(3)(ii), (b)(2), (b)(3)(i), and (b)(3)(ii) of the final rule to allow replacement of any discrepant forward trunnion spacer assembly with a part that has been reworked in accordance with Chapter 32-10-01 of Douglas Aircraft Company Component Maintenance Manual.\n\nConclusion\n\n\tAfter careful review of the available data, including the comments noted above, the FAA has determined that air safety and the public interest require the adoption of the rule with the changes previously described. The FAA has determined that these changes will neither increase the economic burden on any operator nor increase the scope of the AD.\n\nCost Impact\n\n\tThere are approximately 522 airplanes of the affected design in the worldwide fleet. The FAA estimates that 326 airplanes of U.S. registry will be affected by this AD, that it will take approximately 18 work hours per airplane to accomplish the required inspection, and that the average labor rate is $60 per work hour. Based on these figures, the cost impact of the AD on U.S. operators is estimated to be $352,080, or $1,080 per airplane. \n\n\tThe cost impact figure discussed above is based on assumptions that no operator has yet accomplished any of the requirements of this AD action, and that no operator would accomplish those actions in the future if this AD were not adopted. \n\nRegulatory Impact\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 andresponsibilities 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\tFor the reasons discussed above, I certify that this action (1) is not a "significant regulatory action" under Executive Order 12866; (2) is not a "significant rule" under DOT Regulatory Policies and Procedures (44 FR 11034, February 26, 1979); and (3) 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 final evaluation has been prepared for this action and it is contained in the Rules Docket. A copy of it 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. The authority citation for part 39 continues to read as follows:\n\nAuthority: 49 U.S.C. 106(g), 40113, 44701. \n\n§ 39.13 (Amended)\n\n\t2. Section 39.13 is amended by adding the following new airworthiness directive: