01-25183. Airworthiness Directives; Boeing Model 757 Series Airplanes

AGENCY:

Federal Aviation Administration, DOT.

ACTION:

Final rule.

SUMMARY:

This amendment supersedes an existing airworthiness directive (AD), applicable to certain Boeing Model 757 series airplanes, that currently requires repetitive freeplay checks of the elevator, and replacement of worn elevator power control actuator (PCA) reaction link rod-end bearings and the PCA rod-end bearing, if necessary. That AD also provides for an optional terminating action for the repetitive checks. This amendment removes the optional terminating action provided by the existing AD, expands the applicability of the existing AD to include additional airplanes, and requires repetitive freeplay checks of the elevator at a revised repeat interval and repetitive lubrication of bearings of the elevator actuator load loop and hinge line. The actions specified by this AD are intended to prevent unacceptable airframe vibration during flight, which could lead to excessive wear of bearings of the elevator PCA load loop and hinge line and result in reduced controllability of the airplane. This action is intended to address the identified unsafe condition.

DATES:

Effective November 15, 2001.

The incorporation by reference of certain publications listed in the regulations is approved by the Director of the Federal Register as of November 15, 2001.

ADDRESSES:

The service information referenced in this AD may be obtained from Boeing Commercial Airplane Group, P.O. Box 3707, Seattle, Washington 98124-2207. This information may be examined at the Federal Aviation Administration (FAA), Transport Airplane Directorate, Rules Docket, 1601 Lind Avenue, SW., Renton, Washington; or at the Office of the Federal Register, 800 North Capitol Street, NW., suite 700, Washington, DC.

FOR FURTHER INFORMATION CONTACT:

Dennis Stremick, Aerospace Engineer, Airframe Branch, ANM-120S, FAA, Seattle Aircraft Certification Office, 1601 Lind Avenue, SW., Renton, Washington 98055-4056; telephone [phone]; fax [phone].

SUPPLEMENTARY INFORMATION:

A proposal to amend part 39 of the Federal Aviation Regulations (14 CFR part 39) by superseding AD 89-03-05, amendment 39-6120 (54 FR 3430, January 24, 1989), which is applicable to certain Model 757 series airplanes, was published in the Federal Register on March 20, 2001 (66 FR 15670). The action proposed to continue to require repetitive freeplay checks of the elevator, and replacement of worn elevator power control actuator (PCA) reaction link rod-end bearings and the PCA rod-end bearing, if necessary. The action also proposed to remove the optional terminating action provided by the existing AD, expand the applicability of the existing AD to include additional airplanes, and require repetitive freeplay checks of the elevator at a revised repeat interval and repetitive lubrication of bearings of the elevator actuator load loop and hinge line.

Comments Received

Interested persons have been afforded an opportunity to participate in the making of this amendment. Due consideration has been given to the comments received.

Request To Withdraw the Proposed AD as Unnecessary

One commenter, an operator, considers the proposed AD unnecessary. This commenter reports that the fleet has not experienced any problems with airframe vibration due to elevator PCA load loop bearings. The commenter adds that the fleet has incorporated the terminating actions as specified by Boeing Service Bulletin 757-27A0086, Revision 2, dated July 27, 1989, and is scheduled for bearing lubrication every 18 months. According to the commenter, it is unclear how the nature of the airframe vibration is unsafe, unless it is not addressed when first identified.

The FAA infers that the operator is requesting that the proposed AD be withdrawn. The FAA does not agree with the commenter's rationale as a basis for withdrawal. Other operators have reported vibration events despite having incorporated the terminating action of AD 89-03-05 and scheduling lubrication at 18-month intervals. Further, not all vibration events are addressed immediately. In some cases, no action was taken until the vibration worsened. The FAA has determined that issuance of this AD is necessary to ensure the safety of the fleet.

Request To Replace Proposed Service Information

Several commenters request that the proposed AD be revised to replace the cited source of service information (Boeing Service Bulletin 757-27A0086). The commenters provide the following reasons for this request:

1. The service bulletin specifies use of BMS3-24 grease (Aeroshell 16), which has been replaced by the bearing manufacturer with BMS3-33 grease. The commenters state that BMS3-33 grease has better corrosion-preventive properties.

2. The freeplay check procedures specified by the service bulletin can produce “unnecessary” failures that would require unnecessary corrective action.

3. The service bulletin specifies a sequence for replacing specific bearings. The commenters request that operators be allowed to assess the serviceability of individual components and, based on that assessment, to replace, in any order, the defective component to correct the elevator freeplay.

4. The part number for the bearing has been changed.

The FAA partially concurs with the request and provides the following responses, numbered to correspond to the comments listed above.

1. The FAA has determined that use of either the BMS3-24 or BMS3-33 grease will be acceptable, as long as the grease types are not intermixed on any individual bearing. The FAA does agree that BMS3-33 grease does have better corrosion-preventive properties, but is unable to concur with the request to change the requirement as proposed without documented, approved procedures for purging existing grease. However, once those procedures are defined, the FAA may approve requests for alternative methods of compliance under the provisions of paragraph (f)(1) of the final rule if data are submitted to substantiate that adequate purging procedures have been developed.

2. The FAA has determined that an “unnecessary” failure (false positive result) does not represent a serious safety risk. Use of too-conservative criteria for allowable freeplay outweighs any inconvenience to operators from a false positive result.

3. The FAA agrees that the replacement sequence described in the service bulletin may need clarification. Defective bearings must be replaced when they are discovered, regardless of the sequence listed in the service bulletin. Paragraphs (a) and (b) of the final rule have been revised to clarify the requirement.

4. As indicated in the service bulletin, the bearings may be replaced with reaction link bearings having either Boeing part number (P/N) S251N214-8 (Rexnord P/N DRX34C) or S251N214-11 (Rexnord P/N DRX34B). The Boeing PCA assembly, P/N S251N211-11, contains Rexnord P/N DRX32B. The FAA has added new Note 3 to this final rule to clarify the part numbers.

Request To Require Future Service Information

One commenter requests that the proposed AD be revised to require compliance with procedures that will be included in a future service bulletin expected to be issued in September 2001. The commenter advises that the new service bulletin will include minor refinements to the procedures described in Boeing Service Bulletin 757-27A0086, which is cited in AD 89-03-05 as the appropriate source of service information for the freeplay check. The minor refinements are intended to adequately detect freeplay and yet avoid “unnecessary” failures. The commenter requests that the AD also require a second freeplay check, which would terminate the repetitive freeplay checks and lubrication, and follow-up maintenance review board (MRB) actions, which are in the process of being revised. The commenter states that the revised MRB tasks will improve detection of elevator freeplay and improve prevention of corrosion by shorter lubrication intervals. The commenter concludes that incorporation of the new service information will be adequate to prevent elevator vibration in flight.

The FAA does not concur with the request. The FAA cannot approve the use of a document that does not yet exist. In addition, in an AD, reference to an unpublished service bulletin violates Office of the Federal Register (OFR) regulations regarding approval of materials “incorporated by reference” in rules. However, if a new service bulletin is issued in the future, operators may request approval to use it as an alternative method of compliance under the provisions of paragraph (f)(1) of this final rule. In consideration of the urgency of the identified unsafe condition and the amount of time that has already elapsed since the proposed AD was issued, the FAA has determined that further delay of this final rule is not appropriate. If the FAA finds that a substantial safety benefit can be derived from the future service bulletin that would justify mandating its incorporation, the FAA may consider further rulemaking. Furthermore, there is no guarantee that the service bulletin will be issued in September 2001; any delay would further expose the fleet to risks. Accomplishment of MRB actions are not mandatory, so reliance on their accomplishment by operators cannot satisfy any terminating requirements of an AD. In addition, incorporation of a new service bulletin having new actions would alter the actions of the proposed AD; therefore, additional rulemaking would be required. The FAA finds that delaying this action would be inappropriate in light of the identified unsafe condition. No change to the final rule is necessary in this regard.

Request To Extend Freeplay Check Interval

Several commenters request that the proposed compliance time be extended to better accommodate operators' schedules. One commenter suggests mandating the elevator freeplay check as an MRB task at a “2C-check” or 36-month interval. Another commenter suggests a 24-month interval. Another commenter, an operator, anticipates that the proposed interval would place a significant and undue financial burden on its operations, which would extend to the flying public.

The FAA does not concur. Designating these actions as MRB tasks, which are not mandatory, would provide no assurance that operators would follow the prescribed actions within the prescribed schedule. Furthermore, although the maintenance planning data document currently recommends a “2C” freeplay check, the fleet is still subject to vibration. Service history for the affected airplanes has shown that vibration can occur in less than 24 months after a “C” check. Therefore, the FAA finds the 18-month interval to be appropriate; no change to the final rule is warranted in this regard.

Request To Shorten Lubrication Interval

One commenter requests that the lubrication interval be shortened to reduce the incidence of corrosion (the main contributor to excessive freeplay) in the bearings. The commenter recommends accomplishing the bearing lubrication at 6-to 9-month intervals for airplanes on which the terminating action of AD 89-03-05 has been accomplished, and at 1,000-flight-hour intervals for airplanes on which the terminating action has not been accomplished.

The FAA does not concur. The FAA finds that delaying this action would be inappropriate in light of the identified unsafe condition. Furthermore, shortening the proposed interval would alter the requirements, so additional rulemaking would be required. However, the FAA may consider further rulemaking to revise the lubrication intervals, if data are provided that demonstrate that shorter intervals are necessary to ensure safety.

Request To Extend Compliance Time for Certain Airplanes

Several commenters request an extension of the proposed compliance time for the initial check and lubrication for certain airplanes. For airplanes that are not subject to paragraph (a) or (b) of the proposed AD, the commenters suggest a revised threshold of 5,000—rather than 3,000—total flight cycles, and a revised grace period of 180—rather than 90—days; and revised repetitive intervals of up to 24 months. The commenters suggest these extensions to circumvent an anticipated significant impact on operators' schedules and maintenance.

The FAA partially concurs. The FAA finds it necessary to retain the 3,000-flight-cycle threshold as proposed, in light of an event in which an airplane that had accumulated fewer than 5,000 total flight cycles did experience a vibration event. However, the FAA concurs with the request to extend the grace period to 180 days for those airplanes that are not subject to AD 89-03-05; the bearings on those airplanes have improved bearing seals with improved grease retention. The FAA has determined that the grace period, as proposed, represents an appropriate interval in which the initial check/lubrication can be accomplished in a timely manner within the fleet and still maintain an adequate level of safety. Paragraph (d)(3) of this final rule has been revised accordingly.

Request To Clarify Compliance Times

Two commenters state that the compliance requirements in the proposed AD are vague. One commenter states that the proposed AD does not specify if compliance can be taken on airplanes that have completed the inspection but are not incorporated into the service bulletin effectivity. The other commenter requests that Table 1 be revised for the group that has accomplished neither paragraph (a) nor (b) by including “aircraft which previously accomplished the terminating actions of AD 89-03-05.” The commenter states that this additional language would clarify the requirement indicating that those airplanes are subject to the new rule.

The FAA does not concur. The applicability of this AD includes all Model 757 series airplanes. An affected airplane that does not fall within the applicability in paragraph (a) or (b) of the AD is included in the requirement for paragraph (d)(3). No change to the final rule (except for the addition of subparagraph numbers (1), (2), and (3) in paragraph (d)) is necessary in this regard.

Request To Approve Alternative Measuring Devices

Several commenters request that the proposed AD be revised to allow the use of measuring devices specified in the airplane maintenance manual (AMM) to measure the deflection in the elevator. (The proposed AD would require measuring the freeplay by use of a dial indicator, as specified by Boeing Service Bulletin 757-27A0086.) The commenters suggest a scale or ruler with 0.001 or 0.010 graduations.

The FAA concurs with this request and finds that use of a scale or ruler having graduations of 0.010 inch or finer to measure the freeplay will provide the accuracy necessary to ensure safety. New Note 2 of the final rule has been added to advise operators of the acceptability of alternative measuring devices.

Request To Allow Interim Corrective Action

One commenter requests that the proposed AD be revised to allow interim corrective action if the freeplay is between certain limits specified by Section III.F.1 of Boeing Service Bulletin 757-27A0086. The commenter states that this interim action would allow affected airplanes to remain in service until the next “C-check.”

The interim corrective action, provided by AD 89-03-05, is retained in this AD; therefore, no change to the final rule is necessary in this regard.

Request for Clarification of Certain Requirements

Two commenters questioned the location of certain parts that are required to be lubricated. The commenters request (1) clarification of the identity of the bearings in the load loop and hinge line, and (2) a reference to or demonstration of the location of the PCA load loop and hinge line.

The commenter may have misinterpreted “PCA load loop” as including the PCA input linkage. Mandated checks and lubrication of this entire area are not included in the requirements of this AD. No change to the final rule is necessary in this regard.

Request for Clarification of Terminology

One commenter requests a change to the heading of the fourth column in Table 1 of the proposed AD. The commenter requests that “MPD ‘2C’ check” be changed to read, “MPD item 27-02-00-6A” to show that the current MPD “2C” check is no longer a requirement.

The FAA does not concur. Except for Section 9, the MPD is not approved or required by the FAA. The item designations may change without FAA knowledge or approval. No change to the final rule is necessary in this regard.

Request To Extend Compliance Time To Accommodate Parts Availability

Several commenters express concern about the availability of replacement bearings for failed PCAs. With only a single source for their manufacture, the bearings may not be in adequate supply to accommodate the affected fleet, and as a result operators may experience unnecessary down time.

The FAA infers that the commenters are requesting an extension of the compliance time to accommodate anticipated parts shortages. The FAA does not concur. The FAA has determined that used PCAs may be used for replacement parts if they are modified in accordance with Boeing Service Bulletin 757-27A0086. Also, as discussed previously, the grace period for the freeplay checks has been extended in the final rule, further mitigating the problem of parts availability.

Request for Terminating Action

One commenter requests that the proposed AD be revised to provide terminating action for the repetitive freeplay checks. Terminating action would ease the burden of repetitive checks.

The FAA does not concur. The FAA is not aware of any terminating action that is being considered or developed. If such action is developed, approved, and available, the FAA may consider additional rulemaking. However, due to the nature of corrosion, even modified areas would likely continue to need repetitive inspections.

Conclusion

After 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.

Cost Impact

There are approximately 906 airplanes of the affected design in the worldwide fleet.

The actions that are currently required by AD 89-03-05 affect approximately 90 airplanes of U.S. registry. Those actions take approximately 30 work hours per airplane to accomplish, at an average labor rate of $60 per work hour. Based on these figures, the cost impact of the currently required actions on U.S. operators is estimated to be $162,000, or $1,800 per airplane, per check cycle.

The FAA estimates that 598 airplanes of U.S. registry will be affected by this new AD. The new actions required by this AD will take approximately 28 work hours per airplane to accomplish, at an average labor rate of $60 per work hour. Based on these figures, the cost impact of the new requirements of this AD on U.S. operators is estimated to be $1,004,640, or $1,680 per airplane, per check cycle.

The cost impact figures discussed above are 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. The cost impact figures discussed in AD rulemaking actions represent only the time necessary to perform the specific actions actually required by the AD. These figures typically do not include incidental costs, such as the time required to gain access and close up, planning time, or time necessitated by other administrative actions.

Regulatory Impact

The regulations adopted herein will not have a substantial direct effect 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, it is determined that this final rule does not have federalism implications under Executive Order 13132.

For 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.

List of Subjects in 14 CFR Part 39

• Air transportation
• Aircraft
• Aviation safety
• Incorporation by reference
• Safety

Adoption of the Amendment

Accordingly, 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:

PART 39—AIRWORTHINESS DIRECTIVES

1. The authority citation for part 39 continues to read as follows:

Authority: 49 U.S.C. 106(g), 40113, 44701.

§ 39.13

[Amended]

2. Section 39.13 is amended by removing amendment 39-6120 ( 54 FR 3430, January 24, 1989), and by adding a new airworthiness directive (AD), amendment 39-12459, to read as follows:

2001-20-11 Boeing: Amendment 39-12459. Docket 2000-NM-361-AD. Supersedes AD 89-03-05, Amendment 39-6120.

Applicability: All Model 757 series airplanes, certificated in any category.

Note 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)(1) 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.

Compliance: Required as indicated, unless accomplished previously.

To prevent unacceptable airframe vibration during flight, which could lead to excessive wear of elevator bearings and result in reduced controllability of the airplane, accomplish the following:

RESTATEMENT OF REQUIREMENTS OF AD 89-03-05

Repetitive Elevator Freeplay Checks

(a) For Boeing Model 757 series airplanes listed in Boeing Alert Service Bulletin 757-27A0086, dated June 9, 1988, on which the elevator power control actuator (PCA) rod-end and reaction link rod-end bearings are lubricated at intervals of 1,000 flight hours or less, in accordance with Boeing Service Letter 757-SL-27-26, dated April 1, 1988, and on which paragraph (d) of AD 89-03-05 was not done: Within the next 90 days after March 6, 1989 (the effective date of AD 89-03-05, amendment 39-6120), or prior to the accumulation of 4,000 flight hours total time-in-service, whichever occurs later, and thereafter at intervals not to exceed 4,000 flight hours, perform an elevator freeplay check in accordance with Boeing Alert Service Bulletin 757-27A0086, dated June 9, 1988, or Revision 2, dated July 27, 1989. Doing paragraph (d) of this AD ends the repetitive inspections required by this paragraph.

Note 2:

Use of a scale having graduations of 0.010 inch or finer may be used to measure the freeplay, as required by paragraphs (a), (b), and (d) of this AD.

(b) For Boeing Model 757 series airplanes listed in Boeing Alert Service Bulletin 757-27A0086, dated June 9, 1988, not subject to paragraph (a) of this AD, and on which paragraph (d) of AD 89-03-05 was not done: Within the next 90 days after March 6, 1989, or prior to the accumulation of 3,000 flight hours total time-in-service, whichever occurs later, and thereafter at intervals not to exceed 3,000 flight hours, perform an elevator freeplay check in accordance with Boeing Alert Service Bulletin 757-27A0086, dated June 9, 1988, or Revision 2, dated July 27, 1989. Doing paragraph (d) of this AD ends the repetitive inspections required by this paragraph.

Replacement

(c) If freeplay of the elevator exceeds the limits specified in the service bulletin during any check per this AD: Before further flight, replace elevator PCA reaction link rod-end bearings and PCA rod-end bearings, as necessary, with new, improved bearings, in accordance with Boeing Alert Service Bulletin 757-27A0086, dated June 9, 1988, or Revision 2, dated July 27, 1989. After the effective date of this AD, use only Revision 2 of the service bulletin. Regardless of the sequence for replacing specific bearings listed in the alert service bulletin, defective bearings must be replaced when they are discovered.

NEW REQUIREMENTS OF THIS AD

Repetitive Elevator Freeplay Checks

(d) For all airplanes, do elevator freeplay checks per Boeing Service Bulletin 757-27A0086, Revision 2, dated July 27, 1989. Before further flight after the freeplay checks, lubricate the bearings in the elevator PCA load loop and hinge line. Use of either the BMS3-24 or BMS3-33 grease will be acceptable, as long as the grease types are not intermixed on any individual bearing. Do these actions per the schedule in the following table:

Table 1.—Compliance Schedule

For airplanes subject to—	Do the initial check and lubrication—	Repeat the check and lubrication thereafter at least every—	Inspection per paragraph (d) of this AD ends the requirements of—
(1) Paragraph (a) of this AD	Within 4,000 flight hours after the most recent inspection per paragraph (a) of AD 89-03-05, or 18 months after the effective date of this AD, whichever occurs first	18 months	Paragraph (a) of this AD.
(2) Paragraph (b) of this AD	Within 3,000 flight hours after the most recent inspection per paragraph (b) of AD 89-03-05 or 18 months after the effective date of this AD, whichever occurs first	18 months	Paragraph (b) of this AD.
(3) Neither paragraph (a) nor (b) of this AD	3,000 total flight hours or 180 days after the effective date of this AD, whichever occurs later	18 months	N/A.

Replacement

(e) If freeplay of the elevator exceeds the limits specified in the service bulletin during any check per paragraph (d) of this AD: Before further flight, replace elevator PCA reaction link rod-end bearings and PCA rod-end bearings, as necessary, with new, improved bearings, per Boeing Service Bulletin 757-27A0086, Revision 2, dated July 27, 1989.

Note 3:

The replacement required by paragraph (e) of this AD may be accomplished with reaction link bearings having either Boeing part number (P/N) S251N214-8 (Rexnord P/N DRX34C) or S251N214-11 (Rexnord P/N DRX34B). The Boeing PCA assembly, P/N S251N211-11, contains Rexnord P/N DRX32B.

Alternative Methods of Compliance

(f)(1) An 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, Seattle Aircraft Certification Office (ACO), FAA. Operators shall submit their requests through an appropriate FAA Principal Maintenance Inspector, who may add comments and then send it to the Manager, Seattle ACO.

(2) Alternative methods of compliance, approved previously in accordance with AD 89-03-05, amendment 39-6120, are NOT considered to be approved as alternative methods of compliance with this AD.

Note 4:

Information concerning the existence of approved alternative methods of compliance with this AD, if any, may be obtained from the Seattle ACO.

Special Flight Permits

(g) Special 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.

Incorporation by Reference

(h) The actions shall be done in accordance with Boeing Alert Service Bulletin 757-27A0086, dated June 9, 1988; or Boeing Service Bulletin 757-27A0086, Revision 2, dated July 27, 1989; 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 Boeing Commercial Airplane Group, P.O. Box 3707, Seattle, Washington 98124-2207. Copies may be inspected at the FAA, Transport Airplane Directorate, 1601 Lind Avenue, SW., Renton, Washington; or at the Office of the Federal Register, 800 North Capitol Street, NW., suite 700, Washington, DC.

Effective Date

(i) This amendment becomes effective on November 15, 2001.

Issued in Renton, Washington, on October 2, 2001.

Vi L. Lipski,

Manager, Transport Airplane Directorate, Aircraft Certification Service.