Airworthiness directives: Airbus,

As Enacted ( Federal Register)

Cited authorities 5

Cited in

[Federal Register: April 5, 2004 (Volume 69, Number 65)]

[Proposed Rules]

[Page 17610-17615]

From the Federal Register Online via GPO Access [wais.access.gpo.gov]

[DOCID:fr05ap04-20]

Proposed Rules Federal Register

This section of the FEDERAL REGISTER contains notices to the public of the proposed issuance of rules and regulations. The purpose of these notices is to give interested persons an opportunity to participate in the rule making prior to the adoption of the final rules.

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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 2001-NM-243-AD]

RIN 2120-AA64

Airworthiness Directives; Airbus Model A330, A340-200, and A340- 300 Series Airplanes

AGENCY: Federal Aviation Administration, DOT.

ACTION: Notice of proposed rulemaking (NPRM).

SUMMARY: This document proposes the supersedure of an existing airworthiness directive (AD); applicable to certain Airbus Model A330, A340-200, and A340-300 series airplanes; that currently requires repetitive inspections to detect discrepancies of the transfer tubes and the collar of the ball nut of the trimmable horizontal stabilizer actuator (THSA); and corrective action, if necessary. This action would expand the applicability of the existing AD; and would require new repetitive inspections for discrepancies of the ball screw assembly; corrective action if necessary; repetitive greasing of the THSA ball nut, and replacement of the THSA if necessary; and a modification or replacement (as applicable) of the ball nut assembly. Such modification or replacement (as applicable) terminates certain repetitive inspections. The actions specified by the proposed AD are intended to prevent degraded operation of the THSA due to the entrance of water into the ball nut. Degraded operation could lead to reduced controllability of the airplane. This action is intended to address the identified unsafe condition.

DATES: Comments must be received by May 5, 2004.

ADDRESSES: Submit comments in triplicate to the Federal Aviation Administration (FAA), Transport Airplane Directorate, ANM-114, Attention: Rules Docket No. 2001-NM-243-AD, 1601 Lind Avenue, SW., Renton, Washington 98055-4056. Comments may be inspected at this location between 9 a.m. and 3 p.m., Monday through Friday, except Federal holidays. Comments may be submitted via fax to (425) 227-1232. Comments may also be sent via the Internet using the following address: 9-anm-nprmcomment@faa.gov. Comments sent via fax or the Internet must

contain ``Docket No. 2001-NM-243-AD'' in the subject line and need not be submitted in triplicate. Comments sent via the Internet as attached electronic files must be formatted in Microsoft Word 97 or 2000 or ASCII text.

The service information referenced in the proposed rule may be obtained from Airbus, 1 Rond Point Maurice Bellonte, 31707 Blagnac Cedex, France. This information may be examined at the FAA, Transport Airplane Directorate, 1601 Lind Avenue, SW., Renton, Washington.

FOR FURTHER INFORMATION CONTACT: Dan Rodina, Aerospace Engineer, International Branch, ANM-116, FAA, Transport Airplane Directorate, 1601 Lind Avenue, SW., Renton, Washington 98055-4056; telephone (425) 227-2125; fax (425) 227-1149.

SUPPLEMENTARY INFORMATION:

Comments Invited

Interested persons are invited to participate in the making of the proposed 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 above. All communications received on or before the closing date for comments, specified above, will be considered before taking action on the proposed rule. The proposals contained in this action may be changed in light of the comments received.

Submit comments using the following format:

Organize comments issue-by-issue. For example, discuss a request to change the compliance time and a request to change the service bulletin reference as two separate issues.

For each issue, state what specific change to the proposed AD is being requested.

Include justification (e.g., reasons or data) for each request.

Comments are specifically invited on the overall regulatory, economic, environmental, and energy aspects of the proposed 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 summarizing each FAA-public contact concerned with the substance of this proposal will be filed in the Rules Docket.

Commenters wishing the FAA to acknowledge receipt of their comments submitted in response to this action must submit a self-addressed, stamped postcard on which the following statement is made: ``Comments to Docket Number 2001-NM-243-AD.'' The postcard will be date stamped and returned to the commenter.

Availability of NPRMs

Any person may obtain a copy of this NPRM by submitting a request to the FAA, Transport Airplane Directorate, ANM-114, Attention: Rules Docket No. 2001-NM-243-AD, 1601 Lind Avenue, SW., Renton, Washington 98055-4056.

Discussion

On May 25, 2001, the FAA issued AD 2001-11-09, amendment 39-12252 (66 FR 31143, June 11, 2001), applicable to certain Airbus Model A330 and A340 series airplanes. That AD requires repetitive inspections to detect discrepancies of the transfer tubes and the collar of the ball nut of the trimmable horizontal stabilizer actuator (THSA); and corrective action, if necessary. That action was prompted by several reports of disconnection of the transfer tube from the ball nut of the THSA. The requirements of that AD are intended to prevent degraded operation of the THSA due to the entrance of water into the ball nut. Degraded operation could lead to reduced controllability of the airplane.

Actions Since Issuance of Previous Rule

Since the issuance of that AD, the Direction G[eacute]n[eacute]rale de l'Aviation Civile (DGAC), which is the airworthiness authority for France, has advised us of additional incidents in which transfer tubes disconnected from the ball nut of the THSA. In response to these initial incidents, Airbus has revised the A330/A340 Airplane Maintenance Manual (AMM) to enhance existing maintenance instructions for repetitive greasing of the

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THSA, and has developed procedures for new repetitive inspections for discrepancies of the ball screw assembly.

Also, the preamble to AD 2001-11-09 explains that we considered the requirements of that AD ``interim action'' and were considering further rulemaking. We now have determined that further rulemaking is indeed necessary, and this proposed AD follows from that determination.

Explanation of Relevant Service Information

Airbus has issued the following Service Bulletins (SBs):

A330-27-3088 (for Model A330 series airplanes) and A340-27-4093 (for Model A340-200 and -300 series airplanes), both Revision 04, both including Appendix 01, and both dated September 5, 2002. These SBs describe procedures for repetitive detailed visual inspections of the transfer tubes and collar on the THSA ball nut to detect discrepancies, including ball migration, distortion, or evidence of disconnection of the THSA ball nut. If any discrepancy is found, the SBs specify to replace the THSA with a new or serviceable part. (These inspections are similar to those specified in Airbus All Operators Telexes (AOT) A330-27A3088 and A340-27A4093, both dated April 5, 2001, which the existing AD refers to as the appropriate source of service information for accomplishment of the actions required by that AD.)

A330-27-3102, Revision 03, including Appendix 01 (for Model A330 series airplanes); and A340-27-4107, Revision 04, including Appendix 01 (for Model A340-200 and -300 series airplanes); both dated June 20, 2003. These SBs describe procedures for repetitive detailed visual inspections of the ball screw assembly for discrepancies, including cracks, metallic debris, dents, corrosion, loose nuts, and damaged or missing lock washers and pins. These SBs also describe procedures for an inspection of the gap between the secondary nut tenons and the transfer plates using a feeler gage to ensure free movement.

A330-27-3085 (for Model A330 series airplanes) and A340-27-4089 (for Model A340-313 series airplanes), both Revision 02, both dated September 5, 2002. These SBs describe procedures for modifying the ball nut assembly by installing new steel balls, seals, and a strengthened collar and transfer tubes, to minimize ball migration. These SBs also describe procedures for an alternative procedure to replace the existing ball nut assembly with an improved THSA. These SBs refer to TRW Aeronautical Systems SB 47172-27-03 for additional instructions for accomplishing the modification.

A330-27-3093 (for Model A330 series airplanes) and A340-27-4099 (for Model A340-200 and -300 series airplanes), both Revision 01, both dated September 5, 2002. These SBs describe procedures for modifying the ball nut assembly on the THSA, or, for certain airplanes, replacing the THSA with an improved THSA. These SBs refer to TRW Aeronautical Systems SB 47172-27-10 for additional instructions for accomplishing the modification.

Accomplishment of the actions in A330-27-3085, Revision 02; A330- 27-3093, Revision 01; A340-27-4089, Revision 02; or A340-27-4099, Revision 01; as applicable; eliminates the need for the repetitive inspections for discrepancies of the transfer tubes and collar on the THSA ball nut.

The DGAC classified these SBs as mandatory and issued French airworthiness directives 2002-414(B) R2 and 2002-415(B) R2, both dated October 30, 2002, to ensure the continued airworthiness of these airplanes in France.

Explanation of Previous/Concurrent Service Information

Airbus also has issued SBs A330-27-3052 and A340-27-4059, both Revision 03, both dated December 5, 2001. (Airbus SB A330-27-3093, Revision 01, and Airbus SB A340-27-4099, Revision 01, specify that SBs A330-27-3052 and A340-27-4059, respectively, must be accomplished previously or concurrently.) Those SBs describe procedures for replacing the THSA with a THSA modified per Lucas Aerospace SB 47147- 27-07. The Lucas SB introduces a modified screwjack with ceramic balls and spacer balls, modifies the motor shafts and planet gear assembly, and installs machined seals on the transfer tubes.

Airbus SB A330-27-3052, Revision 03, specifies that the actions in Airbus SBs A330-27-3007, A330-27-3015, A330-27-3047, A330-27-3050, and A330-27-3020 must be accomplished previously or concurrently. The current revisions of those SBs and the actions they describe, as well as additional sources of service information referenced in those SBs, are as follows:

Additional source of service Airbus SB

Revision level

Date

Main action

information

A330-27-3007.................... 01................... September 18, 1996................. Replace rudder servo Samm Avionique SB 5300-27-24- controls with modified 01. parts. A330-27-3015.................... Original............. June 7, 1995....................... Modify the control valve Lucas Aerospace SB 47147-27-02. detent and the jamming protection device on the THSA. A330-27-3047.................... 01................... November 26, 1997.................. Replace hydraulic motors Lucas Aerospace SB 47147-27-04. on the THSA with new parts. A330-27-3050.................... Original............. November 15, 1996.................. Replace mechanical input Lucas Aerospace SB 47147-27-05. shaft for THSA with modified part. A330-55-3020.................... 01................... October 21, 1998................... Perform a visual

None. inspection of the THSA screw jack fitting assembly for correct installation of a washer; and correctly install washer as applicable.

Airbus SB A340-27-4059, Revision 03, specifies that Airbus SBs A340-27-4007, A340-27-4025, A340-27-4054, A340-27-4057, and A340-55- 4021, must be accomplished previously or concurrently. The current revisions of those SBs and the actions they describe, as well as secondary sources of service information referenced in those SBs, are as follows:

Additional source of service Airbus SB

Revision level

Date

Main action

information

A340-27-4007.................... Original............. April 7, 1994...................... Replace hydraulic motors Lucas Aerospace SB 47147-27-01. on the THSA with new parts.

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A340-27-4025.................... Original............. June 7, 1995....................... Modify the control valve Lucas Aerospace SB 47147-27-02. detent and the jamming protection device on the THSA. A340-27-4054.................... 01................... November 26, 1997.................. Replace hydraulic motors Lucas Aerospace SB 47147-27-04. on the THSA with new parts. A340-27-4057.................... Original............. November 15, 1996.................. Replace mechanical input Lucas Aerospace SB 47147-27-05. shaft for THSA with modified part. A340-55-4021.................... 01................... October 21, 1998................... Perform a visual

None. inspection of the THSA screw jack fitting assembly for correct installation of a washer; and correctly install washer as applicable.

FAA's Conclusions

These airplane models are manufactured in France and are type certificated for operation in the United States under the provisions of section 21.29 of the Federal Aviation Regulations (14 CFR 21.29) and the applicable bilateral airworthiness agreement. Pursuant to this bilateral airworthiness agreement, the DGAC has kept the FAA informed of the situation described above. The FAA has examined the findings of the DGAC, reviewed all available information, and determined that AD action is necessary for products of this type design that are certificated for operation in the United States.

Explanation of Requirements of Proposed Rule

Since an unsafe condition has been identified that is likely to exist or develop on other airplanes of the same type design registered in the United States, the proposed AD would supersede AD 2001-11-09 to continue to require repetitive inspections to detect discrepancies of the transfer tubes and the collar of the ball nut of the THSA, and corrective action if necessary. The proposed AD also would require the actions specified in the SBs described previously, except as discussed below. In addition, the proposed AD would require repetitive greasing of the ball nut of all THSAs per a method approved by the FAA or the DGAC. (Airbus A330 AMM, Chapter 12-22-27, dated July 1, 2001; or Airbus A340 AMM, Chapter 12-22-27, dated April 1, 2001; as applicable; is one acceptable method of compliance with this action.) If, during any accomplishment of the greasing procedure, the new grease is expelled from the transfer tube (instead of through the drain hole), the proposed AD would require replacement of the THSA with a new or serviceable THSA, per Airbus Service Bulletin A330-27-3102, Revision 03 (for Model A330 series airplanes); or A340-27-4107, Revision 04; both dated June 20, 2003; as applicable.

Differences Among Proposed AD, French Airworthiness Directive, and Service Bulletins

Although the Accomplishment Instructions of Airbus SBs A330-27- 3088, Revision 04; A340-27-4093, Revision 04; A330-27-3102, Revision 03; and A340-27-4107, Revision 04; describe procedures for completing a reporting sheet with inspection results, this proposed AD would not require those actions.

Although Airbus SBs A330-27-3102, Revision 03, and A340-27-4107, Revision 04, specify that operators may contact the manufacturer for disposition of certain repair conditions, this proposal would require operators to repair the THSA per a method approved by the FAA, or the DGAC (or its delegated agent).

For the modification of the ball nut of each THSA, the French airworthiness directive specifies a compliance time of December 31, 2003, or July 31, 2004, depending on the part number of the THSA. Paragraph (f) of the proposed AD specifies a compliance time of 24 months after the effective date of the AD for this action. In developing an appropriate compliance time for this AD, we considered the DGAC's recommendation, as well as the manufacturer's recommendation, and the degree of urgency associated with the subject unsafe condition. In light of all of these factors, we find that a 24- month compliance time represents an appropriate interval of time for affected airplanes to continue to operate without compromising safety.

Paragraph (d) of the proposed AD specifies that, if the new grease applied during the greasing procedure is expelled from the transfer tube (instead of through the drain hole), the proposed AD would require replacement of the THSA with a new or serviceable THSA. For this condition, the French airworthiness directive specifies replacement of the THSA, or contacting Airbus, depending on the part number of the THSA. We find that replacement of the THSA with a new or serviceable THSA will be an acceptable corrective action for this condition. As provided by 14 CFR part 39 (67 FR 47997, July 22, 2002), operators may request approval of an alternative method of compliance with this proposed requirement, if necessary, by submitting a request to the office specified in paragraph (j) of this AD.

Explanation of Changes Made To Existing Requirements

We have changed all references to a ``detailed visual inspection'' in the existing AD to ``detailed inspection'' in this action.

Also, for clarification, we have also revised the references to ``Model A340 series airplanes'' in the existing AD to ``Model A340-200 and -300 series airplanes'' in this action.

Cost Impact

There are approximately 9 Model A330 series airplanes of U.S. registry that would be affected by this proposed AD. Currently, there are no affected Model A340-200 or -300 series airplanes on the U.S. Register. However, if an affected Model A340-200 or -300 series airplane is imported and placed on the U.S. Register in the future, the following costs would also apply to those airplanes.

The inspections (per All Operators Telex (AOT) A330-27A3088 or A340-27A4093, as applicable) that are currently required by AD 2001-11- 09 take approximately 1 work hour per airplane, per inspection cycle, at an average labor rate of $65 per work hour. Based on these figures, the cost impact of the currently required actions on U.S. operators is estimated to be $585, or $65 per airplane, per inspection cycle.

The new inspections (per Airbus SBs A330-27-3088 or A340-27-4093, as applicable) that are proposed in this AD action would take approximately 1 work hour per airplane, per inspection cycle, at an average labor rate of $65 per work hour. Based on these figures, the cost impact of this proposed requirement on U.S. operators is estimated to be $585, or $65 per airplane, per inspection cycle.

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The new greasing action that is proposed in this AD action would take approximately 1 work hour per airplane, per maintenance cycle, at an average labor rate of $65 per work hour. Based on these figures, the cost impact of this proposed requirement on U.S. operators is estimated to be $585, or $65 per airplane, per maintenance cycle.

In addition to the actions stated above, certain airplanes may be subject to additional actions. The following table contains the cost impact estimate for each airplane affected by the SBs listed below, at an average labor rate of $65 per work hour:

Estimated For airplanes listed in Airbus SB-- number of work

Estimated parts cost

Estimated cost hours

per airplane

A330-27-3085 or A340-27-4089, both Revision

12 No charge.......................

$780 02. A330-27-3093 or A340-27-4099, both Revision

6 No charge.......................

390 01. A330-27-3052, Revision 03...................

6 No charge.......................

390 A330-27-3007, Revision 01...................

1 No charge.......................

65 A330-27-3015................................