AD 2017-24-07

We are superseding Airworthiness Directive (AD) 2014-08-01, which applied to all Airbus Model A318, A319, A320, and A321 series airplanes. AD 2014-08-01 required an inspection for part numbers of the interconnecting struts and, for affected interconnecting struts, identification of the part and serial numbers of the associated target and proximity sensors and replacement or re-identification of the flap interconnecting strut if necessary. This AD continues to require an inspection to verify the interconnecting strut part number. This AD also provides a new compliance time and an additional inspection for previously inspected airplanes. This AD was prompted by an investigation that showed that when a certain combination of target/ proximity sensor serial numbers is installed on a flap interconnecting strut, a ``target FAR'' signal cannot be detected when reaching the mechanical end stop of the interconnecting strut. We are issuing this AD to address the unsafe condition on these products.

Final rule.

Adoption of the Amendment

Accordingly, under the authority delegated to me by the Administrator, the FAA amends 14 CFR part 39 as follows:

PART 39--AIRWORTHINESS DIRECTIVES

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

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

Sec. 39.13 [Amended]

0 2. The FAA amends Sec. 39.13 by removing Airworthiness Directive (AD) 2014-08-01, Amendment 39-17825 (79 FR 23900, April 29, 2014), and adding the following new AD:

2017-24-07 Airbus: Amendment 39-19111; Docket No. FAA-2017-0476; Product Identifier 2016-NM-110-AD.

(a) Effective Date

This AD is effective January 5, 2018.

(b) Affected ADs

This AD replaces AD 2014-08-01, Amendment 39-17825 (79 FR 23900, April 29, 2014) (``AD 2014-08-01'').

(c) Applicability

This AD applies to Airbus Model A318-111, -112, -121, and -122 airplanes; Model A319-111, -112, -113, -114, -115, -131, -132, and - 133 airplanes; Model A320-211, -212, -214, -231, -232, and -233 airplanes; and Model A321-111, -112, -131, -211, -212, -213, -231, and -232 airplanes; certificated in any category; all manufacturer serial numbers.

(d) Subject

Air Transport Association (ATA) of America Code 27, Flight controls.

(e) Reason

This AD was prompted by an investigation that showed that when a certain combination of target/proximity sensor serial numbers is installed on a flap interconnecting strut, a ``target FAR'' signal cannot be detected when reaching the mechanical end stop of the interconnecting strut. We are issuing this AD to prevent an undetected flap down drive disconnection due to an already-failed interconnecting strut sensor, which could result in asymmetric flap panel movement and consequent loss of control of the airplane.

(f) Compliance

Comply with this AD within the compliance times specified, unless already done.

(g) Retained Inspection To Determine the Part Number of the Interconnecting Struts, With Revised Service Information

This paragraph restates the requirements of paragraph (g) of AD 2014-08-01, with revised service information. Within 8,000 flight hours after March 26, 2014 (the effective date of AD 2014-03-08, Amendment 39-17745 (79 FR 9398, February 19, 2014) (``AD 2014-03- 08'')), inspect to determine the part number of the interconnecting struts installed on both the left-hand (LH) and right-hand (RH) wings of the airplane, in accordance with the Accomplishment Instructions of Airbus Service Bulletin A320-27-1206, Revision 01, dated October 10, 2011; or Airbus Service Bulletin A320-27-1206, Revision 02, dated November 2, 2015. A review of the airplane maintenance records is acceptable for determining the part number of the installed interconnecting struts, in lieu of the inspection, if the part number of the installed interconnecting struts, and the part number and the serial number of the associated target and proximity sensor, can be conclusively determined from that review. Accomplishment of the requirements of paragraph (i) of this AD terminates the requirements of this paragraph.
(1) Airplanes on which Airbus Modification 27956 has been embodied in production, and on which no interconnecting strut has been replaced with a strut having a part number specified in figure 1 to paragraphs (g) and (h) of this AD since the airplane's first flight: No further work is required by paragraph (g) of this AD.
(2) If, during the inspection required by paragraph (g) of this AD, any interconnecting strut is installed with a part number specified in figure 1 to paragraphs (g) and (h) of this AD: Within 8,000 flight hours after March 26, 2014 (the effective date of AD 2014-03-08), determine the part number and the serial number of the associated target and proximity sensor.
(i) For airplanes having conditions specified in paragraphs (g)(2)(i)(A), (g)(2)(i)(B), (g)(2)(i)(C), and (g)(2)(i)(D) of this AD: Before further flight, replace the interconnecting strut with a serviceable unit, in accordance with the Accomplishment Instructions of Airbus Service Bulletin A320-27-1206, Revision 01, dated October 10, 2011; or Airbus Service Bulletin A320-27-1206, Revision 02, dated November 2, 2015. For the purposes of paragraph (g) of this AD, a serviceable interconnecting strut is a unit that has been determined to be in compliance with the requirements of paragraph (g) of this AD.
(A) A target part number (P/N) ABS0121-13 or P/N 8-536-01; and
(B) A target serial number lower than 1600, or a target serial number that is unreadable; and
(C) A proximity sensor having P/N ABS0121-31 or P/N 8-372-04; and
(D) A proximity sensor having a serial number between C59198 and C59435, or a serial number (S/N) C500000 or higher.
(ii) For a target having S/N 1600 or higher and target P/N ABS0121-13 or P/N 8-536-01: Within 8,000 flight hours after March 26, 2014 (the effective date of AD 2014-03-08), re-identify the interconnecting strut, in accordance with the Accomplishment Instructions of Airbus Service Bulletin A320-27-1206, Revision 01, dated October 10, 2011; or Airbus Service Bulletin A320-27-1206, Revision 02, dated November 2, 2015. BILLING CODE 4910-13-P

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(h) Retained Parts Installation Prohibition, With No Changes

This paragraph restates the requirements of paragraph (h) of AD 2014-08-01, with no changes. As of March 26, 2014 (the effective date of AD 2014-03-08), no person may install an interconnecting strut with a part number specified in figure 1 to paragraphs (g) and (h) of this AD, on any airplane, except for parts identified in paragraph (g)(2)(ii) of this AD, provided that the actions in paragraph (g)(2)(ii) are done. As of the effective date of this AD, comply with the requirements of paragraph (l) of this AD in lieu of the requirements of this paragraph.

(i) New Requirements of This AD: Inspection To Determine the Part Number of the Interconnecting Struts and the Part Number and Serial Number of the Associated Target and Proximity Sensor

Within 24 months after the effective date of this AD, accomplish the actions specified in paragraphs (i)(1) and (i)(2) of this AD, in accordance with the Accomplishment Instructions of Airbus Service Bulletin A320-27-1206, Revision 02, dated November 2, 2015. Accomplishment of the actions specified in this paragraph terminates the requirements of paragraph (g) of this AD. In lieu of doing the actions specified in paragraphs (i)(1) and (i)(2) of this AD, a review of the airplane maintenance records is acceptable for determining the part number of the installed interconnecting struts and the part number and the serial number of the associated target and proximity sensor, if the part number and serial numbers can be conclusively determined from that review.
(1) Inspect to determine the part number of the interconnecting struts installed on both theLH and RH wings on the airplane.
(2) If an interconnecting strut is installed with a part number specified in figure 2 to paragraphs (i)(2), (k), and (l) of this AD, identify the part number and the serial number of the associated target and proximity sensor; and for the target and proximity sensor part number and serial number combination specified in paragraph (j) of this AD, within the compliance times specified in paragraph (j) of this AD, do the actions specified in paragraph (j) of this AD for that interconnecting strut.

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(j) New Requirements of This AD: Replacement or Re-Identification

(1) If the target serial number is lower than 1600 or is unreadable, and the proximity sensor part number is P/N ABS0121-31 or P/N 8-372-04 with a serial number between S/N C59198 and C59435, or S/N C500000 or higher: Before further flight, do the actions specified by paragraph (j)(1)(i) or (j)(1)(ii) of this AD. For the purposes of paragraph (j) of this AD, a serviceable interconnecting strut is a unit that has been determined to be in compliance with the requirements of paragraphs (i) and (j) of this AD.
(i) Replace the interconnecting strut with a serviceable unit, in accordance with the Accomplishment Instructions of Airbus Service Bulletin A320-27-1206, Revision 02, dated November 2, 2015.
(ii) Do a general visual inspection of the flap down drive to detect discrepancies, in accordance with the Accomplishment Instructions of Airbus Service Bulletin A320-27-1206, Revision 02, dated November 2, 2015.
(A) If no discrepancy is found, within 50 flight cycles after the inspection, replace the interconnecting strut with a serviceable unit, in accordance with the Accomplishment Instructions of Airbus Service Bulletin A320-27-1206, Revision 02, dated November 2, 2015.
(B) If any discrepancy is found, before further flight, replace the interconnecting strut with a serviceable unit, in accordance with the Accomplishment Instructions of Airbus Service Bulletin A320-27-1206, Revision 02, dated November 2, 2015.
(2) If the target serial number is 1600 or higher (with any proximity sensor part number and serial number): Within 24 months after the effective date of this AD, re-identify the interconnecting strut, in accordance with the Accomplishment Instructions of Airbus Service Bulletin A320-27-1206, Revision 02, dated November 2, 2015.

(k) Additional Provisions of This AD

(1) Airplanes on which Airbus Modification 27956 has been embodied in production, and on which no interconnecting strut with a part number identified in figure 2 to paragraphs (i)(2), (k), and (l) of this AD has been installed since the airplane's first flight, are not affected by the requirements of paragraph (i) of this AD, except for those manufacturer serial numbers specified in figure 3 to paragraph (k)(1) of this AD. Airplanes having manufacturer serial numbers specified in figure 3 to paragraph (k)(1) of this AD are affected by the requirements of paragraph (i) of this AD.
(2) For an airplane that has already been inspected before the effective date of this AD as specified in the Accomplishment Instructions of Airbus Service Bulletin A320-27-1206, dated January 28, 2011; or Revision 01, dated October 10, 2011: Within the compliance time specified in paragraph (i) of this AD, accomplish the additional work specified in and in accordance with the Accomplishment Instructions of Airbus Service Bulletin A320-27-1206, Revision 02, dated November 2, 2015, unless it is determined that no interconnecting strut with a part number specified in figure 2 to paragraphs (i)(2), (k), and (l) of this AD is installed on that airplane. A review of airplane maintenance records is acceptable to make this determination, provided the part number can be conclusively identified from that review.

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BILLING CODE 4910-13-C

(l) NewRequirement of This AD: Parts Installation Limitations

As of the effective date of this AD, no person may install, on any airplane, an interconnecting strut with a part number specified in figure 2 to paragraphs (i)(2), (k), and (l) of this AD, unless it is in compliance with the requirements of this AD.

(m) Credit for Previous Actions

This paragraph provides credit for the actions required by paragraph (g) of this AD, if those actions were performed before March 26, 2014 (the effective date of AD 2014-03-08), using Airbus Service Bulletin A320-27-1206, dated January 28, 2011, and if additional work since March 26, 2014 (the effective date of AD 2014- 03-08) has been accomplished using Airbus Service Bulletin A320-27- 1206, Revision 01, dated October 10, 2011.

(n) Other FAA AD Provisions

The following provisions also apply to this AD:
(1) Alternative Methods of Compliance (AMOCs): The Manager, International

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Section, Transport Standards Branch, FAA, has the authority to approve AMOCs for this AD, if requested using the procedures found in 14 CFR 39.19. In accordance with 14 CFR 39.19, send your request to your principal inspector or local Flight Standards District Office, as appropriate. If sending information directly to the International Section, send it to the attention of the person identified in paragraph (o)(2) of this AD. Information may be emailed to: 9-ANM-116-AMOC-REQUESTS@faa.gov.
(i) Before using any approved AMOC, notify your appropriate principal inspector, or lacking a principal inspector, the manager of the local flight standards district office/certificate holding district office.
(ii) AMOCs approved previously for AD 2014-08-01 are approved as AMOCs for the corresponding provisions of paragraphs (g) and (h) of this AD.
(2) Contacting the Manufacturer: As of the effective date of this AD, for any requirement in this AD to obtain corrective actions from a manufacturer, the action must beaccomplished using a method approved by the Manager, International Section, Transport Standards Branch, FAA; or the European Aviation Safety Agency (EASA); or Airbus's EASA Design Organization Approval (DOA). If approved by the DOA, the approval must include the DOA-authorized signature.
(3) Required for Compliance (RC): If any service information contains procedures or tests that are identified as RC, those procedures and tests must be done to comply with this AD; any procedures or tests that are not identified as RC are recommended. Those procedures and tests that are not identified as RC may be deviated from using accepted methods in accordance with the operator's maintenance or inspection program without obtaining approval of an AMOC, provided the procedures and tests identified as RC can be done and the airplane can be put back in an airworthy condition. Any substitutions or changes to procedures or tests identified as RC require approval of an AMOC.

(o) Related Information(1) Refer to Mandatory Continuing Airworthiness Information (MCAI) EASA AD 2016-0113, dated June 15, 2016, for related information. This MCAI may be found in the AD docket on the Internet at http://www.regulations.gov by searching for and locating Docket No. FAA-2017-0476.
(2) For more information about this AD, contact Sanjay Ralhan, Aerospace Engineer, International Section, Transport Standards Branch, FAA, 1601 Lind Avenue SW., Renton, Washington 98057-3356; telephone 425-227-1405; fax 425-227-1149.
(3) Service information identified in this AD that is not incorporated by reference is available at the addresses specified in paragraphs (p)(5) and (p)(6) of this AD.

(p) Material Incorporated by Reference

(1) The Director of the Federal Register approved the incorporation by reference (IBR) of the service information listed in this paragraph under 5 U.S.C. 552(a) and 1 CFR part 51.
(2) You must use this service information as applicable to do the actions required by this AD, unless this AD specifies otherwise.
(3) The following service information was approved for IBR on January 5, 2018.
(i) Airbus Service Bulletin A320-27-1206, Revision 02, dated November 2, 2015.
(ii) Reserved.
(4) The following service information was approved for IBR on March 26, 2014 (79 FR 9398, February 19, 2014).
(i) Airbus Service Bulletin A320-27-1206, Revision 01, dated October 10, 2011.
(ii) Reserved.
(5) For service information identified in this AD, contact Airbus, Airworthiness Office--EIAS, 1 Rond Point Maurice Bellonte, 31707 Blagnac Cedex, France; telephone +33 5 61 93 36 96; fax +33 5 61 93 44 51; email account.airworth-eas@airbus.com; Internet http://www.airbus.com.
(6) You may view this service information at the FAA, Transport Standards Branch, 1601 Lind Avenue SW., Renton, WA. For information on the availability of this material at the FAA, call 425-227-1221.
(7) You may view this service information that is incorporated by reference at the National Archives and Records Administration (NARA). For information on the availability of this material at NARA, call 202-741-6030, or go to: http://www.archives.gov/federal-register/cfr/ibr-locations.html.

Discussion

We issued a notice of proposed rulemaking (NPRM) to amend 14 CFR part 39 to supersede AD 2014-08-01, Amendment 39-17825 (79 FR 23900, April 29, 2014) (``AD 2014-08-01''). AD 2014-08-01 applied to all Airbus Model A318, A319, A320, and A321 series airplanes. The NPRM published in the Federal Register on May 19, 2017 (82 FR 22918).
The European Aviation Safety Agency (EASA), which is the Technical Agent for the Member States of the European Union, has issued EASA AD 2016-0113, dated June 15, 2016 (referred to after this as the Mandatory Continuing Airworthiness Information, or ``the MCAI''), to correct an unsafe condition for all Airbus Model A318, A319, A320, and A321 series airplanes. The MCAI states:

The flap interconnecting strut is a safety device of the High Lift System which acts as an alternative load path from one flap surface to another in case of a flap drive system disconnection. In such a failure case, the installedproximity sensors provide information to the slat flap control computer (SFCC) and the operation of the flap drive system is inhibited.
An engineering investigation showed that, when a certain combination of target/sensor serial number (s/n) is installed on a flap interconnecting strut, a ``target FAR'' signal cannot be detected when reaching the mechanical end stop of the interconnecting strut.
This condition, if not corrected, could cause a flap down drive disconnection to remain undetected, due to an already-failed interconnecting strut sensor, potentially resulting in asymmetric flap panel movement and consequent loss of control of the aeroplane.
To address this potential unsafe condition, Airbus issued Service Bulletin (SB) A320-27-1206 and SB A320-57-1164, to provide identification and replacement instructions for struts that have a certain target/sensor s/n combination installed. Aeroplanes on which modification (mod) 27956 had been accomplished in production were identified as not affected by the unsafe condition. Consequently, EASA issued [EASA] AD 2012-0012 [which corresponds to FAA AD 2014- 08-01] to require accomplishment of these inspections and corrective actions.
Since that [EASA] AD was issued, Airbus has informed EASA about a batch of aeroplanes that were delivered with pre-mod 27956 Part Number (P/N) flap interconnecting strut(s) installed, but declared to be in post-mod configuration in the Aircraft Inspection Report. Airbus SB A320-57-1202 has been issued to provide instructions to verify the interconnecting strut P/N, and to update aircraft documentation.
In addition, to ensure that all pre-mod parts are checked and corrected as required, SB A320-27-1206 was revised to include a wider range of P/N of affected interconnecting struts.
For the reasons described above, this [EASA] AD retains the requirements of EASA

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AD 2012-0012, which is superseded, expands the Applicability [adds affected part numbers], changes the compliance time and requires an additional inspection for aeroplanes that have already been inspected.

You may examine the MCAI in the AD docket on the Internet at http://www.regulations.gov by searching for and locating Docket No. FAA-2017- 0476.

Comments

We gave the public the opportunity to participate in developing this AD. The following presents the comments received on the NPRM and the FAA's response to each comment. United Airlines and the Air Line Pilots Association, International supported the NPRM.

Request To Add Additional Identification Steps

Delta Airlines (DAL) requested that additional identification steps be required in the NPRM to ensure that the affected parts are correctly identified. DAL stated that figure 1 to paragraphs (g) and (h) of the proposed AD contains part numbers for affected interconnecting struts. DAL commented that a review of its records from inspections conducted during compliance with AD 2014-08-01 determined that other part numbers were possible. DAL stated that it has had at least one instance of a part with the part number D5757032200000A.
DAL stated that figure 2 to paragraphs (i)(2), (k), and (l) of the proposed AD adds the provision that additional alphanumeric characters may exist. DAL commented that while the NPRM removes some of the ambiguity that existed in AD 2014-08-01, a review of Airbus's Aircraft Illustrated Parts Catalog (AIPC) does not show any parts with a ``letter'' suffix. DAL provided a photo that showed that the part number appears to ``wrap'' (to the next line) on the part. DAL stated that this ``wrapping'' condition has led to confusion in identifying the parts.
DAL stated that per the Airbus AIPC Front Matter, the 13th, 14th, and 15th characters are controlled in specific ways. DAL also stated that the 13th and 14th characters are expected to be ``00'' and are used to fill out 12-digit base numbers on the part installed during production. DAL stated that the 15th character is a paint code designator and found the use of a paint code designator unusual on a part that is not viewable or expected to be painted to match an air carrier paint scheme. DAL commented that it believes the AD should be updated to show 00A, 00B, or the list of true possibilities, and the XXX allowance creates a significant number of possible part numbers that DAL must identify as prohibited.
We agree to clarify the requirement to identify affected parts. Regarding the characters in the part number, identifying the last three characters are not required to identify a discrepant part; only the first twelve base numbers are required. Therefore, we do not agree to revise this AD to include a complete list of all possible combinations of these characters.
We acknowledge the commenter's concern about the ``wrapping'' condition for part identification. However, in the photo provided by the commenter only the last three characters are ``wrapped.'' As stated previously, thelast three characters are not required to identify a discrepant part.

Formatting Change to a Figure

Figure 3 to paragraph (k)(1) of this AD has been reformatted to clarify affected manufacturer serial numbers.

Records Review

We have determined that a review of maintenance records is acceptable for complying with the actions specified in paragraphs (i)(1) and (i)(2) of this AD, provided the part number of the installed interconnecting struts and the part number and the serial number of the associated target and proximity sensor can be conclusively determined from that review. We have revised paragraph (i) of this AD accordingly.

Conclusion

We reviewed the available data, including the comments received, and determined that air safety and the public interest require adopting this AD as proposed except for minor editorial changes. We have determined that these minor changes:
Are consistent with the intent that was proposed in the NPRM for correcting the unsafe condition; and
Do not add any additional burden upon the public than was already proposed in the NPRM.
We also determined that these changes will not increase the economic burden on any operator or increase the scope of this AD.

Related Service Information Under 1 CFR Part 51

Airbus has issued Service Bulletin A320-27-1206, Revision 02, dated November 2, 2015. The service information describes procedures for an inspection to determine the part number of the installed interconnecting struts and the part number and serial number of the associated target and proximity sensors, and procedures for replacement and re-identification of the interconnecting struts. This service information is reasonably available because the interested parties have access to it through their normal course of business or by the means identified in the ADDRESSES section.

Costs of Compliance

We estimate that this AD affects 1,032 airplanes of U.S. registry.
We estimate the following costs to comply with this AD:

Estimated Costs ----------------------------------------------------------------------------------------------------------------
Cost per Cost on U.S.
Action Labor cost Parts cost product operators ---------------------------------------------------------------------------------------------------------------- Inspection and replacement 8 work-hours x $85 per hour $0 $680 $701,760
(retained actions from AD 2014-08- = $680.
01). Inspection and replacement (new 15 work-hours x $85 per 0 1,275 1,315,800
action). hour = $1,275. ----------------------------------------------------------------------------------------------------------------

We have received no definitive data that would enable us to provide cost estimates for the on-condition actions specified in this AD.

Authority for This Rulemaking

Title 49 of the United States Code specifies the FAA's authority to issue rules on aviation safety. Subtitle I, section 106, describes the authority of the FAA Administrator. ``Subtitle VII: Aviation Programs,'' describes in more detail the scope of the Agency's authority.
We are issuing this rulemaking under the authority described in ``Subtitle VII, Part A, Subpart III, Section 44701: General requirements.'' Under that section, Congress charges the FAA with

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promoting safe flight of civil aircraft in air commerce by prescribing regulations for practices, methods, and procedures the Administrator finds necessary for safety in air commerce. This regulation is within the scope of that authority because it addresses an unsafe condition that is likely to exist or develop on products identified in this rulemaking action.
This AD is issued in accordance with authority delegated by the Executive Director, Aircraft Certification Service, as authorized by FAA Order 8000.51C. In accordance with that order, issuance of ADs is normally a function of the Compliance and Airworthiness Division, but during this transition period, the Executive Director has delegated the authority to issue ADs applicable to transport category airplanes to the Director of the System Oversight Division.

Regulatory Findings

We determined that this AD will not have federalism implications under Executive Order 13132. This AD 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.
For the reasons discussed above, I certify that this AD:
1. Is not a ``significant regulatory action'' under Executive Order 12866;
2. Is not a ``significant rule'' under the DOT Regulatory Policies and Procedures (44 FR 11034, February 26, 1979);
3. Will not affect intrastate aviation in Alaska; and
4. 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.

List of Subjects in 14 CFR Part 39

Air transportation, Aircraft, Aviation safety, Incorporation by reference, Safety.