Skip to Content

Rule

Airworthiness Directives; Airbus Airplanes

Document Details

Information about this document as published in the Federal Register.

Enhanced Content

Relevant information about this document from Regulations.gov provides additional context. This information is not part of the official Federal Register document.

Published Document

This document has been published in the Federal Register. Use the PDF linked in the document sidebar for the official electronic format.

Start Preamble Start Printed Page 10255

AGENCY:

Federal Aviation Administration (FAA), Department of Transportation (DOT).

ACTION:

Final rule.

SUMMARY:

We are adopting a new airworthiness directive (AD) for certain Airbus Model A300 series airplanes; and Model A300 B4-600, B4-600R, and F4-600R series airplanes, and Model A300 C4-605R Variant F airplanes (collectively called Model A300-600 series airplanes). This AD was prompted by a determination that certain inspection thresholds and intervals must be reduced. This AD requires repetitive detailed inspections for corrosion of the lower wing root joint, and related investigative and corrective actions if necessary. We are issuing this AD to address the unsafe condition on these products.

DATES:

This AD is effective March 17, 2017.

The Director of the Federal Register approved the incorporation by reference of certain publications listed in this AD as of March 17, 2017.

ADDRESSES:

For service information identified in this final rule, contact Airbus SAS, Airworthiness Office—EAW, 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. You may view this referenced service information at the FAA, Transport Airplane Directorate, 1601 Lind Avenue SW., Renton, WA. For information on the availability of this material at the FAA, call 425-227-1221. It is also available on the Internet at http://www.regulations.gov by searching for and locating Docket No. FAA-2016-5040.

Examining the AD Docket

You may examine the AD docket on the Internet at http://www.regulations.gov by searching for and locating Docket No. FAA-2016-5040; or in person at the Docket Management Facility between 9 a.m. and 5 p.m., Monday through Friday, except Federal holidays. The AD docket contains this AD, the regulatory evaluation, any comments received, and other information. The street address for the Docket Office (telephone 800-647-5527) is Docket Management Facility, U.S. Department of Transportation, Docket Operations, M-30, West Building Ground Floor, Room W12-140, 1200 New Jersey Avenue SE., Washington, DC 20590.

Start Further Info

FOR FURTHER INFORMATION CONTACT:

Dan Rodina, Aerospace Engineer, International Branch, ANM-116, Transport Airplane Directorate, FAA, 1601 Lind Avenue SW., Renton, WA 98057-3356; telephone (425) 227-2125; fax (425) 227-1149.

End Further Info End Preamble Start Supplemental Information

SUPPLEMENTARY INFORMATION:

Discussion

We issued a notice of proposed rulemaking (NPRM) to amend 14 CFR part 39 by adding an AD that would apply to certain Airbus Model A300 series airplanes; and Model A300 B4-600, B4-600R, and F4-600R series airplanes, and Model A300 C4-605R Variant F airplanes (collectively called Model A300-600 series airplanes). The NPRM published in the Federal Register on April 5, 2016 (81 FR 19509) (“the NPRM”).

The European Aviation Safety Agency (EASA), which is the Technical Agent for the Member States of the European Union, has issued EASA AD 2013-0230, dated September 24, 2013 (referred to after this as the Mandatory Continuing Airworthiness Information, or “the MCAI”), to correct an unsafe condition for certain Airbus Model A300 series airplanes; and Model A300 B4-600, B4-600R, and F4-600R series airplanes, and Model A300 C4-605R Variant F airplanes (collectively called Model A300-600 series airplanes). The MCAI states:

Several cases of corrosion on the lower wing root joint, located in the wing bottom skin inboard and outboard of the external lower surface splice, have been reported by operators.

This condition, if not detected and corrected, could affect the structural integrity of the airframe.

Prompted by these findings, [Direction Générale de l'Aviation Civile] (DGAC) France issued AD 1997-006-210 [which corresponds to FAA AD 98-21-34, Amendment 39-10842 (63 FR 55524, October 16, 1998)] to require repetitive inspections to detect the presence of corrosion and prevent crack propagation at the wing bottom skin, inboard and outboard of the Rib 1 external lower surface splice, between Frame (FR) 40 and FR47.

DGAC France * * * issued [an AD] to expand the choice of applicable Service Bulletins (SB). [The] DGAC France AD * * * was issued to allow A300-600 operators to use Revision 04 of Airbus SB A300-57-6047, converting flight cycles/”Fatigue rating” into flight cycles (FC)/flight hours (FH).

Subsequently, Airbus modification 10599 was developed to improve the corrosion behaviour of the area. This improvement allowed refining the inspection programme of the A300-600 aeroplane. For post-modification 10599 A300-600 aeroplanes, the application of the Maintenance Review Board Report (MRBR) inspection tasks was deemed sufficient for maintaining an adequate level of safety on these aeroplanes.

Consequently, EASA issued AD 2008-0208 (later revised), retaining the requirements of [a] DGAC France AD * * *, which was superseded, to require the use of Airbus SB A300-57-6047 Revision 05 for the inspections and to exclude post-modification 10599 A300-600 aeroplanes from the Applicability.

Since EASA AD 2008-0208R1 was issued, a fleet survey and updated Fatigue and Damage Tolerance analyses have been performed in order to substantiate the second A300-600 Extended Service Goal (ESG2) exercise. The results of these analyses determined that the threshold and interval must be reduced to allow timely detection of these cracks and the accomplishment of an applicable corrective action.

For the reasons described above, this [EASA] AD takes over and retains the requirements for A300 and A300-600 aeroplanes from EASA AD 2008-0208R1 (which has been revised, remaining applicable only to A310 aeroplanes) and requires accomplishment of the inspections within the new thresholds and intervals.

Required actions include repetitive detailed inspections for corrosion of the Start Printed Page 10256rib 1 external lower surface splice between FR40 and FR47, repetitive fatigue inspections for cracking of the fasteners and on the surface of the forward and aft lower surface panels if necessary, and corrective actions (including application of new protective coating, removal of corrosion, and measurement of the reworked depth) if necessary.

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-2016-5040.

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.

Request To Clarify the Applicability

United Parcel Service (UPS) requested that we change the information in paragraph (c), Applicability, of the proposed AD. UPS explained that paragraph (c) of the proposed AD defines the airplane models applicable to the proposed rule, then has an exclusion later in paragraph (g) of the proposed AD. UPS reasoned that we should simplify by having related information in the same location, and suggested we combine paragraph (c) and paragraph (g) of the proposed AD into a single paragraph (c) of the proposed AD.

For the reasons stated by the commenter, we agree to include the phrase, “except those on which Airbus modification 10599 has been incorporated,” in paragraph (c)(2) of this AD. However, we disagree with moving the statement, “As of the effective date of this AD, the actions specified in AD 98-21-34, Amendment 39-10842 (63 FR 55524, October 16, 1998) (“AD 98-21-34”) are no longer required” from paragraph (g) of this AD to paragraph (c) of this AD because the Applicability should not include this type of information; it is appropriately included in other regulatory text such as paragraph (g) of this AD.

Request To Clarify the Headings of Paragraphs (h) and (i) of the Proposed AD

UPS requested that we revise the headings of paragraphs (h) and (i) of the proposed AD because the paragraph titles do not reflect what is contained within the respective paragraphs. UPS explained that paragraph (h) of the proposed AD does not contain any corrective actions, and paragraph (i) of the proposed AD contains fatigue inspection requirements.

For the reasons stated by the commenter, we agree and have revised the headings of both paragraphs (h) and (i) of this AD.

Request for Grace Period

UPS stated that upon its review of the fatigue inspection requirements, it identified that there is not a transition/grace period for airplanes on which inspections are already being accomplished, but for which the new repetitive inspection intervals have already been exceeded due to the service bulletin interval reductions.

We agree with the commenter's statement. We had erroneously specified Airbus Service Bulletin A300-57-6047, Revision 06, dated October 17, 2011, in the compliance time in paragraph (i)(2)(ii)(B) of the proposed AD; the correct reference is Airbus Service Bulletin A300-57-6047, Revision 05, dated May 27, 2008. We have changed paragraph (i)(2)(ii)(B) of this AD to include a grace period of 500 flight cycles or 1,050 flight hours (whichever occurs first), without exceeding the compliance time specified in Airbus Service Bulletin A300-57-6047, Revision 05, dated May 27, 2008.

Request To Remove Paragraph (j) of the Proposed AD

UPS requested that we delete paragraph (j) of the proposed AD. UPS explained that paragraphs (j)(1) and (j)(2) of the proposed AD identify differences between the service bulletin requirements specified by the original equipment manufacturer (OEM) and the proposed AD. UPS stated that in its review of paragraphs (j)(1) and (j)(2) of the proposed AD, it does not recognize a difference between contacting Airbus for corrective action, and using a method approved by the FAA for either situation. UPS reasoned that, as the discrepancy is located on primary structure and allowable/approved rework limits are exceeded, damage tolerance analysis is required as part of the repair definition process. UPS adds that the existing OEM process, the Repair Design Approval Sheet (RDAS), contains instructions for continued airworthiness and is approved by an EASA-designated airworthiness engineer. Based on the existing process and procedures in place, UPS does not believe that paragraph (j) of the proposed AD is necessary.

We disagree with the request to delete paragraph (j) of this AD. Paragraph (j)(1) of this AD is required to address certain inspection findings. The service information specifies that Airbus be contacted for corrective action; however, paragraph (j)(1) of this AD requires that one of the specific organizations identified must approve those corrective actions. Likewise, paragraph (j)(2) of this AD specifies the appropriate organizations for compliance time determinations. Therefore, we have not changed this AD in this regard.

Request To Define Average Flight Time (AFT)

UPS requested that we revise paragraph (k) of the proposed AD to match paragraph (i) of AD 2016-07-20, Amendment 39-18465 (81 FR 21255, April 11, 2016). UPS reasoned that AD 2016-07-20 clearly defines when the AFT value is calculated in subsequent repetitive inspection interval determinations. UPS explained that recent FAA ADs have included using AFT to determine repetitive inspection intervals, but the definition of calculating the AFT value has varied among ADs, which further complicates compliance across several mandatory ADs.

For the reasons stated by the commenter, we have added more specific criteria for establishing the AFT in paragraph (k) of this AD.

Request To Include Approval for Previous Alternative Methods of Compliance (AMOCs)

UPS requested that we revise paragraph (m) of the proposed AD to include approval for previous AMOCs. UPS explained that other final rules include approved AMOCs for prior or superseded ADs. UPS explained further that it received AMOC approval for AD 98-21-34 in which the intent is embodied within the proposed AD (i.e., no additional action for an airplane with modification 10599 embodied), and that there may be other AMOC approvals applicable to the previous AD.

We agree for the reasons stated by the commenter. We added the previous AMOC approval information in paragraph (m)(1)(ii) of this final rule.

Conclusion

We reviewed the relevant data, considered the comments received, and determined that air safety and the public interest require adopting this AD with the changes described previously and 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.Start Printed Page 10257

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

We reviewed Airbus Service Bulletin A300-57-0204, Revision 01, dated April 2, 1999; and Airbus Service Bulletin A300-57-6047, Revision 06, dated October 17, 2011. This service information describes procedures for repetitive detailed inspections for corrosion of the rib 1 external lower surface splice between FR40 and FR47, repetitive fatigue inspections for cracking of the fasteners and on the surface of the forward and aft lower surface panels if necessary, and corrective actions (including application of new protective coating, removal of corrosion, and measurement of the reworked depth) if necessary. These documents are distinct since they apply to different airplane models. 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 29 airplanes of U.S. registry. We also estimate that it would take about 8 work-hours per product to comply with the basic requirements of this AD. The average labor rate is $85 per work-hour. Based on these figures, we estimate the cost of this AD on U.S. operators to be $19,720, or $680 per product.

In addition, we estimate that any necessary follow-on actions would take about 8 work-hours, for a cost of $680 per product. We have no way of determining the number of aircraft that might need these actions.

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 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.

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.

Start List of Subjects

List of Subjects in 14 CFR Part 39

  • Air transportation
  • Aircraft
  • Aviation safety
  • Incorporation by reference
  • Safety
End List of Subjects

Adoption of the Amendment

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

Start Part

PART 39—AIRWORTHINESS DIRECTIVES

End Part Start Amendment Part

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

End Amendment Part Start Authority

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

End Authority
[Amended]
Start Amendment Part

2. The FAA amends § 39.13 by adding the following new airworthiness directive (AD):

End Amendment Part

2017-02-08 Airbus: Amendment 39-18787; Docket No. FAA-2016-5040; Directorate Identifier 2013-NM-192-AD.

(a) Effective Date

This AD is effective March 17, 2017.

(b) Affected ADs

This AD affects AD 98-21-34, Amendment 39-10842 (63 FR 55524, October 16, 1998) (“AD 98-21-34”).

(c) Applicability

This AD applies to Airbus airplanes, certificated in any category, identified in paragraphs (c)(1) and (c)(2) of this AD.

(1) All Model A300 B2-1A, B2-1C, B2K-3C, B2-203, B4-2C, B4-103, and B4-203 airplanes.

(2) Model A300 B4-601, B4-603, B4-620, B4-622, B4-605R, B4-622R, F4-605R, F4-622R, and C4-605R Variant F airplanes, except those on which Airbus modification 10599 has been incorporated.

(d) Subject

Air Transport Association (ATA) of America Code 57, Wings.

(e) Reason

This AD was prompted by reports of corrosion on the lower wing root joint located in the wing bottom skin inboard and outboard of the external lower surface splice, and the determination that certain existing inspection thresholds and intervals must be reduced. We are issuing this AD to detect and correct corrosion and cracking on the lower wing root joint, which could reduce the structural integrity of the airframe.

(f) Compliance

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

(g) Airplanes Excluded From the Requirements of AD 98-21-34 and This AD

For Model A300 B4-601, B4-603, B4-620, B4-622, B4-605R, B4-622R, F4-605R, F4-622R, and C4-605R Variant F airplanes, on which Airbus modification 10599 has been incorporated: As of the effective date of this AD, the actions specified in AD 98-21-34 are no longer required. No action is required by this AD.

(h) Repetitive Inspections

Within 60 months since the airplane's first flight, or within 60 months since accomplishment of the last inspection specified in Airbus Service Bulletin A300-57-0204 or A300-57-6047, whichever occurs later: Do a detailed inspection for corrosion of the rib 1 external lower surface splice between frame (FR)40 and FR47, in accordance with the Accomplishment Instructions of Airbus Service Bulletin A300-57-0204, Revision 01, dated April 2, 1999; or Airbus Service Bulletin A300-57-6047, Revision 06, dated October 17, 2011; as applicable. Repeat the inspection thereafter at intervals not to exceed 60 months. Accomplishment of the initial inspection required by this paragraph terminates the requirements of AD 98-21-34 for Model A300 and A300-600 series airplanes.

(i) Corrective Actions, Repetitive Fatigue Inspections, and Repair

If any corrosion is found during any inspection required by paragraph (h) of this AD, do the actions specified in paragraph (i)(1) and (i)(2) of this AD.

(1) Before further flight, do all applicable corrective actions, in accordance with the Accomplishment Instructions of Airbus Service Bulletin A300-57-0204, Revision 01, dated April 2, 1999; or Airbus Service Bulletin A300-57-6047, Revision 06, dated October 17, 2011; as applicable; except as required by paragraph (j)(1) of this AD.

(2) At the applicable time specified in paragraph (i)(2)(i) or (i)(2)(ii) of this AD, except as required by paragraph (j)(2) of this AD: Do fatigue inspections to detect cracks of Start Printed Page 10258the fasteners and on the surface of the forward and aft lower surface panels, in accordance with the Accomplishment Instructions of Airbus Service Bulletin A300-57-0204, Revision 01, dated April 2, 1999; or Airbus Service Bulletin A300-57-6047, Revision 06, dated October 17, 2011; as applicable. Repeat the fatigue inspections thereafter at the applicable interval specified in paragraph B.(5) of Airbus Service Bulletin A300-57-0204, Revision 01, dated April 2, 1999; or Figure A-FBGAA, Sheet 01, of Airbus Service Bulletin A300-57-6047, Revision 06, dated October 17, 2011; as applicable; except as required by paragraph (j)(2) of this AD. If any cracking is found during any fatigue inspection required by this paragraph: Before further flight, repair using a method approved by the Manager, International Branch, ANM-116, Transport Airplane Directorate, FAA; or the European Aviation Safety Agency (EASA); or Airbus's EASA Design Organization Approval (DOA).

(i) For Model A300 series airplanes: Do the initial inspection at the applicable time specified in paragraph B.(5) of Airbus Service Bulletin A300-57-0204, Revision 01, dated April 2, 1999.

(ii) For Model A300-600 series airplanes: Do the initial inspection at the later of the times specified in paragraphs (i)(2)(ii)(A) and (i)(2)(ii)(B) of this AD.

(A) At the applicable time specified in Figure A-FBGAA, Sheet 01, of Airbus Service Bulletin A300-57-6047, Revision 06, dated October 17, 2011.

(B) Within 500 flight cycles or 1,050 flight hours after the effective date of this AD, whichever occurs first, without exceeding the compliance time specified in Airbus Service Bulletin A300-57-6047, Revision 05, dated May 27, 2008.

(j) Exceptions to Service Bulletin Specifications

(1) Where Airbus Service Bulletin A300-57-0204, Revision 01, dated April 2, 1999; or Airbus Service Bulletin A300-57-6047, Revision 06, dated October 17, 2011; specifies to contact Airbus for appropriate corrective action, this AD requires repair before further flight using a method approved by the Manager, International Branch, ANM-116, Transport Airplane Directorate, FAA; or EASA; or Airbus's EASA DOA.

(2) Where Airbus Service Bulletin A300-57-6047, Revision 06, dated October 17, 2011, specifies to contact Airbus for the appropriate threshold or repetitive interval, this AD requires that the compliance time be determined using a method approved by the Manager, International Branch, ANM-116, Transport Airplane Directorate, FAA; or EASA; or Airbus's EASA DOA.

(k) Calculating Average Flight Time (AFT)

For the purposes of paragraph (i)(2) of this AD, the AFT must be established as specified in paragraphs (k)(1), (k)(2), and (k)(3) of this AD.

(1) For the initial inspection, the AFT is the total accumulated flight hours, counted from take-off to touch-down, divided by the total accumulated flight cycles at the effective date of this AD.

(2) For the first repeated inspection interval, the AFT is the total accumulated flight hours divided by the total accumulated flight cycles at the time of the inspection threshold.

(3) For all inspection intervals onward, the AFT is the flight hours accumulated between the two most recent inspections divided by the flight cycles accumulated between the two most recent inspections.

(l) Credit for Previous Actions

This paragraph provides credit for the inspections and corrective actions required by paragraphs (h) and (i) of this AD, if those actions were performed before the effective date of this AD using the applicable service information specified in paragraphs (l)(1) through (l)(3) of this AD.

(1) Airbus Service Bulletin A300-57-6047, Revision 02, dated April 2, 1999.

(2) Airbus Service Bulletin A300-57-6047, Revision 03, dated September 28, 1999.

(3) Airbus Service Bulletin A300-57-6047, Revision 05, dated May 27, 2008.

(m) Other FAA AD Provisions

The following provisions also apply to this AD:

(1) Alternative Methods of Compliance (AMOCs): The Manager, International Branch, ANM-116, Transport Airplane Directorate, 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 Branch, send it to ATTN: Dan Rodina, Aerospace Engineer, International Branch, ANM-116, Transport Airplane Directorate, FAA, 1601 Lind Avenue SW., Renton, WA 98057-3356; telephone (425) 227-2125; fax (425) 227-1149. 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. The AMOC approval letter must specifically reference this AD.

(ii) AMOCs approved previously for AD 98-21-34 are approved as AMOCs for the corresponding provisions of paragraphs (h) and (i) of this AD.

(2) Contacting the Manufacturer: For any requirement in this AD to obtain corrective actions from a manufacturer, the action must be accomplished using a method approved by the Manager, International Branch, ANM-116, Transport Airplane Directorate, FAA; or the EASA; or Airbus's EASA DOA. If approved by the DOA, the approval must include the DOA-authorized signature.

(n) Related Information

(1) Refer to Mandatory Continuing Airworthiness Information (MCAI) EASA AD 2013-0230, dated September 24, 2013, 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-2016-5040.

(2) Service information identified in this AD that is not incorporated by reference is available at the addresses specified in paragraphs (o)(3) and (o)(4) of this AD.

(o) 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.

(i) Airbus Service Bulletin A300-57-0204, Revision 01, dated April 2, 1999.

(ii) Airbus Service Bulletin A300-57-6047, Revision 06, dated October 17, 2011.

(3) For service information identified in this AD, contact Airbus SAS, Airworthiness Office—EAW, 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.

(4) You may view this service information at the FAA, Transport Airplane Directorate, 1601 Lind Avenue SW., Renton, WA. For information on the availability of this material at the FAA, call 425-227-1221.

(5) 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.

Start Signature

Issued in Renton, Washington, on January 18, 2017.

Michael Kaszycki,

Acting Manager, Transport Airplane Directorate, Aircraft Certification Service.

End Signature End Supplemental Information

[FR Doc. 2017-01776 Filed 2-9-17; 8:45 am]

BILLING CODE 4910-13-P