### 3053 Federal Register / Vol. 81, No. 12 / Wednesday, January 20, 2016 / Proposed Rules

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. The Proposed Amendment

Accordingly, under the authority delegated to me by the Administrator, the FAA proposes to amend 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. The FAA amends § 39.13 by adding the following new airworthiness directive (AD):

Fokker Services B.V.: Docket No. FAA– 2015–8467; Directorate Identifier 2014– NM–107–AD.
(a) Comments Due Date

We must receive comments by March 7,
2016.
(b) Affected ADs

None. (c) Applicability

This AD applies to Fokker Services B.V. Model F.28 Mark 1000, 2000, 3000, and 4000 airplanes, certificated in any category, all serial numbers.
(d) Subject

Air Transport Association (ATA) of America Code 28, Fuel.

(e) Reason

This AD was prompted by a design review that revealed no controlled bonding provisions are present on a number of critical locations inside the fuel tanks or connected to the walls of the fuel tanks. We are issuing this AD to prevent an ignition source in the fuel tank vapor space, which could result in a fuel tank explosion and consequent loss of the airplane.
(f) Compliance

Comply with this AD within the compliance times specified, unless already done.
(g) Installation of Bonding Provisions

At the next scheduled opening of the fuel tanks after the effective date of this AD, but no later than 84 months after the effective date of this AD, install additional and improved bonding provisions in the fuel tanks, and do the applicable related investigative and corrective actions, in accordance with the Accomplishment Instructions of Fokker Services Proforma Service Bulletin SBF28–28–058, dated January 9, 2014, including Appendix SBF28– 28–058/APP01, dated July 15, 2014.
(h) Revision of Maintenance or Inspection Program

Before further flight after completing the installation specified in paragraph (g) of this AD, or within 30 days after the effective date of this AD, whichever occurs later: Revise the airplane maintenance or inspection program, as applicable, by incorporating the fuel airworthiness limitation items and critical design configuration control limitations (CDCCLs) specified in paragraph 1.L.(1)(c) of Fokker Services Proforma Service Bulletin SBF28–28–058, dated January 9, 2014, including Appendix SBF28–28–058/APP01, dated July 15, 2014. The initial compliance times for the tasks are at the latest of the times specified in paragraphs (h)(1), (h)(2), and (h)(3) of this AD.

(1) At the applicable time specified in Fokker Service Bulletin SBF28–28–050, Revision 3, dated December 11, 2014.

(2) Before further flight after completing the installation specified in paragraph (g) of this AD.

(3) Within 30 days after the effective date of this AD.

(i) No Alternative Actions, Intervals, and CDCCLs

After accomplishment of the revision required by paragraph (h) of this AD, no alternative actions ( e.g., inspections), intervals, or CDCCLs may be used unless the actions, intervals, or CDCCLs are approved as an alternative method of compliance (AMOC) in accordance with the procedures specified in paragraph (j)(1) of this AD.
(j) Other FAA AD Provisions

The following provisions also apply to this AD:

(1) Alternative Methods of Compliance: 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: Tom Rodriguez, Aerospace Engineer, International Branch, ANM–116, Transport Airplane Directorate, FAA, 1601 Lind Avenue SW., Renton, WA 98057–3356; telephone 425–227–1137; fax 425–227–1149. Information may be emailed to: 9-ANM-116- AMOC-REQUESTS@faa.gov. 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.

(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 European Aviation Safety Agency (EASA); or Fokker B.V. Service’s EASA Design Organization Approval (DOA). If approved by the DOA, the approval must include the DOA-authorized signature.
(k) Related Information

(1) Refer to Mandatory Continuing Airworthiness Information (MCAI) European Aviation Safety Agency Airworthiness Directive 2014–0108, dated May 8, 2014, 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–2015–8467.

(2) For service information identified in this AD, contact Fokker Services B.V., Technical Services Dept., P.O. Box 1357, 2130 EL Hoofddorp, the Netherlands; telephone +31 (0)88–6280–350; fax +31 (0)88–6280–111; email technicalservices@ fokker.com ; Internet http:// www.myfokkerfleet.com. 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.

Issued in Renton, Washington, on January 5, 2016. Victor Wicklund, Acting Manager, Transport Airplane Directorate, Aircraft Certification Service.
[FR Doc. 2016–00636 Filed 1–19–16; 8:45 am]

**BILLING CODE 4910–13–P**

**DEPARTMENT OF TRANSPORTATION**

**Federal Aviation Administration**

**14 CFR Part 39**

**[Docket No. FAA–2014–0922; Directorate Identifier 2014–NM–156–AD]** 

**RIN 2120–AA64**

**Airworthiness Directives; Airbus Airplanes** 

**AGENCY :**  Federal Aviation Administration (FAA), DOT.

**ACTION :**  Supplemental notice of proposed rulemaking (NPRM); reopening of comment period.

**SUMMARY :**  We are revising an earlier proposed airworthiness directive (AD) for certain Airbus Model A319 and A320 series airplanes. The NPRM proposed to require the modification of eight fastener locations in the longeron area below the emergency exit cut-outs on the left-hand (LH) and right-hand (RH) sides. The NPRM was prompted by a report that fatigue cracking could appear at certain fastener locations in the longeron area below the emergency exit cut-outs. This proposed AD is intended to complete certain mandated programs intended to support the airplane reaching its limit of validity (LOV) of the engineering data that support the established structural maintenance program. This action


### 3054 Federal Register / Vol. 81, No. 12 / Wednesday, January 20, 2016 / Proposed Rules

revises the applicability by adding postAirbus modification 32208 airplanes, which are also affected. We are proposing this supplemental NPRM (SNPRM) to detect and correct cracking at certain fastener locations in the longeron area below the emergency exit cut-outs, which could lead to failure of the fasteners and reduced structural integrity of the airplane. Since these actions impose an additional burden over those proposed in the NPRM, we are reopening the comment period to allow the public the chance to comment on these proposed changes.

**DATES :**  We must receive comments on this SNPRM by March 7, 2016.

**ADDRESSES :**  You may send comments, using the procedures found in 14 CFR 11.43 and 11.45, by any of the following methods:

• Federal eRulemaking Portal: Go to http://www.regulations.gov. Follow the instructions for submitting comments.

• Fax: 202–493–2251.

• Mail: U.S. Department of Transportation, Docket Operations, M– 30, West Building Ground Floor, Room W12–140, 1200 New Jersey Avenue SE., Washington, DC 20590.

• Hand Delivery: U.S. Department of Transportation, Docket Operations, M– 30, West Building Ground Floor, Room W12–140, 1200 New Jersey Avenue SE., Washington, DC, between 9 a.m. and 5 p.m., Monday through Friday, except Federal holidays.

For service information identified in this proposed 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 . You may view this referenced service information at the FAA, Transport Airplane Directorate, 1601 Lind Avenue SW., Renton, WA. 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. 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–2014– 0922; 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 proposed AD, the regulatory evaluation, any comments received, and other information. The street address for the Docket Office (telephone: 800–647–5527) is in the

**ADDRESSES** section. Comments will be available in the AD docket shortly after receipt.

**FOR FURTHER INFORMATION CONTACT :**  Sanjay Ralhan, Aerospace Engineer, International Branch, ANM–116, Transport Airplane Directorate, FAA, 1601 Lind Avenue SW., Renton, WA 98057–3356; telephone 425–227–1405; fax 425–227–1149.

**SUPPLEMENTARY INFORMATION :** 
Comments Invited

We invite you to send any written relevant data, views, or arguments about this proposed AD. Send your comments to an address listed under the

**ADDRESSES** section. Include ‘‘Docket No. FAA–2014–0922; Directorate Identifier 2014–NM–156–AD’’ at the beginning of your comments. We specifically invite comments on the overall regulatory, economic, environmental, and energy aspects of this proposed AD. We will consider all comments received by the closing date and may amend this proposed AD based on those comments.

We will post all comments we receive, without change, to http:// www.regulations.gov, including any personal information you provide. We will also post a report summarizing each substantive verbal contact we receive about this proposed AD.

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 A319 and A320 series airplanes. The NPRM published in the Federal Register on December 15, 2014 (79 FR 74035).

The NPRM was prompted by a report that fatigue cracking could appear at certain fastener locations in the longeron area below the emergency exit cut-outs. The NPRM was intended to complete certain mandated programs intended to support the airplane reaching its LOV of the engineering data that support the established structural maintenance program. The NPRM proposed to require the modification of eight fastener locations in the longeron area below the emergency exit cut-outs on the LH and RH sides.
Actions Since Previous NPRM (79 FR 74035, December 15, 2014) Was Issued

Since we issued the NPRM (79 FR 74035, December 15, 2014), we have determined that airplanes having Airbus modification 32208, which were excluded from the applicability of NPRM (79 FR 74035, December 15, 2014), are also affected. For this reason, the FAA added airplanes having Airbus modification 32208 to the applicability of this proposed AD and increased the number of airplanes in the Costs of Compliance section to 294 airplanes. The European Aviation Safety Agency, which is the Technical Agent for the Member States of the European Union, has issued EASA Airworthiness Directive 2015–0085, dated May 13, 2015 (referred to after this as the Mandatory Continuing Airworthiness Information, or ‘‘the MCAI’’), to correct an unsafe condition on certain Model A319 and Model A320 series airplanes. The MCAI states:

During the A320 fatigue test campaign for Extended Service Goal (ESG), it was determined that fatigue damage could appear at certain fastener locations on the longeron [area] below the emergency exit cut-outs, on the left-hand (LH) and right-hand (RH) sides of the fuselage.

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

To address this potential unsafe condition, Airbus developed a modification, which has been published through Airbus Service Bulletin (SB) A320–53–1265 for in-service application to allow aeroplanes to operate up to the new ESG limit. Consequently, EASA issued AD 2014–0176 to require modification (cold working) of 8 fastener locations in the longeron area (Stringer 20A) below the emergency exit cut-outs on the LH and RH sides.

Since that [EASA] AD was issued, it was identified that post-mod 32208 aeroplanes, which were excluded from the Applicability of that [EASA] AD, are also affected.

For the reason described above, this [EASA] AD retains the requirements of EASA AD 2014–0176, which is superseded, but no longer excludes post-mod 32208 aeroplanes from the Applicability.

As described in FAA Advisory Circular 120–104 (http://www.faa.gov/ documentLibrary/media/Advisory

_ Circular/120-104.pdf ), several programs have been developed to support initiatives that will ensure the continued airworthiness of aging airplane structure. The last element of those initiatives is the requirement to establish a LOV of the engineering data that support the structural maintenance program under 14 CFR 26.21. This proposed AD is the result of an assessment of the previously established programs by the design approval holder (DAH) during the process of establishing the LOV for Airbus Model A319 and A320 series airplanes. The actions specified in this proposed AD are necessary to complete certain programs to ensure the continued airworthiness of aging airplane structure and to support an airplane reaching its LOV.

You may examine the MCAI in the AD docket on the Internet at http://


### 3055 Federal Register / Vol. 81, No. 12 / Wednesday, January 20, 2016 / Proposed Rules

www.regulations.gov/ #!documentDetail;D=FAA-2014-0922

. Related Service Information Under 1 CFR Part 51

Airbus has issued Service Bulletin A320–53–1265, Revision 02, dated July 10, 2014. The service information describes procedures for modifying the fastener locations in the longeron area below the emergency exit cut-outs on both RH and LH sides of the fuselage. 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.

Comments

We gave the public the opportunity to participate in developing this proposed AD. We considered the comment received. The following presents the comment received on the NPRM (79 FR 74035, December 15, 2014) and the FAA’s response to the comment. Request To Allow the Use of Later Revisions of Service Bulletin

United Airlines (United) requested that the NPRM (79 FR 74035, December 15, 2014) contain a statement allowing use of later revisions of the service information as an acceptable method of compliance for the proposed AD. United stated the modification addressed by the NPRM allows operators to reach an ESG. United stated that the service information mentioned in the NPRM may not incorporate the proper effectivity, since Airbus Service Bulletin A320–53–1265, Revision 01, dated July 2, 2013, is restricted to operators who have applied for Airbus’s request for change/request for modification order (RFC/RMO) process. United stated the effectivity of Airbus Service Bulletin A320–53–1265, Revision 02, dated July 10, 2014, will likely not agree with the applicability of the NPRM.

We partially agree. We disagree to allow use of later revisions of service documents in an AD because use of unpublished service information is not allowed by the Office of the Federal Register’s regulations for approving materials incorporated by reference. However, we have reviewed Airbus Service Bulletin A320–53–1265, Revision 02, dated July 10, 2014, which updated the kit information and the effectivity. We revised the applicability in this proposed AD to reflect the effectivity of Airbus Service Bulletin A320–53–1265, Revision 02, dated July 10, 2014. We also revised the references in paragraph (g) of this proposed AD to refer to Airbus Service Bulletin A320– 53–1265, Revision 02, dated July 10, 2014, and revised paragraph (h) of this proposed AD to allow credit for actions done using Airbus Service Bulletin A320–53–1265, Revision 01, dated July 2, 2013. Affected operators may request approval to use a later revision of the referenced service information as an Alternative Method of Compliance (AMOC) using the procedures specified in paragraph (i) of this proposed AD. FAA’s Determination and Requirements of This SNPRM

This product has been approved by the aviation authority of another country, and is approved for operation in the United States. Pursuant to our bilateral agreement with the State of Design Authority, we have been notified of the unsafe condition described in the MCAI and service information referenced above. We are proposing this AD because we evaluated all pertinent information and determined an unsafe condition exists and is likely to exist or develop on other products of these same type designs.

Certain changes described above expand the scope of the NPRM (79 FR 74035, December 15, 2014). As a result, we have determined that it is necessary to reopen the comment period to provide additional opportunity for the public to comment on this SNPRM. Explanation of ‘‘RC’’ Procedures and Tests in Service Information

The FAA worked in conjunction with industry, under the Airworthiness Directive Implementation Aviation Rulemaking Committee (ARC), to enhance the AD system. One enhancement was a new process for annotating which procedures and tests in the service information are required for compliance with an AD. Differentiating these procedures and tests from other tasks in the service information is expected to improve an owner’s/operator’s understanding of crucial AD requirements and help provide consistent judgment in AD compliance. The procedures and tests identified as RC (required for compliance) in any service information have a direct effect on detecting, preventing, resolving, or eliminating an identified unsafe condition.

As specified in a NOTE under the Accomplishment Instructions of the specified service information, procedures and tests that are identified as RC in any service information must be done to comply with the proposed AD. However, procedures and 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 alternative method of compliance (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 will require approval of an AMOC. Costs of Compliance

We estimate that this SNPRM affects 294 airplanes of U.S. registry.

We estimate that it would take about 12 work-hours per product to comply with the new basic requirements of this SNPRM. The average labor rate is $85 per work-hour. Required parts would cost about $0 per product. Based on these figures, we estimate the cost of this SNPRM on U.S. operators to be $299,880, or $1,020 per product. 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 proposed AD would not have federalism implications under Executive Order 13132. This proposed AD would 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 this proposed regulation:

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);


### 3056 Federal Register / Vol. 81, No. 12 / Wednesday, January 20, 2016 / Proposed Rules

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. The Proposed Amendment

Accordingly, under the authority delegated to me by the Administrator, the FAA proposes to amend 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. The FAA amends § 39.13 by adding the following new airworthiness directive (AD):

Airbus: Docket No. FAA–2014–0922; Directorate Identifier 2014–NM–156–AD.

(a) Comments Due Date

We must receive comments by March 7,
2016.
(b) Affected ADs

None. (c) Applicability

This AD applies to the Airbus airplanes identified in paragraphs (c)(1) and (c)(2) of this AD, certificated in any category, except those on which Airbus modification (mod) 152637 has been embodied in production.

(1) Airbus Model A319–111, –112, –113, –114, –115, –131, –132, and –133 airplanes, all manufacturer serial numbers (MSN).

(2) Airbus Model A320–211, –212, –214, –231, –232, and –233 airplanes, all manufacturer serial numbers (MSN).
(d) Subject

Air Transport Association (ATA) of America Code 53, Fuselage.

(e) Reason

This AD was prompted by a report that fatigue cracking could appear at certain fastener locations in the longeron area below the emergency exit cut-outs. We are issuing this AD to detect and correct cracking at certain fastener locations in the longeron area below the emergency exit cut-outs, which could lead to failure of the fasteners and reduced structural integrity of the airplane.
(f) Compliance

Comply with this AD within the compliance times specified, unless already done. (g) Modification of Fastener Locations Before the accumulation of 48,000 total flight cycles or 96,000 total flight hours, whichever occurs first since the airplane’s first flight, modify the 8 fastener locations in the longeron area (stringer 20A) below the emergency exit cut-outs on both RH and LH sides, in accordance with the Accomplishment Instructions of Airbus Service Bulletin A320–53–1265, Revision 02, dated July 10, 2014.
(h) Credit for Previous Actions

This paragraph provides credit for the actions required by paragraph (g) of this AD, if those actions were performed before the effective date of this AD using Airbus Service Bulletin A320–53–1265, dated January 2, 2013; or Airbus Service Bulletin A320–53– 1265, Revision 01, dated July 2, 2013; which are not incorporated by reference in this AD.
(i) 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: Sanjay Ralhan, Aerospace Engineer, International Branch, ANM–116, Transport Airplane Directorate, FAA, 1601 Lind Avenue SW., Renton, WA 98057–3356; telephone 425–227–1405; fax 425–227–1149. Information may be emailed to: 9-ANM-116- AMOC-REQUESTS@faa.gov. 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.

(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 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. (j) Related Information (1) Refer to Mandatory Continuing Airworthiness Information (MCAI) EASA Airworthiness Directive 2015–0085, dated May 13, 2015, for related information. This MCAI may be found in the AD docket on the Internet at http://www.regulations.gov/ #!documentDetail;D=FAA-2014-0922-0002

.

(2) 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

. You may view this referenced service information at the FAA, Transport Airplane Directorate, 1601 Lind Avenue SW., Renton, WA. 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.

Issued in Renton, Washington, on January 5, 2016. Victor Wicklund, Acting Manager, Transport Airplane Directorate, Aircraft Certification Service.
[FR Doc. 2016–00699 Filed 1–19–16; 8:45 am]

**BILLING CODE 4910–13–P**

**DEPARTMENT OF TRANSPORTATION**

**Federal Aviation Administration**

**14 CFR Part 39**

**[Docket No. FAA–2015–8469; Directorate Identifier 2014–NM–105–AD]** 

**RIN 2120–AA64**

**Airworthiness Directives; Fokker Services B.V. Airplanes** 

**AGENCY :**  Federal Aviation Administration (FAA), DOT.

**ACTION :**  Notice of proposed rulemaking (NPRM).

**SUMMARY :**  We propose to adopt a new airworthiness directive (AD) for all Fokker Services B.V. Model F.28 Mark 1000, 2000, 3000, and 4000 airplanes. This proposed AD was prompted by a design review that revealed insufficient measures were taken to ensure the correct locking of the attachments of the fuel quantity tank units (FQTUs) in each wing tank. When an FQTU becomes loose, this could lead to insufficient clearance between the FQTU and the adjacent tank structure or other metal parts, and under certain conditions, create an ignition source inside the wing fuel vapor space. This proposed AD would require modifying the FQTUs by applying sealant to cover the nuts, washers, and stud ends at the FQTU attachments in each main wing tank. This proposed AD would also require