2010-33002. Airworthiness Directives; The Boeing Company Model 727, 727C, 727-100, 727-100C, 727-200, and 727-200F Series Airplanes

AGENCY:

Federal Aviation Administration (FAA), DOT.

ACTION:

Notice of proposed rulemaking (NPRM).

SUMMARY:

We propose to adopt a new airworthiness directive (AD) for the products listed above. This proposed AD would require replacing the existing unshielded fuel quantity indication system (FQIS) wire bundles with double shielded FQIS wire bundles, installing a new wire feed-through fitting, and grounding the wire shields, as applicable; and doing repetitive low frequency eddy current (LFEC) inspections for cracking of the fuselage skin, and corrective actions if necessary. This proposed AD also would require revising the maintenance program to incorporate certain airworthiness limitations. This proposed AD was prompted by fuel system reviews conducted by the manufacturer. We are proposing this AD to increase the level of protection from lightning strikes and prevent the potential of ignition sources inside fuel tanks, which, in combination with flammable fuel vapors, could result in fuel tank explosions and consequent loss of the airplane.

DATES:

We must receive comments on this proposed AD by February 17, 2011.

ADDRESSES:

You may send comments by any of the following methods:

• Federal eRulemaking Portal: Go to http://www.regulations.gov. Follow the instructions for submitting comments.
• Fax: [phone].
• 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: Deliver to Mail address above between 9 a.m. and 5 p.m., Monday through Friday, except Federal holidays.

For service information identified in this proposed AD, contact Boeing Commercial Airplanes, Attention: Data & Services Management, P.O. Box 3707, MC 2H-65, Seattle, Washington 98124-2207; telephone [phone], extension 1; fax [phone]; e-mail [e-mail]; Internet https://www.myboeingfleet.com. You may review copies of the referenced service information at the FAA, Transport Airplane Directorate, 1601 Lind Avenue, SW., Renton, Washington. 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;​; 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 (phone: [phone]) is in the ADDRESSES section. Comments will be available in the AD docket shortly after receipt.

FOR FURTHER INFORMATION CONTACT:

Louis Natsiopoulos, Aerospace Engineer, Systems and Equipment Branch, ANM-130S, FAA, Seattle Aircraft Certification Office, 1601 Lind Avenue, SW., Renton, Washington 98057-3356; telephone [phone]; fax [phone]; e-mail: [e-mail].

SUPPLEMENTARY INFORMATION:

Comments Invited

We invite you to send any written relevant data, views, or arguments about this proposal. Send your comments to an address listed under the ADDRESSES section. Include “Docket No. FAA-2010-1272; Directorate Identifier 2010-NM-226-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 because of 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

The FAA has examined the underlying safety issues involved in fuel tank explosions on several large transport airplanes, including the adequacy of existing regulations, the service history of airplanes subject to those regulations, and existing maintenance practices for fuel tank systems. As a result of those findings, we issued a regulation titled “Transport Airplane Fuel Tank System Design Review, Flammability Reduction and Maintenance and Inspection Requirements” (66 FR 23086, May 7, 2001). In addition to new airworthiness standards for transport airplanes and new maintenance requirements, this rule included Special Federal Aviation Regulation No. 88 (“SFAR 88,” Amendment 21-78, and subsequent Amendments 21-82 and 21-83).

Among other actions, SFAR 88 requires certain type design (i.e., type certificate (TC) and supplemental type certificate (STC)) holders to substantiate that their fuel tank systems can prevent ignition sources in the fuel tanks. This requirement applies to type design holders for large turbine-powered transport airplanes and for subsequent modifications to those airplanes. It requires them to perform design reviews and to develop design changes and maintenance procedures if their designs do not meet the new fuel tank safety standards. As explained in the preamble to the rule, we intended to adopt airworthiness directives to mandate any changes found necessary to address unsafe conditions identified as a result of these reviews.

In evaluating these design reviews, we have established four criteria intended to define the unsafe conditions associated with fuel tank systems that require corrective actions. The percentage of operating time during which fuel tanks are exposed to flammable conditions is one of these criteria. The other three criteria address the failure types under evaluation: Single failures, single failures in combination with a latent condition(s), and in-service failure experience. For all four criteria, the evaluations included consideration of previous actions taken that may mitigate the need for further action.

We have determined that the actions identified in this AD are necessary to reduce the potential of ignition sources inside fuel tanks, which, in combination with flammable fuel vapors, could result in fuel tank explosions and consequent loss of the airplane.

A safety assessment has determined that shielding was not provided for the FQIS wire bundles. Unshielded wire bundles could result in a reduced level of protection against a lightning strike which could be a potential ignition source for the fumes in the fuel tanks. This condition, if not corrected, could result in fuel tank explosions and consequent loss of the airplane.

Relevant Service Information

We reviewed Boeing Service Bulletin 727-28-0131, dated August 18, 2010. The service information describes procedures for the following:

• For airplanes in Groups 1, 12, 13, and 14: Replacing the FQIS wire bundles between the fitting and ground brackets at the pressure seal and the tank connectors on the wing tanks with double shielded wire bundles; installing a new wire feed-through fitting and ground brackets for the wires at the pressure seal, and ground brackets at the wing tank connectors; and grounding the wire shields at the pressure seal feed-through fitting and ground brackets and at the tank connector brackets.
• For airplanes in Groups 2 through 11 and 15 through 49: Replacing the FQIS wire bundles between the pressure seal and the volumetric top-off (VTO) connectors with double shielded wire bundles and working the ground wires at the VTO connectors.
• For all airplanes: Doing repetitive LFEC inspections for cracking in the fuselage skin on the left and right sides of the airplane, and contacting Boeing for repair instructions and doing the repair if necessary.

We have also reviewed Section 9 of the Boeing 727-100/200 Airworthiness Limitations (AWLs), D6-8766-AWL, Revision August 2010. Sub-Section D of Section 9 of the Boeing 727-100/200 Airworthiness Limitations (AWLs), D6-8766-AWL describes AWLs for fuel tank systems, including the following fuel system AWLs:

• AWL No. 28-AWL-18 which is a check of the fuel quantity indicating system (FQIS)—out-tank wiring lightning shield to ground termination, applicable to all Model 727-100 and -200 airplanes that have incorporated Boeing Service Bulletin 727-28-0131.
• AWL No. 28-AWL-19 which is a critical design configuration control limitation (CDCCL) that specifies to do a check of the FQIS—out-tank wiring lightning shield to ground termination, following any FQIS out-tank wire bundle replacement, wire bundle shield repair or shield path to ground reconnection, applicable to all Model 727-100 and -200 airplanes that have incorporated Boeing Service Bulletin 727-28-0131.

FAA's Determination

We are proposing this AD because we evaluated all the relevant information and determined the unsafe condition described previously is likely to exist or develop in other products of the same type design.

Proposed AD Requirements

This proposed AD would require accomplishing the actions specified in the service information described previously, except as discussed under “Differences Between Proposed Rule and Service Bulletin.”

Differences Between Proposed Rule and Service Bulletin

Although Boeing Service Bulletin 727-28-0131, dated August 18, 2010, specifies that operators may contact the manufacturer for disposition of certain repair conditions, this proposed AD would require operators to repair those cracks using a method approved by the FAA.

Costs of Compliance

We estimate that this proposed AD will affect 566 airplanes of U.S. registry.

We estimate the following costs to comply with this proposed AD:

Estimated Costs

Action	Labor cost	Parts cost	Cost per product	Cost on U.S. operators
Installation	Between 86 and 247 work-hours × $85 per hour = Between $7,310-$20,995.1	Between $16,191 and $34,712.1	Between $23,501 and $55,707.1	Up to $27,195,925.2
Inspection	2 work-hours × $85 per hour = $170 per inspection cycle	0	170	96,220 per inspection cycle.
Maintenance Program Revision	1 work-hour × $85 per hour = $85	0	85	48,110.
1 Depending on configuration.
2 The cost on U.S. operators is based on configuration and number of airplanes in that configuration.

We have received no definitive data that would enable us to provide a cost estimate for the on-condition action specified in this proposed 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 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),

(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):

The Boeing Company: Docket No. FAA-2010-1272; Directorate Identifier 2010-NM-226-AD.

Comments Due Date

(a) We must receive comments by February 17, 2011.

Affected ADs

(b) None.

Applicability

(c) This AD applies to The Boeing Company Model 727, 727C, 727-100, 727-100C, 727-200, and 727-200F series airplanes, all variable numbers, certificated in any category.

Note 1:

This AD requires revisions to certain operator maintenance documents to include new inspections. Compliance with these inspections is required by 14 CFR 91.403(c). For airplanes that have been previously modified, altered, or repaired in the areas addressed by these inspections, the operator may not be able to accomplish the inspections described in the revisions. In this situation, to comply with 14 CFR 91.403(c), the operator must request approval for an alternative method of compliance according to paragraph (l) of this AD. The request should include a description of changes to the required inspections that will ensure the continued operational safety of the airplane.

Subject

(d) Joint Aircraft System Component (JASC)/Air Transport Association (ATA) of America Code 28, Fuel.

Unsafe Condition

(e) This AD was prompted by fuel system reviews conducted by the manufacturer. We are issuing this AD to increase the level of protection from lightning strikes and prevent the potential of ignition sources inside fuel tanks, which, in combination with flammable fuel vapors, could result in fuel tank explosions and consequent loss of the airplane.

Compliance

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

Installation

(g) Within 60 months after the effective date of this AD, install double shielded fuel quantity indicating system (FQIS) wire bundles, install a new wire feed-through fitting, and ground the wire shields, as applicable, in accordance with Part 1 of the Accomplishment Instructions of Boeing Service Bulletin 727-28-0131, dated August 18, 2010.

Repetitive Inspections

(h) At the applicable times specified in paragraphs (h)(1) or (h)(2) of this AD, do low frequency eddy current (LFEC) inspections for cracking of the fuselage skin, in accordance with Part 2 of the Accomplishment Instructions of Boeing Service Bulletin 727-28-0131, dated August 18, 2010.

(1) For Model 727, 727-100, 727-100C, and 727C series airplanes: Before the accumulation of 45,000 total flight cycles, or within 8,000 flight cycles after the effective date of this AD, whichever occurs later. Repeat the inspections thereafter at intervals not to exceed 8,000 flight cycles.

(2) For Model 727-200 and 727-200F series airplanes: Before the accumulation of 45,000 total flight cycles, or within 16,000 flight cycles after the effective date of this AD, whichever occurs later. Repeat the inspections thereafter at intervals not to exceed 16,000 flight cycles.

(i) If any cracking is found during any inspection required by paragraph (h) of this AD: Before further flight, repair the crack in accordance with a method approved by the Manager, Seattle Aircraft Certification Office (ACO), FAA. For a repair method to be approved, the repair must meet the certification basis of the airplane, and the approval must specifically refer to this AD.

Maintenance Program Revision

(j) Before or concurrently with doing the actions required by paragraph (g) of this AD, or within 30 days after the effective date of this AD, whichever occurs later: Revise the maintenance program by incorporating airworthiness limitations (AWL) No. 28-AWL-18 and 28-AWL-19 in Section D of Section 9 (“AIRWORTHINESS LIMITATIONS—FUEL SYSTEMS”) of the Boeing 727-100/200 Airworthiness Limitations (AWLs) Document, D6-8766-AWL, Revision August 2010. The initial compliance time for AWL No. 28-AWL-18 is within 10 years after the accomplishment of paragraph (g) of this AD, or within 10 years after the effective date of this AD, whichever occurs later.

No Alternative Inspections, Inspection Intervals, or Critical Design Configuration Control Limitations (CDCCLs)

(k) After accomplishing the action specified in paragraph (j) of this AD, no alternative inspections, inspection intervals, or CDCCLs may be used unless the inspections, intervals, or CDCCLs are approved as an Alternative Method of Compliance (AMOC) in accordance with the procedures specified in paragraph (l) of this AD.

Alternative Methods of Compliance (AMOCs)

(l)(1) The Manager, Seattle Aircraft Certification Office (ACO), 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 manager of the ACO, send it to the attention of the person identified in the Related Information section of this AD. Information may be e-mailed to: [e-mail].

(2) Before using any approved AMOC, notify your Principal Maintenance Inspector or Principal Avionics Inspector, as appropriate, or lacking a principal inspector, your local Flight Standards District Office.

Related Information

(m) For more information about this AD, contact Louis Natsiopoulos, Aerospace Engineer, Systems and Equipment Branch, ANM-130S, FAA, Seattle Aircraft Certification Office, 1601 Lind Avenue, SW., Renton, Washington 98057-3356; telephone [phone]; fax [phone]; e-mail: [e-mail].

(n) For service information identified in this AD, contact Boeing Commercial Airplanes, Attention: Data & Services Management, P. O. Box 3707, MC 2H-65, Seattle, Washington 98124-2207; telephone [phone], extension 1; fax [phone]; e-mail [e-mail]; Internet https://www.myboeingfleet.com. You may review copies of the referenced service information at the FAA, Transport Airplane Directorate, 1601 Lind Avenue, SW., Renton, Washington. For information on the availability of this material at the FAA, call 425-227-1221.

Issued in Renton, Washington, on December 17, 2010.

Ali Bahrami,

Manager, Transport Airplane Directorate, Aircraft Certification Service.