E7-17830. Airworthiness Directives; Boeing Model 767 Airplanes

AGENCY:

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

ACTION:

Notice of proposed rulemaking (NPRM).

SUMMARY:

The FAA proposes to adopt a new airworthiness directive (AD) for all Boeing Model 767 airplanes. This proposed AD would require installing an automatic shutoff system for the auxiliary fuel tank pump, revising the airplane flight manual (AFM) to advise the flight crew of certain operating restrictions for airplanes equipped with an automatic auxiliary fuel tank pump shutoff control, revising the Airworthiness Limitations (AWLs) section of certain maintenance documents to include new inspections of the automatic shutoff system for the auxiliary fuel tank boost pumps, and, for certain airplanes, installing a placard to alert the flight crew of certain fuel usage restrictions. This proposed AD results from a design review of the fuel tank systems. We are proposing this AD to prevent an overheat condition outside the pump explosion-resistance area that is open to the pump inlet, which could cause an ignition source for the fuel vapors in the fuel tank and result in fuel tank explosions and consequent loss of the airplane.

DATES:

We must receive comments on this proposed AD by October 26, 2007.

ADDRESSES:

Use one of the following addresses to submit comments on this proposed AD.

• DOT Docket Web site: Go to http://dms.dot.gov and follow the instructions for sending your comments electronically.
• Government-wide rulemaking Web site: Go to http://www.regulations.gov and follow the instructions for sending your comments electronically.
• 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.
• Fax: [phone].
• Hand Delivery: Room W12-140 on the ground floor of the West Building, 1200 New Jersey Avenue, SE., Washington, DC, between 9 a.m. and 5 p.m., Monday through Friday, except Federal holidays.

Contact Boeing Commercial Airplanes, P.O. Box 3707, Seattle, Washington 98124-2207, for the service information identified in this proposed AD.

FOR FURTHER INFORMATION CONTACT:

Judy Coyle, Aerospace Engineer, Propulsion Branch, ANM-140S, FAA, Seattle Aircraft Certification Office, 1601 Lind Avenue, SW., Renton, Washington 98057-3356; telephone [phone]; fax [phone].

SUPPLEMENTARY INFORMATION:

Comments Invited

We invite you to submit any relevant written data, views, or arguments regarding this proposed AD. Send your comments to an address listed in the ADDRESSES section. Include the docket number “FAA-2007-29173; Directorate Identifier 2006-NM-283-AD” at the beginning of your comments. We specifically invite comments on the overall regulatory, economic, environmental, and energy aspects of the proposed AD. We will consider all comments received by the closing date and may amend the proposed AD in light of those comments.

We will post all comments we receive, without change, to http://dms.dot.gov,, including any personal information you provide. We will also post a report summarizing each substantive verbal contact with FAA personnel concerning this proposed AD. Using the search function of that Web site, anyone can find and read the comments in any of our dockets, including the name of the individual who sent the comment (or signed the comment on behalf of an association, business, labor union, etc.). You may review DOT's complete Privacy Act Statement in the Federal Register published on April 11, 2000 (65 FR 19477-78), or you may visit http://dms.dot.gov.

Examining the Docket

You may examine the AD docket on the Internet at http://dms.dot.gov,, or in person at the Docket Operations office between 9 a.m. and 5 p.m., Monday through Friday, except Federal holidays. The Docket Operations office (telephone [phone]) is located on the ground floor of the West Building at the DOT street address stated in the ADDRESSES section. Comments will be available in the AD docket shortly after the Docket Management System receives them.

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.

Initial results from the SFAR 88 analysis show that fuel pumps that run dry could cause an overheat condition outside the pump explosion-resistance area that is open to the pump inlet, which could cause an ignition source for the fuel vapors in the fuel tank.

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.

Relevant Service Information

We have reviewed Boeing Alert Service Bulletins 767-28A0083 and 767-28A0084, both Revision 1, dated April 26, 2007. The service bulletins describe procedures for installing an automatic shutoff system for the auxiliary fuel tank pump. The actions involve installing new relay brackets and relays in the P36 and P37 panels, and, for certain airplanes, in the P33 panels; changing the wiring in the panels; and installing wiring between the panels.

We have also reviewed Section 9, “Airworthiness Limitations (AWLs) and Certification Maintenance Requirements (CMRs),” of Boeing 767 Maintenance Planning Data (MPD) Document D622T001-9, Revision March 2006. That revision adds new fuel system Airworthiness Limitations Instruction (ALI) 28-AWL-20 to Subsection G, “AIRWORTHINESS LIMITATIONS—FUEL SYSTEM AWLs, of Section 9, which includes periodic inspections of the automatic shutoff system for the auxiliary tank fuel boost pumps to detect latent failures that could contribute to an ignition source. That revision also adds critical design configuration control limitation (CDCCL) 28-AWL-19, which includes a post-maintenance inspection of certain wiring in the fuel quantity indicating system. CDCCLs are limitation requirements to preserve a critical ignition source prevention feature of the fuel tank system design that is necessary to prevent the occurrence of an unsafe condition. The purpose of a CDCCL is to provide instruction to retain the critical ignition source prevention feature during configuration change that may be caused by alterations, repairs, or maintenance actions. A CDCCL is not a periodic inspection.

Accomplishing the actions specified in the service information is intended to adequately address the unsafe condition.

FAA's Determination and Requirements of the Proposed AD

We have evaluated all pertinent information and identified an unsafe condition that is likely to exist or develop on other airplanes of this same type design. For this reason, we are proposing this AD, which would require accomplishing the actions specified in the service information described previously. For certain airplanes, this proposed AD would also require installing a placard to alert the flight crew of certain fuel usage restrictions imposed by AD 2001-15-08. This proposed AD would also allow accomplishing the AWL revision in accordance with later revisions of the MPD as an acceptable method of compliance if they are approved by the Manager, Seattle Aircraft Certification Office (ACO), FAA.

Costs of Compliance

There are about 941 airplanes of the affected design in the worldwide fleet; of these, 414 are U.S. registered. The following table provides the estimated costs for U.S. operators to comply with this proposed AD. The total fleet cost could be as high as $4,655,016.

Estimated Costs

Affected airplanes	Affected airplane groups	Work hours	Average hourly labor rate	Parts	Cost per airplane
767-200, 767-300, 767-300F	1-39	29	$80	$8,924	$11,244
	40-79	25	80	8,495	10,495
	80-81	3	80	420	660
767-400ER	All	23	80	7,911	9,751

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 have 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 that the 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); and

3. 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.

We prepared a regulatory evaluation of the estimated costs to comply with this proposed AD and placed it in the AD docket. See the ADDRESSES section for a location to examine the regulatory evaluation.

List of Subjects in 14 CFR Part 39

• Air transportation
• Aircraft
• Aviation safety
• 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 Federal Aviation Administration (FAA) amends § 39.13 by adding the following new airworthiness directive (AD):

Boeing: Docket No. FAA-2007-29173; Directorate Identifier 2006-NM-283-AD.

Comments Due Date

(a) The FAA must receive comments on this AD action by October 26, 2007.

Affected ADs

(b) Accomplishment of certain requirements of this AD terminates certain requirements of AD 2001-15-08, amendment 39-12342.

Applicability

(c) This AD applies to all Boeing Model 767-200, -300, -300F, and -400ER series airplanes, certificated in any category.

Unsafe Condition

(d) This AD results from a design review of the fuel tank systems. We are issuing this AD to prevent an overheat condition outside the pump explosion-resistance area that is open to the pump inlet, which could cause an ignition source for the fuel vapors in the fuel tank and result in fuel tank explosions and consequent loss of the airplane.

Compliance

(e) You are responsible for having the actions required by this AD performed within the compliance times specified, unless the actions have already been done.

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 (m) of this AD.

Installation

(f) Within 36 months after the effective date of this AD, install an automatic shutoff system for the auxiliary fuel tank pump, in accordance with Boeing Alert Service Bulletin 767-28A0083 (for Model 767-200, -300, and -300F airplanes) or 767-28A0084 (for Model 767-400ER airplanes), both Revision 1, dated April 26, 2007; as applicable.

Installation According to Previous Issue of Service Bulletin

(g) Installing an automatic shutoff system is also acceptable for compliance with the requirements of paragraph (f) of this AD if done before the effective date of this AD in accordance with Boeing Alert Service Bulletin 767-28A0083 or 767-28A0084, both dated May 3, 2006; as applicable.

Revision of Airplane Flight Manual (AFM)

(h) Concurrently with accomplishing the actions required by paragraph (f) of this AD: Revise the Boeing 767 AFM as specified in paragraphs (h)(1) and (h)(2) of this AD. This may be done by inserting a copy of this AD into the AFM.

(1) Revise Section 1, Certificate Limitations, to include the following:

“Intentional dry running of a center tank fuel pump (CTR L FUEL PUMP or CTR R FUEL PUMP message displayed on EICAS) is prohibited.

Do not reset a tripped fuel pump or fuel pump control circuit breaker.”

(2) Revise Section 3.1, Normal Procedures, to include the following:

“CENTER TANK FUEL PUMPS

Center tank fuel pumps must not be “ON” unless personnel are available in the flight deck to monitor low PRESS lights.

For ground operations prior to engine start:

The center tank fuel pump switches must not be positioned ON unless the center tank contains usable fuel. With center tank fuel pump switches ON, verify both center tank fuel pump low PRESS lights are illuminated and EICAS CTR L FUEL PUMP and CTR R FUEL PUMP messages are displayed.

For ground operations after engine start and flight operations: The center tank fuel pump switch must be selected OFF when the respective CTR L FUEL PUMP or CTR R FUEL PUMP message displays. Both center tank fuel pump switches must be selected OFF when either the CTR L FUEL PUMP or CTR R FUEL PUMP message displays if the center tank is empty. During cruise flight, both center tank pump switches may be reselected ON whenever center tank usable fuel is indicated.

DE-FUELING AND FUEL TRANSFER

When transferring fuel or de-fueling center or main wing tanks, the center fuel pump low PRESS must be monitored and the fuel pump switches positioned to “OFF” at the first indication of low pressure. Prior to transferring fuel or de-fueling, conduct a lamp test of the respective fuel pump low PRESS lights.”

Note 2:

When statements identical to those in paragraph (g) of this AD have been included in the general revisions of the AFM, the general revisions may be inserted into the AFM, and the copy of this AD may be removed from the AFM.

Revision of Airworthiness Limitations

(i) Concurrently with accomplishing the actions required by paragraph (f) of this AD: Revise Section 9 of the Boeing 767 Maintenance Planning Data (MPD) Document D622T001-9, “Airworthiness Limitations (AWLs) and Certification Maintenance Requirements (CMRs),” to incorporate Revision March 2006. Accomplishing the revision in accordance with a later revision of the MPD is an acceptable method of compliance if the revision is approved by the Manager, Seattle Aircraft Certification Office (ACO), FAA.

Placard Installation

(j) For Model 767-200, -300, or -300F airplanes that meet the conditions of paragraphs (j)(1) and (j)(2) of this AD: Within 30 days after the effective date of this AD, install a placard in the flight deck adjacent to each pilot's primary flight display, to alert the flight crew to follow the procedures required by paragraph (b) of AD 2001-15-08. The placard must include the following statement:

“AD 2001-15-08 fuel usage restrictions required.”

Alternative placard wording may be used if approved by an appropriate FAA Principal Operations Inspector. Alternative placard methods and alternative methods of mixed fleet configuration control may be used if submitted for review in accordance with the procedures specified in paragraph (l) of this AD.

(1) The airplane is operated in a fleet of airplanes on which the actions specified in paragraph (f) of this AD have been done on at least one of the fleet's airplanes.

(2) The actions specified in paragraph (i) of AD 2001-15-08 (installation of modified center tank override and override/jettison fuel pumps that are not subject to the unsafe condition described in this AD) or paragraph (f) of this AD have not been done on the airplane.

Note 3:

If the actions specified in paragraph (f) of this AD have been done on all airplanes operated within an operator's fleet, or if operation according to the fuel usage restrictions of AD 2001-15-08 is maintained until automatic shutoff systems are installed on all airplanes in an operator's fleet: No placard is necessary before removal of the wet shutoff restrictions of AD 2001-15-08.

Terminating Action for AD 2001-15-08

(k) For airplanes that have automatic shutoff systems installed: Accomplishment of paragraphs (f) and (j) of this AD terminates the requirements of paragraphs (b) and (c) of AD 2001-15-08.

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 in accordance with the procedures found in 14 CFR 39.19.

(2) To request a different method of compliance or a different compliance time for this AD, follow the procedures in 14 CFR 39.19. Before using any approved AMOC on any airplane to which the AMOC applies, notify your appropriate principal inspector (PI) in the FAA Flight Standards District Office (FSDO), or lacking a PI, your local FSDO.

Issued in Renton, Washington, on August 31, 2007.

Stephen P. Boyd,

Acting Manager, Transport Airplane Directorate, Aircraft Certification Service.