2010-24717. Airworthiness Directives; The Boeing Company Model 747-100, 747-100B, 747-100B SUD, 747-200B, 747-200C, 747-200F, 747-300, 747SR, and 747SP Series 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 Model 747-100, 747-100B, 747-100B SUD, 747-200B, 747-200C, 747-200F, 747-300, 747SR, and 747SP series airplanes. The original NPRM would have required adding two new indicator lights on the P10 panel to inform the captain and first officer of a low pressure condition in the left and right override/jettison pumps of the center wing tanks. The original NPRM would also have required replacing the left and right override/jettison switches on the M154 fuel control module on the P4 panel with improved switches and doing the associated wiring changes. The original NPRM would have also required a revision to the maintenance program to incorporate airworthiness limitation No. 28-AWL-22. The original NPRM resulted from fuel system reviews conducted by the manufacturer. This action revises the original NPRM by adding a revision to the airplane flight manual to advise the flightcrew what to do in the event that the pump low pressure light on the flight engineer's panel does not illuminate when the pump is selected off; and requiring, for certain airplanes, installation of a mounting bracket for the new indicator lights. We are proposing this supplemental NPRM to prevent uncommanded operation of the override/jettison pumps of the center wing tanks, and failure to manually shut off the override/jettison pumps at the correct time, either of which could lead to an ignition source inside the center wing tank. This condition, in combination with flammable fuel vapors, could result in a center fuel tank explosion and consequent loss of the airplane.

DATES:

We must receive comments on this supplemental NPRM by October 26, 2010.

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: U.S. Department of Transportation, Docket Operations, M-30, West Building Ground Floor, Room W12-140, 1200 New Jersey Avenue, SE., Washington, DC 20590, 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 (telephone [phone]) is in the ADDRESSES section. Comments will be available in the AD docket shortly after receipt.

FOR FURTHER INFORMATION CONTACT:

Douglas Bryant, 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 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-2008-1098; Directorate Identifier 2008-NM-108-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

We issued a notice of proposed rulemaking (NPRM) (the “original NPRM”) to amend 14 CFR part 39 to include an airworthiness directive (AD) that would apply to certain Model 747-100, 747-100B, 747-100B SUD, 747-200B, 747-200C, 747-200F, 747-300, 747SR, and 747SP series airplanes. That original NPRM was published in the Federal Register on October 16, 2008 (73 FR 61369). That original NPRM proposed to require adding two new indicator lights on the P10 panel to inform the captain and first officer of a low pressure condition in the left and right override/jettison pumps of the center wing tanks. The original NPRM also proposed to require replacing the left and right override/jettison switches on the M154 fuel control module on the P4 panel with improved switches and doing the associated wiring changes. The original NPRM also proposed to require a revision to the maintenance program to incorporate airworthiness limitation No. 28-AWL-22.

Comments

We gave the public the opportunity to participate in developing this AD. We considered the comments received from the two commenters.

Request To Revise the Airplane Flight Manual (AFM)

Boeing requests that the original NPRM be revised to add a requirement to revise Section 3, “Normal Procedures,” of the AFM to require actions by the flight engineer in the event that the pump low pressure light on the flight engineer's panel does not illuminate when the pump is selected off.

We agree that this supplemental NPRM should be revised to require including this information in the AFM. However, we disagree with the specific wording and AFM section proposed by Boeing. In evaluating Boeing's request, we found that there are two causes for an override/jettison pump to run dry. The actions proposed by the original NPRM were intended to prevent an uncommanded-on event that could result in the override/jettison pump running dry, which could lead to an ignition source in the center wing fuel tank. We found that the original proposed actions would address events where the pumps run dry for extended periods of time as might happen when the flight engineer does not shut off the pump at the appropriate time.

However, since the cause of the uncommanded-on event still exists, we find that the AFM must be revised to provide instructions to the flightcrew in the event of a relay failure which leaves the fuel pump powered on after the pump has been switched off (uncommanded-on). We have determined that more precise wording must be used in the supplemental NPRM and that the wording should be added to Section 1, “Certificate Limitations,” of the AFM.

Therefore, we have added a new paragraph (i) to this supplemental NPRM and re-identified subsequent paragraphs. We have also revised the Costs of Compliance section of this supplemental NPRM to include the estimated costs for this new action. In addition, we revised the unsafe condition statement to include the additional cause.

Request To Reference Later Revision of Service Bulletin Cited in Original NPRM

Northwest Airlines (NWA) requests that we reference updated service information (i.e., Boeing Service Bulletin 747-28A2288, Revision 1, dated January 21, 2010), instead of Boeing Alert Service Bulletin 747-28A2288, dated March 20, 2008, which was referenced in the original NPRM as the appropriate source of service information for doing the required actions. NWA notes that steps 3.B.46.b.(1) through 3.B.46.b.(11) of Boeing Alert Service Bulletin 747-28A2288, dated March 20, 2008, do not state when the two new installed LOW PRESS lights on the P10 panel come on. NWA explains that if the LOW PRESS lights on the P10 panel are not wired correctly, and those steps are used, the lights could be illuminated properly in the `Test' mode, but might not illuminate in the actual non-`test' mode with the override/jettison pump switch in the ON position. NWA states that Boeing responded to this concern and stated that the original issue of the alert service bulletin would be revised and would reference actions that are the same as those provided in AWL No. 28-AWL-22 for the functional tests.

Since we published the original NPRM, Boeing has published Boeing Service Bulletin 747-28A2288, Revision 1, dated January 21, 2010. We agree to reference the updated service bulletin as the appropriate source of service information for accomplishing the installation of indicator lights and replacement of switches required by this supplemental NPRM. Boeing has clarified Steps 3.B.44.b.(1) through 3.B.44.b.(11) of Boeing Service Bulletin 747-28A2288, Revision 1, dated January 21, 2010.

In addition, Boeing has also included installation instructions (which include installing a mounting bracket) of the LOW PRESS indicator lights for airplanes that do not have the warning panel (i.e., the P10 panel) installed, and revised the airplane groups.

We have revised paragraphs (c) and (g) of this supplemental NPRM to reference Boeing Service Bulletin 747-28A2288, Revision 1, dated January 21, 2010. For certain airplanes, we also revised paragraph (g) of this supplemental NPRM to require adding a mounting bracket.

Request To Revise Summary and Discussion Sections of Original NPRM

Boeing requests that we revise the Summary and Discussion sections of the original NPRM to add additional detail to the description of required actions.

For the Summary section, Boeing suggests that the text be revised to point out:

• The redundancy in functionality between the two P4 panel indicator lights and the new indicator lights added to the P10 panel;
• The different configurations of the P10 panel (which means that for some airplanes, a bracket would also be installed to provide a mounting surface for the new indicator lights); and
• To explain which flightcrew member is responsible for responding to indications of a pump uncommanded-on event.

For the Discussion section, Boeing also suggests that the text be revised to point out the redundancy in functionality between the two P4 panel indicator lights and the new indicator lights added to the P10 panel. Boeing suggests that, in addition, the text should be revised to provide further details on the similarities and differences between the indicator lights on the P10 and P4 panels; information on a switch replacement for the P4 panel; and further detail on how and when the indicator lights turn on and off along with a detailed description of how a flight engineer should respond to the indicator lights.

We agree that the sections of text need to be clarified. The Summary section of an AD is intended to provide only a brief summary of the AD. Therefore, we have not revised the Summary section of this supplemental NPRM. Also, while the Discussion section is the appropriate section for the detailed information that Boeing proposes, the Discussion section from the original NPRM is not repeated in this supplemental NPRM.

Request To Revise the Work-Hour Estimate

NWA requests that the work-hour estimate to accomplish the original NPRM be increased from the 28 work-hours estimated in the original NPRM to 56.75 work-hours. NWA states that Boeing Alert Service Bulletin 747-28A2288, dated March 20, 2008, does not include a work-hour estimate for accomplishing access and closeup actions provided in BAE Service Bulletin 65B46124-28-03, dated March 28, 2007. NWA points out that the BAE service bulletins, referenced in the original NPRM (and the following table) as additional sources of guidance, provide an estimate of 10 work-hours for access and closeup actions.

BAE Systems Service Bulletins

BAE Systems Service Bulletin—	Dated—
65B46124-28-01	February 16, 2006.
65B46124-28-02	March 28, 2007.
65B46124-28-03	March 28, 2007.
65B46214-28-01	February 16, 2006.
65B46214-28-02	March 28, 2007.
65B46214-28-03	March 28, 2007.

We agree to revise the work-hour estimate. However, we do not agree to include incidental costs such as access and closeup. Boeing Service Bulletin 747-28A2288, Revision 1, dated January 21, 2010, provides an estimate of 28 work-hours to accomplish the proposed modification. The BAE service bulletins referenced in that Boeing service bulletin as additional sources of guidance each provide an estimate of 2 additional work-hours to accomplish the modification actions specified in Boeing Service Bulletin 747-28A2288, Revision 1, dated January 21, 2010. The cost analysis in AD rulemaking actions, however, typically does not include incidental costs such as the time required to gain access and closeup, time necessary for planning, or time necessitated by other administrative actions. Those incidental costs, which might vary significantly among operators, are almost impossible to calculate. We cannot provide specific information regarding the cost of parts from BAE to do the proposed modification. The parts costs will likely vary depending on the airplane group. However, we can reasonably estimate that the cost of the parts from BAE will be at least between $100 and $200 per airplane, depending on airplane group. We specifically invite the submission of comments and other data regarding the costs of this proposed AD.

We have revised the estimate to between 30 and 32 work-hours, depending on airplane group. Also, Boeing Service Bulletin 747-28A2288, Revision 1, dated January 21, 2010, revises the parts cost estimate provided in the original issue of that service bulletin. We have revised the parts costs estimate in the Costs of Compliance section of this supplemental NPRM accordingly.

Incorrect Numbers

AWL No. 28-AWL-22 of Section D of the Boeing 747-100/200/300/SP Airworthiness Limitations (AWLs) and Certification Maintenance Requirements (CMRs), D6-13747-CMR, Revision March 2008, contains an incorrect section number. Where the AWL states “28-31-00,” the correct section number is “28-42-00.” Boeing is aware of this discrepancy and plans to issue a revision. We have included this information in paragraph (h) of this AD.

Boeing Service Bulletin 747-28A2288, Revision 1, dated January 21, 2010, contains an incorrect sub-section number and incorrect part numbers. Where Boeing Service Bulletin 747-28A2288, Revision 1, dated January 21, 2010, states “20-60-00,” the correct sub-section number is “28-60-06.” Where Figures 22 through 32 of Boeing Service Bulletin 747-28A2288, Revision 1, dated January 21, 2010, state certain part numbers for a nut, a bolt, and a washer (BACN10JC06CD, BACS12HN06-10, and NAS1149D0632J respectively), the correct part numbers are BACN10NW1, BACS12HN04-6 (for a screw instead of a bolt), and NAS1149DN416J, respectively. Boeing is aware of these discrepancies and plans to issue a revision. We have included this information in paragraph (g) of this AD.

FAA's Determination and Proposed Requirements of the Supplemental NPRM

We are proposing this supplemental NPRM because we evaluated all pertinent information and determined an unsafe condition exists and is likely to exist or develop on other products of the same type design. Certain changes described above expand the scope of the original NPRM. 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 supplemental NPRM.

Costs of Compliance

We estimate that this proposed AD would affect 185 airplanes of U.S. registry. The average labor rate per work-hour is $85. The following table provides the estimated costs for U.S. operators to comply with this proposed AD.

Estimated Costs

Action	Work-hours	Parts	Cost per product	Number of U.S.-registered airplanes	Fleet cost
Boeing Service Bulletin 747-28A2288, Revision 1	Between 30 and 32	Between $2,768 and $2,868	Between $5,318 and $5,588	185	Between $983,830 and $1,033,780.
AFM revision	1	None	$85	185	$15,725

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), 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.

You can find our regulatory evaluation and the estimated costs of compliance in the AD Docket.

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 AD:

The Boeing Company: Docket No. FAA-2008-1098; Directorate Identifier 2008-NM-108-AD.

Comments Due Date

(a) We must receive comments by October 26, 2010.

Affected ADs

(b) None.

Applicability

(c) This AD applies to The Boeing Company Model 747-100, 747-100B, 747-100B SUD, 747-200B, 747-200C, 747-200F, 747-300, 747SR, and 747SP series airplanes, certificated in any category; as identified in Boeing Service Bulletin 747-28A2288, Revision 1, dated January 21, 2010.

Note 1:

This AD requires revisions to certain operator maintenance documents to include a new inspection. Compliance with this inspection is required by 14 CFR 91.403(c). For airplanes that have been previously modified, altered, or repaired in the areas addressed by this inspection, 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 (AMOC) according to paragraph (1) of this AD. The request should include a description of changes to the required inspection that will ensure the continued operational safety of the airplane.

Subject

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

Unsafe Condition

(e) This AD results from fuel system reviews conducted by the manufacturer. The Federal Aviation Administration is issuing this AD to prevent uncommanded operation of the override/jettison pumps of the center wing tanks, and failure to manually shut off the override/jettison pumps at the correct time, either of which could lead to an ignition source inside the center wing tank. This condition, in combination with flammable fuel vapors, could result in a center fuel tank explosion and consequent loss of the airplane.

Compliance

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

Installation of Indicator Lights and Replacement of Switches

(g) Within 36 months after the effective date of this AD: Add two new indicator lights on the P10 panel to inform the captain and first officer of a low pressure condition in the left and right override/jettison pumps of the center wing tanks; and, for airplanes that do not have the warning panel (P10 panel) installed, add a mounting bracket; and replace the left and right override/jettison switches on the M154 fuel control module on the P4 panel with improved switches; and do the associated wiring changes. Accomplish these actions by doing all of the applicable actions specified in the Accomplishment Instructions of Boeing Service Bulletin 747-28A2288, Revision 1, dated January 21, 2010, except where that service bulletin states “20-60-00,” the correct sub-section number is “28-60-06,” and as described in Table 1 of this AD.

Table 1—Part Number Correction

Part name	Part number specified in Figures 22 through 32 of Boeing Service Bulletin 747-28A2288, Revision 1, dated January 21, 2010	Part name of correct part	Correct part number
Nut	BACN10JC06CD	Nut	BACN10NW1
Bolt	BACS12HN06-10	Screw	BACS12HN04-6
Washer	NAS1149D0632J	Washer	NAS1149DN416J

Note 2:

For airplanes equipped with certain M154 fuel control modules, paragraph 2.C.2 of Boeing Service Bulletin 747-28A2288, Revision 1, dated January 21, 2010, refers to the BAE Systems service bulletins identified in Table 2 of this AD, as applicable, as additional sources of guidance for replacing the switches.

Table 2—Additional Sources of Guidance

Service bulletin	Date
BAE Systems Service Bulletin 65B46124-28-01	February 16, 2006.
BAE Systems Service Bulletin 65B46124-28-02	March 28, 2007.
BAE Systems Service Bulletin 65B46124-28-03	March 28, 2007.
BAE Systems Service Bulletin 65B46214-28-01	February 16, 2006.
BAE Systems Service Bulletin 65B46214-28-02	March 28, 2007.
BAE Systems Service Bulletin 65B46214-28-03	March 28, 2007.

Maintenance Program Revision

(h) Concurrently with accomplishing the actions required by paragraph (g) of this AD, revise the maintenance program by incorporating Airworthiness Limitation (AWL) No. 28-AWL-22 of Section D of the Boeing 747-100/200/300/SP Airworthiness Limitations (AWLs) and Certification Maintenance Requirements (CMRs), D6-13747-CMR, Revision March 2008. Where the AWL states “28-31-00,” the correct section number is “28-42-00.”

Airplane Flight Manual (AFM) Revision

(i) Concurrently with accomplishing the actions required by paragraph (g) of this AD, revise Section 1, “Certificate Limitations,” of the applicable Boeing 747 AFM to include the following statement. This may be done by inserting a copy of this AD into the AFM.

“When the center tank override jettison pumps are selected off, the amber pump low pressure lights on the Flight Engineer's panel should illuminate and remain on. If a pump low pressure light on the Flight Engineer's panel does not illuminate, open the associated pump circuit breaker.”

Note 3:

When a statement identical to that in paragraph (i) of this AD has 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.

No Alternative Inspections or Inspection Intervals

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

Terminating Action for Maintenance Program Revision

(k) Incorporating AWL No. 28-AWL-22 into the maintenance program in accordance with paragraph (g) of AD 2008-10-07, Amendment 39-15513, or AD 2008-10-07 R1, Amendment 39-16070, terminates the action required by paragraph (h) 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. Send information to ATTN: Douglas Bryant, Aerospace Engineer, Propulsion Branch, ANM-140S, FAA, Seattle ACO, 1601 Lind Avenue, SW., Renton, Washington 98057-3356; telephone [phone]; fax [phone]. Information may be e-mailed to: [e-mail].

(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 principal maintenance inspector (PMI) or principal avionics inspector (PAI), as appropriate, or lacking a principal inspector, your local Flight Standards District Office. The AMOC approval letter must specifically reference this AD.

Issued in Renton, Washington, on September 20, 2010.

Ali Bahrami,

Manager, Transport Airplane Directorate, Aircraft Certification Service.