Airworthiness Directives; Boeing Model 747 Series Airplanes

AGENCY:

Federal Aviation Administration, DOT.

ACTION:

Final rule.

SUMMARY:

This amendment adopts a new airworthiness directive (AD), applicable to certain Boeing Model 747 series airplanes. This AD requires a one-time inspection of the potable water and drain lines in the forward and aft cargo compartments for indications of overheating of the heater tape, exposed foam insulation, missing or damaged protective tape, or debris around the potable water fill and drain lines; and corrective action, if necessary. This action is necessary to prevent overheating of the heater tape on potable water fill and drain lines, which may ignite accumulated debris or contaminants on or near the potable water fill and drain lines, resulting in a fire in the airplane. This action is intended to address the identified unsafe condition.

DATES:

Effective June 4, 2004.

The incorporation by reference of a certain publication listed in the regulations is approved by the Director of the Federal Register as of June 4, 2004.

ADDRESSES:

The service information referenced in this AD may be obtained from Boeing Commercial Airplanes, P.O. Box 3707, Seattle, Washington 98124-2207. This information may be examined at the Federal Aviation Administration (FAA), Transport Airplane Directorate, Rules Docket, 1601 Lind Avenue, SW., Renton, Washington; or at the Office of the Federal Register, 800 North Capitol Street, NW., suite 700, Washington, DC.

FOR FURTHER INFORMATION CONTACT:

Donald Eiford, Aerospace Engineer, Systems and Equipment Branch, ANM-130S, FAA, Seattle Aircraft Certification Office, 1601 Lind Avenue, SW., Renton, Washington 98055-4056; telephone (425) 917-6465; fax (425) 917-6590.

SUPPLEMENTARY INFORMATION:

A proposal to amend part 39 of the Federal Aviation Regulations (14 CFR part 39) to include an airworthiness directive (AD) that is applicable to certain Boeing Model 747 series airplanes was published in the Federal Register on April 29, 2003 (68 FR 22639). That action proposed to require a one-time inspection of the potable water and drain lines in the forward and aft cargo compartments for indications of overheating of the heater tape, exposed foam insulation, missing or damaged protective tape, or debris around the potable water fill and drain lines; and corrective action, if necessary.

Comments

Interested persons have been afforded an opportunity to participate in the making of this amendment. Due consideration has been given to the comments received.

Request To Allow Deactivation of Heater Tape Prior to Further Flight

Three commenters request that paragraph (b)(1) of the notice of proposed rulemaking (NPRM) be changed so that, after the inspection required by paragraph (b)(1), either replacement or deactivation of the heater tape prior to further flight is allowed. The commenters note that Figure 1 of the service bulletin states that operators may deactivate the heater tape prior to further flight, and replace the heater tape when materials, time, and manpower are available.

One of the commenters states that, due to the proposed 90-day compliance time in the NPRM, it is important not to ground airplanes and to give operators the flexibility to accomplish the heater tape replacement at a more opportune time. Another commenter suggests that a compliance time not to exceed 90 days after the completion of the inspection required by paragraph (b)(1) of the NPRM be allowed so operators can schedule the heater tape replacement at a convenient time.

We agree with the commenters' requests to allow deactivation of the heater tape prior to further flight. We have determined that this action will not affect safety because once the heater tape is deactivated it cannot become overheated. Paragraph (b)(1) of this final rule has been changed accordingly.

We also agree with the commenter's request for a compliance time of within 90 days after the date of the inspection required by paragraph (b)(1) of this AD for operators to replace the heater tape. We find that this is an acceptable amount of time because, as previously mentioned, once the heater tape is deactivated it cannot become overheated. Paragraph (b)(1) of this final rule has been changed accordingly.

Request To Change Wording of Paragraph (b)(2)

One commenter requests either removing the words “prior to further flight” or changing the wording of paragraph (b)(2). This paragraph requires that any exposed foam insulation over the heater tape be covered with a continuous wrap of protective tape, and replacement of any missing or damaged protective tape over the heater tape prior to further flight. We infer that the basis for this request is to give operators the flexibility to accomplish the actions required in paragraph (b)(2) of the AD at a more convenient time.

We agree with the commenter's request to change the wording of paragraph (b)(2) of this AD. We will include a compliance time of within 90 days after the date of the inspection required by paragraph (b)(2) for operators to install or replace protective wrap in areas where the wrap is missing or damaged. We find that this compliance time will not compromise safety because the protective tape is a preventative measure and is not directly related to overheating of the heater tape. Paragraph (b)(2) of this final rule has been changed accordingly.

Request To Allow Deactivation of the Heater Tape for the Potable Water System Per the Operator's Minimum Equipment List (MEL)

One commenter requests the option to deactivate the heater tape for the potable water system per the procedures in the applicable MEL, instead of following the procedures specified in Figure 1 of Boeing Alert Service Bulletin 747-30A2079, dated December 12, 2002. The commenter implies that, since the MEL does not require capping and stowing the wires to the heater tape as the service bulletin does, the MEL procedure is more convenient for an operator to accomplish.

We agree with the commenter's request to allow deactivation of the heater tape per the procedures in the applicable MEL as an alternative to accomplishing the procedures specified in the service bulletin. We have determined that this change will not compromise safety. Paragraph (b)(1) of this final rule has been changed accordingly.

Request To Clarify Meaning of “Visually Accessible”

One commenter requests that the term “visually accessible” used in paragraphs (a) and (b) of the NPRM be defined as “only those areas that can be visually accessed and do not require the disassembly of cargo wall liners.” The commenter states that Boeing Alert Service Bulletin 747-30A2079, dated December 12, 2002, includes the inspection of heater tapes that are located behind cargo wall liners. The areas located behind the cargo wall liners are not visually accessible and are not susceptible to debris collection, therefore they should not be required to be inspected.

We agree with the commenter that the term “visually accessible” should be clarified. The intent of the NPRM was to require inspection of only the visually accessible areas below the cargo floor in the forward and aft cargo compartments. Since publication of the NPRM, Boeing has issued and the FAA has approved Revision 1 of Boeing Service Bulletin 747-30A2079, dated October 16, 2003. Revision 1 of the service bulletin deletes the inspection of areas behind the cargo wall liners and specifies that only areas not covered by floor panel or sidewall panels should be inspected. The term “visually accessible” has been deleted from paragraphs (a) and (b) of this final rule and replaced with “areas not covered by floor panels or sidewall panels.” As a result of this change, Note 2 in the body of the NPRM has been omitted from this final rule. Note 2 stated “The inspection of potable water and drain lines in areas not covered by floor panels or sidewall panels areas does not require removal of floor panels.” The subsequent Notes in this final rule have been renumbered accordingly.

Request for Distinction Between Fiberglass Insulation and Foam Insulation

One commenter requests that a distinction be made between the types of insulation used in the cargo compartment. The commenter states that the wording of one of the caution notes in Boeing Alert Service Bulletin 747-30A2079, dated December 12, 2002, specifies “a minimum clearance of one inch (2.54 centimeters) between the heater tape and any insulation.” The commenter states that some airplanes may have foam insulation surrounding the heater tape, and that the one-inch clearance should be between the heater tape and the floor or fuselage fiberglass insulation, not the foam insulation surrounding the potable water lines.

We agree with the commenter's request to make a distinction between the types of insulation located in the cargo compartment. It was not the intent of the NPRM or the service bulletin to require a one-inch separation between the foam insulation and the heater tape, especially since the foam insulation was designed to be installed directly over the heater tape. Since publication of the NPRM, Boeing has issued and the FAA has approved Revision 1 of Boeing Service Bulletin 747-30A2079, dated October 16, 2003. Revision 1 of the service bulletin deletes the caution note cited by the commenter, which should eliminate the confusion regarding the need for clearance between the heater tape and foam insulation. Revision 1 will be cited in this final rule as the appropriate source of service information; however, paragraph (d) of this AD gives credit to operators who accomplished the actions required by this AD, before the effective date of this AD, per Boeing Alert Service Bulletin 747-30A2079, dated December 12, 2002.

Request To Clarify That Foam Insulation Should Only Be Removed If It Exhibits Signs of Overheating

The same commenter also requests that the AD specify that foam insulation should only be removed if it exhibits signs of overheating, or that the AD reference a subsequent service bulletin revision which contains this information. One of the caution notes in Boeing Alert Service Bulletin 747-30A2079, dated December 12, 2002, implies that if foam insulation is installed, it must be removed to verify heater tape pitch. The work instructions in Figure 1 of the service bulletin only gives procedures for inspection of the heater tape and foam insulation for signs of overheating. The work instructions do not specify that the foam insulation should be removed to verify heater tape pitch.

We agree with the commenter's request to reference a subsequent revision of the service bulletin. It was not the intent of the NPRM to require removal of undamaged foam insulation to verify the installation pitch of the heater tape. As previously stated, the caution note, which may have caused confusion regarding the intent of the service bulletin, was deleted from Revision 1 of Boeing Service Bulletin 747-30A2079, dated October 16, 2003. Revision 1 will be cited in this final rule as the appropriate source of service information.

Conclusion

After careful review of the available data, including the comments noted above, the FAA has determined that air safety and the public interest require the adoption of the rule with the changes previously described. The FAA has determined that these changes will neither increase the economic burden on any operator nor increase the scope of the AD.

Changes to 14 CFR Part 39/Effect on the AD

On July 10, 2002, the FAA issued a new version of 14 CFR part 39 (67 FR 47997, July 22, 2002), which governs the FAA's airworthiness directives system. The regulation now includes material that relates to altered products, special flight permits, and alternative methods of compliance. However, for clarity and consistency in this final rule, we have retained the language of the NPRM regarding that material.

Interim Action

This is considered to be interim action until final action is identified, at which time the FAA may consider further rulemaking.

Change to Labor Rate Estimate

After the NPRM was issued, we reviewed the figures we use to calculate the labor rate to do the required actions. To account for various inflationary costs in the airline industry, we find it appropriate to increase the labor rate used in these calculations from $60 per work hour to $65 per work hour. The economic impact information, below, has been revised to reflect this increase in the specified hourly labor rate.

Cost Impact

There are approximately 1,129 airplanes (968 passenger and 161 freighter) of the affected design in the worldwide fleet. We estimate that 250 airplanes of U.S. registry will be affected by this AD. We provide the following cost estimates associated with this AD:

The cost impact figures discussed above are based on assumptions that no operator has yet accomplished any of the requirements of this AD action, and that no operator would accomplish those actions in the future if this AD were not adopted. The cost impact figures discussed in AD rulemaking actions represent only the time necessary to perform the specific actions actually required by the AD. These figures typically do not include incidental costs, such as the time required to gain access and close up, planning time, or time necessitated by other administrative actions.

Regulatory Impact

The regulations adopted herein will not have a substantial direct effect on the States, on the relationship between the national Government and the States, or on the distribution of power and responsibilities among the various levels of government. Therefore, it is determined that this final rule does not have federalism implications under Executive Order 13132.

For the reasons discussed above, I certify that this action (1) is not a “significant regulatory action” under Executive Order 12866; (2) is not a “significant rule” under 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. A final evaluation has been prepared for this action and it is contained in the Rules Docket. A copy of it may be obtained from the Rules Docket at the location provided under the caption ADDRESSES.

List of Subjects in 14 CFR Part 39

• Air transportation
• Aircraft
• Aviation safety
• Incorporation by reference
• Safety

Adoption of the Amendment

Accordingly, pursuant to the authority delegated to me by the Administrator, the Federal Aviation Administration amends part 39 of the Federal Aviation Regulations (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.

2. Section 39.13 is amended by adding the following new airworthiness directive:

2004-09-10 Boeing: Amendment 39-13599. Docket 2002-NM-341-AD.

Applicability: Model 747 series airplanes, certificated in any category, with lower cargo floors (floors in the lower cargo areas) that are not fully enclosed. A fully enclosed cargo floor is a floor with panels installed between all roller trays in the cargo compartment. A cargo floor that is not fully enclosed is a floor without panels installed between all roller trays in the cargo compartment.

Compliance: Required as indicated, unless accomplished previously.

To prevent overheating of the heater tape on potable water fill and drain lines, which may ignite accumulated debris or contaminants on or near the potable water fill and drain lines, resulting in a fire in the airplane, accomplish the following:

Debris Removal

(a) At the later of the times specified in paragraphs (a)(1) and (a)(2) of this AD: Perform a one-time general visual inspection for foreign object debris (FOD) and contamination on or near potable water and drain lines located below the cargo floor in the forward and aft cargo compartments, in areas not covered by floor panels or sidewall panels. Do the inspection in accordance with the Accomplishment Instructions of Boeing Service Bulletin 747-30A2079, Revision 1, dated October 16, 2003. Remove any FOD or contamination observed on or near the potable water or drain lines prior to further flight in accordance with the service bulletin.

(1) Inspect within 18 months since the date of issuance of the original Airworthiness Certificate or within 18 months since the date of issuance of the Export Certificate of Airworthiness, whichever occurs first; or

(2) Inspect within 90 days after the effective date of this AD.

Note 1:

For the purposes of this AD, a general visual inspection is defined as: “A visual examination of an interior or exterior area, installation, or assembly to detect obvious damage, failure, or irregularity. This level of inspection is made from within touching distance unless otherwise specified. A mirror may be necessary to enhance visual access to all exposed surfaces in the inspection area. This level of inspection is made under normally available lighting conditions such as daylight, hangar lighting, flashlight, or droplight and may require removal or opening of access panels or doors. Stands, ladders, or platforms may be required to gain proximity to the area being checked.”

Inspection for Discrepant Heater Tape

(b) At the applicable time specified in paragraph (c) of this AD: Perform a general visual inspection for discrepancies of potable water and drain lines located below the cargo floor in the forward and aft cargo compartments, in areas not covered by floor panels or sidewall panels, as specified in paragraphs (b)(1) and (b)(2) of this AD. Do the inspection in accordance with the Accomplishment Instructions of Boeing Service Bulletin 747-30A2079, Revision 1, dated October 16, 2003.

(1) Inspect potable water and drain lines for indications of overheating of the heater tape, including localized darkening of foam insulation or protective tape. If overheating is observed: Prior to further flight, either replace the defective heater tape, removing floor panels as necessary, in accordance with the service bulletin; deactivate the heater tape in accordance with the provisions and limitations specified in the operator's Minimum Equipment List (MEL); or deactivate the heater tape in accordance with Figure 1 of the service bulletin. If the heater tape is deactivated it must be replaced within 90 days after the date of the inspection required by this paragraph.

(2) Inspect potable water and drain lines for exposed foam insulation and missing or damaged protective tape. If exposed foam insulation is observed: Within 90 days after the date of the inspection required by this paragraph, cover the foam insulation with a continuous wrap of protective tape, in accordance with the service bulletin. If protective tape is missing or damaged: Within 90 days after the date of the inspection required by this paragraph, replace the protective tape in accessible areas in accordance with the service bulletin. It is not necessary to remove floor panels to replace the protective tape.

(c) Do the inspections required by paragraph (b) at the later of the times specified in paragraphs (c)(1) and (c)(2) of this AD.

(1) Within 18 months since the date of issuance of the original Airworthiness Certificate or the date of issuance of the Export Certificate of Airworthiness, whichever occurs first.

(2) Within 90 days after the effective date of this AD.

Credit for Actions Accomplished Previously

(d) Actions accomplished before the effective date of this AD, per Boeing Alert Service Bulletin 747-30A2079, dated December 12, 2002, are acceptable for compliance with the corresponding actions required by paragraphs (a) and (b) of this AD.

Alternative Methods of Compliance

(e) An alternative method of compliance or adjustment of the compliance time that provides an acceptable level of safety may be used if approved by the Manager, Seattle Aircraft Certification Office (ACO), FAA. Operators shall submit their requests through an appropriate FAA Principal Maintenance Inspector, who may add comments and then send it to the Manager, Seattle ACO.

Note 2:

Information concerning the existence of approved alternative methods of compliance with this AD, if any, may be obtained from the Seattle ACO.

Incorporation by Reference

(f) Unless otherwise specified in this AD, the actions shall be done in accordance with Boeing Service Bulletin 747-30A2079, Revision 1, dated October 16, 2003. This incorporation by reference was approved by the Director of the Federal Register in accordance with 5 U.S.C. 552(a) and 1 CFR part 51. Copies may be obtained from Boeing Commercial Airplanes, PO Box 3707, Seattle, Washington 98124-2207. Copies may be inspected at the FAA, Transport Airplane Directorate, 1601 Lind Avenue, SW., Renton, Washington; or at the Office of the Federal Register, 800 North Capitol Street, NW., suite 700, Washington, DC.

Effective Date

(g) This amendment becomes effective on June 4, 2004.