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###### Department of Transportation

###### Federal Aviation Administration 

          - 14 CFR Part 39 
          - [Docket No. 99-NM-377-AD; Amendment 39-12014; AD 2000-24-07] 
          - RIN 2120-AA64 

# 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, that requires inspections to detect cracking of the frame web, doubler, and inner chord of the forward edge frame of main entry door number 1, and various follow-on actions. This amendment is prompted by reports of cracking in the frame web, doubler, inner chord, and strap of the forward edge frame of main entry door number 1. The actions specified by this AD are intended to prevent cracks in the frame web and doubler of the forward edge frame of main entry door number 1, which could result in inability of the edge frame to react door stop loads, and consequent rapid depressurization of the airplane. 

# DATES:

Effective January 8, 2001. 

                        The incorporation by reference of certain publications listed in the regulations is approved by the Director of the                         **Federal Register**                         as of January 8, 2001.                     

# ADDRESSES:

The service information referenced in this AD may be obtained from Boeing Commercial Airplane Group, 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:

Rick Kawaguchi, Aerospace Engineer, Airframe Branch, ANM-120S, FAA, Seattle Aircraft Certification Office, 1601 Lind Avenue, SW., Renton, Washington 98055-4056; telephone (425) 227-1153; fax (425) 227-1181. 

# 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                           ( print page 75583)                        June 15, 2000 (65 FR 37497). That action proposed to require inspections to detect cracking of the frame web, doubler, and inner chord of the forward edge frame of main entry door number 1, and various follow-on actions.                 

## 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. 

## Support for the Proposal 

Three commenters support the proposed rule. 

## Request to Reference New Service Information 

One commenter requests that the FAA revise paragraphs (a), (b), and (c) of the proposed rule to reference Boeing Alert Service Bulletin 747-53A2417, Revision 2, dated August 10, 2000, as an acceptable means of compliance for the actions required by those paragraphs. (Certain paragraphs of the proposed rule reference Boeing Service Bulletin 747-53A2417, Revision 1, dated July 23, 1998, as the appropriate source of service information for accomplishment of the actions required by those paragraphs.) 

Because paragraph (a) of the proposed rule does not reference a service bulletin but only specifies compliance times, the FAA infers that the commenter is requesting that the FAA revise paragraphs (b) and (c), as well as paragraphs (d) and (e), of the proposed rule. The FAA concurs with the commenter's request. Since the issuance of the proposed rule, the FAA has reviewed and approved Boeing Alert Service Bulletin 747-53A2417, Revision 2. The procedures in that service bulletin are substantially similar to those in Boeing Service Bulletin 747-53A2417, Revision 1. Thus, paragraphs (b), (d), and (e) of this final rule have been revised accordingly to reference Revision 2 of the service bulletin, in addition to Revision 1, as an acceptable source of service information. 

Also, Revision 2 of the service bulletin expands the area of inspection specified in Revision 1 of the service bulletin, to include detailed visual inspections of the aft side of the frame web (referred to as “Area 3” in the service bulletin), an area which is specified in paragraph (c) of the proposed rule and this final rule. Accordingly, paragraph (c) of this AD has been revised to note that Boeing Alert Service Bulletin 747-53A2417, Revision 2, dated August 10, 2000, may be used to accomplish the inspections specified in that paragraph. Also, “Note 5” of the proposed rule has been amended to clarify that the inspections in paragraph (c) of this AD are described in Revision 2 of the service bulletin. 

## Difference Between Revision 2 of the Service Bulletin and This AD

Operators should note that, in addition to the detailed visual inspections of Area 3, the aft side of the frame web, that are specified in this AD, Revision 2 of the service bulletin also specifies detailed visual inspections of an “Area 2,” which comprises the forward and aft sides of the frame web and chord. The FAA has determined that, because inspections in this area were not specified in the proposed rule, to require inspections of this area would expand the scope of this AD, necessitating additional notice to the public and reopening of the comment period. Due to the criticality of the unsafe condition addressed in this AD, the FAA finds that to delay issuance of this final rule in this way would be inappropriate. Therefore, this AD does not require inspections of “Area 2,” as defined in the service bulletin. However, the FAA may consider further rulemaking to require inspections in this area. 

## Requests to Correct Typographical Error, Remove Doorstop Locations 

                    One commenter, who otherwise supports the proposed rule, requests that the FAA revise paragraph (c) of the proposed rule to correct a typographical error in a reference to a doorstop location. In the                     **Federal Register**                     version of the AD, the sentence that is the subject of the commenter's request reads, “Perform a detailed visual inspection to detect cracking of the aft side of the forward edge door frame web of main entry door number 1 in the exposed area from doorstop                     #                    2 [approximately water line (WL) 218] to doorstop                     #                    2 (approximately WL 245) at body station 434.” Another commenter suggests that the references to doorstop locations be removed entirely from the paragraph.                 

The FAA acknowledges the typographical error pointed out by the first commenter. The FAA has determined that the WL references in the subject sentence of the proposed rule are correct, and the references to the doorstop locations are not necessary to adequately define the area that needs to be inspected. Therefore, the FAA concurs with the second commenter's suggestion to remove the references to doorstop locations. The affected sentence of paragraph (c) of this final rule has been revised to read, “Perform a detailed visual inspection to detect cracking of the aft side of the forward edge door frame web of main entry door number 1 in the exposed area from approximately [WL] 218 to approximately WL 245 at body station 434.” 

## 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. 

## Cost Impact 

There are approximately 685 Model 747 series airplanes of the affected design in the worldwide fleet. The FAA estimates that 211 airplanes of U.S. registry will be affected by this AD. 

For Group 1 airplanes (approximately 191 U.S.-registered airplanes), it will take approximately 3 work hours per airplane to accomplish the required inspections, at an average labor rate of $60 per work hour. Based on these figures, the cost impact of these inspections on U.S. operators of Group 1 airplanes is estimated to be $34,380, or $180 per airplane, per inspection cycle. 

For Group 2 airplanes (approximately 20 U.S.-registered airplanes), it will take approximately 2 work hours per airplane to accomplish the required inspections, at an average labor rate of $60 per work hour. Based on these figures, the cost impact of these inspections on U.S. operators of Group 2 airplanes is estimated to be $2,400, or $120 per airplane, per inspection cycle. 

For Group 1 airplanes (approximately 191 U.S.-registered airplanes), it will take approximately 128 work hours per airplane to accomplish the required repair, at an average labor rate of $60 per work hour. Based on these figures, the cost impact of this repair on U.S. operators of Group 1 airplanes is estimated to be $1,466,880, or $7,680 per airplane. 

For Group 2 airplanes (approximately 20 U.S.-registered airplanes), it will take approximately 64 work hours per airplane to accomplish the required repair, at an average labor rate of $60 per work hour. Based on these figures, the cost impact of this repair on U.S. operators of Group 2 airplanes is estimated to be $76,800, or $3,840 per airplane. 

                    The cost impact figures discussed above are based on assumptions that no                           ( print page 75584)                        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.                 

Should an operator elect to accomplish the reinforcement of the door frame on a Group 1 airplane, it would take approximately 9 work hours per airplane to accomplish the reinforcement, at an average labor rate of $60 per work hour. Based on these figures, the cost impact of the reinforcement on a Group 1 airplane is estimated to be $540 per airplane. 

Should an operator elect to accomplish the reinforcement of the door frame on a Group 2 airplane, it would take approximately 5 work hours per airplane to accomplish the reinforcement, at an average labor rate of $60 per work hour. Based on these figures, the cost impact of the reinforcement on a Group 2 airplane is estimated to be $300 per airplane. 

## 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. 

§ 39.13

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

**2000-24-07 Boeing:**                             Amendment 39-12014. Docket 99-NM-377-AD.                         

*Applicability:*                             Model 747 series airplanes, line numbers 1 through 685 inclusive, certificated in any category.                         

# Note 1:

This AD applies to each airplane identified in the preceding applicability provision, regardless of whether it has been modified, altered, or repaired in the area subject to the requirements of this AD. For airplanes that have been modified, altered, or repaired so that the performance of the requirements of this AD is affected, the owner/operator must request approval for an alternative method of compliance in accordance with paragraph (g) of this AD. The request should include an assessment of the effect of the modification, alteration, or repair on the unsafe condition addressed by this AD; and, if the unsafe condition has not been eliminated, the request should include specific proposed actions to address it.

*Compliance:*                             Required as indicated, unless accomplished previously.                         

To prevent fatigue cracking of the frame web and doubler of the forward edge frame of main entry door number 1, which could result in inability of the edge frame to react door stop loads, and consequent rapid depressurization of the airplane, accomplish the following: 

## Initial Inspection: Compliance Time 

(a) At the time specified in paragraph (a)(1), (a)(2), (a)(3), or (a)(4) of this AD; as applicable; accomplish the requirements of paragraphs (b) and (c) of this AD. 

(1) For airplanes that have accumulated fewer than 13,000 total flight cycles as of the effective date of this AD: Inspect prior to the accumulation of 13,000 total flight cycles, or within 1,500 flight cycles after the effective date of this AD, whichever occurs later. 

(2) For airplanes that have accumulated 13,000 or more total flight cycles but fewer than 20,000 total flight cycles as of the effective date of this AD: Inspect prior to the accumulation of 21,000 total flight cycles, or within 1,500 flight cycles after the effective date of this AD, whichever occurs first. 

(3) For airplanes that have accumulated 20,000 or more total flight cycles but fewer than 25,000 total flight cycles as of the effective date of this AD: Inspect prior to the accumulation of 25,500 total flight cycles, or within 1,000 flight cycles after the effective date of this AD, whichever occurs first. 

(4) For airplanes that have accumulated 25,000 or more total flight cycles as of the effective date of this AD: Inspect within 500 flight cycles after the effective date of this AD. 

## Initial Detailed Visual and High Frequency Eddy Current Inspections 

(b) Perform a detailed visual inspection and a high frequency eddy current inspection of the frame web, doubler, and inner chord of the forward edge door frame to detect cracking of main entry door number 1, in accordance with Boeing Service Bulletin 747-53A2417, Revision 1, dated July 23, 1998; or Boeing Alert Service Bulletin 747-53A2417, Revision 2, dated August 10, 2000. For Group 1 airplanes (as identified in the service bulletin), accomplish the inspections on the left and right sides of the airplane. For Group 2 airplanes (as identified in the service bulletin), accomplish the inspections on the left side of the airplane only. 

# Note 2:

For the purposes of this AD, it is not necessary to count flight cycles accumulated at 2.0 pounds per square inch or less differential pressure.

# Note 3:

Inspections, reinforcements, and repairs accomplished prior to the effective date of this AD in accordance with Boeing Alert Service Bulletin 747-53A2417, dated June 25, 1998, are considered acceptable for compliance with paragraph (b) of this AD. 

# Note 4:

For the purposes of this AD, a detailed visual inspection is defined as: “An intensive visual examination of a specific structural area, system, installation, or assembly to detect damage, failure, or irregularity. Available lighting is normally supplemented with a direct source of good lighting at intensity deemed appropriate by the inspector. Inspection aids such as mirror, magnifying lenses, etc., may be used. Surface cleaning and elaborate access procedures may be required.” 

## Repetitive Detailed Visual Inspections (No Terminating Action) 

(c) Remove the cover assembly for the body torque tube located between the door hinge attachments. Perform a detailed visual inspection to detect cracking of the aft side of the forward edge door frame web of main entry door number 1 in the exposed area from approximately water line (WL) 218 to approximately WL 245 at body station 434. Pay particular attention to the row of fasteners that attach the frame web to the frame outer chord. After completing inspections, replace the cover assembly. Repeat the inspection thereafter at intervals not to exceed 3,000 flight cycles. Boeing Alert Service Bulletin 747-53A2417, Revision 2, dated August 10, 2000, may be used to accomplish these inspections. 

# Note 5:

The inspections required by paragraph (c) of this AD are not described in Boeing Service Bulletin 747-53A2417, Revision 1, dated July 23, 1998. However, these inspections are described in Boeing Alert Service Bulletin 747-53A2417, Revision 2, dated August 10, 2000.
      ( print page 75585)    

# Note 6:

There is no terminating action currently available for the inspections required by paragraph (c) of this AD.

## Repetitive Inspections/Reinforcement/Repair (No Cracks Detected) 

(d) If no crack is detected during the inspection required by paragraph (b) of this AD, prior to further flight, oversize fastener holes in accordance with Boeing Service Bulletin 747-53A2417, Revision 1, dated July 23, 1998; or Boeing Alert Service Bulletin 747-53A2417, Revision 2, dated August 10, 2000; and accomplish the requirements of paragraph (d)(1), (d)(2), or (d)(3) of this AD. 

(1) Repeat the inspections specified in paragraph (b) of this AD one time within 3,000 flight cycles. Within 3,000 flight cycles after accomplishment of the repeat inspection, accomplish paragraph (d)(2) or (d)(3) of this AD.

(2) Reinforce the door frame, in accordance with Figure 5 of the service bulletin. Thereafter, at intervals not to exceed 3,000 flight cycles, perform a detailed visual inspection to detect cracks of the forward and aft side of the frame, in accordance with Figure 6 of the service bulletin. Within 10,000 flight cycles after the reinforcement, accomplish the requirements of paragraph (d)(3) of this AD. 

(3) Accomplish the web replacement repair (“Terminating Action”) in accordance with the service bulletin. Such repair constitutes terminating action for the repetitive inspection requirements of paragraphs (d)(1) and (d)(2) of this AD. 

## Repair (Cracks Detected) 

(e) If any crack is detected during any inspection required by paragraph (b), (d)(1), or (d)(2) of this AD, prior to further flight, accomplish the repair (“Terminating Action”) in accordance with Boeing Service Bulletin 747-53A2417, Revision 1, dated July 23, 1998; or Boeing Alert Service Bulletin 747-53A2417, Revision 2, dated August 10, 2000. Such repair constitutes terminating action for the repetitive inspection requirements of paragraphs (d)(1) and (d)(2) of this AD. 

## Repair 

(f) If any cracking is detected during the inspection required by paragraph (c) of this AD, prior to further flight, repair in accordance with a method approved by the Manager, Seattle Aircraft Certification Office (ACO), FAA; or in accordance with data meeting the type certification basis of the airplane approved by a Boeing Company Designated Engineering Representative (DER) who has been authorized by the Manager, Seattle ACO, to make such findings. For a repair method to be approved by the Manager, Seattle ACO, as required by this paragraph, the approval letter must specifically reference this AD. 

## Alternative Methods of Compliance 

(g) 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 ACO. 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 7:

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

## Special Flight Permits 

(h) Special flight permits may be issued in accordance with sections 21.197 and 21.199 of the Federal Aviation Regulations (14 CFR 21.197 and 21.199) to operate the airplane to a location where the requirements of this AD can be accomplished. 

## Incorporation by Reference 

(i) Except as provided in paragraph (f) of this AD, the actions shall be done in accordance with Boeing Service Bulletin 747-53A2417, Revision 1, dated July 23, 1998; or Boeing Alert Service Bulletin 747-53A2417, Revision 2, dated August 10, 2000. 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 Airplane Group, P.O. 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 

(j) This amendment becomes effective on January 8, 2001. 

Issued in Renton, Washington, on November 22, 2000. 

Donald L. Riggin, 

Acting Manager, Transport Airplane Directorate, Aircraft Certification Service.

[FR Doc. 00-30399 Filed 12-1-00; 8:45 am] 

BILLING CODE 4910-13-P