[Federal Register Volume 62, Number 138 (Friday, July 18, 1997)]
[Proposed Rules]
[Pages 38493-38495]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 97-18936]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 97-NM-03-AD]
RIN 2120-AA64


Airworthiness Directives; Boeing Model 727 Series Airplanes

AGENCY: Federal Aviation Administration, DOT.

ACTION: Notice of proposed rulemaking (NPRM).

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SUMMARY: This document proposes the adoption of a new airworthiness 
directive (AD) that is applicable to all Boeing Model 727 series 
airplanes. This proposal would require repetitive inspections to detect 
cracks in the forward flange of the vertical beam of the aft fuselage 
bulkhead at certain buttock lines, and installation of a splice repair, 
if necessary. The proposed AD also would require installation of a 
preventative modification on the door frames in certain cases. This 
proposal is prompted by reports of fatigue cracks found in the vertical 
beam web and forward flange of the aft fuselage bulkhead. The actions 
specified by the proposed AD are intended to detect and correct such 
fatigue cracking, which could result in the inability of the subject 
vertical beam to withstand the fail-safe loads, and consequent loss of 
cabin pressurization.

DATES: Comments must be received by August 25, 1997.

ADDRESSES: Submit comments in triplicate to the Federal Aviation 
Administration (FAA), Transport Airplane Directorate, ANM-103, 
Attention: Rules Docket No. 97-NM-03-AD, 1601 Lind Avenue, SW., Renton, 
Washington 98055-4056. Comments may be inspected at this location 
between 9:00 a.m. and 3:00 p.m., Monday through Friday, except Federal 
holidays.
    The service information referenced in the proposed rule may be 
obtained from Boeing Commercial Airplane Group, P.O. Box 3707, Seattle, 
Washington 98124-2207.
    This information may be examined at the FAA, Transport Airplane 
Directorate, 1601 Lind Avenue, SW., Renton, Washington.

FOR FURTHER INFORMATION CONTACT: Walter Sippel, Aerospace Engineer, 
Airframe Branch, ANM-120S, FAA, Seattle Aircraft Certification Office, 
1601 Lind Avenue, SW., Renton, Washington; telephone (425) 227-2774; 
fax (425) 227-1181.

[[Page 38494]]

SUPPLEMENTARY INFORMATION:

Comments Invited

    Interested persons are invited to participate in the making of the 
proposed rule by submitting such written data, views, or arguments as 
they may desire. Communications shall identify the Rules Docket number 
and be submitted in triplicate to the address specified above. All 
communications received on or before the closing date for comments, 
specified above, will be considered before taking action on the 
proposed rule. The proposals contained in this notice may be changed in 
light of the comments received.
    Comments are specifically invited on the overall regulatory, 
economic, environmental, and energy aspects of the proposed rule. All 
comments submitted will be available, both before and after the closing 
date for comments, in the Rules Docket for examination by interested 
persons. A report summarizing each FAA-public contact concerned with 
the substance of this proposal will be filed in the Rules Docket.
    Commenters wishing the FAA to acknowledge receipt of their comments 
submitted in response to this notice must submit a self-addressed, 
stamped postcard on which the following statement is made: ``Comments 
to Docket Number 97-NM-03-AD.'' The postcard will be date stamped and 
returned to the commenter.

Availability of NPRMs

    Any person may obtain a copy of this NPRM by submitting a request 
to the FAA, Transport Airplane Directorate, ANM-103, Attention: Rules 
Docket No. 97-NM-03-AD, 1601 Lind Avenue, SW., Renton, Washington 
98055-4056.

Discussion

    The FAA has received reports of fatigue cracks in the vertical beam 
web and forward flange of the aft fuselage bulkhead at body station 
1183 at the left and right buttock lines 17.8. This cracking occurred 
on Boeing Model 727 series airplanes. These cracks were discovered 
during inspections conducted as part of the Supplemental Structural 
Inspection Document (SSID) program, required by AD 84-21-05, amendment 
39-4920 (49 FR 38931, October 2, 1984). Investigation revealed that 
such cracking was caused by pressurization cycles. Such fatigue 
cracking, if not detected and corrected in a timely manner, could 
result in the inability of the subject vertical beam to withstand the 
fail-safe loads, and consequent loss of cabin pressurization.

Explanation of Relevant Service Information

    The FAA has reviewed and approved Boeing Service Bulletin 727-53-
0210, dated April 1, 1993, as revised by Notice of Status Change 727-
53-0210 NSC 1, dated June 17, 1993, and Notice of Status Change 727-53-
0210 NSC 2, dated September 21, 1995. The service bulletin describes 
procedures for repetitive close visual inspections and high frequency 
eddy current (HFEC) inspections to detect cracks in the forward flange 
of the vertical beam at left and right buttock lines 17.8 from water 
lines 265 through 288 inclusive, and installation of a splice repair, 
if necessary. The service bulletin also describes procedures for 
installation of a preventative modification on the door frames in 
certain cases. Accomplishment of the splice repair and the preventative 
modification will minimize the possibility of cracks in the vertical 
beam and forward flange of the aft fuselage bulkhead. (The service 
bulletin references Boeing Service Bulletin 727-53-0055 as an 
additional source of service information for identical procedures to 
repair and modify the affected area.)

Explanation of Requirements of Proposed Rule

    Since an unsafe condition has been identified that is likely to 
exist or develop on other products of this same type design, the 
proposed AD would require repetitive close visual inspections and HFEC 
inspections to detect cracks in the forward flange of the vertical beam 
at left and right buttock lines 17.8 from water lines 265 through 288 
inclusive, and installation of a splice repair, if necessary. The 
proposed AD also would require installation of a preventative 
modification on the door frames in certain cases. The actions would be 
required to be accomplished in accordance with the service bulletin 
described previously.

Cost Impact

    There are approximately 1,560 Boeing Model 727 series airplanes of 
the affected design in the worldwide fleet. The FAA estimates that 
1,054 airplanes of U.S. registry would be affected by this proposed AD.
    It would take approximately 2 work hours per airplane to accomplish 
the proposed inspections, and that the average labor rate is $60 per 
work hour. Based on these figures, the cost impact of the inspection 
proposed by this AD on U.S. operators is estimated to be $126,480, or 
$120 per airplane, per inspection cycle.
    Should an operator be required to accomplish the proposed 
preventative modification, it would take approximately 100 work hours 
per airplane to accomplish, at an average labor rate of $60 per work 
hour. The cost of required parts could range between $910 and $1,042 
per preventative modification kit (2 kits per airplane). Based on these 
figures, the cost impact of the preventative modification proposed by 
this AD on U.S. operators is estimated to be between $7,820, and $8,084 
per airplane.
    Should an operator be required to accomplish the proposed splice 
repair, it would take approximately 148 work hours per airplane to 
accomplish, at an average labor rate of $60 per work hour. Required 
parts would cost approximately $3,545 per airplane ($1,756 for the left 
side splice repair kit and $1,789 for the right side splice repair 
kit). Based on these figures, the cost impact of the proposed splice 
repair on U.S. operators is estimated to be $12,425 per airplane.
    The cost impact figures discussed above are based on assumptions 
that no operator has yet accomplished any of the proposed requirements 
of this AD action, and that no operator would accomplish those actions 
in the future if this AD were not adopted.

Regulatory Impact

    The regulations proposed herein would not have substantial direct 
effects 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, in 
accordance with Executive Order 12612, it is determined that this 
proposal would not have sufficient federalism implications to warrant 
the preparation of a Federalism Assessment.
    For the reasons discussed above, I certify that 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) if promulgated, 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 copy of the draft 
regulatory evaluation prepared for this action is contained in the 
rules docket. A copy of it may be obtained by contacting the rules 
docket at the location provided under the caption ADDRESSES.

[[Page 38495]]

List of Subjects in 14 CFR Part 39

    Air transportation, Aircraft, Aviation safety, Safety.

The Proposed Amendment

    Accordingly, pursuant to the authority delegated to me by the 
Administrator, the Federal Aviation Administration proposes to amend 
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.


Sec. 39.13  [Amended]

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

Boeing: Docket 97-NM-03-AD.

    Applicability: All Model 727 series airplanes, certificated in 
any category.

    Note 1: This AD applies to each airplane identified in the 
preceding applicability provision, regardless of whether it has been 
otherwise 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 (d) 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 detect and correct fatigue cracking in the forward flange of 
the vertical beam of the aft pressure bulkhead, which could result 
in the inability of the subject vertical beam to withstand the fail-
safe loads, and consequent loss of cabin pressurization, accomplish 
the following:
    (a) Perform a close visual inspection and a high frequency eddy 
current (HFEC) inspection to detect cracks in the forward flange of 
the vertical beam at left and right buttock line 17.8 from water 
lines 265 through 288 inclusive, in accordance with Boeing Service 
Bulletin 727-53-0210, dated April 1, 1993, as revised by Notice of 
Status Change 727-53-0210 NSC 1, dated June 17, 1993, and Notice of 
Status Change 727-53-0210 NSC 2, dated September 21, 1995; at the 
time specified in paragraph (a)(1) or (a)(2) of this AD, as 
applicable.
    (1) For airplanes on which the preventative modification 
specified in Boeing Service Bulletin 727-53-0210, dated April 1, 
1993; or Boeing Service Bulletin 727-53-0055, Revision 6, dated 
February 28, 1986, Revision 7, dated March 5, 1987, Revision 8, 
dated December 17, 1987, or Revision 9, dated August 3, 1989; has 
not been accomplished: Inspect prior to the accumulation of 18,500 
total flight cycles, or within 1,500 flight cycles after the 
effective date of this AD, whichever occurs later.
    (2) For airplanes on which the preventative modification 
specified in Boeing Service Bulletin 727-53-0210, dated April 1, 
1993, or Boeing Service Bulletin 727-53-0055, Revision 6, dated 
February 28, 1986, Revision 7, dated March 5, 1987, Revision 8, 
dated December 17, 1987, or Revision 9, dated August 3, 1989, has 
been accomplished: Inspect prior to the accumulation of 40,000 
flight cycles since installation of preventative modification, or 
with 1,500 flight cycles after the effective date of this AD, 
whichever occurs later. Repeat the close visual and HFEC inspections 
thereafter at intervals not to exceed 6,000 flight cycles.

    Note 2: The compliance times specified in paragraphs (a)(1) or 
(a)(2) of this AD remain the same regardless of whether any splice 
repair has or has not been accomplished in accordance with any 
service bulletin specified in those paragraphs.

    (b) If no crack is detected during any inspection required by 
paragraph (a)(1) or (a)(2) of this AD, accomplish paragraph (b)(1) 
or (b)(2) of this AD.
    (1) Prior to further flight, install the preventative 
modification on the door frames in accordance with Boeing Service 
Bulletin 727-53-0210, dated April 1, 1993, as revised by Notice of 
Status Change 727-53-0210 NSC 1, dated June 17, 1993, and Notice of 
Status Change 727-53-0210 NSC 2, dated September 21, 1995. Prior to 
the accumulation of 40,000 flight cycles following accomplishment of 
the preventative modification, accomplish the close visual and HFEC 
inspections specified in paragraph (a) of this AD. Repeat those 
inspections thereafter at intervals not to exceed 6,000 flight 
cycles. Or
    (2) Repeat the close visual and HFEC inspections required by 
paragraph (a) of this AD thereafter at the intervals not to exceed 
3,000 flight cycles.
    (c) If any crack is detected during any inspection required by 
paragraph (a)(1), (a)(2), or (a)(3) of this AD, prior to further 
flight, install the splice repair kits in accordance with Boeing 
Service Bulletin 727-53-0210, dated April 1, 1993, as revised by 
Notice of Status Change 727-53-0210 NSC 1, dated June 17, 1993, and 
Notice of Status Change 727-53-0210 NSC 2, dated September 21, 1995. 
Prior to further flight following accomplishment of the splice 
repair, install the splice repair with the preventative modification 
on the door frames in accordance with the service bulletin. Prior to 
the accumulation of 40,000 flight cycles following accomplishment of 
the preventative modification, accomplish the close visual and HFEC 
inspections specified in paragraph (a) of this AD. Repeat those 
inspections thereafter at intervals not to exceed 6,000 flight 
cycles.
    (d) 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, Transport Airplane Directorate. 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 3: Information concerning the existence of approved 
alternative methods of compliance with this AD, if any, may be 
obtained from the Seattle ACO.

    (e) 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.

    Issued in Renton, Washington, on July 11, 1997.
James V. Devany,
Acting Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. 97-18936 Filed 7-17-97; 8:45 am]
BILLING CODE 4910-13-U