[Federal Register Volume 59, Number 117 (Monday, June 20, 1994)]
[Unknown Section]
[Page 0]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 94-14361]


[[Page Unknown]]

[Federal Register: June 20, 1994]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 93-NM-173-AD; Amendment 39-8940; AD 94-12-12]

 

Airworthiness Directives; Boeing Model 737-300 Series Airplanes 
Equipped With a Pemco Aeroplex Main Deck Cargo Door That Has Been 
Modified in Accordance With Supplemental Type Certificate (STC) 
SA2969S0

AGENCY: Federal Aviation Administration, DOT.

ACTION: Final rule.

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SUMMARY: This amendment adopts a new airworthiness directive (AD), 
applicable to certain Boeing Model 737-300 series airplanes, that 
requires replacement of the forward and aft hinge shims and the lower 
hinge fairings of the main cargo door with new shims and fairings. This 
amendment is prompted by reports of a slight separation between the end 
hinge shims and the cargo door; this separation can cause bending loads 
on the fasteners. The actions specified by this AD are intended to 
prevent fatigue failure of the hinge fasteners, loss of structural 
integrity of the cargo door hinge, possible loss of the cargo door, and 
subsequent rapid decompression of the airplane.

DATES: Effective July 20, 1994.
    The incorporation by reference of certain publications listed in 
the regulations is approved by the Director of the Federal Register as 
of July 20, 1994.

ADDRESSES: The service information referenced in this AD may be 
obtained from Pemco Aeroplex Inc., P.O. Box 2287, Birmingham, Alabama 
34201. 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 FAA, Small 
Airplane Directorate, Atlanta Aircraft Certification Office, suite 
210C, 1669 Phoenix Parkway, Atlanta, Georgia; or at the Office of the 
Federal Register, 800 North Capitol Street NW., suite 700, Washington, 
DC.

FOR FURTHER INFORMATION CONTACT: Curtis Jackson, Aerospace Engineer, 
Airframe Branch, ACE-120A, FAA, Small Airplane Directorate, Atlanta 
Aircraft Certification Office, suite 210C, 1669 Phoenix Parkway, 
Atlanta, Georgia 30349; telephone (404) 991-2910; fax (404) 991-3606.

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 737-300 series 
airplanes was published in the Federal Register on December 6, 1993 (58 
FR 64198). That action proposed to require replacement of the forward 
and aft hinge shims and the lower hinge fairings of the main cargo door 
with new shims and fairings.
    Interested persons have been afforded an opportunity to participate 
in the making of this amendment. Due consideration has been given to 
the comments received. -
    Two commenters support the proposal. -
    One commenter considers there is no justification for issuing the 
proposed rule, since most of the affected airplanes have already been 
modified in accordance with the proposed requirements. The FAA does not 
concur. Although the commenter has provided the FAA with data 
indicating that the proposed modification has been accomplished on all 
airplanes currently on the U.S. Register, this data did not provide 
positive indication, verified by FAA personnel, that the modification 
had been accomplished on airplanes not currently on the U.S. Register. 
Should one of these affected airplanes be imported to the U.S. in the 
future, this AD is necessary in order to ensure that the required 
actions are accomplished on the airplane prior to it being placed on 
the U.S. Register. Further, as is indicated in the final rule, 
operators are given ``credit'' for previously accomplishing the 
requirements of the rule; therefore, no further action is required on 
the part of the operators in these cases. -
    Another commenter contends that there is no justification for the 
proposed AD, since the Supplemental Type Certificate (STC) holder 
(Pemco) has not indicated that the referenced Pemco service bulletin 
concerns an airworthiness problem. The commenter states that Pemco has 
portrayed the service bulletin as addressing only a reliability 
problem. The FAA does not concur. In developing this AD action, the FAA 
reviewed the relevant data which indicated that this STC door design 
allows slight separation between the end hinge shims and the cargo door 
during pressurization cycles; such separation can cause increased 
bending loads on the door hinge fasteners. The FAA determined that this 
situation constitutes an unsafe condition since, if not corrected, it 
could lead to fatigue failure of the hinge fasteners, loss of 
structural integrity of the cargo door hinge, possible loss of the 
cargo door, and subsequent rapid decompression of the airplane. 
Regardless of whether or not the wording in the service bulletin 
describes the procedures specified within it as addressing an 
airworthiness problem, the FAA finds that accomplishment of those 
procedures will serve to eliminate the identified unsafe condition.
    One commenter suggests that the wording that identifies the 
location of the affected cargo door be clarified. The commenter points 
out that the notice identified this door as the ``main cargo door;'' 
however, a more correct identification would be ``main deck cargo 
door.'' The FAA concurs and has changed the pertinent wording in the 
final rule accordingly. -
    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 change previously 
described. The FAA has determined that this change will neither 
increase the economic burden on any operator nor increase the scope of 
the AD.
    There are approximately 11 Model 737-300 series airplanes of the 
affected design in the worldwide fleet. The FAA estimates that 2 
airplanes of U.S. registry will be affected by this AD, that it will 
take approximately 280 work hours per airplane to accomplish the 
required actions, and that the average labor rate is $55 per work hour. 
Required parts will be provided by Pemco Aeroplex at no cost to the 
operators. Based on these figures, the total cost impact of the AD on 
U.S. operators is estimated to be $30,800, or $15,400 per airplane. -
    The total cost impact figure discussed above is 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. However, the 
FAA has been advised that all affected U.S.-registered airplanes have 
been modified previously in accordance with the requirements of this 
AD. Therefore, there is no cost impact of this AD on U.S. operators. -
    The regulations adopted herein will 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 final 
rule does not have sufficient federalism implications to warrant the 
preparation of a Federalism Assessment. -
    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. App. 1354(a), 1421 and 1423; 49 U.S.C. 
106(g); and 14 CFR 11.89.


Sec. 39.13  [Amended] -

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

94-12-12 Boeing: Amendment 39-8940. Docket 93-NM-173-AD.

    -Applicability: Boeing Model 737-300 series airplanes, as listed 
in Pemco Aeroplex Inc. Service Bulletin 737-52-0012, dated February 
9, 1993; equipped with a Pemco Aeroplex main deck cargo door that 
has been modified in accordance with Supplemental Type Certificate 
(STC) SA2969S0; certificated in any category. -
    Compliance: Required as indicated, unless accomplished 
previously. -
    To prevent fatigue failure of the hinge fasteners, loss of 
structural integrity of the cargo door hinge, possible loss of the 
cargo door, and subsequent rapid decompression of the airplane, 
accomplish the following: -
    (a) Within 12,000 landings from the date of STC SA2969S0 
installation or within 6 months after the effective date of this AD, 
whichever occurs later, replace the forward and aft hinge shims and 
the lower hinge fairings of the main deck cargo door, with new shims 
and fairings, in accordance with Pemco Aeroplex Inc. Service 
Bulletin 737-52-0012, dated February 9, 1993. -
    (b) 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, Atlanta Aircraft Certification 
Office (ACO), FAA, Small 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, Atlanta ACO.

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

    -(c) 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. -
    (d) The replacement shall be done in accordance with Pemco 
Aeroplex Inc. Service Bulletin 737-52-0012, dated February 9, 1993. 
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 Pemco Aeroplex Inc. Service Bulletin 
737-52-0012, dated February 9, 1993. Copies may be inspected at the 
FAA, Transport Airplane Directorate, 1601 Lind Avenue, SW., Renton, 
Washington; or at the FAA, Small Airplane Directorate, Atlanta 
Aircraft Certification Office, Suite 210C, 1669 Phoenix Parkway, 
Atlanta, Georgia; or at the Office of the Federal Register, 800 
North Capitol Street, NW., suite 700, Washington, DC. -
    (e) This amendment becomes effective on July 20, 1994..
    Issued in Renton, Washington, on June 8, 1994.
Darrell M. Pederson,
Acting Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. 94-14361 Filed 6-17-94; 8:45 am]
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