[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]
=======================================================================
-----------------------------------------------------------------------
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.
-----------------------------------------------------------------------
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]
BILLING CODE 4910-13-U
