[Federal Register Volume 61, Number 112 (Monday, June 10, 1996)]
[Rules and Regulations]
[Pages 29277-29279]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 96-14382]



-----------------------------------------------------------------------

[[Page 29278]]


DEPARTMENT OF TRANSPORTATION
14 CFR Part 39

[Docket No. 95-NM-164-AD; Amendment 39-9662; AD 96-12-19]
RIN 2120-AA64


Airworthiness Directives; Fokker Model F28 Mark 0100 Series 
Airplanes

AGENCY: Federal Aviation Administration, DOT.

ACTION: Final rule.

-----------------------------------------------------------------------

SUMMARY: This amendment adopts a new airworthiness directive (AD), 
applicable to certain Fokker Model F28 Mark 0100 series airplanes, that 
requires installation of reinforcement plates under each hook latch 
fitting on the frame of each large cargo door. For some airplanes, this 
amendment requires inspections to detect cracking in the area around 
each hook latch fitting, and repair, if necessary. This amendment is 
prompted by the results of stress analyses and destructive tests which 
revealed that fatigue-related cracking may develop in the vicinity of 
the hook latch fittings on the frame of the large cargo doors. The 
actions specified by this AD are intended to prevent reduced structural 
integrity of the frames of the cargo door due to fatigue cracking, 
which may lead to the cargo door(s) opening while the airplane is in 
flight.

DATES: Effective July 15, 1996. The incorporation by reference of 
certain publications listed in the regulations is approved by the 
Director of the Federal Register as of July 15, 1996.
ADDRESSES: The service information referenced in this AD may be 
obtained from Fokker Aircraft USA, Inc., 1199 North Fairfax Street, 
Alexandria, Virginia 22314. 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: Ruth Harder, Aerospace Engineer, 
Standardization Branch, ANM-113, FAA, Transport Airplane Directorate, 
1601 Lind Avenue, SW., Renton, Washington 98055-4056; telephone (206) 
227-1721; fax (206) 227-1149.

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 Fokker Model F28 Mark 0100 
series airplanes was published in the Federal Register on January 19, 
1996 (61 FR 1294). That action proposed to require installation of 
reinforcement plates under each hook latch fitting on the frame of each 
large cargo door. For some airplanes, the action proposed to require 
inspections to detect cracking in the area around each hook latch 
fitting, and repair, if necessary.
    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

    Two commenters support the proposed rule.

Request to Extend Proposed Compliance Time for Installation

    One commenter requests that paragraph (a) of the rule be revised to 
extend the compliance time for accomplishing the installation. The 
commenter requests that the proposed compliance threshold of 11,000 
flight cycles be extended to 16,000 flight cycles, and that the 
proposed ``grace period'' of 500 flight cycles (after the effective 
date of the AD) be extended to 2,200 flight cycles. This commenter, a 
U.S. operator, requests this extension so that its remaining fleet of 
affected airplanes can be modified during a regularly scheduled ``Q'' 
check (which occurs at approximately 16,000 flight cycles), and so that 
this operator can avoid special scheduling of airplanes, which would 
entail considerable expense over that estimated by the FAA's cost 
impact analysis. This commenter considers the extension justified 
because:
    1. No cracks have been found on any of the airplanes that it has 
modified so far, which have accumulated an average of 13,755 total 
flight cycles; and
    2. The proposed compliance threshold was based on only test data 
and not on in-service experience.
    The FAA does not concur with the commenter's request to extend the 
compliance threshold. The proposed compliance time was developed not 
only in consideration of the urgency of the safety implications, but in 
consideration of normal maintenance schedules for timely accomplishment 
of the modification, and the recommendations of both the airplane 
manufacturer and the Netherlands airworthiness authority. The FAA 
determined that 11,000 flight cycles is the maximum acceptable 
threshold for accomplishing the installation without the need for 
additional inspections. Any cracking that may develop in the subject 
area during the period up to the accumulation of 11,000 total flight 
cycles on the airplane can be fully repaired with the accomplishment of 
the installation described in Fokker Service Bulletin SBF100-52-050, 
Revision 1. However, if cracks are not detected and repaired by the 
11,000-flight cycle threshold, they could grow to lengths such that the 
installation would not be sufficient to ensure the long-term structural 
integrity of the area associated with the cargo door frame, and may 
even necessitate the replacement of the complete door frame.
    In addition, if the compliance threshold were extended beyond the 
11,000-flight cycle threshold to 16,000 flight cycles as requested by 
the commenter, the FAA would find it necessary to require operators to 
conduct inspections (to detect cracking) during the extended period. 
Each inspection of the area would take approximately 4.5 hours to 
accomplish, which is the same amount of time required to accomplish the 
installation itself. Therefore, delaying the threshold for the 
installation to 16,000 flight cycles by performing necessary repetitive 
inspections in the meantime would not reduce operators' workload or 
costs.
    However, the FAA does concur with the commenter's request to extend 
the ``grace period.'' The FAA has determined that the proposed ``grace 
period'' of 500 flight cycles may be extended to 1,200 flight cycles, 
without the need for repetitive inspections beyond the inspection 
specified in paragraph (b) of the final rule. The FAA bases this 
determination not only on the safety implications associated with the 
unsafe condition, but on recent in-service data and inspection results. 
Accordingly, the FAA has revised paragraph (a) of the final rule to 
specify a ``grace period'' of 1,200 flight cycles.

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

    The FAA estimates that 100 airplanes of U.S. registry will be 
affected by this AD, that it will take approximately 4.5 work hours per 
airplane to accomplish the required installation, and that the average 
labor rate is $60 per work hour. Required parts will cost approximately 
$10,000 per airplane. Based on these figures, the cost impact of the AD 
on

[[Page 29279]]

U.S. operators is estimated to be $1,027,000, or $10,270 per airplane.
    The FAA estimates that it would take approximately 4.5 work hours 
per airplane to accomplish the required inspection (that is required 
for certain airplanes), and that the average labor rate is $60 per work 
hour. Based on these figures, the cost impact of the required 
inspection on U.S. operators is estimated to be $270 per airplane.
    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. However, the FAA has been advised 
that the required installation already has been accomplished on at 
least 8 affected airplanes; therefore, the future cost impact of this 
AD is reduced by at least $82,160.

Regulatory Impact

    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. 106(g), 40113, 44701.


Sec. 39.13  [Amended]

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

96-12-19  Fokker: Amendment 39-9662. Docket 95-NM-164-AD.

    Applicability: Model F28 Mark 0100 series airplanes; as listed 
in Fokker Service Bulletin SBF100-52-050, Revision 1, dated 
September 14, 1994; 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 (c) 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 reduced structural integrity of the frame of the 
large cargo door, which may lead to the cargo door(s) opening while 
the airplane is in flight, accomplish the following:
    (a) Prior to the accumulation of 11,000 total flight cycles, or 
within 1,200 flight cycles after the effective date of this AD, 
whichever occurs later, install two reinforcement plates under each 
hook latch fitting on the frame of each large cargo door, in 
accordance with the Accomplishment Instructions of Fokker Service 
Bulletin SBF100-52-050, Revision 1, dated September 14, 1994.
    (b) For airplanes that have accumulated 11,000 or more total 
flight cycles at the time of compliance with paragraph (a) of this 
AD: Concurrent with the accomplishment of the requirements of 
paragraph (a) of this AD, perform an inspection to detect cracking 
in the area around each hook latch fitting on the frame of each 
large cargo door, in accordance with a method approved by the 
Manager, Standardization Branch, ANM-113, FAA, Transport Airplane 
Directorate.
    (1) If no cracking is detected, no further action is required by 
this paragraph.
    (2) If any cracking is detected, prior to completing the 
requirements of paragraph (a) of this AD, repair in accordance with 
a method approved by the Manager, Standardization Branch, ANM-113.
    (c) 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, Standardization Branch, ANM-113. 
Operators shall submit their requests through an appropriate FAA 
Principal Maintenance Inspector, who may add comments and then send 
it to the Manager, Standardization Branch, ANM-113.

    Note 2: Information concerning the existence of approved 
alternative methods of compliance with this AD, if any, may be 
obtained from the Standardization Branch, ANM-113.

    (d) 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.
    (e) The installation shall be done in accordance with Fokker 
Service Bulletin SBF100-52-050, Revision 1, dated September 14, 
1994. 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 Fokker Aircraft USA, Inc., 1199 
North Fairfax Street, Alexandria, Virginia 22314. 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.
    (f) This amendment becomes effective on July 15, 1996.

    Issued in Renton, Washington, on June 3, 1996.
Darrell M. Pederson,
Acting Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. 96-14382 Filed 6-7-96; 8:45 am]
BILLING CODE 4910-13-U