[Federal Register Volume 62, Number 35 (Friday, February 21, 1997)]
[Rules and Regulations]
[Pages 7924-7926]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 97-3695]


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DEPARTMENT OF TRANSPORTATION
14 CFR Part 39

[Docket No. 96-NM-32-AD; Amendment 39-9932; AD 97-04-08]
RIN 2120-AA64


Airworthiness Directives; Fokker Model F27 Mark 050, 100, 200, 
300, 400, 600, and 700 Series Airplanes

AGENCY: Federal Aviation Administration, DOT.

ACTION: Final rule.

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SUMMARY: This amendment adopts a new airworthiness directive (AD), 
applicable to certain Fokker Model F27 Mark 050, 100, 200, 300, 400, 
600, and 700 series airplanes, that requires an ultrasonic inspection 
to determine if certain tubes are installed in the drag stay units of 
the main landing gear (MLG), and various follow-on actions. This 
amendment is prompted by a report that, due to fatigue cracking from an 
improperly machined radius of the inner tube, a drag stay broke, and, 
consequently, lead to the collapse of the MLG during landing. The 
actions specified by this AD are intended to prevent such fatigue 
cracking, which could result in reduced structural integrity or 
collapse of the MLG.

DATES: Effective March 28, 1997.

    The incorporation by reference of certain publications listed in 
the regulations is approved by the Director of the Federal Register as 
of March 28, 1997.
ADDRESSES: The service information referenced in this AD may be 
obtained from Fokker Services B.V., Technical Support Department, P.O. 
Box 75047, 1117 ZN Schiphol Airport, The Netherlands. 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 F27 Mark 050, 
100, 200, 300, 400, 600, and 700 series airplanes was published in the 
Federal Register on October 31, 1996 (61 FR 56170). That action 
proposed to require an ultrasonic inspection to determine if certain 
tubes are installed on the DSUs of the MLG, and various follow-on 
actions.
    Interested persons have been afforded an opportunity to participate 
in the making of this amendment. No comments were submitted in response 
to the proposal or the FAA's determination of the cost to the public.

Conclusion

    The FAA has determined that air safety and the public interest 
require the adoption of the rule as proposed.

[[Page 7925]]

Cost Impact

    The FAA estimates that 10 Model F27 Mark 050, 100, 200, 300, 400, 
600, and 700 series airplanes of U.S. registry will be affected by this 
AD, that it will take approximately 2 work hours per airplane to 
accomplish the required inspection, at an average labor rate of $60 per 
work hour. Based on these figures, the cost impact of the inspection 
required by this AD on U.S. operators is estimated to be $1,200, or 
$120 per airplane. This cost impact figure 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.
    There currently are no Fokker Model F27 Mark 050 series airplanes 
on the U.S. Register that will require the inspection of the DSU. The 
only airplanes that will require this inspection are currently operated 
by non-U.S. operators under foreign registry; therefore, they are not 
directly affected by this AD action. However, the FAA considers that 
inclusion of these airplanes in the applicability of this rule is 
necessary to ensure that the unsafe condition is addressed in the event 
that any of these airplanes are imported and placed on the U.S. 
Register in the future.

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:

97-04-08  Fokker: Amendment 39-9932. Docket 96-NM-32-AD.

    Applicability: Model F27 Mark 050, 100, 200, 300, 400, 600, and 
700 series airplanes, equipped with Dowty Aerospace main landing 
gear (MLG) drag stay units (DSU) having part number (P/N) 200684001, 
200261001, or 200485001; 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 (e) 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 in drag stay unit of the MLG, which 
could result in reduced structural integrity or collapse of the MLG, 
accomplish the following:
    (a) Within 60 days after the effective date of this AD, perform 
an ultrasonic inspection to determine if a tube having part number 
(P/N) 200485300 with a straight bore, or a tube having P/N 200259300 
with a change in section (stepped bore), is installed on the DSU's 
of the MLG, in accordance with Fokker Service Bulletin F27/32-167, 
dated November 19, 1993 (for Model F27 Mark 100, 200, 300, 400, 600, 
and 700 series airplanes), or Fokker Service Bulletin SBF50-32-029, 
dated February 11, 1994 (for Model F27 Mark 050 series airplanes), 
as applicable.

    Note 2: Fokker Service Bulletin F27/32-167 references Dowty 
Service Bulletins 23-169B and 32-82W; and Fokker Service Bulletin 
SBF50-32-029 references Dowty Service Bulletin F50-32-50; as 
additional sources of service information for procedures to 
accomplish the actions specified in this AD.

    (b) For all airplanes: If any tube having P/N 200485300 with a 
straight bore is found installed during the inspection required by 
paragraph (a) of this AD, prior to further flight, reidentify it in 
accordance with Fokker Service Bulletin F27/32-167, dated November 
19, 1993 (for Model F27 Mark 100, 200, 300, 400, 600, and 700 series 
airplanes); or Fokker Service Bulletin SBF50-32-029, dated February 
11, 1994 (for Model F27 Mark 050 series airplanes); as applicable.
    (c) For Model F27 Mark 50 series airplanes: If any tube having 
P/N 200259300 with a change in section (stepped bore) is found 
installed during the inspection required by paragraph (a) of this 
AD, prior to further flight, replace the DSU with a new or 
serviceable DSU having P/N 200684004, in accordance with Fokker 
Service Bulletin SBF50-32-029, dated February 11, 1994.
    (d) For F27 Mark 100, 200, 300, 400, 600, and 700 series 
airplanes: If any tube having P/N 200259300 with a change in section 
(stepped bore) is found installed during the inspection required by 
paragraph (a) of this AD, prior to further flight, re-identify the 
DSU in accordance with Fokker Service Bulletin F27/32-167, dated 
November 19, 1993. Following accomplishment of the re-
identification, prior to further flight, perform an ultrasonic 
inspection to detect cracks in the re-identified DSU's, in 
accordance with that service bulletin.
    (1) For airplanes equipped with any DSU re-identified as P/N 
200684003, 200261003, or 200485003: If no crack is detected, no 
further action is required by this AD.
    (2) For airplanes equipped with any DSU re-identified as P/N 
200684002, 200261002, or 200485002: If no crack is detected, 
accomplish paragraphs (c)(2)(i) and (c)(2)(ii) of this AD.
    (i) Repeat the ultrasonic inspection required by paragraph (d) 
of this AD thereafter at intervals not to exceed 1,500 flight 
cycles.
    (ii) At the next MLG overhaul, but no later than 12,000 flight 
cycles after the effective date of this AD, rework and re-identify 
the DSU again, or replace the DSU with a re-identified DSU, in 
accordance with the service bulletin. Accomplishment of the rework 
and re-identification, or replacement constitutes terminating action 
for the repetitive inspection requirements of this AD.
    (3) If any crack signal indication of any DSU tube is greater 
than or equal to 80 percent, prior to further flight, replace the 
DSU with a re-identified DSU, in accordance with the service 
bulletin.
    (4) If any crack signal indication of any DSU tube is greater 
than or equal to 1 percent but less than 80 percent, accomplish 
paragraphs (d)(4)(i) and (d)(4)(ii) of this AD.
    (i) Repeat the ultrasonic inspection required by paragraph (d) 
of this AD thereafter at intervals not to exceed 1,500 flight 
cycles.
    (ii) At the next MLG overhaul, but no later than 12,000 flight 
cycles after the effective

[[Page 7926]]

date of this AD, replace the DSU with a re-identified DSU, in 
accordance with the service bulletin. Accomplishment of the 
replacement constitutes terminating action for the repetitive 
inspection requirements of this AD.
    (e) 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, Manager, Standardization Branch, 
ANM-113, 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, 
Standardization Branch, ANM-113.

    Note 3: Information concerning the existence of approved 
alternative methods of compliance with this AD, if any, may be 
obtained from the Standardization Branch, ANM-113.

    (f) 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.
    (g) The actions shall be done in accordance with Fokker Service 
Bulletin F27/32-167, dated November 19, 1993; or Fokker Service 
Bulletin SBF50-32-029, dated February 11, 1994; as applicable. 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 Services B.V., Technical 
Support Department, P.O. Box 75047, 1117 ZN Schiphol Airport, The 
Netherlands. 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.
    (h) This amendment becomes effective on March 28, 1997.

    Issued in Renton, Washington, on February 7, 1997.
Darrell M. Pederson,
Acting Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. 97-3695 Filed 2-20-97; 8:45 am]
BILLING CODE 4910-13-U