AD 96-22-09

[Federal Register Volume 61, Number 216 (Wednesday, November 6, 1996)]
[Rules and Regulations]
[Pages 57311-57313]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 96-27396]


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DEPARTMENT OF TRANSPORTATION
14 CFR Part 39

[Docket No. 96-NM-09-AD; Amendment 39-9797; AD 96-22-09]
RIN 2120-AA64


Airworthiness Directives; Shorts Model SD3-60 and SD3-SHERPA 
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 Shorts Model SD3-60 and SD3-SHERPA series 
airplanes, that requires a one-time inspection to detect cracks and/or 
corrosion of the gland nut on the shock absorber of the main landing 
gear (MLG), and follow-on actions. This amendment also requires repair 
or replacement of any cracked/corroded gland nut with a new nut. This 
amendment is prompted by a report indicating that, due to stress 
corrosion and cracking of the gland nut on the shock absorber, the MLG 
collapsed on an in-service airplane. The actions specified by this AD 
are intended to detect and correct such stress corrosion or cracking in 
a timely manner and consequent reduced structural integrity of the 
gland nut, which could result in separation of the shock absorber 
cylinder from the MLG shock absorber body and consequently, lead to the 
collapse of the MLG during landing.

DATES: Effective December 11, 1996.
    The incorporation by reference of certain publications listed in 
the regulations is approved by the Director of the Federal Register as 
of December 11, 1996.


[[Page 57312]]


ADDRESSES: The service information referenced in this AD may be 
obtained from Short Brothers PLC, 2011 Crystal Drive, Suite 713, 
Arlington, Virginia 22202-3719. 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:
Greg Dunn, Aerospace Engineer, Standardization Branch, ANM-113, FAA, 
Transport Airplane Directorate, 1601 Lind Avenue, SW., Renton, 
Washington 98055-4056; telephone (206) 227-2799; 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 Shorts Model SD3-60 and 
SD3-SHERPA series airplanes was published in the Federal Register on 
July 29, 1996 (61 FR 39364). That action proposed to require a one-time 
visual and fluorescent dye penetrant inspection to detect cracks and/or 
corrosion of the gland nut on the shock absorber of the main landing 
gear (MLG), and repair or replacement of the gland nut with a new nut, 
if necessary. That action also proposed to require, after the 
inspection is completed, the application of grease to the threads of 
the cylinder and the application of sealant to the inner radius of the 
gland nut.
    Interested persons have been afforded an opportunity to participate 
in the making of this amendment. Due consideration has been given to 
the single comment received. The commenter supports the proposed rule.

Conclusion

    After careful review of the available data, including the comment 
noted above, the FAA has determined that air safety and the public 
interest require the adoption of the rule as proposed.

Cost Impact

    The FAA estimates that 88 airplanes (72 Model SD3-60 series 
airplanes and 16 Model SD3-SHERPA series airplanes) of U.S. registry 
will be affected by this AD, that it will take approximately 5 work 
hours per airplane to accomplish the required actions, and that the 
average labor rate is $60 per work hour. Based on these figures, the 
cost impact of the AD on U.S. operators is estimated to be $26,400, or 
$300 per airplane.
    The 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.

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:

96-22-09  Short Brothers, PLC: Amendment 39-9797. Docket 96-NM-09-
AD.

    Applicability: Model SD3--60 and Model SD3-SHERPA series 
airplanes, as listed in Shorts Service Bulletin SD360-32-34 (for 
Model SD3-60 series airplanes), and Shorts Service Bulletin SD3 
SHERPA-32-2 (for Model SD3-SHERPA series airplanes), both dated 
September 22, 1995; 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 detect and correct stress corrosion or cracking of the gland 
nut on the shock absorber of the main landing gear (MLG) in a timely 
manner and consequent reduced structural integrity of the nut, which 
could result in separation of the shock absorber cylinder from the 
MLG shock absorber body and, consequently, lead to the collapse of 
the MLG during landing; accomplish the following:
    (a) Within 90 days after the effective date of this AD, perform 
a one-time visual and fluorescent dye penetrant inspection to detect 
cracks and/or corrosion of the gland nut on the shock absorber of 
the MLG, in accordance with Shorts Service Bulletin SD360-32-34 (for 
Model SD3-60 series airplanes), and Shorts Service Bulletin SD3 
SHERPA-32-2 (for Model SD3-SHERPA series airplanes), both dated 
September 22, 1995, as applicable.

    Note 2: Short Service Bulletins SD360-32-34 and SD3 SHERPA-32-2 
reference Messier-Dowty Service Bulletin 32-78SD, dated July 19, 
1995, as an additional source of service information.

    (1) If no crack and/or corrosion is detected, no further action 
is required by paragraph (a) of this AD.
    (2) If no crack is detected, but corrosion is detected that is 
within the limits specified in the service bulletin, prior to 
further flight, repair the gland nut in accordance with the 
applicable service bulletin.
    (3) If any crack is detected, or if any corrosion is detected 
that is outside the limits specified in the service bulletin, prior 
to further flight, replace the gland nut with a new gland nut, in 
accordance with the applicable service bulletin.
    (b) Following accomplishment of paragraph (a) of this AD, prior 
to further flight, apply grease to the threads of the cylinder, and 
apply sealant to the inner radius of the gland nut, in accordance 
with Shorts Service Bulletin SD360-32-34 (for Model SD3-60 series 
airplanes), and Shorts Service Bulletin SD3 SHERPA-32-2 (for Model 
SD3-SHERPA series airplanes), both dated September 22, 1995, as 
applicable.
    (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, Manager,

[[Page 57313]]

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, is 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 actions shall be done in accordance with Shorts Service 
Bulletin SD360-32-34, dated September 22, 1995, and Shorts Service 
Bulletin SD3 SHERPA-32-2, dated September 22, 1995, 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 Short Brothers PLC, 2011 Crystal 
Drive, Suite 713, Arlington, Virginia 22202-3719. 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 December 11, 1996.

    Issued in Renton, Washington, on October 18, 1996.
Darrell M. Pederson,
Acting Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. 96-27396 Filed 11-5-96; 8:45 am]
BILLING CODE 4910-13-P