AD 97-07-11

[Federal Register Volume 62, Number 62 (Tuesday, April 1, 1997)]
[Rules and Regulations]
[Pages 15375-15378]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 97-8248]


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DEPARTMENT OF TRANSPORTATION
14 CFR Part 39

[Docket No. 95-CE-10-AD; Amendment 39-9985; AD 97-07-11]


Airworthiness Directives; Jetstream Aircraft Limited HP137 Mk1, 
Jetstream Series 200, and Jetstream Models 3101 and 3201 Airplanes

AGENCY: Federal Aviation Administration, DOT.

ACTION: Final rule.

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SUMMARY: This amendment supersedes Airworthiness Directive (AD) 81-20-
01, which currently requires repetitively inspecting the nose landing 
gear (NLG) actuator support structure and the front pressure bulkhead 
for cracks on Jetstream Aircraft Limited (JAL) HP137 Mk1 and Jetstream 
series 200 airplanes, and replacing any cracked part. This AD retains 
the repetitive inspections required by AD 81-20-01; requires 
repetitively inspecting the NLG retraction jack upper mounting fitting 
and attachment hardware for security bolt failure and for bolts with 
improper torque levels on the HP137 Mk1, Jetstream series 200, and 
Jetstream Model 3101 airplanes, and requires replacing any failed 
security bolts and adjusting any bolt with an improper torque level; 
and requires modifying the NLG retraction jack on all affected 
airplanes, as terminating action for the repetitive inspections. This 
AD results from reports of NLG jack mounting fitting failures on 
several of the affected airplanes, and the Federal Aviation 
Administration's policy on aging commuter-class aircraft. The actions 
specified by this AD are intended to prevent failure of the NLG caused 
by a cracked NLG actuator support structure or cracked front pressure 
bulkhead, which, if not detected and corrected, could lead to nose gear 
collapse and damage to the airplane.

DATES: Effective May 23, 1997.
    The incorporation by reference of certain publications listed in 
the regulations is approved by the Director of the Federal Register as 
of May 23, 1997.

ADDRESSES: Service information that applies to this AD may be obtained 
from Jetstream Aircraft Limited, Prestwick International Airport, 
Ayrshire, KA9 2RW, Scotland, telephone (44-292) 79888; facsimile (44-
292) 79703; or Jetstream Aircraft Inc., Librarian, P.O. Box 16029, 
Dulles International Airport, Washington, D.C. 20041-6029; telephone 
(703) 406-1161; facsimile (703) 406-1469. This information may also be 
examined at the Federal Aviation Administration (FAA), Central Region, 
Office of the Assistant Chief Counsel, Attention: Rules Docket No. 95-
CE-10-AD, Room 1558, 601 E. 12th Street, Kansas City, Missouri 64106; 
or at the Office of the Federal Register, 800 North Capitol Street, 
NW., suite 700, Washington, DC.

FOR FURTHER INFORMATION CONTACT: Mr. Tom Rodriguez, Program Manager, 
Brussels Aircraft Certification Division, FAA, Europe, Africa, and 
Middle East Office, c/o American Embassy, B-1000 Brussels, Belgium; 
telephone (32 2) 508.2715; facsimile (32 2) 230.6899; or Mr. S.M. 
Nagarajan, Project Officer, Small Airplane Directorate, Aircraft 
Certification Service, FAA, 1201 Walnut, suite 900, Kansas City, 
Missouri 64106; telephone (816) 426-6932; facsimile (816) 426-2169.

SUPPLEMENTARY INFORMATION:

Events Leading to the Issuance of This AD

    A proposal to amend part 39 of the Federal Aviation Regulations (14 
CFR part 39) to include an AD that would apply to certain JAL HP137 
Mk1, Jetstream series 200, and Jetstream Models 3101 and 3201 airplanes 
that do not have an improved design attachment bracket (Modification JM 
5285) installed for the nose landing gear (NLG) retraction jack was 
published in the Federal Register as a notice of proposed rulemaking 
(NPRM) on September 19, 1995 (60 FR 48429). The NPRM proposed to 
supersede AD 81-20-01 with a new AD that would:

--Retain the requirement contained in AD 81-20-01 of repetitively 
inspecting (using dye penetrant methods) the NLG actuator support 
structure and the front pressure bulkhead for cracks on JAL HP137 Mk1 
and Jetstream series 200 airplanes that do not have the front pressure 
bulkhead strengthened in the area of the NLG jack attachment fitting 
(Modification No. 5127), and replacing or repairing any cracked NLG 
actuator support structure or cracked front pressure bulkhead. 
Accomplishment of the proposed inspections as specified in the NPRM 
would be in accordance with Jetstream Service Bulletin (SB) No. 6/5, 
dated September 4, 1978.
--Require repetitively inspecting the NLG retraction jack upper 
mounting fitting and attachment hardware for security bolt failure and 
bolts with improper torque levels on the HP137 Mk1, Jetstream series 
200, and Jetstream Model 3101 airplanes, and replacing any failed 
security bolts and adjusting any bolt with an improper torque level. 
Accomplishment of the proposed inspections as specified in the NPRM 
would be in accordance with Jetstream SB 53-A-JA870510, which consists 
of the following pages and revision levels:

------------------------------------------------------------------------
              Pages                 Revision level           Date       
------------------------------------------------------------------------
3, 5, 6, 8, 9, and 10...........  Original Issue....  May 26, 1987.     
1, 2, 4 and 7...................  Revision 1........  Nov. 10, 1987.    
------------------------------------------------------------------------

--Require modifying the NLG retraction jack on the HP137 Mk1, Jetstream 
series 200, and Jetstream Models 3101 and 3201 airplanes, as 
terminating action for all the repetitive inspections, including the 
inspections referenced in the Model 3201 maintenance manual. 
Accomplishment of the proposed modification as specified in the NPRM 
would be in accordance with Jetstream SB 53-JM 5285, which consists of 
the following pages and revision levels:

------------------------------------------------------------------------
              Pages                 Revision level           Date       
------------------------------------------------------------------------
1 and 4.........................  Revision 2........  Nov. 12, 1992.    
2, 3, and 5 through 26..........  Revision 1........  May 18, 1992.     
------------------------------------------------------------------------

    Interested persons have been afforded an opportunity to participate 
in the making of this amendment. One comment was received regarding the 
NPRM. An analysis of the comment follows:
    The commenter provides information on the company's fleet size and 
the estimated projection on when the proposed replacement would be 
mandatory on the affected airplanes in the company's fleet, as well as 
the number of repetitive inspections that would be required during that 
time. The commenter states that it is more economical for the company 
to incorporate the modification on its entire fleet immediately rather 
than continuing to repetitively inspect. The commenter also mentions 
that parts to

[[Page 15376]]

modify the NLG retraction jack cost $1,800 instead of $1,600. The FAA 
concurs with the correction to the cost and has incorporated this 
change.
    As written, the original NPRM would have allowed continued flight 
if cracks are found in the front pressure bulkhead membrane or actuator 
support structure when the cracks do not exceed certain limits. Since 
issuing that NPRM, the FAA established a policy to disallow airplane 
operation when known cracks exist in primary structure, unless the 
ability to sustain ultimate load with these cracks is proven. The front 
pressure bulkhead and actuator support structure are considered primary 
structure, and the FAA has not received any analysis to prove that 
ultimate load can be sustained with cracks in this area.
    For this reason, the FAA has determined that the crack limits 
contained in the NPRM should be eliminated and that AD action should be 
taken to require immediate replacement of any cracked front pressure 
bulkhead membrane or actuator support structure. Since revising the 
proposed AD to require immediate replacement of any cracked part went 
beyond the scope of what was presented in the original NPRM, the FAA 
published a supplemental NPRM in the Federal Register on October 21, 
1996 (61 FR 54582), in order to give the public an opportunity to 
comment on the proposal.
    Interested persons were again afforded an opportunity to 
participate in the making of this amendment. No comments were received 
regarding the substance of the supplemental NPRM or the FAA's 
determination of the cost to the public.

The FAA's Determination

    After careful review of all available information related to the 
subject presented above, the FAA has determined that air safety and the 
public interest require the adoption of the AD as proposed except for 
minor editorial corrections. The FAA has determined that these minor 
corrections will not change the meaning of the AD and will not add any 
additional burden upon the public than was already proposed.

The FAA's Aging Commuter Aircraft Policy

    The actions required by this AD are consistent with the FAA's aging 
commuter aircraft policy, which briefly states that, when a 
modification exists that could eliminate or reduce the number of 
required critical inspections, the modification should be incorporated. 
This policy is based on the FAA's determination that reliance on 
critical repetitive inspections on airplanes utilized in commuter 
service carries an unnecessary safety risk when a design change exists 
that could eliminate or, in certain instances, reduce the number of 
those critical inspections. In determining what inspections are 
critical, the FAA considers (1) the safety consequences of the airplane 
if the known problem is not detected by the inspection; (2) the 
reliability of the inspection such as the probability of not detecting 
the known problem; (3) whether the inspection area is difficult to 
access; and (4) the possibility of damage to an adjacent structure as a 
result of the problem.

Cost Impact

    The FAA estimates that 170 airplanes in the U.S. registry will be 
affected by this AD, that it will take approximately 41 workhours per 
airplane to accomplish the proposed modification, and that the average 
labor rate is approximately $60 an hour. Parts cost approximately 
$1,800 per airplane. Based on these figures, the total cost impact of 
this AD on U.S. operators is estimated to be $724,200 or $4,260 per 
airplane. This figure only takes into account the cost of the 
inspection-terminating modification and does not take into account the 
cost of the repetitive inspections. The FAA has no way of determining 
the number of repetitive inspections each HP137 Mk1, Jetstream series 
200, and Jetstream Model 3101 airplane owner/operator will incur over 
the life of the airplane.
    This figure is also based on the presumption that no affected 
airplane owner/operator has accomplished the required modification. 
This AD eliminates the need for the repetitive inspections required by 
AD 81-20-01. The FAA has no way of determining the operational levels 
of each individual operator of the affected airplanes, and subsequently 
cannot determine the repetitive inspection costs that will be 
eliminated by this AD. The FAA estimates these costs to be substantial 
over the long term.
    In addition, JAL has informed the FAA that parts have been 
distributed to owners/operators to equip approximately 39 of the 
affected airplanes. Presuming that each set of parts has been installed 
on an affected airplane, the cost impact of the required modification 
upon the public is reduced $166,140 from $724,200 to $558,060.
    The intent of the FAA's aging commuter airplane program is to 
ensure safe operation of airplanes that are in commercial service 
without adversely impacting private operators. Of the approximately 170 
airplanes in the U.S. registry that will be affected by this AD, the 
FAA has determined that approximately 95 percent are operated in 
scheduled passenger service by 10 different operators.

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 copy of the final evaluation prepared for this 
action is contained in the Rules Docket. A copy of it may be obtained 
by contacting 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 USC 106(g), 40113, 44701.


Sec. 39.13  [Amended]

    2. Section 39.13 is amended by removing Airworthiness Directive 
(AD) 81-20-01, Amendment 39-4223, and by adding a new AD to read as 
follows:

97-07-11  Jetstream Aircraft Limited: Amendment 39-9985; Docket No. 
95-CE-10-AD. Supersedes AD 81-20-01, Amendment 39-4223.

    Applicability: The following airplanes, certificated in any 
category, that do not have

[[Page 15377]]

an improved design attachment bracket for the nose landing gear 
(NLG) retraction jack (Modification JM 5285) installed in accordance 
with the ACCOMPLISHMENT INSTRUCTIONS section of Jetstream Service 
Bulletin (SB) 53-JM 5285:

--HP137 Mk1 airplanes, all serial numbers;
--Jetstream Series 200 airplanes, all serial numbers;
--Jetstream Model 3101 airplanes, all serial numbers; and
--Jetstream Model 3201 airplanes, serial numbers 601 through 840.

    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 in the body of this AD, unless 
already accomplished.
    To prevent failure of the NLG caused by a cracked NLG actuator 
support structure or cracked front pressure bulkhead, which could 
lead to nose gear collapse and damage to the airplane, accomplish 
the following:

    Note 2: The paragraph structure of this AD is as follows:
Level 1: (a), (b), (c), etc.
Level 2: (1), (2), (3), etc.
Level 3: (i), (ii), (iii), etc.
Level 2 and Level 3 structures are designations of the Level 1 
paragraph they immediately follow.

    (a) For HP137 Mk1 and Jetstream series 200 airplanes that do not 
have the front pressure bulkhead strengthened in the area of the NLG 
jack attachment fitting (Modification 5127), upon accumulating 1,600 
landings or within the next 200 landings after the effective date of 
this AD, whichever occurs later, and thereafter at intervals not to 
exceed 200 landings until the modification required by paragraph (c) 
of this AD is incorporated, inspect (using dye penetrant methods) 
the nose landing gear actuator support structure, part number (P/N) 
137139C-13 and P/N 137139C-25 (or FAA-approved equivalents), and the 
membrane of the front pressure bulkhead for cracks. Accomplish the 
inspection in accordance with British Aerospace (BAe) SB No. 6/5, 
dated September 4, 1978.
    (1) Prior to further flight after any of the inspections 
required by paragraph (a) of this AD, replace any cracked P/N 
137139C-13 (or FAA-approved equivalent) NLG actuator support 
structure. This replacement does not eliminate the repetitive 
inspection requirement of this AD.
    (2) Prior to further flight after any of the inspections 
required by paragraph (a) of this AD, repair any cracked P/N 
137139C-25 (or FAA-approved equivalent) NLG actuator support 
structure in accordance with the applicable maintenance manual. This 
repair does not eliminate the repetitive inspection requirement of 
this AD.
    (3) Prior to further flight after any of the inspections 
required by paragraph (a) of this AD, repair any cracked front 
pressure bulkhead membrane in accordance with the applicable 
maintenance manual. This repair does not eliminate the repetitive 
inspection requirement of this AD.
    (b) For all HP137 Mk1, Jetstream series 200, and Jetstream Model 
3101 airplanes, upon accumulating 3,500 landings or within the next 
200 landings after the effective date of this AD, whichever occurs 
later, accomplish the following:
    (1) Inspect the NLG retraction jack upper mounting fitting and 
attaching hardware for correct installation, security bolt failure, 
and bolts with improper torque levels in accordance with Part A and 
B of the ACCOMPLISHMENT INSTRUCTIONS section of Jetstream SB 53-A-
JA870510, which incorporates the following pages and revision 
levels:

------------------------------------------------------------------------
              Pages                 Revision level           Date       
------------------------------------------------------------------------
3, 5, 6, 8, 9, and 10...........  Original Issue....  May 26, 1987.     
1, 2, 4 and 7...................  Revision 1........  November 10, 1987.
------------------------------------------------------------------------

Prior to further flight, replace any failed security bolt and adjust 
any bolt with an improper torque level in accordance with Jetstream 
SB 53-A-JA870510.
    (2) Reinspect the NLG retraction jack upper mounting fitting and 
attaching hardware for security bolt failure and bolts with improper 
torque levels in accordance with Part A of the ACCOMPLISHMENT 
INSTRUCTIONS section of Jetstream SB 53-A-JA870510 at intervals not 
to exceed 1,600 landings until the modification required by 
paragraph (c) of this AD is incorporated. Prior to further flight, 
replace any failed security bolt and adjust any bolt with an 
improper torque level in accordance with Jetstream SB 53-A-JA870510.
    (3) Reinspect the NLG retraction jack upper mounting fitting 
security nuts for correct installation in accordance with Part B of 
the ACCOMPLISHMENT INSTRUCTIONS section of Jetstream SB 53-A-
JA870510 at intervals not to exceed 200 landings until the 
modification required by paragraph (c) of this AD is incorporated. 
If correct installation is not evident, prior to further flight, 
accomplish the reinspection specified in paragraph (b)(2) of this 
AD.
    (c) For all applicable HP137 Mk1, Jetstream series 200, and 
Jetstream Models 3101 and 3201 airplanes, upon accumulating 25,000 
landings or within the next 2,000 landings after the effective date 
of this AD, whichever occurs later, install an improved design 
attachment bracket for the NLG retraction jack (Modification JM 
5285) in accordance with the ACCOMPLISHMENT INSTRUCTIONS section of 
Jetstream SB 53-JM 5285, which incorporates the following pages and 
revision levels:

------------------------------------------------------------------------
              Pages                 Revision level           Date       
------------------------------------------------------------------------
1 and 4.........................  Revision 2........  November 12, 1992.
2, 3, and 5 through 26..........  Revision 1........  May 18, 1992.     
------------------------------------------------------------------------

    (1) Incorporating Modification JM 5285 on Jetstream HP137 Mk1, 
Jetstream series 200, and Jetstream Model 3101 airplanes terminates 
the repetitive inspection requirement of this AD.
    (2) Incorporating Modification JM 5285 on Jetstream Model 3201 
airplanes eliminates the need for the repetitive inspections 
specified in the applicable maintenance manual.
    (3) Modification JM 5285 may be accomplished at any time prior 
to accumulating 25,000 landings or within the next 2,000 landings 
after the effective date of this AD, whichever occurs later, at 
which time it must be incorporated.
    (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) An alternative method of compliance or adjustment of the 
initial or repetitive compliance times that provides an equivalent 
level of safety may be approved by the Manager, Brussels Aircraft 
Certification Division, Europe, Africa, Middle East office, FAA, c/o 
American Embassy, 1000 Brussels, Belgium. The request should be 
forwarded through an appropriate FAA Maintenance Inspector, who may 
add comments and then send it to the Manager, Brussels Aircraft 
Certification Division. Alternative methods of compliance approved 
in accordance with AD 81-20-01 (superseded by this action) are not 
considered approved as alternative methods of compliance with this 
AD.

    Note 3: Information concerning the existence of approved 
alternative methods of compliance with this AD, if any, may be 
obtained from the Brussels Aircraft Certification Division.

    (f) The NLG actuator support structure inspections required by 
this AD shall be done in accordance with British Aerospace (BAe) 
Service Bulletin No. 6/5, dated September 4, 1978. The inspection of 
the NLG retraction jack upper mounting fitting and attaching 
hardware required by this AD shall be done in accordance with 
Jetstream Service Bulletin 53-A-JA870510, which incorporates the 
following pages and revision levels:

------------------------------------------------------------------------
              Pages                 Revision level           Date       
------------------------------------------------------------------------
3, 5, 6, 8, 9, and 10...........  Original Issue....  May 26, 1987.     
1, 2, 4 and 7...................  Revision 1........  Nov. 10, 1987.    
------------------------------------------------------------------------

The installation required by this AD shall be accomplished in 
accordance with Jetstream SB 53-JM 5285, which incorporates the 
following pages and revision levels:

[[Page 15378]]


------------------------------------------------------------------------
              Pages                 Revision level           Date       
------------------------------------------------------------------------
1 and 4.........................  Revision 2........  November 12, 1992.
2, 3, and 5 through 26..........  Revision 1........  May 18, 1992.     
------------------------------------------------------------------------

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 Jetstream Aircraft Limited, Manager 
Product Support, Prestwick Airport, Ayrshire, KA9 2RW Scotland; or 
Jetstream Aircraft Inc., Librarian, P.O. Box 16029, Dulles 
International Airport, Washington, DC, 20041-6029. Copies may be 
inspected at the FAA, Central Region, Office of the Assistant Chief 
Counsel, Room 1558, 601 E. 12th Street, Kansas City, Missouri, or at 
the Office of the Federal Register, 800 North Capitol Street, NW., 
suite 700, Washington, DC.
    (g) This amendment (39-9985) becomes effective on
    May 23, 1997.

    Issued in Kansas City, Missouri, on March 26, 1997.
Michael Gallagher,
Manager, Small Airplane Directorate, Aircraft Certification Service.
[FR Doc. 97-8248 Filed 3-31-97; 8:45 am]
BILLING CODE 4910-13-U