AD 96-17-12

This amendment supersedes Airworthiness Directive (AD) 87-07-01, which currently requires the following on Jetstream Aircraft Limited (JAL) HP137 Mk1, Jetstream series 200, and Jetstream Model 3101 airplanes: repetitively inspecting the nose landing gear (NLG) top cap assembly securing bolts for looseness or cracks, retorquing any loose security bolt, and replacing any cracked security bolt. AD 87-07-01 also provides the option of incorporating a NLG modification as terminating action for the repetitive inspections. A report of cracked and loose bolts found on an airplane with the above-referenced NLG modification prompted this action. This action: retains the repetitive inspections required by AD 87-07-01; increases the AD applicability to include Jetstream Model 3201 airplanes and airplanes that have the NLG top cap assembly modified in accordance with AD 87-07-01; requires replacing two of the NLG top cap assembly securing bolts; and incorporates a new NLG top cap assembly that would eliminate the repetitive inspection requirement of the AD. The actions specified in this AD are intended to prevent failure of the NLG caused by cracked or loose securing bolts, which, if not detected and corrected, could lead to NLG collapse and damage to the airplane.

Final rule

96-17-12 JETSTREAM AIRCRAFT LIMITED: Amendment 39-9722; Docket No. 95-CE- 94-AD. Supersedes AD 87-07-01, Amendment 39-5582.
Applicability: The following airplane models and serial numbers, certificated in any category, that do not have a modified nose landing gear (NLG) top cap assembly incorporated (Amendment JA 901040) in accordance with Jetstream Service Bulletin (SB) 32-JA 901040, Revision No. 3, dated August 9, 1995:

Model
Serial Numbers
HP137 Mk1
all serial numbers;
Jetstream series 200
all serial numbers;
Jetstream Model 3101
all serial numbers; and
Jetstream Model 3201
serial numbers 790 through 854.

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 (f) 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 cracked or loose securing bolts, which, if not detected and corrected, could lead to NLG 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) Within the next 300 landings accumulated on the NLG after the effective date of this AD, accomplish the following in accordance with the applicable portion of the ACCOMPLISHMENT INSTRUCTIONS section of Jetstream SB 32-JA 901040, Revision No. 3, dated August 9, 1995, and AP Precision Hydraulics Ltd SB 32-41, which incorporates the following pages:

Pages
Revision Level
Date
1, 2, 6, 7, 8 and 15
Revision No. 2
March 9, 1993
4 and 10
Revision No. 1
July 11, 1991

3, 5, 9, 11, 12, 13,
and 14
Original Issue
November 17, 1990

(1) Replace two of the NLG top cap assembly securing bolts, and check the other two for correct length in accordance with part 1A of the ACCOMPLISHMENT INSTRUCTIONS section of AP Precision Hydraulics Ltd SB 32-41. Prior to further flight, replace any NLG top securing bolt that is not the length specified in AP Precision Hydraulics Ltd SB 32-41.

(2) Check the tightness of the four NLG top cap assembly securing bolts and ensure that these bolts are not broken in accordance with part 1b ofthe ACCOMPLISHMENT INSTRUCTIONS section of AP Precision Hydraulics Ltd SB 32-41.

(i) Prior to further flight, retorque any bolts with incorrect torque values.

(ii) If any bolts are broken or gaps are found as specified in paragraph A.(4) of part 1b of the ACCOMPLISHMENT INSTRUCTIONS section of AP Precision Hydraulics Ltd SB 32-41, prior to further flight, replace the NLG in accordance with the applicable maintenance manual.

(b) Within 1,200 landings after the actions required by paragraph (a) of this AD (all paragraph designations), and thereafter at intervals not to exceed 1,200 landings, until the modification required by paragraph (c) of this AD is incorporated, check the tightness of the four NLG top cap assembly securing bolts and ensure that these bolts are not broken in accordance with part 1b of the ACCOMPLISHMENT INSTRUCTIONS section of AP Precision Hydraulics Ltd SB 32-41.

(1) Prior to further flight, retorque any bolts with incorrect torque values.(2) If any bolts are broken or gaps are found as specified in paragraph A.(4) of part 1b of the ACCOMPLISHMENT INSTRUCTIONS section of AP Precision Hydraulics Ltd SB 32-41, prior to further flight, replace the NLG in accordance with the applicable maintenance manual.

(c) Upon accumulating 20,000 landings on the NLG or within the next 2,500 landings accumulated on the NLG after the effective date of this AD, whichever occurs later, install a new NLG top cap assembly or modify the existing NLG top cap assembly in accordance with Part 2 of the ACCOMPLISHMENT INSTRUCTIONS section of AP Precision Hydraulics Ltd SB 32-41, which incorporates the following pages:

Pages
Revision Level
Date
1, 2, 6, 7, 8 and 15
Revision No. 2
March 9, 1993

4 and 10
Revision No. 1
July 11, 1991
3, 5, 9, 11, 12, 13,
and 14
Original Issue
November 17, 1990

(d) Incorporating the modification required by paragraph (c) of this AD is considered terminating action for the repetitive torque checks required by this AD and may be incorporated at any time prior to 20,000 landings on a NLG or within the next 2,500 landings accumulated on the NLG after the effective date of this AD, whichever occurs later (at which time it must be incorporated).

(e) 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.

(f) 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 87-07-01 (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.

(g) The replacements, check, retorque, and installation required by this AD shall be done in accordance with Jetstream Service Bulletin 32-JA 901040, Revision No. 3, dated August 9, 1995, and AP Precision Hydraulics Ltd Service Bulletin 32-41, which incorporates the following pages:

Pages
Revision Level
Date
1, 2, 6, 7, 8 and 15
Revision No. 2
March 9, 1993
4 and 10
Revision No. 1
July 11, 1991
3, 5, 9, 11, 12, 13,
and 14
Original Issue
November 17, 1990

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 part51. 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. 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.

(h) This amendment (39-9722) supersedes AD 87-07-01, Amendment 39-5582.

(i) This amendment becomes effective on October 21, 1996.

Events Leading to the AD
A proposal to amend part 39 of the Federal Aviation Regulations (14 CFR part 39) to include an AD that would apply to JAL HP137 Mk1, Jetstream series 200, and Jetstream Models 3101 and 3201 airplanes that do not have a modified NLG top cap assembly incorporated (Amendment JA 901040) was published in the Federal Register on March 22, 1996 (61 FR 11786). The action proposed to supersede AD 87-07-01 with a new AD that would:

- retain the requirement contained in AD 87-07-01 of repetitively inspecting the NLG top cap assembly securing bolts for looseness, retorquing any loose security bolt, and replacing any cracked security bolt;

- require replacing two of the NLG top cap assembly securing bolts and checking the other two NLG top cap assembly securing bolts for the correct length; and

- require replacing (at a specified time) the NLG top cap assembly with a part of improved design (Amendment JA 901040) as terminating action for the repetitive inspections.

Accomplishment of the proposed actions would be in accordance with Jetstream Service Bulletin (SB) 32-JA 901040, Revision No. 3, dated August 9, 1995, and AP Precision Hydraulics Ltd SB 32-41, which incorporates the following pages:

Pages
Revision Level
Date
1, 2, 6, 7, 8 and 15
Revision No. 2
March 9, 1993
4 and 10
Revision No. 1
July 11, 1991
3, 5, 9, 11, 12, 13,
and 14
Original Issue
November 17, 1990

A report of cracked and loose bolts found on an airplane with the above-referenced NLG modification prompted the proposal.

Interested persons have been afforded an opportunity to participate in the making of this amendment. One comment was received in support of the proposed rule and no comments were received regarding the FAA's determination of the cost to the public.

FAA's Determination
After careful review of all available information related to the subject presented above, the FAA has determined that airsafety and the public interest require the adoption of the rule 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.

Cost Impact
The FAA estimates that 150 airplanes in the U.S. registry will be affected by this AD, that it will take approximately 18 workhours (inspection: 6 workhours; replacement: 12 workhours) to accomplish the required actions, and that the average labor rate is approximately $60 an hour. Parts cost approximately $1,200 per airplane. Based on these figures, the total cost impact of this AD on U.S. operators is estimated to be $342,000 or $2,280 per airplane. This figure only takes into account the cost of the required initial inspection and required inspection-terminating modification and does not take into account the cost of the required repetitive inspections. The FAA has no way of determining the number of repetitive inspections each of the owners/operators would incur over the life of the affected airplanes.

This figure is also based on the assumption that none of the affected airplane owners/operators have accomplished the required modification. This action eliminates the repetitive inspections required by AD 87-07-01. The FAA has no way of determining the operation levels of each individual operator of the affected airplanes, and subsequently cannot determine the repetitive inspection costs that will be eliminated by this action. 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 62 of the affected airplanes. Assuming that each set of parts has been installed on an affected airplane, the cost impact of the required modification upon the public will be reduced $141,360 from $342,000 to $200,640.

FAA's Aging Commuter-Class Aircraft Policy
This action is consistent with the FAA's aging commuter-class airplane policy. This policy simply states that reliance on repetitive inspections of critical areas on commuter-class airplanes carries an unnecessary safety risk when a design change exists that could eliminate or, in certain instances, reduce the number of those critical inspections.

The intent of the FAA's aging commuter airplane program is to ensure safe operation of commuter-class airplanes that are in commercial service without adversely impacting private operators. Of the approximately 150 airplanes in the U.S. registry that are 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.

Section 39.13 - [AMENDED]
2. Section 39.13 is amended by removing Airworthiness Directive (AD) 87-07-01, Amendment 39-5582, and adding a new AD to read as follows: