AD 95-12-08 ACTIVE

This amendment adopts a new airworthiness directive (AD), applicable to certain Aerospatiale Model ATR72 series airplanes. This action requires repetitive inspections to detect displacement of the rear hinge bush, and to detect cracking or rupture of the rear hinge pin on the main landing gear (MLG) leg; and the correction of any discrepancies. This amendment is prompted by a report of the failure of this hinge pin on an in-service airplane. The actions specified in this AD are intended to prevent failure of the hinge pin, which can lead to failure of the MLG leg or MLG attachment assembly.

Final rule; request for comments.

95-12-08 AEROSPATIALE: Amendment 39-9258. Docket 95-NM-60-AD.

Applicability: Model ATR72-101, -102, and -202 series airplanes, as listed in ATR Service Bulletin ATR72-32-1028, dated September 1, 1994; equipped with main landing gear hinge pins having part number (P/N) D 61000 with serial numbers MN 76 through MN 86 inclusive; 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 use the authority provided in paragraph (d) to request approval from the FAA. This approval may address either no action, if the current configuration eliminates the unsafe condition; or different actions necessary to address the unsafe condition described inthis AD. Such a request should include an assessment of the effect of the changed configuration on the unsafe condition addressed by this AD. In no case does the presence of any modification, alteration, or repair remove any airplane from the applicability of this AD.

Compliance: Required as indicated, unless accomplished previously.

To prevent failure of the rear hinge pin on the main landing gear (MLG) leg, which can lead to failure of the MLG leg or attachment assembly, accomplish the following:

(a) Within 90 days after the effective date of this AD, perform a detailed visual inspection of the MLG rear hinge pin bush to determine if the bush has moved or if the sealant at the level of the bush shows any cracks, in accordance with ATR Service Bulletin ATR72-32-1028, dated September 1, 1994.

NOTE 2: ATR Service Bulletin ATR72-32-1028 references Messier-Eram Service Bulletin 631-32-110, dated August 31, 1994, for additional inspection instructions.

(1) Ifno discrepancies are detected, repeat this inspection at intervals not to exceed 7 days.

(2) If any discrepancies are detected, prior to further flight, correct them in accordance with the service bulletin.

(b) Within 300 hours time-in-service after the effective date of this AD, perform a boroscope (endoscope) inspection to detect cracks of the MLG leg-to-aircraft rear hinge pin, in accordance with ATR Service Bulletin ATR72-32-1028, dated September 1, 1994.

NOTE 3: ATR Service Bulletin ATR72-32-1028 references Messier-Eram Service Bulletin 631-32-110, dated August 31, 1994, for additional inspection instructions.

(1) If no crack is detected, repeat this inspection at intervals not to exceed 300 hours time-in-service.

(2) If any crack is detected, prior to further flight, replace the hinge pin in accordance with the service bulletin.

(c) Within 6 months after the effective date of this AD, perform a one-time ultrasonic inspection of the MLG aft hingepins to determine if the pin is free of material defects, in accordance with ATR Service Bulletin ATR72-32-1029, dated November 4, 1994.

NOTE 4: ATR Service Bulletin ATR72-32-1029 references Messier-Eram Service Bulletin 631-32-111, dated October 14, 1994, for additional inspection instructions.

(1) If the results of the inspection (echo percentage) are within the limits specified in the service bulletin, no further action is required by this AD, and the inspections required by paragraph (a) and (b) of this AD may be terminated.

(2) If the results of the inspection are outside the limits specified in the service bulletin, prior to further flight, replace the pin with a new pin in accordance with the service bulletin. After such replacement, no further action is required by this AD, and the inspections required by paragraph (a) and (b) of this AD may be terminated.

(d) 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, 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 5: Information concerning the existence of approved alternative methods of compliance with this AD, if any, may be obtained from the Standardization Branch, ANM-113.

(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) The inspections and replacement shall be done in accordance with ATR Service Bulletin ATR72-32-1028, dated September 1, 1994; and ATR Service Bulletin ATR72-32-1029, dated November 4, 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 Aerospatiale, 316 Route de Bayonne, 31060 Toulouse, Cedex 03, France. 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.

(g) This amendment becomes effective on June 28, 1995.

The Direction G n rale de l'Aviation Civile (DGAC), which is the airworthiness authority for France, recently notified the FAA that an unsafe condition may exist on certain Aerospatiale Model ATR72-101, -102, and -202 series airplanes. The DGAC advises that there has been a report of the failure (rupture) of the rear hinge pin on the main landing gear (MLG) leg of one in-service airplane. The cause of the failure is associated with a quality problem during the manufacture of these hinge pins, which apparently causes the pin to be susceptible to cracking. The suspect pins have part number (P/N) D 61000. Failure of the hinge pin could lead to the failure of the MLG leg or the MLG attachment assembly.

Avions de Transport Regional (ATR) has issued Service Bulletin ATR72-32-1028, dated September 1, 1994, which describes procedures for performing the following actions:

1. repetitive visual inspections of the MLG rear hinge pin bush to ensure that the bush has not moved and that the sealant at the level of the bush does not show any cracks, and correction of discrepancies; and

2. repetitive boroscope inspections to detect cracks of the MLG leg-to-aircraft rear hinge pin, and replacement of the pin, if necessary
(This ATR service bulletin references Messier-Eram Service Bulletin 631-32-110, dated August 31, 1994, for additional inspection instructions.)

ATR has also issued Service Bulletin ATR72-32-1029, dated November 4, 1994, which describes procedures for performing an ultrasonic inspection of the MLG aft hinge pins to ensure that the pin is free of material defects, and replacement of the pin with new pin, if necessary. (This service bulletin references Messier-Eram Service Bulletin 631-32-111, dated October 14, 1994, for additional inspection instructions.)

The DGAC classified these service bulletins as mandatory and issued French Airworthiness Directive (CN) 94-197-023(B), dated August 31, 1994, in order to assure thecontinued airworthiness of these airplanes in France.

This airplane model is manufactured in France and is type certificated for operation in the United States under the provisions of section 21.29 of the Federal Aviation Regulations (14 CFR 21.19) and the applicable bilateral airworthiness agreement. Pursuant to this bilateral airworthiness agreement, the DGAC has kept the FAA informed of the situation described above. The FAA has examined the findings of the DGAC, reviewed all available information, and determined that AD action is necessary for products of this type design that are certificated for operation in the United States.

Since an unsafe condition has been identified that is likely to exist or develop on other airplanes of the same type design, this AD is being issued to prevent failure of the rear hinge pin on the MLG leg, which could lead to failure of the MLG leg or the MLG attachment assembly. This AD requires, initially, repetitive visual inspections off the MLG rear hinge pin bush to ensure that the bush has not moved and that the sealant at the level of the bush does not show any cracks, and correction of discrepancies. It also requires repetitive boroscope inspections to detect cracks of the MLG leg-to-aircraft rear hinge pin, and replacement of the pin, if necessary. As terminating action for those inspections, this AD requires an ultrasonic inspection of the MLG aft hinge pins to ensure that the pin is free of material defects, and replacement of the pin with new pin, if necessary. These actions are required to be accomplished in accordance with the service bulletins described previously.

As a result of recent communications with the Air Transport Association (ATA) of America, the FAA has learned that, in general, some operators may misunderstand the legal effect of AD's on airplanes that are identified in the applicability provision of the AD, but that have been altered or repaired in the area addressed by the AD. The FAA points out that all airplanes identified in the applicability provision of an AD are legally subject to the AD. If an airplane has been altered or repaired in the affected area in such a way as to affect compliance with the AD, the owner or operator is required to obtain FAA approval for an alternative method of compliance with the AD, in accordance with the paragraph of each AD that provides for such approvals. A note has been included in this AD to clarify this long-standing requirement.

There currently are no affected Model ATR72-101, -102, or -202 series airplanes on the U.S. Register. All airplanes included in the applicability of this rule currently are operated by non-U.S. operators under foreign registry; therefore, they are not directly affected by this AD action. However, the FAA considers that this rule is necessary to ensure that the unsafe condition is addressed in the event that any of these subject airplanes are imported and placed on the U.S. Register in the future.Should an affected airplane be imported and placed on the U.S. Register in the future, the following costs would apply:

Accomplishment of a required repetitive visual inspections would require approximately .5 work hour per bush, at an average labor charge of $60 per work hour. Based on these figures, the total cost impact of this requirement would be $30 per bush per inspection.

Accomplishment of a required repetitive boroscope inspections would require approximately 3 work hours per pin, at an average labor charge of $60 per work hour. Based on these figures, the total cost impact of this requirement would be $180 per pin per inspection.

Accomplishment of a required one-time ultrasonic inspection would require approximately 11 work hours per pin, at an average labor charge of $60 per work hour. Based on these figures, the total cost impact of this requirement would be $180 per pin.

Since this AD action does not affect any airplane that is currently on the U.S. register, it has no adverse economic impact and imposes no additional burden on any person. Therefore, notice and public procedures hereon are unnecessary and the amendment may be made effective in less than 30 days after publication in the Federal Register.

Comments Invited
Although this action is in the form of a final rule and was not preceded by notice and opportunity for public comment, comments are invited on this rule. Interested persons are invited to comment on this rule by submitting such written data, views, or arguments as they may desire. Communications shall identify the Rules Docket number and be submitted in triplicate to the address specified under the caption "ADDRESSES." All communications received on or before the closing date for comments will be considered, and this rule may be amended in light of the comments received. Factual information that supports the commenter's ideas and suggestions is extremely helpful in evaluating the effectiveness of the AD action and determining whether additional rulemaking action would be needed.

Comments are specifically invited on the overall regulatory, economic, environmental, and energy aspects of the rule that might suggest a need to modify the rule. All comments submitted will be available, both before and after the closing date for comments, in the Rules Docket for examination by interested persons. A report that summarizes each FAA-public contact concerned with the substance of this AD will be filed in the Rules Docket.

Commenters wishing the FAA to acknowledge receipt of their comments submitted in response to this rule must submit a self-addressed, stamped postcard on which the following statement is made: "Comments to Docket Number 95-NM-60-AD." The postcard will be date stamped and returned to the commenter.

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. App. 1354(a), 1421 and 1423; 49 U.S.C. 106(g); and 14 CFR 11.89.
39.13 - [Amended]
2. Section 39.13 is amended by adding the following new airworthiness directive:

Submit comments in triplicate to the Federal Aviation Administration (FAA), Transport Airplane Directorate, ANM-103, Attention: Rules Docket No. 95-NM-65-AD, 1601 Lind Avenue, SW., Renton, Washington 98055-4056.

The service information referenced in this AD may be obtained from Aerospatiale, 316 Route de Bayonne, 31060 Toulouse, Cedex 03, France. This information may be examined 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.

Sam Grober, Aerospace Engineer, Standardization Branch, ANM-113, FAA, Transport Airplane Directorate, 1601 Lind Avenue, SW., Renton, Washington 98055-4056; telephone (206) 227-1187; fax (206) 227-1320.