Airworthiness Directives; British Aerospace Model BAe 146 and Avro 146-RJ Series Airplanes

Comments Invited

Interested persons are invited to participate in the making of the proposed 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 above. All communications received on or before the closing date for comments, specified above, will be considered before taking action on the proposed rule. The proposals contained in this notice may be changed in light of the comments received. Comments are specifically invited on the overall regulatory, economic, environmental, and energy aspects of the proposed 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 summarizing each FAA-public contact concerned with the substance of this proposal will be filed in the Rules Docket. Commenters wishing the FAA to acknowledge receipt of their comments submitted in response to this notice must submit a self-addressed, stamped postcard on which the following statement is made: ``Comments to Docket Number 96-NM-26-AD.'' The postcard will be date stamped and returned to the commenter.

Availability of NPRMs

Any person may obtain a copy of this NPRM by submitting a request to the FAA, Transport Airplane Directorate, ANM-103, Attention: Rules Docket No. 96-NM-26-AD, 1601 Lind Avenue, SW., Renton, Washington 98055-4056.

Discussion

On August 23, 1993, the FAA issued AD 93-17-04, amendment 39-8674 (58 FR 47036, September 7, 1993), applicable to British Aerospace Model BAe 146 series airplanes, to require repetitive inspections to detect cracking of the upper main fitting of the nose landing gear (NLG), and replacement or repair of cracked parts, if necessary. That action was prompted by reports of cracking of the upper main fitting of the NLG. The requirements of that AD are intended to prevent failure of the main fitting, which could lead to collapse of the NLG during landing. On February 15, 1995, the FAA issued AD 95-04-06, amendment 39-9158 (60 FR 12413, March 7, 1995), applicable to British Aerospace Model Avro 146-RJ series airplanes. That AD is similar to AD 93-17-04 in that it requires repetitive inspections to detect cracking of the upper main fitting of the NLG, and replacement or repair of cracked parts, if necessary. Likewise, that action was prompted by reports of cracking of the upper main fitting of the NLG. The requirements of that AD are intended to prevent failure of the main fitting, which could lead to collapse of the NLG during landing.

Action Since Issuance of Previous AD's

Since the issuance of those AD's, a fatigue analysis and a review of the service reports were conducted by the manufacturer of the NLG. The results of the analysis and review indicate that crack growth can occur at a faster rate than what was considered previously. The repetitive inspection interval should be reduced for NLG part number

200876001 or 200876003 from 4,000 landings to 2,000 landings. The results of the review and analysis also indicated that the current repetitive inspection interval of 8,000 landings is adequate for NLG part numbers 200876002, 200876004, and 201138002.

Explanation of Relevant Service Information

Subsequent to the fatigue analysis and review of the service reports, British Aerospace issued Service Bulletin S.B. 32-131, Revision 3, dated October 18, 1995, which describes procedures for either an eddy current or ultra sensitive penetrant inspection of the NLG to detect cracking, and replacement or repair of cracked parts, if necessary. (The service bulletin also references Messier-Dowty Service Bulletin, Revision 2, dated August 2, 1995, as an additional source of service information.) The CAA classified the British Aerospace service bulletin as mandatory in order to assure the continued airworthiness of these airplanes in the United Kingdom.

FAA's Conclusions

This airplane model is manufactured in the United Kingdom and is type certificated for operation in the United States under the provisions of section 21.29 of the Federal Aviation Regulations (14 CFR 21.29) and the applicable bilateral airworthiness agreement. Pursuant to this bilateral airworthiness agreement, the CAA has kept the FAA informed of the situation described above. The FAA has examined the findings of the CAA, 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.

Explanation of Requirements of Proposed Rule

Since an unsafe condition has been identified that is likely to exist or develop on other airplanes of the same type design registered in the United States, the proposed AD would supersede AD 93-17-04 and AD 95-04-06 to continue to require either eddy current or ultra sensitive penetrant inspections to detect cracking of the upper main fitting of the NLG, and replacement or repair of cracked parts, if necessary. Although the inspections required by this proposal are the same as the inspections required by AD 93-17-04 and AD 95-04-06, this proposal would combine the requirements of the previous AD's, but require that the repetitive inspection interval for certain airplanes (equipped with certain NLG part numbers) would occur more frequently. The actions would be required to be accomplished in accordance with the British Aerospace service bulletin described previously.

Cost Impact

There are approximately 52 Model BAe 146 and Model Avro 146-RJ series airplanes of U.S. registry that would be affected by this proposed AD. The inspections that are currently required by AD 93-17-04 and AD 95-04-06, and retained in this proposal, take approximately 3 work hours per airplane to accomplish, at an average labor rate of $60 per work hour. Based on these figures, the cost impact on U.S. operators of the actions currently required is estimated to be $9,360, or $180 per airplane, per inspection cycle. Although this proposal adds no new actions, the associated costs for some operators would increase somewhat since certain inspections would be required to be performed more frequently. The cost impact figures discussed above are based on assumptions that no operator has yet accomplished any of the current or proposed 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 proposed herein would 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 proposal would not have sufficient federalism implications to warrant the preparation of a Federalism Assessment. For the reasons discussed above, I certify that this proposed regulation (1) is not a ``significant regulatory action'' under Executive Order 12866; (2) is not a ``significant rule'' under the DOT Regulatory Policies and Procedures (44 FR 11034, February 26, 1979); and (3) if promulgated, 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 draft regulatory 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, Safety.

The Proposed Amendment

Accordingly, pursuant to the authority delegated to me by the Administrator, the Federal Aviation Administration proposes to amend 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 removing amendment 39-8674 (58 FR 47036, September 7, 1993), and amendment 39-9158 (60 FR 12413, March 7, 1995), and by adding a new airworthiness directive (AD), to read as follows:

British Aerospace Regional Aircraft Limited, AVRO International: Docket 96-NM-26-AD. Supersedes AD 93-17-04, Amendment 39-8674; and AD 95-04-06, Amendment 39-9158.

Applicability: Model BAe 146 and Avro 146-RJ series airplanes, 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 (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, unless accomplished previously. To prevent the failure of the main fitting, which could lead to collapse of the nose landing gear (NLG) during landing, accomplish the following:

Restatement of Continuing Requirements

(a) For all Model BAe 146 series airplanes on which NLG part number 200876002, 200876004, or 201138002 has been installed: (1) Prior to the accumulation of 16,000 total landings or within 30 days after October 7, 1993 (the effective date of AD 93-17-04, Amendment 39-8674), whichever occurs later, conduct an eddy current or ultra sensitivity penetrant inspection of the NLG, in accordance with British Aerospace Service Bulletin S.B. 32-131, dated December 6, 1991; Revision 1, dated November 12, 1992;

Revision 2, dated July 10, 1993; or Revision 3, dated October 18, 1995. Repeat the inspection thereafter at intervals not to exceed 8,000 landings. (2) If cracking is detected during any inspection required by this paragraph, prior to further flight, replace the currently installed NLG with a new or serviceable unit, or repair the crack, in accordance with a method approved by the Manager, Standardization Branch, ANM-113, FAA, Transport Airplane Directorate. After replacement or repair, repeat the inspection at intervals not to exceed 8,000 landings. (b) For all Model Avro 146-RJ series airplanes on which NLG part number 200876002, 200876004, or 201138002 has been installed: (1) Prior to the accumulation of 16,000 total landings or within 30 days after April 6, 1995 (the effective date of AD 95-04-06, Amendment 39-9158), whichever occurs later, conduct an eddy current or ultra sensitivity penetrant inspection of the NLG, in accordance with British Aerospace Service Bulletin S.B. 32-131, dated December 6, 1991; Revision 1, dated November 12, 1992; Revision 2, dated July 10, 1993; or Revision 3, dated October 18, 1995. Repeat the inspection thereafter at intervals not to exceed 8,000 landings. (2) If cracking is detected during any inspection required by this paragraph, prior to further flight, replace the currently installed NLG with a new or serviceable unit, or repair the crack, in accordance with a method approved by the Manager, Standardization Branch, ANM-113, FAA, Transport Airplane Directorate. After replacement or repair, repeat the inspection at intervals not to exceed 8,000 landings. (c) For all Model BAe 146 series airplanes on which NLG part number 200876001 or 200876003 has been installed: (1) Prior to the accumulation of 4,000 total landings or within 30 days after October 7, 1993 (the effective date of AD 93-17-04, Amendment 39-8674), whichever occurs later, conduct an eddy current or ultra high sensitivity penetrant inspection of the NLG, in accordance with British Aerospace Service Bulletin S.B. 32-131, dated December 6, 1991; Revision 1, dated November 12, 1992; Revision 2, dated July 10, 1993; or Revision 3, dated October 18, 1995. Repeat the inspection thereafter at intervals not to exceed 4,000 landings until the inspection required by paragraph (e) of this AD is accomplished. (2) If cracking is detected during any inspection required by this paragraph, prior to further flight, replace the currently installed NLG with a new or serviceable unit, or repair the crack, in accordance with a method approved by the Manager, Standardization Branch, ANM-113, FAA, Transport Airplane Directorate. After replacement or repair, repeat the inspection at intervals not to exceed 4,000 landings until the inspection required by paragraph (e) of this AD is accomplished. (d) For all Model Avro 146-RJ series airplanes on which NLG part number 200876001 or 200876003 has been installed: (1) Prior to the accumulation of 4,000 total landings or within 30 days after April 6, 1995 (the effective date of AD 95-04-06, Amendment 39-9158), whichever occurs later, conduct an eddy current or ultra high sensitivity penetrant inspection of the NLG, in accordance with British Aerospace Service Bulletin S.B. 32-131, dated December 6, 1991; Revision 1, dated November 12, 1992; Revision 2, dated July 10, 1993; or Revision 3, dated October 18, 1995. Repeat the inspection thereafter at intervals not to exceed 4,000 landings until the inspection required by paragraph (e) of this AD is accomplished. (2) If cracking is detected during any inspection required by this paragraph, prior to further flight, replace the currently installed NLG with a new or serviceable unit, or repair the crack, in accordance with a method approved by the Manager, Standardization Branch, ANM-113, FAA, Transport Airplane Directorate. After replacement or repair, repeat the inspection at intervals not to exceed 4,000 landings until the inspection required by paragraph (e) of this AD is accomplished.

New Requirements

(e) For all Model BAe 146 and Avro 146-RJ series airplanes on which NLG part number 200876001 or 200876003 has been installed: Within 2,000 landings from the immediately preceding inspection conducted in accordance with paragraph (c) or (d) of this AD, or within 3 months after the effective date of this AD, whichever occurs later, accomplish the following: (1) Conduct an eddy current or ultra high sensitivity penetrant inspection of the NLG, in accordance with British Aerospace Service Bulletin S.B. 32-131, Revision 3, dated October 18, 1995. Repeat the inspection thereafter at intervals not to exceed 2,000 landings. Accomplishment of this inspection terminates the requirements of paragraph (c) and (d) of this AD.

Note 2: The British Aerospace service bulletin references a Messier-Dowty Service Bulletin 145-32-109, Revision 2, dated August 2, 1995, as an additional source of service information.

(2) If cracking is detected during any inspection required by this paragraph, prior to further flight, replace the currently installed NLG with a new or serviceable unit, or repair the crack, in accordance with a method approved by the Manager, Standardization Branch, ANM-113. After replacement or repair, repeat the inspection at intervals not to exceed 2,000 landings. (f) 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. 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.

(g) 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.

Issued in Renton, Washington, on October 9, 1996. S.R. Miller, Acting Manager, Transport Airplane Directorate, Aircraft Certification Service. [FR Doc. 96-26706 Filed 10-17-96; 8:45 am] BILLING CODE 4910-13-U