01-29596. Airworthiness Directives; Pilatus Britten-Norman Limited BN-2, BN-2A, BN-2B, and BN-2T Series Airplanes

AGENCY:

Federal Aviation Administration, DOT.

ACTION:

Notice of proposed rulemaking (NPRM).

SUMMARY:

This document proposes to adopt a new airworthiness directive (AD) that would apply to certain Pilatus Britten-Norman Limited (Pilatus Britten-Norman) BN-2, BN-2A, BN-2B, and BN-2T series airplanes. This proposed AD would require you to repetitively inspect the inboard brackets of the elevator outboard hinge for loose rivets, structural damage, or cracks and replace any suspect bracket. The proposed AD would also require you to replace the hinge bracket at a certain time period if no discrepancies are found. This replacement includes modifying this area and installing modified brackets. This replacement allows you to increase the time period between inspections (reduce the number of repetitive inspections). This proposed AD is the result of mandatory continuing airworthiness information (MCAI) issued by the airworthiness authority for the United Kingdom. The actions specified by this proposed AD are intended to detect and correct inboard brackets of the elevator outboard hinge with loose rivets, structural damage, or cracks. Such conditions could cause the outboard elevator to become loose with a consequent reduction in elevator and airplane control.

DATES:

The Federal Aviation Administration (FAA) must receive any comments on this proposed rule on or before January 3, 2002.

ADDRESSES:

Submit comments to FAA, Central Region, Office of the Regional Counsel, Attention: Rules Docket No. 2001-CE-38-AD, 901 Locust, Room 506, Kansas City, Missouri 64106. You may view any comments at this location between 8 a.m. and 4 p.m., Monday through Friday, except Federal holidays.

You may get service information that applies to this proposed AD from Pilatus Britten-Norman Limited, Bembridge, Isle of Wight, United Kingdom PO35 5PR; telephone: [phone]; facsimile: [phone]. You may also view this information at the Rules Docket at the address above.

FOR FURTHER INFORMATION CONTACT:

Doug Rudolph, Aerospace Engineer, FAA, Small Airplane Directorate, 901 Locust, Room 301, Kansas City, Missouri 64106; telephone: [phone]; facsimile: [phone].

SUPPLEMENTARY INFORMATION:

Comments Invited

How Do I Comment on This Proposed AD?

The FAA invites comments on this proposed rule. You may submit whatever written data, views, or arguments you choose. You need to include the rule's docket number and submit your comments to the address specified under the caption ADDRESSES. We will consider all comments received on or before the closing date. We may amend this proposed rule in light of comments received. Factual information that supports your ideas and suggestions is extremely helpful in evaluating the effectiveness of this proposed AD action and determining whether we need to take additional rulemaking action.

Are There Any Specific Portions of This Proposed AD I Should Pay Attention to?

The FAA specifically invites comments on the overall regulatory, economic, environmental, and energy aspects of this proposed rule that might suggest a need to modify the rule. You may view all comments we receive before and after the closing date of the rule in the Rules Docket. We will file a report in the Rules Docket that summarizes each contact we have with the public that concerns the substantive parts of this proposed AD.

How Can I Be Sure FAA Receives My Comment?

If you want FAA to acknowledge the receipt of your comments, you must include a self-addressed, stamped postcard. On the postcard, write “Comments to Docket No. 2001-CE-38-AD.” We will date stamp and mail the postcard back to you.

Discussion

What Events Have Caused This Proposed AD?

The Civil Aviation Authority (CAA), which is the airworthiness authority for United Kingdom, recently notified FAA that an unsafe condition may exist on BN-2, BN-2A, BN-2B, and BN-2T series airplanes. The United Kingdom CAA reports several instances where the inboard brackets of the elevator outboard hinge had loose rivets, structural damage, or cracks.

These inboard brackets of the elevator outboard hinge incorporate part number NB-31-0077.

What Are the Consequences if the Condition Is Not Corrected?

Loose rivets, structural damage, or cracks in the inboard brackets of the elevator outboard hinge, if not detected and corrected, could cause the outboard elevator to become loose with a consequent reduction in elevator and airplane control.

Is There Service Information That Applies to This Subject?

Pilatus Britten-Norman has issued BN Bulletin Number BN2/SB.259, Issue 1, dated July 1, 2000.

What Are the Provisions of This Service Information?

The service bulletin includes procedures for:

—Part 1: Repetitively inspecting the inboard brackets of the elevator outboard hinge for loose rivets, structural damage, or cracks; and

—Part 2: Replacing the hinge bracket each time loose rivets, structural damage, or cracks are found during an inspection. This replacement includes modifying this area and installing modified brackets, part number NB-31-0901.

What Action Did the CAA Take?

The CAA classified this service bulletin as mandatory and issued CAA AD Number 002-07-2000, not dated, in order to ensure the continued airworthiness of these airplanes in the United Kingdom.

Was This in Accordance With the Bilateral Airworthiness Agreement?

These airplane models are manufactured in the United Kingdom and are 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 United Kingdom CAA has kept FAA informed of the situation described above.

The FAA's Determination and an Explanation of the Provisions of This Proposed AD

What Has FAA Decided?

The FAA has examined the findings of the United Kingdom CAA; reviewed all available information, including the service information referenced above; and determined that:

—The unsafe condition referenced in this document exists or could develop on Pilatus Britten-Norman BN-2, BN-2A, BN-2B, and BN-2T series (all models as specified in the actual AD) airplanes of the same type design that are on the U.S. registry;

—The actions specified in the previously-referenced service information should be accomplished on the affected airplanes;

—The replacement/modification specified in the service bulletin should be incorporated to increase the time period between inspections (reduce the number of repetitive inspections); and

—AD action should be taken in order to correct this unsafe condition.

What Would This Proposed AD Require?

The proposed AD would also require you to replace the hinge bracket at a certain time period if no discrepancies are found. This replacement includes modifying this area and installing modified brackets. This proposed AD would require you to repetitively inspect the inboard brackets of the elevator outboard hinge for loose rivets, structural damage, or cracks and replace any suspect bracket. The proposed AD would also require you to replace the hinge bracket at a certain time period if no discrepancies are found. This replacement includes modifying this area and installing modified brackets, part number NB-31-0901. This replacement allows you to increase the time period between inspections (reduce the number of repetitive inspections).

Are There Differences Between This Proposed AD, the Service Information, and the CAA AD?

This proposed AD would require you to replace/modify the hinge bracket at a certain time period if no discrepancies are found to increase the time period between inspections (reduce the number of repetitive inspections). BN Bulletin Number BN2/SB 259 and CAA AD Number 002-07-2000 do not specify this provision; they both specify this replacement/modification only if a suspect bracket is found during an inspection. This provision of incorporating the replacement/modification regardless of whether a suspect bracket is found is consistent with 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 our 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.

The alternative to incorporating this replacement/modification would be to repetitively inspect this area every 100 hours time-in-service (TIS) for the life of the airplane instead of every 1,000 hours TIS.

Cost Impact

How Many Airplanes Would This Proposed AD Impact?

We estimate that this proposed AD affects 118 airplanes in the U.S. registry.

What Would Be the Cost Impact of This Proposed AD on Owners/Operators of the Affected Airplanes?

We estimate the following costs to accomplish each proposed inspection:

Labor cost	Parts cost	Total cost per airplane	Total cost on U.S.operators
1 workhour at $60 per hour = $60	No parts necessary to accomplish the inspection	$60 per air plane	$7,080

We estimate the following costs to accomplish the proposed replacement/modification:

Labor cost	Parts cost	Total cost per airplane	Total cost on U.S.operators
10 workhours at $60 per hour = $600	$240 per airplane	$840 per airplane	$99,120.

Regulatory Impact

Would This Proposed AD Impact Various Entities?

The regulations proposed herein would not have a substantial direct effect 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, it is determined that this proposed rule would not have federalism implications under Executive Order 13132.

Would This Proposed AD Involve a Significant Rule or Regulatory Action?

For the reasons discussed above, I certify that this proposed 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) 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 has been placed 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, under 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.

§ 39.13

[Amended]

2. FAA amends § 39.13 by adding a new airworthiness directive (AD) to read as follows:

Pilatus Britten-Norman Ltd.: Docket No. 2001-CE-38-AD

(a) What airplanes are affected by this AD? This AD affects Models BN-2, BN-2A, BN-2A-2, BN-2A-3, BN-2A-6, BN-2A-8, BN-2A-9, BN-2A-20, BN-2A-21, BN-2A-26, BN-2A-27, BN-2B-20, BN-2B-21, BN-2B-26, BN-2B-27, BN-2T, and BN-2T-4R airplanes, all constructor numbers, that are certificated in any category and do not have one of the following incorporated:

(1) BN Modification NB-M-1695. This modification is incorporated at production and includes different designs in the area of the inboard brackets of the elevator outboard hinge. This modification is not available as a field installation. The maintenance manual for these production airplanes specifies 1,000-hour time-in-service (TIS) interval repetitive inspections. Owners/operators of airplanes with this production modification should be accomplishing these inspections or an FAA-approved equivalent; or

(2) Reinforcing plates installed at manufacture. These plates were installed on Constructor Number C2298 of the Model BN-2B airplanes.

(b) Who must comply with this AD? Anyone who wishes to operate any of the above airplanes must comply with this AD.

(c) What problem does this AD address? The actions specified by this AD are intended to detect and correct inboard brackets of the elevator outboard hinge with loose rivets, structural damage, or cracks. Such conditions could cause the outboard elevator to become loose with a consequent reduction in elevator and airplane control.

(d) What actions must I accomplish to address this problem? To address this problem, you must accomplish the following:

Actions	Compliance	Procedures
(1) For airplanes that do not have modified inboard brackets of the elevator outboard hinge installed (part number NB-31-0901 installed in accordance with Part 2 of the service bulletin), accomplish the following: (i) Repetitively inspect the inboard brackets of the elevator outboard hinge for loose rivets, structural damage, or cracks; (ii) Replace the inboard brackets of the elevator outboard hinge, which includes modifying this area and installing modified brackets, part number NB-31-0901; and (iii) Comply with paragraphs (d)(2)(i) and (d)(2)(ii) of this AD	Initially inspect within the next 100 hours time-in-service (TIS) after the effective date of this AD, and thereafter at intervals not to exceed 100 hours TIS until the replacement/modification required by paragraph (d)(1)(ii) of this AD is accomplished. Do the replacement initially within 1,000 hours TIS after the effective date of this AD or prior to further flight when any loose rivet, structural damage, or crack is found, whichever occurs first; and thereafter prior to further flight after any loose rivet, structural damage, or crack is found	In accordance with BN Bulletin Number BN2/SB.259, Issue 1, dated July 1, 2000.
(2) For airplanes that have modified inboard brackets of the elevator outboard hinge installed (part number NB-31-0901 in accordance with Part 2 of the service bulletin), accomplish the following: (i) Repetitively inspect the inboard brackets of the elevator outboard hinge for loose rivet, structural damage, or cracks; and (ii) Replace the inboard brackets of the elevator outboard hinge, which includes modifying this area and installing modified brackets, part number NB-31-0901	Inspect within 1,000 hours TIS after incorporating the replacement/modification or within the 100 hours TIS after the effective date of this AD, whichever occurs later, and thereafter at intervals not to exceed 1,000 hours TIS. Accomplish the replacement/modification prior to further flight when any loose rivet, structural damage, or crack is found during any inspection required by this AD	In accordance with BN Bulletin Number BN2/SB.259, Issue 1, dated July 1, 2000.
(3) This AD does not apply to airplanes with one of the following incorporated: (i) BN Modification NB-M-1695. This modification is incorporated at production and includes different designs in the area of the inboard brackets of the elevator outboard hinge. This modification is not available as a field installation. The maintenance manual for these production airplanes specifies 1,000-hour TIS interval repetitive inspections. Owners/operators of airplanes with this production modification should be accomplishing these inspections or an FAA-approved equivalent; or (ii) Reinforcing plates installed at manufacture. These plates were installed on Constructor Number C2298 of the Model BN-2B airplanes	Not applicable	Not applicable.

(e) Can I comply with this AD in any other way? You may use an alternative method of compliance or adjust the compliance time if:

(1) Your alternative method of compliance provides an equivalent level of safety; and

(2) The Manager, Small Airplane Directorate, approves your alternative. Submit your request through an FAA Principal Maintenance Inspector, who may add comments and then send it to the Manager, Small Airplane Directorate.

Note 1:

This AD applies to each airplane identified in paragraph (a) of this AD, 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 you have not eliminated the unsafe condition, specific actions you propose to address it.

(f) Where can I get information about any already-approved alternative methods of compliance? Contact Doug Rudolph, Aerospace Engineer, FAA, Small Airplane Directorate, 901 Locust, Room 301, Kansas City, Missouri 64106; telephone: [phone]; facsimile: [phone].

(g) What if I need to fly the airplane to another location to comply with this AD? The FAA can issue a special flight permit under sections 21.197 and 21.199 of the Federal Aviation Regulations (14 CFR 21.197 and 21.199) to operate your airplane to a location where you can accomplish the requirements of this AD.

(h) How do I get copies of the documents referenced in this AD? You may get copies of the documents referenced in this AD from Pilatus Britten-Norman Limited, Bembridge, Isle of Wight, United Kingdom PO35 5PR; telephone: [phone]; facsimile: [phone]. You may view these documents at FAA, Central Region, Office of the Regional Counsel, 901 Locust, Room 506, Kansas City, Missouri 64106.

Note 2:

The subject of this AD is addressed in CAA AD Number 002-07-2000, not dated.

Issued in Kansas City, Missouri, on November 20, 2001.

Michael K. Dahl,

Acting Manager, Small Airplane Directorate, Aircraft Certification Service.