01-29192. Airworthiness Directives; Pilatus Britten-Norman Limited BN-2, BN-2A, BN-2B, BN-2T, and BN2A MK. III 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 all Pilatus Britten-Norman Limited (Pilatus Britten-Norman) BN-2, BN-2A, BN-2B, BN-2T, and BN2A MK. III series airplanes. This proposed AD would require you to repetitively inspect certain oleo attachment brackets for cracks and replace any cracked bracket found during any inspection. 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 cracked oleo attachment brackets. Such a condition could cause the attachment bracket to fail, which could result in detachment of the main landing gear.

DATES:

The Federal Aviation Administration (FAA) must receive any comments on this proposed rule on or before December 21, 2001.

ADDRESSES:

Submit comments to FAA, Central Region, Office of the Regional Counsel, Attention: Rules Docket No. 2001-CE-39-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-39-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 the United Kingdom, notified FAA that an unsafe condition may exist on all BN-2, BN-2A, BN-2B, BN-2T, and BN2A MK. III series airplanes. The United Kingdom CAA reports five occurrences of failure of the oleo attachment bracket, part number (P/N) NB-40-0075. This bracket is the main attachment point for the main landing gear. The CAA determined that the cause for failure of these brackets is the current design of the part.

What are the consequences if the condition is not corrected? Cracked oleo attachment brackets, if not detected and corrected, could fail and detach from the main landing gear.

Is there service information that applies to this subject? Pilatus Britten-Norman has issued B-N Service Bulletin Number SB 273, Issue 2, dated January 12, 2000.

What are the provisions of this service information? The service bulletin includes procedures for:

—Repetitively inspecting the oleo attachment brackets, P/N NB-40-0075, for cracks; and

—Replacing any cracked attachment bracket found during any inspection.

What action did the CAA take? The CAA classified this service bulletin as mandatory and issued CAA AD Number 005-09-2000, 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 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 all Pilatus Britten-Norman BN-2, BN-2A, BN-2B, BN-2T, and BN2A MK. III series 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; and

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

What would this proposed AD require? This proposed AD would require you to repetitively inspect the oleo attachment brackets, P/N NB-40-0075, for cracks and replace any cracked bracket found during any inspection.

Are there differences between this proposed AD, the service information, and the CAA AD? The service information requires repetitive inspections at intervals not to exceed 500 hours time-in-service (TIS) or 1,200 landings, whichever occurs first. This proposed AD and the CAA AD require repetitive inspections at intervals not to exceed 100 hours TIS or 200 landings, whichever occurs first, in order to ensure that the unsafe condition specified in this proposed AD does not go undetected for a long period of time.

Is there a modification I can incorporate instead of repetitively inspecting the oleo attachment brackets? The FAA has determined that long-term continued operational safety would be better assured by design changes that remove the source of the problem rather than by repetitive inspections or other special procedures. With this in mind, FAA will continue to work with Pilatus Britten-Norman.

The manufacturer is now in the process of changing the design of the oleo attachment bracket, P/N NB-40-0075. The design change will eliminate the need for the repetitive inspection. The newly designed part will be introduced by a new modification that will be included as part of Issue 3 of Service Bulletin SB 273.

Cost Impact

How many airplanes would this proposed AD impact? We estimate that this proposed AD affects 126 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 the proposed inspections:

Labor cost	Parts cost	Total cost per airplane
3 workhours × $60 per hour = $180	No cost for parts.	$180.

We estimate the following costs to accomplish any necessary replacements that would be required based on the results of the proposed inspection. We have no way of determining the number of airplanes that may need such repair/replacement:

Labor cost	Parts cost	Total cost per airplane
12 workhours × $60 per hour = $720	$370.	$720 + $370 = $1,090.

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-39-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, BN-2T-4R, BN2A MK. III, BN2A MK. III-2, and BN2A MK. III-3 airplanes, all constructor numbers, that are certificated in any category.

(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 cracked oleo attachment brackets. Such a condition could cause the attachment bracket to fail, which could result in detachment of the main landing gear.

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

Actions	Compliance	Procedures
(1) Inspect, visually or using 10× magnifying glass, the oleo attachment brackets, part number (P/N) NB-40-0075, for cracks	Within the next 25 hours time-in-service (TIS) or 50 landings, whichever occurs first, after the effective date of this AD, and thereafter at intervals not to exceed 100 hours TIS or 2000 landings, whichever occurs first	In accordance with B-N Service Bulletin Number SB 273, Issue 2, dated January 12, 200.
(2) If cracks are found during any inspection required by this AD, replace the bracket with another oleo attachment bracket, P/N NB-40-0075	Prior to further flight after the inspection(s) required in paragraph (d)(1) of this AD in which the crack is found. Repetitively inspect thereafter at intervals not to exceed 100 hours TIS or 200 landings, whichever occurs first	In accordance with B-N Service Bulletin Number SB 273, Issue 2, dated January 12, 2000, and the applicable maintenance manual.
(3) Do not install any oleo attachment bracket, P/N NB-40-0075 (or FAA-approved equivalent part number), unless it has been inspected as required in paragraph (d)(1) of this AD and determined to be airworthy	As of the effective date of this AD.	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 United Kingdom CAA AD 005-09-2000, not dated.

Issued in Kansas City, Missouri, on November 14, 2001.

Michael K. Dahl,

Acting Manager, Small Airplane Directorate, Aircraft Certification Service.