02-4865. Airworthiness Directives; Pilatus Aircraft Ltd. Models PC-12 and PC-12/45 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 Aircraft Ltd. (Pilatus) Models PC-12 and PC-12/45 airplanes. This proposed AD would require you to inspect the left and right main landing gear (MLG) assemblies for bolts with a serial number (S/N) beginning with the letters “AT” and numbers 299 or lower and replace each bolt with a bolt that does not have a S/N with both the letters “AT” and a number of 299 or lower. This proposed AD is the result of mandatory continuing airworthiness information (MCAI) issued by the airworthiness authority for Switzerland. The actions specified by this proposed AD are intended to detect and replace defective MLG assembly bolts that have an improper cadmium plating, which could cause hydrogen embrittlement and bolt failure. Such failure could lead to MLG collapse during landing.

DATES:

The Federal Aviation Administration (FAA) must receive any comments on this proposed rule on or before April 1, 2002.

ADDRESSES:

Submit comments to FAA, Central Region, Office of the Regional Counsel, Attention: Rules Docket No. 2001-CE-44-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 Aircraft Ltd., Customer Liaison Manager, CH-6371 Stans, Switzerland; telephone: [phone]; facsimile: [phone]; or from Pilatus Business Aircraft Ltd., Product Support Department, 11755 Airport Way, Broomfield, Colorado 80021; 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-44-AD.” We will date stamp and mail the postcard back to you.

Discussion

What events have caused this proposed AD? The Federal Office for Civil Aviation (FOCA), which is the airworthiness authority for Switzerland, recently notified FAA that an unsafe condition may exist on certain Pilatus Models PC-12 and PC-12/45 airplanes. The FOCA reports that, because of a manufacturing defect, certain bolts on the main landing gear (MLG) assembly may be defective. The problem is caused by an improper cadmium process applied to the high strength steel part, which can cause hydrogen embrittlement and subsequent failure of the bolt.

The defective bolts were initially installed on MLG assemblies that have a serial number beginning with the letters “AM”. Each bolt in the defective lot incorporates the letters “AT” and a number of 299 or lower.

What are the consequences if the condition is not corrected? If not corrected, such failure could lead to MLG collapse during landing.

Is there service information that applies to this subject? Pilatus has issued Pilatus PC-12 Service Bulletin No. 32-012, dated October 18, 2001.

What are the provisions of this service information? The service bulletin includes procedures for replacing defective bolts in the main landing gear assemblies.

What action did the FOCA take? The FOCA classified this service bulletin as mandatory and issued Swiss AD Number HB 2001-603, dated November 5, 2001, in order to ensure the continued airworthiness of these airplanes in Switzerland.

Was this in accordance with the bilateral airworthiness agreement? These airplane models are manufactured in Switzerland and are type certificated for operation in the United States under the provisions of § 21.29 of the Federal Aviation Regulations (14 CFR 21.29) and the applicable bilateral airworthiness agreement.

Pursuant to this bilateral airworthiness agreement, the FOCA 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 FOCA; 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 other Pilatus Models PC-12 and PC-12/45 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 incorporate the actions in the previously-referenced service bulletin.

Cost Impact

How many airplanes would this proposed AD impact? We estimate that this proposed AD affects 16 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 inspection and replacement:

Labor cost	Parts cost	Total cost per airplaine	Total cost U.S. operators
Manufacturer will pay for workhours	Parts will be provided at no cost to the owners/operators of the affected aircraft	None	None.

Compliance Time of This Proposed AD

What would be the compliance time of this proposed AD? The compliance time of this proposed AD is “within the next 30 days after the effective date of this AD”.

Why is the compliance time presented in calendar time instead of hours time-in-service (TIS)? Although malfunction of the main landing gear is unsafe during flight, the condition is not a direct result of airplane operation. The chance of this situation occurring is the same for an airplane with 10 hours TIS as it would be for an airplane with 500 hours TIS. A calendar time for compliance would ensure that the unsafe condition is addressed on all airplanes in a reasonable time period.

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 Aircraft Ltd.: Docket No. 2001-CE-44-AD

(a) What airplanes are affected by this AD? This AD affects the following airplane models and serial numbers that are certificated in any category:

(1) Group 1: Pilatus may have installed the affected bolts on the following airplanes at manufacture. All portions of this AD apply to these airplanes:

Model	Serial numbers
PC-12 and PC-12/45	349, 352, 357, 359, 362 through 365, 367, 369, 371, 375, 377, 380, 384, 385, 388, 390, 391, 393, 401, and 409.

(2) Group 2: The affected bolts could be installed through spare replacement on any of the following model airplanes. Paragraphs (d)(3) and (d)(4) of this AD apply to these airplanes:

Model	Serial numbers
PC-12 and PC-12/45	All serial numbers.

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

(c) What problem does this AD address? The actions specified by this AD are intended to detect and replace defective main landing gear (MLG) assembly bolts that have an improper cadmium plating, which could cause hydrogen embrittlement and bolt failure.

(d) What actions must I accomplish to address this problem? To address this problem, accomplish all actions for Group 1 airplanes, and accomplish paragraphs (d)(3) and (d)(4) of this AD for Group 2 airplanes:

Actions	Compliance	Procedures
(1) Inspect the left and right main landing gear (MLG) assembly for the existence of a bolt, part number (P/N) 532.10.12.077, that has a serial number (S/N) with both the letters “AT” and a number of 299 or lower	Inspect within the next 30 days after the effective date of this AD. Prior to further flight, replace bolts found during the inspection required in paragraph (d)(1) of this AD	Pilatus PC-12 Service Bulletin No. 32-012, dated October 18, 2001, provides information about these actions.
(i) If the above referenced bolts are not installed, no further action is required
(ii) If the above referenced bolts are installed, replace each bolt with an FAA-approved bolt that does not have a S/N with both the letters “AT” and a number of 299 or lower
(2) Send the removed bolts to Pilatus Aircraft Ltd. so the bolts cannot be reused and report the results of the inspection (positive or negative) to FAA. The Office of Management and Budget (OMB) approved the information collection requirements contained in this regulation under the provisions of the Paperwork Reduction Act of 1980 (44 U.S.C. 3501 et seq.) and assigned OMB Control Number 2120-0056	Within 10 days after removing the bolts or within 10 days after the effective date of this AD, whichever occurs later	Send the removed bolts to Pilatus Aircraft Ltd. at the address in paragraph (h) of this AD, and send the report to Doug Rudolph, FAA, at the address in paragraph (f) of this AD.
(3) Do not install any bolt, P/N 532.10.12.007, on any MLG assembly that has a S/N with both the letters “AT” and a number of 299 or lower	As of the effective date of this AD	Not Applicable.
(4) If you have already accomplished the actions specified in Pilatus PC-12 Service Bulletin No. 32-012, dated October 18, 2001, send a report to the FAA at the address in paragraph (f) of this AD, stating if one of the affected bolts were replaced and returned to Pilatus	Within the next 30 days after 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 Aircraft Ltd., Customer Liaison Manager, CH-6371 Stans, Switzerland; telephone: [phone]; facsimile: [phone]; or from Pilatus Business Aircraft Ltd., Product Support Department, 11755 Airport Way, Broomfield, Colorado 80021; 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 Swiss AD HB 2001-603, dated November 5, 2001.

Issued in Kansas City, Missouri, on February 21, 2002.

Michael Gallagher,

Manager, Small Airplane Directorate, Aircraft Certification Service.