02-7417. Airworthiness Directives; de Havilland Inc. Models DHC-2 Mk. I, DHC-2 Mk. II, and DHC-2 Mk. III 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 de Havilland Inc. (de Havilland) Models DHC-2 Mk. I, DHC-2 Mk. II, and DHC-2 Mk. III airplanes. This proposed AD would establish a life limit for the front fuselage struts and would require you to repetitively replace the front fuselage struts every 15 years or repetitively inspect the struts for corrosion or fatigue damage and replace when the damage exceeds a certain level. This proposed AD is the result of mandatory continuing airworthiness information (MCAI) issued by the airworthiness authority for Canada. The actions specified by the proposed AD are intended to prevent structural failure of the front fuselage caused by corrosion or fatigue damage to the struts that develops over time, which could result in reduced or loss of control of the airplane.

DATES:

The Federal Aviation Administration (FAA) must receive any comments on this proposed rule on or before May 10, 2002.

ADDRESSES:

Submit comments to FAA, Central Region, Office of the Regional Counsel, Attention: Rules Docket No. 98-CE-124-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 also send comments electronically to the following address: [e-mail]. Comments sent electronically must contain “Docket No. 98-CE-124-AD” in the subject line. If you send comments electronically as attached electronic files, the files must be formatted in Microsoft Word 97 for Windows or ASCII text.

You may get service information that applies to this proposed AD from Bombardier Inc., Bombardier Regional Aircraft Division, 123 Garratt Boulevard, Downsview, Ontario, Canada M3K 1Y5; telephone: [phone]. You may also view this information at the Rules Docket at the address above.

FOR FURTHER INFORMATION CONTACT:

Mr. Jon Hjelm, Aerospace Engineer, New York Aircraft Certification Office, 10 Fifth Street, 3rd Floor, Valley Stream, New York 11581-1200; 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 mailed comments, you must include a self-addressed, stamped postcard. On the postcard, write “Comments to Docket No. 98-CE-124-AD.” We will date stamp and mail the postcard back to you.

Discussion

What Events Have Caused This Proposed AD?

Transport Canada, which is the airworthiness authority for Canada, notified FAA that an unsafe condition may exist on certain de Havilland Models DHC-2 Mk. I, DHC-2 Mk. II, and DHC-2 Mk. III airplanes. Transport Canada reports numerous incidents of corrosion of the front fuselage struts. Further analysis of the front fuselage struts reveals that these parts are not life limited and incur corrosion and fatigue damage over time.

What are the Consequences if the Condition is not Corrected?

Corrosion damage, if not detected and corrected, could result in failure of the front fuselage and possible reduced or loss of control of the airplane.

Is There Service Information That Applies to This Subject?

De Havilland Inc. has issued Parts Service Manual (PSM) No. 1-2-2, Part 5, Temporary Revision 2-22; and PSM No. 1-2T-2, Part 5, Temporary Revision 2T-6, both dated August 3, 1998. These service documents establish a life limit of 15 years for the front fuselage struts. The procedures for replacement of the front fuselage struts are included in the applicable maintenance manual.

What Action did the Transport Canada Take?

Transport Canada issued Canadian AD CF-98-37, dated September 29, 1998, in order to ensure the continued airworthiness of these airplanes in Canada. This Canadian AD established a 15-year life limit on the front fuselage struts and requires replacement at that time on the affected airplanes in the Canadian registry.

Transport Canada revised this AD (Canadian AD CF-98-37R1, dated August 20, 1999) to allow repetitive inspections of the front fuselage struts until corrosion damage exceeds a certain limit. When it exceeds this limit, front fuselage strut replacement is mandatory.

Was This in accordance With the Bilateral Airworthiness Agreement?

These airplane models are manufactured in Canada 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, Transport Canada 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 Transport Canada; 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 de Havilland Inc. Models DHC-2 Mk. I, DHC-2 Mk. II, and DHC-2 Mk. III airplanes of the same type design that are on the U.S. registry;

—A life limit of 15 years should be established on the front fuselage struts of 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 establish a life limit for the front fuselage struts and would require you to repetitively replace the front fuselage struts every 15 years or repetitively inspect the struts for corrosion or fatigue damage and replace when the damage exceeds a certain level.

Cost Impact

How Many Airplanes Would This Proposed AD Impact?

We estimate that this proposed AD would affect 354 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 replacement:

Labor cost	Parts cost per airplane	Total cost per airplane	Total cost on U.S. operators
108 workhours X $60 an hour = $6,480 per airplane	$2,352	$8,832	$3,126,528 per replacement

Compliance Time of this Proposed AD

What Would be the Compliance Time of This Proposed AD?

The replacement compliance time of this proposed AD is upon accumulating 15 years from the date of installation of the front fuselage struts or within the next 12 calendar months after the effective date of this AD, whichever occurs later, and thereafter at intervals not to exceed 15 years. If the repetitive inspection option is used, then the repetitive compliance time interval would be at 1 and 5 years depending on the method used (provided certain corrosion or damage limits are not exceeded).

Why is the Compliance Time Presented in Calendar Time Instead of Hours Time-in-Service (TIS)?

The compliance of the proposed AD is presented in calendar time instead of hours TIS. The need for establishing a life limit for the front fuselage struts as specified in the proposed AD is the result of reports of corrosion found in this area on the affected airplanes. Corrosion can occur regardless of whether the aircraft is in operation. In order to ensure that the unsafe condition specified in the proposed AD does not go undetected if the airplane was not in operation for an extended period of time, the compliance is presented in calendar time instead of hours TIS.

Regulatory Flexibility Determination and Analysis

What are the requirements of the Regulatory Flexibility Act?

The Regulatory Flexibility Act of 1980 was enacted by Congress to assure that small entities are not unnecessarily or disproportionately burdened by government regulations. This Act establishes “as principle of regulatory issuance that agencies shall endeavor, consistent with the objectives of the rule and of applicable statutes, to fit regulatory and informational requirements to the scale of the businesses, organizations, and governmental jurisdictions subject to regulation.” To achieve this principle, the Act requires agencies to solicit and consider flexible regulatory proposals and to explain the rationale for their actions. The Act covers a wide range of small entities, including small businesses, not-for-profit organizations, and small governmental jurisdictions.

Agencies must perform a review to determine whether a proposed or final rule will have a significant economic impact on a substantial number of small entities. If the determination is that the rule will, the Agency must prepare a regulatory flexibility analysis as described in the RFA.

However, if an agency determines that a proposed or final rule is not expected to have a significant economic impact on a substantial number of small entities, section 605(b) of the RFA provides that the head of the agency may so certify and a regulatory flexibility analysis is not required. The certification must include a statement providing the factual basis for this determination, and the reasoning should be clear.

What is FAA's Determination?

The FAA has determined that this proposed AD could have a significant economic impact on a substantial number of small entities. However, we have determined that we should continue with this proposed action in order to address the unsafe condition and ensure aviation safety.

You may obtain a copy of the complete Regulatory Flexibility Analysis (entitled “Initial Regulatory Flexibility Analysis”) that was prepared for this proposed AD from the Docket file at the location listed under the ADDRESSES section of this document.

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, could 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:

de Havilland Inc.: Docket No. 98-CE-124-AD

(a) What airplanes are affected by this AD? This AD affects all serial numbers of Models DHC-2 Mk. I, DHC-2 Mk. II, and DHC-2 Mk. III airplanes that are certificated in any category.

(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 prevent structural failure of the front fuselage caused by corrosion or fatigue damage to the struts that develops over time, which could result in reduced or loss of control of the airplane.

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

Actions	Compliance	Procedures
(1) Replace each front fuselage strut with a new strut. Part numbers for existing and replacement front fuselage struts parts are presented in paragraph (e) of this AD	Initially replace upon accumulating 15 years on each front fuselage strut or within the next 12 calendar months after the effective date of this AD, whichever occurs later. Repetitively replace thereafter upon accumulating 15 years on each front fuselage strut	In accordance with the applicable maintenance manual, as specified in de Havilland Parts Service Manual 1-2-2, Part 5, Temporary Revision 2-22; and de Havilland Parts Service Manual 1-2T-2, Part 5, Temporary Revision 2T-6, both dated August 3, 1998.
(2) As an alternative method of compliance to the replacements in paragraph (d)(1) of this AD, you may repetitively inspect each front fuselage strut, as follows:	Initially inspect upon accumulating 15 years on each front fuselage strut or within the next 12 calendar months after the effective date of this AD, whichever occurs later. Accomplish the repetitive detailed inspection thereafter at intervals not to exceed 12 months and the ultrasonic thickness measurement at intervals not to exceed 5 years. Accomplish the corrosion prevention work prior to further flight after each inspection. Accomplish the replacement prior to further flight after damage is found or the thickness is found below 0.030 inches. Then after replacement either replace with a new strut at 15-year intervals thereafter or repetitively inspect as prescribed above beginning at 15 years after each replacement	For the detailed inspection, use an inspection light, inspection mirror, and 10X magnifying glass. For the ultrasonic inspection, use FAA-approved procedures that follow a similar calibration and measures strut thickness to that detailed in Bombardier Service Bulletin 2/49, Revision C.
(i) perform a detailed inspection of each front fuselage strut and all fittings attached to the frame for damage (corrosion, cracks, dents). When fatigue damage is found, you must replace the damaged strut. After each inspection, clean the drain holes around the bottom end fitting and protect the tube with an appropriate corrosion preventive spray. Part numbers for existing and replacement front fuselage struts parts are presented in paragraph (e) of this AD
(ii) perform an ultrasonic thickness measurement of all surfaces on each front months and the Service fuselage strut. When minimum thickness is below 0.030 inches, you must replace the affected strut. Part numbers for existing and replacement front fuselage struts parts are presented in paragraph (e) of this AD
(3) Do not install, on any affected airplane, any front fuselage strut unless it has a part number specified in the Replacement Part Number column of the chart presented in paragraph (e) of this AD	As of the effective date of this AD	Not Applicable.

(e) What part number front fuselage struts should I use for replacements? The following charts presents the part numbers for existing parts and replacement parts for the front fuselage strut replacements:

Installed part number	Replacement part number	Description
C2FS209 or C2FS3281A	C2FS3281A	Strut Assembly Front Fuselage, Left.
C2FS210 or C2FS3282A	C2FS3282A	Strut Assembly Front Fuselage, Right.

(f) 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, New York Aircraft Certification Office, approves your alternative. Submit your request through an FAA Principal Maintenance Inspector, who may add comments and then send it to the Manager, New York Aircraft Certification Office.

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 (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 you have not eliminated the unsafe condition, specify actions you propose to address it.

(g) Where can I get information about any already-approved alternative methods of compliance? Contact Jon Hjelm, Aerospace Engineer, FAA, New York Aircraft Certification Office, 10 Fifth Street, Third Floor, Valley Stream, New York 11581; telephone: [phone]; facsimile: [phone].

(h) 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.

(i) How do I get copies of the documents referenced in this AD? You may direct technical questions to or get copies of the documents referenced in this AD from Bombardier Inc., Bombardier Regional Aircraft Division, 123 Garratt Boulevard, Downsview, Ontario, Canada M3K 1Y5; telephone: [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 Canadian AD CF-98-37R1, dated August 20, 1999.

Issued in Kansas City, Missouri, on March 20, 2002.

Dorenda D. Baker,

Acting Manager, Small Airplane Directorate, Aircraft Certification Service.