03-27847. Airworthiness Directives; Bombardier Inc. Model Otter DHC-3 Airplanes

AGENCY:

Federal Aviation Administration (FAA), DOT.

ACTION:

Notice of proposed rulemaking (NPRM).

SUMMARY:

The FAA proposes to adopt a new airworthiness directive (AD) for certain Bombardier Inc. (formerly deHavilland Inc.) Model Otter DHC-3 airplanes that have turbine engines installed per one of three supplemental type certificates (STC). This proposed AD would prohibit you from operating any affected airplane with these engine and propeller configurations unless a new STC for an elevator servo-tab with a redundant control linkage is installed. This proposed AD also allows the option of future installations of one of three STCs if a new STC for an elevator servo-tab with a redundant control linkage is also installed. This proposed AD is the result of reports of the control rod to the servo trim tab system detaching from the servo trim tab, which caused the servo trim tab to flutter on airplanes with a turbine engine installed. We are issuing this proposed AD to prevent a single failure of the elevator servo trim tab system, which could cause severe elevator flutter. Such failure could lead to possible loss of control of the airplane.

DATES:

We must receive any comments on this proposed AD by December 15, 2003.

ADDRESSES:

Use one of the following to submit comments on this proposed AD:

• By mail: FAA, Central Region, Office of the Regional Counsel, Attention: Rules Docket No. 2000-CE-73-AD, 901 Locust, Room 506, Kansas City, Missouri 64106.

By fax: [phone].

• By e-mail: [e-mail]. Comments sent electronically must contain “Docket No. 2000-CE-73-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.

You may get the service information identified in this proposed AD from:

• For STC No. SA3777NM: A.M. Luton 3025 Eldridge Avenue, Bellingham, Washington, 98225; telephone [phone]; facsimile [phone].
• For STC No. SA09866SC: Texas Turbine Conversions, Inc., 8955 CR 135, Celina Texas 75009; telephone: [phone]; facsimile: [phone].
• For STC No. SA09857SC: Canada Turbine Conversions, Inc., Lot 16, 105081 Highway 11, Pine Falls MB ROE 1MO, Canada.
• For STC No. SA01059SE: American Aeromotives, Inc. (American Aeromotives), 3025 Eldridge Avenue, Bellingham, Washington 98225, telephone: [phone]; facsimile: [phone].

You may view the AD docket at FAA, Central Region, Office of the Regional Counsel, Attention: Rules Docket No. 2000-CE-73-AD, 901 Locust, Room 506, Kansas City, Missouri 64106. Office hours are 8 a.m. to 4 p.m., Monday through Friday, except Federal holidays.

FOR FURTHER INFORMATION CONTACT:

• For STC No. SA3777NM or STC No. SA01059SE: Richard Simonson, Aerospace Engineer, FAA, Seattle Aircraft Certification Office (ACO), 1601 Lind Avenue, SW, Renton, Washington 98055; telephone: [phone]; facsimile: [phone].
• For STC No. SA09866SC: Richard Karanian, Aerospace Engineer, Special Certification Office, FAA, Rotorcraft Directorate, Special Certification Office, 2601 Meacham Boulevard, Fort Worth, Texas 76193-0190; telephone: [phone]; facsimile: [phone].
• For STC No. SA09857SC: Peter W. Hakala, Aerospace Engineer, FAA, Special Certification Office, Rotorcraft Directorate, 2601 Meacham Boulevard, Fort Worth, Texas 76193-0190; telephone: [phone]; facsimile: [phone].

SUPPLEMENTARY INFORMATION:

Comments Invited

How do I comment on this proposed AD? We invite you to submit any written relevant data, views, or arguments regarding this proposal. Send your comments to an address listed under ADDRESSES. Include “AD Docket No. 2000-CE-73-AD” in the subject line of your comments. If you want us to acknowledge receipt of your mailed comments, send us a self-addressed, stamped postcard with the docket number written on it. We will date-stamp your postcard and mail it back to you.

Are there any specific portions of this proposed AD I should pay attention to? We specifically invite comments on the overall regulatory, economic, environmental, and energy aspects of this proposed AD. If you contact us through a nonwritten communication and that contact relates to a substantive part of this proposed AD, we will summarize the contact and place the summary in the docket. We will consider all comments received by the closing date and may amend this proposed AD in light of those comments and contacts.

Discussion

What events have caused this proposed AD? The FAA has received several reports of situations where pilots of Bombardier Inc. Model Otter DHC-3 airplanes with installed turbine engines have experienced buffeting of the elevators. All pilots declared an emergency and safely landed their aircraft.

Investigation found that the control rod to the servo trim tab system detached from the servo trim tab and caused the servo trim tab to flutter. In all cases, the aircraft had been modified with a Pratt and Whitney PT6A-135 or a PT6A-34 turbine engine per STC No. SA3777NM.

The certification basis for STC SA3777NM includes freedom from flutter and control reversal and divergence, required by 14 CFR 23.629(f)(1). Further review reveals that this requirement was not complied with when the STC was issued. Subsequent to the issuance of the STC, single failures of the control system for the servo tab began causing the servo tab to flutter. The failures were attributed to the increased velocity and airflow over the servo tab caused by the turbine conversion.

As a method of compliance with 14 CFR 23.629(f)(1), American Aeromotives has identified the installation of STC No. SA01059SE (a new elevator servo-tab and redundant control linkage) on aircraft modified with a Pratt and Whitney PT6A-34/-135 turbine engine per STC No. SA3777NM.

FAA has inspected affected airplanes with STC No. SA09866SC or STC No. SA09857SC installed and confirmed that the same unsafe condition exists. At this time, neither of these two STC holders has identified a method of compliance with 14 CFR 23.629(f)(1).

As a method of compliance with 14 CFR 23.629(f)(1), FAA has identified the installation of STC No. SA01059SE (a new elevator servo-tab and redundant control linkage) on aircraft modified with STC No. SA09866SC or STC No. SA09857SC.

What are the consequences if the condition is not corrected? A single failure of the elevator servo trim tab system could cause severe elevator flutter and lead to possible loss of control of the airplane.

Is there service information that applies to this subject? American Aeromotives has issued Service Letter No. AAI-DHC3-02.01, Revision No: IR, dated April 9, 2002.

What are the provisions of this service information? The service letter includes procedures for incorporating STC No. SA01059SE, which includes a new elevator servo-tab and redundant control linkage.

FAA's Determination and Requirements of This Proposed AD

What has FAA decided? We have evaluated all pertinent information and identified an unsafe condition that is likely to exist or develop on other products of this same type design. Therefore, we are proposing AD action.

What would this proposed AD require? This proposed AD would prohibit you from operating any affected airplane that incorporates STC No. SA3777NM, STC No. SA09866SC, or STC No. SA09857SC without incorporation of STC No. SA01059SE.

How does the revision to 14 CFR part 39 affect this proposed AD? On July 10, 2002, we published a new version of 14 CFR part 39 (67 FR 47997, July 22, 2002), which governs FAA's AD system. This regulation now includes material that relates to altered products, special flight permits, and alternative methods of compliance. This material previously was included in each individual AD. Since this material is included in 14 CFR part 39, we will not include it in future AD actions.

Costs of Compliance

How many airplanes would this proposed AD impact? We estimate that this proposed AD affects 32 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 this proposed modification (on Model DHC-3 airplanes with a turbine engine) for installing STC No. SA01059SE, a new elevator servo-tab and redundant control linkage. We have no way of determining the number of airplanes that may need such modification:

Labor cost	Parts cost	Total cost per airplane
20 workhours × $65 per hour = $1,300	$3,000	$1,300+$3,000 = $4,300.

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 3 calendar months or 250 hours time-in-service after the effective date of this AD whichever occurs first.

Why is the compliance time of this proposed AD presented in both hours TIS and calendar time? A single failure of the elevator servo trim tab system is a direct result of airplane operation with a turbine engine installed. For example, a single failure of the elevator servo trim tab system could occur on an affected airplane within a short period of airplane operation while you could operate another affected airplane for a considerable amount of time without experiencing a single failure of the elevator servo trim tab system. Therefore, to assure that a single failure of the elevator servo trim tab system is detected and corrected in a timely manner without inadvertently grounding any of the affected airplanes, we are using a compliance time based upon both hours TIS and calendar time.

Regulatory Findings

Would this proposed AD impact various entities? We have determined that this proposed AD would not have federalism implications under Executive Order 13132. This proposed AD 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.

Would this proposed AD involve a significant rule or regulatory action? For the reasons discussed above, I certify that this proposed AD:

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. 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.

We prepared a summary of the costs to comply with this proposed AD and placed it in the AD Docket. You may get a copy of this summary by sending a request to us at the address listed under ADDRESSES. Include “AD Docket No. 2000-CE-73-AD” in your request.

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 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. The FAA amends § 39.13 by adding the following new airworthiness directive (AD):

Bombardier Inc.: Docket No. 2000-CE-73-AD.

When Is the Last Date I Can Submit Comments on This Proposed AD?

(a) We must receive comments on this proposed airworthiness directive (AD) by December 15, 2003.

What Other ADs Are Affected by This Action?

(b) None.

What Airplanes Are Affected by This AD?

(c) This AD affects any Model Otter DHC-3 airplane (all serial numbers) that:

(1) Has a turbine engine installed per:

(i) Supplemental Type Certificate (STC) No. SA3777NM (A.M. Luton installation of Pratt and Whitney PT6A-34/-135 engine);

(ii) STC No. SA09866SC (Texas Turbines Conversions, Inc. installation of Honeywell TPE-331 engine); or

(iii) STC No. SA09857SC (Canada Turbine Conversions, Inc. installation of Walter M601E-11 engine); and

(2) Is certificated in any category.

What Is the Unsafe Condition Presented in This AD?

(d) This AD is the result of reports of the control rod to the servo trim tab system detached from the servo trim tab causing the servo trim tab to flutter on airplanes with a turbine engine installed. The actions specified in this AD are intended to prevent a single failure of the elevator servo trim tab system causing severe elevator flutter. Such failure could lead to possible loss of control of the airplane.

What Must I Do To Address This Problem?

(e) To address this problem, you must accomplish the following:

Actions	Compliance	Procedures
(1) Do not operate any airplane that has a turbine engine installed per: STC No. SA3777NM, SA09866SC, or SA09857SC and DOES NOT have a new elevator servo-tab and redundant control linkage per STC No. SA01059SE	As of 3 calendar months or 250 hours time-in-service after the effective date of this AD, whichever comes first.	Not Applicable.
(2) You may install at the same time a turbine engine per STC No. SA3777NM, SA09866SC, or SA09857SC and a new elevator servo-tab and redundant control linkage per STC No. SA01059SE	Prior to further flight as of the effective date of this AD.	Per STC No. SA3777NM and American Aeromotives, Inc. DHC-3 Otter Service Letter No. AAI-DHC3-02.01, Revision No. IR, dated April 9, 2002.
(3) You may operate an affected airplane installed with a turbine engin per STC No. SA3777NM, SA09866SC, or SA09857SC if you install a new elevator servo-tab and redundant control linkage per STC No. SA01059SE	Within 3 calendar months or 250 hours time-in-service after the effective date of this AD, whichever occurs first.	Per American Aeromotives, Inc. DHC-3 Otter Service Letter No. AAI-DHC3-02.01, Revision No. IR, dated April 9, 2002.
(4) Do not install a turbine engine per STC No. SA3777NM, SA09866SC or SA09857SC, unless you have installed a new elevator servo-tab and redundant control linkage per STC No. SA01059SE	As of the effective date of this AD.	Not Applicable.

What About Alternative Methods of Compliance?

(f) You may request a different method of compliance or a different compliance time for this AD by following the procedures in 14 CFR 39.13. Send your request to the Manager, Seattle Aircraft Certification Office (ACO), FAA. For information on any already approved alternative methods of compliance, contact:

(1) For STC No. SA3777NM or STC No. SA01059SE: Richard Simonson, Aerospace Engineer, FAA, Seattle Aircraft Certification Office (ACO), 1601 Lind Avenue, SW, Renton, Washington 98055; telephone: [phone]; facsimile: [phone].

(2) For STC No. SA09866SC: Richard Karanian, Aerospace Engineer, Special Certification Office, FAA, Rotorcraft Directorate, Special Certification Office, 2601 Meacham Boulevard, Fort Worth, Texas 76193-0190; telephone: [phone]; facsimile: [phone].

(3) For STC No. SA09857SC: Peter W. Hakala, Aerospace Engineer, FAA, Special Certification Office, Rotorcraft Directorate, 2601 Meacham Boulevard, Fort Worth, Texas 76193-0190; telephone: [phone]; facsimile: [phone].

How Do I Get Copies of the Documents Referenced in This AD?

(g) You may get copies of the documents referenced in this AD from (for STC No. SA3777NM) A.M. Luton, 3025 Eldridge Avenue, Bellingham, Washington, 98225; telephone [phone]; facsimile [phone] (for STC No. SA09866SC) Texas Turbine Conversions, Inc., 8955 CR 135, Celina Texas 75009; telephone: [phone]; facsimile: [phone]; (for STC No. SA09857SC) Canada Turbine Conversions, Inc., Lot 16, 105081 Highway 11, Pine Falls MB ROE 1MO, Canada; and (for STC No. SA01059SE) American Aeromotives, Inc., 3025 Eldridge Avenue, Bellingham, Washington 98225, 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.

Issued in Kansas City, Missouri, on October 29, 2003.

Dorenda D. Baker,

Acting Manager, Small Airplane Directorate, Aircraft Certification Service.