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Proposed Rule

Airworthiness Directives; Short Brothers Model SD3-60 Airplanes

Document Details

Information about this document as published in the Federal Register.

Published Document

This document has been published in the Federal Register. Use the PDF linked in the document sidebar for the official electronic format.

Start Preamble

AGENCY:

Federal Aviation Administration (FAA), Department of Transportation (DOT).

ACTION:

Notice of proposed rulemaking (NPRM).

SUMMARY:

The FAA proposes to supersede two existing airworthiness directives (ADs) that apply to all Short Brothers Model SD3-60 airplanes. One of the ADs currently requires inspection of the welded joints of the balance weight brackets for the elevator trim tabs for cracking; repetitive inspections, as applicable; and corrective actions including the eventual replacement of all brackets. The other AD currently requires, for certain airplanes, repetitive inspections for cracking of the balance weight brackets and replacement of any cracked bracket, and provides for an optional terminating action for the repetitive inspections. This proposed AD would require an additional inspection to detect cracks of the balance weight brackets, applicable related investigative and corrective actions, and replacement of a certain balance weight bracket when it has reached its maximum life limit. This proposed AD results from a report indicating that several reworked balance weight brackets have exhibited signs of premature failure. We are proposing this AD to prevent failure of the balance weight brackets of the elevator trim tabs, which could cause loss of the balance weight. This could result in incorrect trim during takeoff and landing, and reduced controllability of the airplane.

DATES:

We must receive comments on this proposed AD by May 1, 2008.

ADDRESSES:

You may send comments by any of the following methods:

  • Federal eRulemaking Portal: Go to http://www.regulations.gov. Follow the instructions for submitting comments.
  • Fax: 202-493-2251.
  • Mail: U.S. Department of Transportation, Docket Operations, M-30, West Building Ground Floor, Room W12-140, 1200 New Jersey Avenue, SE., Washington, DC 20590.
  • Hand Delivery: U.S. Department of Transportation, Docket Operations, M-30, West Building Ground Floor, Room W12-140, 1200 New Jersey Avenue, SE., Washington, DC 20590, between 9 a.m. and 5 p.m., Monday through Friday, except Federal holidays.

For service information identified in this AD, contact Short Brothers, Airworthiness & Engineering Quality, P.O. Box 241, Airport Road, Belfast BT3 9DZ, Northern Ireland.

Examining the AD Docket

You may examine the AD docket on the Internet at http://www.regulations.gov; or in person at the Docket Management Facility between 9 a.m. and 5 p.m., Monday through Friday, except Federal holidays. The AD docket contains this proposed AD, the regulatory evaluation, any comments received, and other information. The street address for the Docket Office (telephone 800-647-5527) is in the ADDRESSES section. Comments will be available in the AD docket shortly after receipt.

Start Further Info

FOR FURTHER INFORMATION CONTACT:

Todd Thompson, Aerospace Engineer, International Branch, ANM-116, FAA, Transport Airplane Directorate, 1601 Lind Avenue, SW., Renton, Washington 98057-3356; telephone (425) 227-1175; fax (425) 227-1149.

End Further Info End Preamble Start Supplemental Information

SUPPLEMENTARY INFORMATION:

Comments Invited

We invite you to send any written relevant data, views, or arguments about this proposed AD. Send your comments to an address listed under the ADDRESSES section. Include “Docket No. FAA-2008-0375; Directorate Identifier 2007-NM-272-AD” at the beginning of your comments. We specifically invite comments on the overall regulatory, economic, environmental, and energy aspects of this proposed AD. We will consider all comments received by the closing date and may amend this proposed AD because of those comments.

We will post all comments we receive, without change, to http://www.regulations.gov, including any personal information you provide. We will also post a report summarizing each substantive verbal contact we receive about this proposed AD.

Discussion

On June 16, 2004, we issued AD 2004-13-08, amendment 39-13690 (69 FR 38813, June 29, 2004), for all Short Brothers Model SD3-60 airplanes. That AD requires inspection of the welded joints of the balance weight brackets for the left and right elevator trim tabs for cracking; repetitive inspections, as applicable; and corrective actions including the eventual replacement of all brackets, which constitutes terminating action for the repetitive inspections. That AD resulted from a report indicating that a balance weight assembly for an elevator trim tab detached during landing. We issued that AD to prevent the loss of the balance weight for the elevator trim tab, which could result in incorrect trim during takeoff and landing, and reduced controllability of the airplane.

On February 11, 2005, we issued AD 2005-04-13, amendment 39-13985 (70 FR 9212, February 25, 2005), for all Short Brothers Model SD3-60 airplanes. That AD requires, for certain airplanes, repetitive inspections for cracking of the balance weight brackets of the elevator trim tabs, and replacement of any cracked bracket with a new or reworked bracket that conforms to the approved design standard. That AD also provides for an optional terminating action for the repetitive inspections. That AD resulted from reports indicating that balance weight brackets (which might have been installed in accordance with AD 2004-13-08) have been found cracked on both the left and right elevator trim tabs. We issued that AD to prevent failure of the balance weight bracket for the elevator trim tab, which could cause loss of the balance weight. Start Printed Page 17261This could result in incorrect trim during takeoff and landing, and reduced controllability of the airplane.

Actions Since Existing AD Was Issued

Since we issued AD 2005-04-13, the European Aviation Safety Agency (EASA), which is the Technical Agent for the Member States of the European Community, has informed us that a batch of non-conforming balance weight brackets of the elevator trim tabs, manufactured in 2003 and 2004, were reworked by the manufacturer. These balance weight brackets were considered as fully conforming brackets and were installed in accordance with AD 2005-04-13. Several of these reworked balance weight brackets exhibited signs of premature failure. The premature failures were attributed to the welding operations required as part of the rework. Testing confirmed a reduced service life for the balance weight brackets. Failure of the balance weight brackets of the elevator trim tabs, if not corrected, could cause loss of the balance weight. This could result in incorrect trim during takeoff and landing, and reduced controllability of the airplane.

Relevant Service Information

Shorts has issued Alert Service Bulletins SD360-55-A21, Revision 1, dated March 29, 2007; and SD360-55-20, Revision 2, dated March 29, 2007. The service bulletins describe new procedures for a dye penetrant inspection to detect cracks of certain balance weight brackets of the elevator trim tabs, and applicable related investigative and corrective actions. The related investigative actions involve repeating the inspection described previously. The corrective action involves replacing any cracked balance weight bracket with a new bracket. The service bulletins also describe procedures for eventual replacement of certain balance weight brackets with new brackets, when they have reached their maximum life limit (i.e., 1,750 or 28,800 flight hours depending on the airplane configuration). Accomplishing the replacement would eliminate the need for the repetitive dye penetrant inspections described previously and the repetitive inspections required by ADs 2004-13-08 and 2005-04-13.

Accomplishing the actions specified in the service information is intended to adequately address the unsafe condition. The EASA mandated the service information and issued emergency airworthiness directive 2007-0107-E, dated April 18, 2007, to ensure the continued airworthiness of these airplanes in the European Union.

FAA's Determination and Requirements of the Proposed AD

These airplanes are manufactured in the United Kingdon 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. As described in FAA Order 8100.14A, “Interim Procedures for Working with the European Community on Airworthiness Certification and Continued Airworthiness,” dated August 12, 2005, the EASA has kept the FAA informed of the situation described above. We have examined the EASA's findings, evaluated all pertinent information, and determined that AD action is necessary for airplanes of this type design that are certificated for operation in the United States.

This proposed AD would supersede ADs 2004-13-08 and 2005-04-13 and would retain the requirements of the existing ADs. This proposed AD also would require accomplishing the actions specified in service bulletins described previously.

Differences Between the Proposed AD and EASA Airworthiness Directive

Although the EASA emergency airworthiness directive 2007-0107-E does not list a grace period for certain compliance times, this proposed AD adds a grace period to those compliance times. We find that a grace period will keep airplanes from being grounded unnecessarily.

Change to Existing ADs

This proposed AD would retain all requirements of ADs 2004-13-08 and 2005-04-13. Since AD 2004-13-08 was issued, the AD format has been revised, and certain paragraphs have been rearranged. In addition, the need to supersede two ADs requires that we re-identify the paragraphs for AD 2005-04-13. As a result, the corresponding paragraph identifiers have changed in this proposed AD, as listed in the following tables:

Revised Paragraph Identifiers for AD 2004-13-08

Requirement in AD 2004-13-08Corresponding requirement in this proposed AD
paragraph (a)paragraph (f).
paragraph (b)paragraph (g).
paragraph (c)paragraph (h).
paragraph (d)paragraph (i).
paragraph (e)paragraph (j).
paragraph (f)paragraph (k).

Revised Paragraph Identifiers for AD 2005-04-13

Requirement in AD 2005-04-13Corresponding requirement in this proposed AD
paragraph (f)paragraph (l).
paragraph (g)paragraph (m).
paragraph (h)paragraph (n).
paragraph (i)paragraph (o).
paragraph (j)paragraph (p).

Costs of Compliance

The following table provides the estimated costs for U.S. operators to comply with this proposed AD.

Estimated Costs

ActionWork hoursAverage labor rate per hourPartsCost per airplaneNumber of U.S.- registered airplanesFleet cost
Inspections (required by AD 2004-13-08)12$80None$960, per inspection cycle21$20,160, per inspection cycle.
Replacement (required by AD 2004-13-08)880$632$1,27221$26,712.
Inspections (required by AD 2005-04-13)1280None$960, per inspection cycle21$20,160, per inspection cycle.
Inspection (new proposed action)1280None$960, per inspection cycle21$20,160, per inspection cycle.
Replacement (new proposed action)880$864$1,504, per replacement cycle21$31,584, per replacement cycle.
Start Printed Page 17262

Authority for This Rulemaking

Title 49 of the United States Code specifies the FAA's authority to issue rules on aviation safety. Subtitle I, Section 106, describes the authority of the FAA Administrator. Subtitle VII, Aviation Programs, describes in more detail the scope of the Agency's authority.

We are issuing this rulemaking under the authority described in Subtitle VII, Part A, Subpart III, Section 44701, “General requirements.” Under that section, Congress charges the FAA with promoting safe flight of civil aircraft in air commerce by prescribing regulations for practices, methods, and procedures the Administrator finds necessary for safety in air commerce. This regulation is within the scope of that authority because it addresses an unsafe condition that is likely to exist or develop on products identified in this rulemaking action.

Regulatory Findings

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.

For the reasons discussed above, I certify that the proposed regulation:

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 regulatory evaluation of the estimated costs to comply with this proposed AD and placed it in the AD docket. See the ADDRESSES section for a location to examine the regulatory evaluation.

Start List of Subjects

List of Subjects in 14 CFR Part 39

End List of Subjects

The Proposed Amendment

Accordingly, under the authority delegated to me by the Administrator, the FAA proposes to amend 14 CFR part 39 as follows:

Start Part

PART 39—AIRWORTHINESS DIRECTIVES

1. The authority citation for part 39 continues to read as follows:

Start Authority

Authority: 49 U.S.C. 106(g), 40113, 44701.

End Authority
[Amended]

2. The Federal Aviation Administration (FAA) amends § 39.13 by removing amendments 39-13690 (69 FR 38813, June 29, 2004) and 39-13985 (70 FR 9212, February 25, 2005) and by adding the following new airworthiness directive (AD):

Short Brothers PLC: Docket No. FAA-2008-0375; Directorate Identifier 2007-NM-272-AD.

Comments Due Date

(a) The FAA must receive comments on this AD action by May 1, 2008.

Affected ADs

(b) This AD supersedes ADs 2004-13-08 and 2005-04-13.

Applicability

(c) This AD applies to all Short Brothers Model SD3-60 airplanes, certificated in any category.

Unsafe Condition

(d) This AD results from a report indicating that several reworked balance weight brackets have exhibited signs of premature failure. We are issuing this AD to prevent failure of the balance weight bracket of the elevator trim tab, which could cause loss of the balance weight. This could result in incorrect trim during takeoff and landing, and reduced controllability of the airplane.

Compliance

(e) You are responsible for having the actions required by this AD performed within the compliance times specified, unless the actions have already been done.

Requirements of AD 2004-13-08

Service Bulletin Reference

(f) The term “service bulletin,” as used in paragraphs (g) through (j) of this AD, means the Accomplishment Instructions of Short Brothers Service Bulletin SD360-55-20, dated June 26, 2003; or Revision 01, dated June 20, 2005.

Initial Inspection

(g) Within 2 months after August 3, 2004 (the effective date of AD 2004-13-08): Do a dye penetrant inspection for cracking in the welded joints of the balance weight brackets for the left and right elevator trim tabs, in accordance with the service bulletin.

Investigative and Corrective Actions if No Cracking is Found

(h) If no cracking is found during the inspection required by paragraph (g) of this AD, do the actions required by paragraphs (h)(1) and (h)(2) of this AD at the applicable compliance times.

(1) Repeat the inspection required by paragraph (g) of this AD at intervals not to exceed 4,800 flight hours until the bracket is replaced per paragraph (h)(2) or (i) of this AD.

(2) Prior to the accumulation of 28,800 total flight hours, or within 6 months after August 3, 2004, whichever occurs later: Replace any bracket that has not been replaced per paragraph (i) of this AD with a new bracket or with a serviceable bracket that has been inspected in accordance with paragraph (g) of this AD. Replace in accordance with the service bulletin. Replacement of the brackets constitutes terminating action for the repetitive inspections required by paragraph (h)(1) of this AD.

Corrective Actions if Any Cracking is Found

(i) If any cracking is found during any inspection required by paragraph (g) or (h) of this AD: Before further flight, accomplish the applicable action in paragraph (i)(1) or (i)(2) of this AD in accordance with the service bulletin.

(1) For airplanes that have accumulated less than 28,800 flight hours and on which all cracking on brackets is less than 0.25 inch in length: Repair the affected bracket in accordance with Part B of the service bulletin (including the additional dye penetrant inspection of the repaired welded joint) and repeat the inspection required by paragraph (g) of this AD at intervals not to exceed 4,800 flight hours; or replace the bracket in accordance with paragraph (h)(2) of this AD. Replacement of the bracket constitutes terminating action for the repetitive inspections.

(2) For any airplane on which any cracking on a bracket is 0.25 inch in length or greater, and for any airplane that has accumulated 28,800 flight hours or more on which any cracking of any length is found on a bracket: Replace the affected bracket with a new bracket or with a serviceable bracket that has been inspected in accordance with paragraph (g) of this AD. Replacement of the bracket constitutes terminating action for the repetitive inspections required by paragraph (i)(1) of this AD.

Refitting

(j) Before further flight following any inspection per paragraph (g) or (h) of this AD; or before further flight following repair or replacement of a bracket per paragraphs (h)(2) or (i) of this AD: Refit the balance weights, covers, and trim tabs, in accordance with the service bulletin. Where the service bulletin specifies to contact the manufacturer for disposition of certain conditions while refitting, obtain further disposition instructions from the Manager, International Branch, ANM-116, FAA, Transport Airplane Directorate; or the Civil Aviation Authority (CAA) (or its delegated agent).

Parts Installation

(k) As of August 3, 2004, no person may install on any airplane a balance weight bracket unless the welded joint has been inspected in accordance with paragraph (g) of this AD.

Requirements of AD 2005-04-13

Service Bulletin Reference

(l) The following information applies to the service bulletin referenced in paragraphs (l) through (o) of this AD:

(1) The term “service bulletin,” as used in paragraphs (l) through (o) of this AD, means Start Printed Page 17263the Accomplishment Instructions of Short Brothers Alert Service Bulletin SD360-55-A21, dated December 16, 2004.

(2) Although the service bulletin specifies to return subject parts to the manufacturer, this AD does not include that requirement.

Repetitive Inspections

(m) For airplanes equipped with balance weight brackets of the elevator trim tabs having part number SD3-07-6011xA, and having a serial number beginning with “X3” or “X4”: Prior to the accumulation of 250 flight hours since installation of the subject balance weight bracket of the elevator trim tab, or within 30 flight hours after March 14, 2005 (the effective date of AD 2005-04-13), whichever is later, do a dye penetrant inspection for cracking of the balance weight brackets for the left and right elevator trim tabs, in accordance with the service bulletin.

(1) For a balance weight bracket on which no cracking is found: Do paragraph (o) of this AD, and repeat the inspection thereafter at intervals not to exceed 250 flight hours until paragraph (n) of this AD is accomplished.

(2) For a balance weight bracket on which any cracking is found: Before further flight, replace the bracket with a new or reworked balance weight bracket that conforms to the approved design standard in accordance with the service bulletin, and do paragraph (o) of this AD.

Optional Terminating Action

(n) For airplanes equipped with balance weight brackets of the elevator trim tabs having part number SD3-07-6011xA, and having a serial number beginning with “X3” or “X4”: Replacement of any subject balance weight bracket with a new or reworked balance weight bracket that conforms to the approved design standard, in accordance with the service bulletin, constitutes terminating action for the repetitive inspections required by paragraph (m) of this AD for the replaced bracket.

Refitting

(o) For airplanes equipped with balance weight brackets of the elevator trim tabs having part number SD3-07-6011xA, and having a serial number beginning with “X3” or “X4”: Before further flight following any inspection or replacement of a bracket in accordance with paragraphs (m) and (n) of this AD: Refit the balance weights, covers, and trim tabs, in accordance with the service bulletin. Where the service bulletin specifies to contact the manufacturer for disposition of certain conditions while refitting, obtain further disposition instructions from the Manager, International Branch, ANM-116, FAA, Transport Airplane Directorate; or the Civil Aviation Authority (CAA) (or its delegated agent).

Parts Installation

(p) For all airplanes: As of March 14, 2005, no person may install, on any airplane subject to this AD, a balance weight bracket having part number SD3-07-6011xA, and having a serial number beginning with “X3” or” X4,” unless the bracket is also marked “Rework batch number R-Bxxxxx” (where “xxxxx” is a number).

New Requirements of This AD

Inspection(s) and Replacements

(q) For airplanes equipped with balance weight brackets of the elevator trim tabs having part number SD3-07-6011xA manufactured in the year 2003 or 2004, including re-worked brackets, installed in accordance with paragraph (h)(2), (i)(2), or (n) of this AD, as applicable: Do the actions specified in paragraphs (q)(1) and (q)(2) of this AD in accordance with Parts A and B of the Accomplishment Instructions of Shorts Alert Service Bulletin SD360-55-A21, Revision 1, dated March 29, 2007.

(1) Within 30 flight hours after the effective date of this AD, or within 250 flight hours since installation of the balance weight brackets of the elevator trim tabs or since the last inspection required by paragraph (g), (h)(1), (i)(1), or (m) of this AD, whichever occurs later: Do a dye penetrant inspection to detect cracks of the balance weight brackets of the elevator trim tabs.

(i) If no crack is detected, repeat the dye penetrant inspection at intervals not to exceed 250 flight hours, until the replacement required by paragraph (q)(2) of this AD is done.

(ii) If any crack is detected, before further flight, do the replacement specified in paragraph (q)(2) of this AD.

(2) Before the accumulation of 1,750 flight hours since installation of the balance weight brackets of the elevator trim tabs, or within 180 days after the effective date of this AD, whichever occurs later: Replace the balance weight brackets with new balance weight brackets manufactured in 2005 or later. Thereafter, replace any balance weight bracket with a new bracket manufactured in 2005 or later at intervals not to exceed the accumulation of 1,750 flight hours on that bracket. Accomplishment of the initial replacement ends the repetitive inspection requirements of this AD.

(r) For airplanes equipped with balance weight brackets of the elevator trim tabs having part number SD3-31-6213xB inspected in accordance with paragraph (g), (h)(1), or (i)(1) of this AD and retained or refitted following approved repair in accordance with paragraph (j) of this AD: Do the actions specified in paragraphs (r)(1) and (r)(2) of this AD in accordance with Parts A and B of the Accomplishment Instructions of Shorts Alert Service Bulletin SD360-55-20, Revision 2, dated March 29, 2007.

(1) Within 4,800 flight hours since last inspection, or within 180 days after the effective date of this AD, whichever occurs later, and thereafter at intervals not to exceed 4,800 flight hours: Do a dye penetrant inspection to detect cracks of the balance weight brackets of the elevator trim tabs.

(i) If no crack is detected, repeat the dye penetrant inspection at intervals not to exceed 4,800 flight hours, until the replacement required by paragraph (r)(2) of this AD is done.

(ii) If any crack is detected, before further flight, do the replacement specified in paragraph (r)(2) of this AD.

(2) Before the accumulation of 28,800 flight hours since any balance weight bracket of the elevator trim tabs is new, or within 180 days after the effective date of this AD, whichever occurs later: Replace the balance weight brackets with new balance weight brackets manufactured in 2005 or later. Thereafter, replace any balance weight bracket with a new bracket manufactured in 2005 or later at intervals not to exceed the accumulation of 28,800 flight hours on that bracket. Accomplishment of the initial replacement ends the repetitive inspection requirements of this AD.

Part Installation

(s) For all airplanes: As of the effective date of this AD, no person may install, on any airplane, a balance weight bracket of the elevator trim tab manufactured earlier than 2005.

Alternative Methods of Compliance (AMOCs)

(t)(1) The Manager, International Branch, ANM-116, Transport Airplane Directorate, FAA, has the authority to approve AMOCs for this AD, if requested in accordance with the procedures found in 14 CFR 39.19.

(2) To request a different method of compliance or a different compliance time for this AD, follow the procedures in 14 CFR 39.19. Before using any approved AMOC on any airplane to which the AMOC applies, notify your appropriate principal inspector (PI) in the FAA Flight Standards District Office (FSDO), or lacking a PI, your local FSDO.

Related Information

(u) EASA emergency airworthiness directive 2007-0107-E, dated April 18, 2007, also addresses the subject of this AD.

Start Signature

Issued in Renton, Washington, on March 24, 2008.

Ali Bahrami,

Manager, Transport Airplane Directorate, Aircraft Certification Service.

End Signature End Part End Supplemental Information

[FR Doc. E8-6614 Filed 3-31-08; 8:45 am]

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