Airworthiness Directives; Robert E. Rust Models DeHavilland DH.C1 Chipmunk 21, 22, and 22A Airplanes

AGENCY:

Federal Aviation Administration, DOT.

ACTION:

Final rule.

SUMMARY:

This amendment adopts a new airworthiness directive (AD) that applies to certain Robert E. Rust (R.E. Rust) Models DeHavilland DH.C1 Chipmunk 21, 22, and 22A airplanes. This AD requires you to repetitively inspect the tailplane attachment brackets and replace each bracket at a specified time. This AD also requires you to repetitively inspect each joint of the port and starboard engine mount frame and the rear upper mount frame tubes for cracks and/or damage and repair any cracks and/or damage found. This AD is the result of reports of stress corrosion cracking found on the tailplane attachment brackets and fatigue cracking and chaffing of the engine mount frame. The actions specified by this AD are intended to prevent failure of the tailplane attachment brackets caused by stress corrosion cracking and failure of the engine mount, which could result in loss of the tail section and separation of the engine from the airplane respectively. Such failures could lead to loss of control of the airplane.

DATES:

This AD becomes effective on October 10, 2003.

The Director of the Federal Register approved the incorporation by reference of certain publications listed in the regulations as of October 10, 2003.

ADDRESSES:

You may get the service information referenced in this AD from DeHavilland Support Limited, Duxford Airfield, Bldg. 213, Cambridgeshire, CB2 4QR, United Kingdom, telephone: +44 1223 830090, facsimile: +44 1223 830085, e-mail: info@dhsupport.com. You may view this information at the Federal Aviation Administration (FAA), Central Region, Office of the Regional Counsel, Attention: Rules Docket No. 2000-CE-64-AD, 901 Locust, Room 506, Kansas City, Missouri 64106; or at the Office of the Federal Register, 800 North Capitol Street NW., suite 700, Washington, DC.

FOR FURTHER INFORMATION CONTACT:

Cindy Lorenzen, Aerospace Engineer, FAA, Atlanta Aircraft Certification Office, 1895 Phoenix Boulevard, suite 450, Atlanta, Georgia; telephone: (770) 703-6078; facsimile: (770) 703-6097.

SUPPLEMENTARY INFORMATION:

Discussion

What Events Have Caused This AD?

We received reports that an unsafe condition exists on certain R.E. Rust Models DeHavilland DH.C1 Chipmunk 21, 22, and 22A airplanes. After reviewing several of these airplanes, stress corrosion cracking was found on the tailplane attachment brackets and fatigue cracks and chaffing were found on the engine mount frame.

Cracks in the engine mount frame were found in the area of the junction of the front and rear top tube and engine mounting foot support brackets and in the front of the frame. We have determined that fatigue is the cause of the cracks. The upper aft mount frame tubes were also found to have damage caused by chaffing by the cowling support rod.

What Is the Potential Impact if FAA Took No Action?

These conditions, if not corrected, could result in failure of the tailplane attachment brackets and failure of the engine mount. Such failures could lead to loss of control of the airplane.

Has FAA Taken Any Action to This Point?

We issued a proposal to amend part 39 of the Federal Aviation Regulations (14 CFR part 39) to include an AD that would apply to certain R.E. Rust Models DeHavilland DH.C1 Chipmunk 21, 22, and 22A airplanes. This proposal was published in the Federal Register as a supplemental notice of proposed rulemaking (NPRM) on April 15, 2003 (68 FR 18571). The supplemental NPRM proposed to require you to repetitively inspect the tailplane attachment brackets and replace each bracket at a specified time. The NPRM also proposed to require you to repetitively inspect each joint of the port and starboard engine mount frame and the rear upper mount frame tubes for cracks and/or damage and repair any cracks and/or damage found.

Was the Public Invited To Comment?

The FAA encouraged interested persons to participate in the making of this amendment. We did not receive any comments on the proposed rule or on our determination of the cost to the public.

FAA's Determination

What Is FAA's Final Determination on This Issue?

After careful review of all available information related to the subject presented above, we have determined that air safety and the public interest require the adoption of the rule as proposed except for minor editorial corrections. We have determined that these minor corrections:

—Provide the intent that was proposed in the supplemental NPRM for correcting the unsafe condition; and

—Do not add any additional burden upon the public than was already proposed in the Supplemental NPRM.

How Does the Revision to 14 CFR Part 39 Affect This AD?

On July 10, 2002, FAA 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 special flight permits, alternative methods of compliance, and altered products. 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.

Cost Impact

How Many Airplanes Does This AD Impact?

We estimate that this AD affects 54 airplanes in the U.S. registry.

What Is the Cost Impact of This AD on Owners/Operators of the Affected Airplanes?

We estimate the following costs to accomplish an inspection of the tailplane attachment brackets:

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 replacement:

We estimate the following costs to accomplish an inspection of the engine mount frame:

The FAA has no method of determining the number of repairs or replacements each owner/operator will incur over the life of each of the affected airplanes based on the results of the proposed inspections. We have no way of determining the number of airplanes that may need such repair. The extent of damage may vary of each airplane.

Compliance Time of This AD

What Will Be the Compliance Time of This AD?

The compliance time for the initial inspections in this AD is “within the next 90 days after the effective date of this AD.”

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

An unsafe condition specified by this AD is caused by corrosion. Corrosion can occur regardless of whether the aircraft is in operation or is in storage. Therefore, to assure that the unsafe condition specified in this AD does not go undetected for a long period of time, the compliance is presented in calendar time instead of TIS.

Regulatory Impact

Does This AD Impact Various Entities?

The regulations adopted herein will 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 final rule does not have federalism implications under Executive Order 13132.

Does This AD Involve a Significant Rule or Regulatory Action?

For the reasons discussed above, I certify that this 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) 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 final evaluation prepared for this action is contained 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
• Incorporation by reference
• Safety

Adoption of the Amendment

Accordingly, under the authority delegated to me by the Administrator, the Federal Aviation Administration amends 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.

2. FAA amends § 39.13 by adding a new AD to read as follows:

2003-17-16 Robert E. Rust: Amendment 39-13291; Docket No. 2000-CE-64-AD.

(a) What airplanes are affected by this AD? This AD affects R.E. Rust Models DeHavilland DH.C1 Chipmunk 21, 22, and 22A airplanes, serial numbers C1-001 through C1-1014, that are type certificated in any category.

Note 1:

We recommend all owners/operators of DeHavilland DH.C1 Chipmunk 21, 22, and 22A airplanes, serial numbers C1-001 through C1-1014, with experimental airworthiness certificates comply with the actions required in this AD.

(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 failure of the tailplane attachment brackets caused by stress corrosion cracking and failure of the engine mount, which could result in loss of the tail section and separation of the engine from the airplane respectively. Such failures could lead to 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:

(e) Can I comply with this AD in any other way? To use an alternative method of compliance or adjust the compliance time, use the procedures in 14 CFR 39.19. Send these requests to the Manager, Atlanta Aircraft Certification Office (ACO). Contact Cindy Lorenzen, Aerospace Engineer, FAA, Atlanta Aircraft Certification Office, 1895 Phoenix Boulevard, Suite 450, Atlanta, Georgia; telephone: (770) 703-6078; facsimile: (770) 703-6097.

(f) Are any service bulletins incorporated into this AD by reference? Actions required by this AD must be done in accordance with British Aerospace Military Aircraft and Aerostructures (BAe Aircraft) Mandatory Technical News Sheet CT (C1) No. 176, Issue 2, dated November 1, 1997; Civil Modification Mandatory Modification No. Chipmunk H357, dated March 12, 1984; British Aerospace Mandatory Technical News Sheet Series: Chipmunk (C1), No. 138, Issue: 5, dated August 1, 1985; and British Aerospace Aerostructures Limited (BAe Aircraft) Mandatory Technical News Sheet CT (C1) No. 190, Issue 2, including Appendix 1 (Part B), dated April 1, 1995. The Director of the Federal Register approved this incorporation by reference under 5 U.S.C. 552(a) and 1 CFR part 51. You may get copies from DeHavilland Support Limited, Duxford Airfield, Bldg. 213, Cambridgeshire, CB2 4QR, United Kingdom, telephone: +44 1223 830090, facsimile: +44 1223 830085, e-mail: info@dhsupport.com. You may view copies at the FAA, Central Region, Office of the Regional Counsel, 901 Locust, Room 506, Kansas City, Missouri, or at the Office of the Federal Register, 800 North Capitol Street, NW., suite 700, Washington, DC.

(g) When does this amendment become effective? This amendment becomes effective on October 10, 2003.