2010-14989. Airworthiness Directives; Robert E. Rust, Jr. Model DeHavilland DH.C1 Chipmunk 21, DH.C1 Chipmunk 22, and DH.C1 Chipmunk 22A Airplanes

AGENCY:

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

ACTION:

Notice of proposed rulemaking (NPRM).

SUMMARY:

We propose to adopt a new airworthiness directive (AD) for all Robert E. Rust, Jr. Model DeHavilland DH.C1 Chipmunk 21, DH.C1 Chipmunk 22, and DH.C1 Chipmunk 22A airplanes. This proposed AD would require a one-time inspection of the flap operating system for an unauthorized latch plate design installation. This proposed AD results from a report of a latch plate failing in service that was not made in accordance with the applicable de Havilland drawing. We are proposing this AD to detect and correct unauthorized latch plate design installation, which could result in an un-commanded retraction of the flaps. This failure could lead to a stall during a landing approach.

DATES:

We must receive comments on this proposed AD by August 5, 2010.

ADDRESSES:

Use one of the following addresses to comment on this proposed AD:

• Federal eRulemaking Portal: Go to http://www.regulations.gov. Follow the instructions for submitting comments.
• Fax: [phone].
• 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 proposed AD, contact de Havilland Support Limited, Duxford Airfield, Cambridgeshire, CB22 4QR, England, phone: [phone]; fax: [phone]; e-mail: [e-mail]; Internet: http://www.dhsupport.com/​.

FOR FURTHER INFORMATION CONTACT:

Carey O'Kelley, Aerospace Engineer, FAA, Atlanta Aircraft Certification Office (ACO), 1701 Columbia Avenue, College Park, Georgia 30337; telephone: [phone]; fax: [phone].

SUPPLEMENTARY INFORMATION:

Comments Invited

We invite you to send any written relevant data, views, or arguments regarding this proposed AD. Send your comments to an address listed under the ADDRESSES section. Include the docket number, “FAA-2010-0632; Directorate Identifier 2010-CE-025-AD” at the beginning of your comments. We specifically invite comments on the overall regulatory, economic, environmental, and energy aspects of the proposed AD. We will consider all comments received by the closing date and may amend the proposed AD in light 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 concerning this proposed AD.

Discussion

We have received a report of a latch plate supplied under part number (P/N) C1-CF-1489 failing in service on a Model DeHavilland DH.C1 Chipmunk 21, DH.C1 Chipmunk 22, or DH.C1 Chipmunk 22A airplane. The part in question was not manufactured to the de Havilland drawing for P/N C1-CF-1489. The unapproved latch plate was made of a shaft that was pressed into a plate, rather than being machined from bar material as one piece. The shaft and plate on the unapproved part can become separated or bent, resulting in rapid wear and failure of the part.

This condition, if not corrected, could result in an un-commanded retraction of the flaps. This failure could lead to a stall during a landing approach.

Relevant Service Information

We have reviewed de Havilland Support Limited Technical News Sheet (TNS) CT(C1) No 208 Issue 1, dated January 3, 2009. The service information describes procedures for inspecting the flap operating system latch plate for an unapproved part installation.

FAA's Determination and Requirements of the Proposed AD

We are proposing this AD because we evaluated all information and determined the unsafe condition described previously is likely to exist or develop on other products of the same type design. This proposed AD would require a one-time inspection of the flap operating system for an unauthorized latch plate design installation.

Costs of Compliance

We estimate that this proposed AD would affect 64 airplanes in the U.S. registry.

We estimate the following costs to do the proposed inspection:

Labor cost	Parts cost	Total cost per airplane	Total cost on U.S. operators
3 work-hours × $85 per hour = $255	Not Applicable	$255	$16,320

We estimate the following costs to do 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 this replacement:

Labor cost	Parts cost	Total cost per airplane
.5 work-hour × $85 per hour = $42.50	$175	$217.50

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.

Examining the AD Docket

You may examine the AD docket that contains the proposed AD, the regulatory evaluation, any comments received, and other information 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 Docket Office (telephone [phone]) is located at the street address stated in the ADDRESSES section. Comments will be available in the AD docket shortly after receipt.

List of Subjects in 14 CFR Part 39

• Air transportation
• Aircraft
• Aviation safety
• Incorporation by reference
• Safety

The Proposed Amendment

Accordingly, under the authority delegated to me by the Administrator, the FAA 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 AD:

Robert E. Rust, Jr.: Docket No. FAA-2010-0632; Directorate Identifier 2010-CE-025-AD.

Comments Due Date

(a) We must receive comments on this airworthiness directive (AD) action by August 5, 2010.

Affected ADs

(b) None.

Applicability

(c) This AD applies to Model DeHavilland DH.C1 Chipmunk 21, DH.C1 Chipmunk 22, and DH.C1 Chipmunk 22A airplanes, all serial numbers, that are certificated in any category.

Note:

These airplanes are also identified as CHIPMUNK 22A, CHIPMUNK DHC-1T10, CHIPMUNK T.10 MK-22, DH.C1 MK22A, DHC-1, DHC-1 CHIPMUNK, DHC-1 CHIPMUNK 22, DHC-1 SERIES 22, or DHC-1 T.MK. 10.

Subject

(d) Air Transport Association of America (ATA) Code 27: Flight Controls.

Unsafe Condition

(e) This AD results from a report of a latch plate supplied under part number C1-CF-1489 failing in service. The part in question was not manufactured to the applicable de Havilland drawing. The unapproved latch plate was made of a shaft that was pressed into a plate, rather than being machined from bar material as one piece. The shaft and plate on the unapproved part can become separated or bent, resulting in rapid wear and failure of the part. This condition, if not corrected, could result in an un-commanded retraction of the flaps. This failure could lead to a stall during a landing approach.

Compliance

(f) To address this problem, you must do the following, unless already done:

Actions	Compliance	Procedures
(1) Inspect the flap operating system to identify the part number (P/N) of the latch plate installed. If latch plate P/N C1-CF-1489 is installed, inspect the latch plate to determine if it is in compliance with the design standard. An unapproved latch plate P/N C1-CF-1489 is made from two pieces pressed together while one that complies with the design standard is machined in one piece from bar material.	Within 50 hours time-in-service (TIS) after the effective date of this AD or within 90 days after the effective date of this AD, whichever occurs first.	Follow de Havilland Support Limited Technical News Sheet (TNS) CT(C1) No 208 Issue 1, dated January 3, 2009.
(2) If during the inspection required in paragraph (f)(1) of this AD an unapproved latch plate P/N C1-CF-1489 is found, replace the latch plate with a latch plate that complies with the design standard. The following U.S. standard hardware may be substituted for the hardware specified in the service information:	Before further flight after the inspection where the unapproved latch plate P/N C1-CF-1849 was found.	Follow de Havilland Support Limited TNS CT(C1) No 208 Issue 1, dated January 3, 2009.
(i) 1/16″ diameter cotter pin that is P/N MS24665-153 (or equivalent) in place of split pin P/N SP90/C and;
(ii) Washer that is P/N MS15795-806B (or equivalent) in place of washer P/N SP13/B.

Alternative Methods of Compliance (AMOCs)

(g) The Manager, Atlanta Aircraft Certification Office (ACO), FAA, has the authority to approve AMOCs for this AD, if requested using the procedures found in 14 CFR 39.19. Send information to Attn: Carey O'Kelley, Aerospace Engineer, FAA, Atlanta Aircraft Certification Office (ACO), 1701 Columbia Avenue, College Park, Georgia 30337; telephone: [phone]; fax: [phone]. 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

(h) To get copies of the service information referenced in this AD, contact de Havilland Support Limited, Duxford Airfield, Cambridgeshire, CB22 4QR, England, phone: [phone]; fax: [phone]; e-mail: [e-mail]; Internet: http://www.dhsupport.com/​. To view the AD docket, go to U.S. Department of Transportation, Docket Operations, M-30, West Building Ground Floor, Room W12-140, 1200 New Jersey Avenue, SE., Washington, DC 20590, or on the Internet at http://www.regulations.gov.

Issued in Kansas City, Missouri, on June 14, 2010.

Sandra J. Campbell,

Acting Manager, Small Airplane Directorate, Aircraft Certification Service.