Discussion
We have received a report indicating that, during a maintenance inspection, a crack was found in one of the lugs on the elevator inboard-hinge bracket of a Cessna Model 750 airplane; cracking was also found on the elevator inboard-hinge brackets on seven other Model 750 airplanes. The cracking was attributed to fatigue caused by excessive side loads on the bracket from the flexing of the elevator during flight. This condition, if not corrected, could result in structural failure of the elevators and consequent loss of control of the airplane.
Relevant Service Information
We have reviewed Cessna Alert Service Letter ASL750-27-21, excluding the attachment titled "Inspection Results Form" and including the attachment titled "Flight Restrictions," dated October 13, 2006. The service letter describes procedures for performing a visual inspection of the inboard-hinge brackets of the left and right elevators. Related investigative and corrective actions include:
If any crack is found: Perform an eddy current inspection of the bracket(s) to confirm the crack and its length.
If the crack is 0.30 inch or more: Replace the bracket(s) before the next flight.
If the crack is less than 0.30 inch: Continued flight for repositioning of the airplane and replacement of the bracket is allowed within the restricted flight envelope included in the attachment to the service letter titled "Flight Restrictions," for a maximum of 10 flight hours" time-in-service.
FAA's Determination and Requirements of This AD
The unsafe condition described previously is likely to exist or develop on other airplanes of the same type design. For this reason, we are issuing this AD to detect and correct cracking of the elevator inboard-hinge brackets, which could result in structural failure of the elevators and consequent loss of control of the airplane. This AD requires inspecting the inboard-hinge brackets of the left and rightelevators for cracking, and doing related investigative and corrective actions if necessary; except as discussed under "Differences Between the AD and the Service Letter."
Differences Between the AD and the Service Letter
While it is not our usual policy to allow flight with known cracks, to be consistent with the service letter, this AD permits further flight with cracks with certain restrictions, as specified in paragraph (g)(2) of this AD. In consideration of these restrictions and the FAA's criteria for flight with known cracking, continued flight for a maximum of 10 flight hours for repositioning of the airplane and replacement of the bracket is allowed, provided the airplane is operated in accordance with the revised flight restrictions specified in the service letter.
The procedures in the service letter refer only to a "visual inspection" for cracking of the inboard-hinge brackets. We have determined that the inspection should be described as a "general visual inspection." Note 1 has been included in this AD to define this type of inspection.
The procedures in the service letter specify submitting a sheet related to inspection results to the manufacturer, but this AD does not require that action.
The procedures in the service letter also specify sending the elevator assembly to the manufacturer for replacement of the inboard- hinge bracket if a crack is found that is 0.30 inch or longer; however, this AD requires corrective actions be done using a method approved by us.
Interim Action
We consider this AD interim action. If final action is later identified, we may consider further rulemaking then.
FAA's Determination of the Effective Date
Since an unsafe condition exists that requires the immediate adoption of this AD, we have found that notice and opportunity for public comment before issuing this AD are impracticable, and that good cause exists to make this AD effective in less than 30 days.
Comments InvitedThis AD is a final rule that involves requirements that affect flight safety and was not preceded by notice and an opportunity for public comment; however, we invite you to submit any relevant written data, views, or arguments regarding this AD. Send your comments to an address listed in the ADDRESSES section. Include "Docket No. FAA-2006- 26242; Directorate Identifier 2006-NM-229-AD" at the beginning of your comments. We specifically invite comments on the overall regulatory, economic, environmental, and energy aspects of the AD that might suggest a need to modify it.
We will post all comments we receive, without change, to http://dms.dot.gov , including any personal information you provide. We will also post a report summarizing each substantive verbal contact with FAA personnel concerning this AD. Using the search function of that Web site, anyone can find and read the comments in any of our dockets, including the name of the individual who sent the comment (or signed the comment on behalf of an association, business, labor union, etc.). You may review the DOT's complete Privacy Act Statement in the Federal Register published on April 11, 2000 (65 FR 19477-78), or you may visit http://dms.dot.gov.
Examining the Docket
You may examine the AD docket on the Internet at http://dms.dot.gov , or in person at the Docket Management Facility office between 9 a.m. and 5 p.m., Monday through Friday, except Federal holidays. The Docket Management Facility office (telephone (800) 647- 5227) is located on the plaza level of the Nassif Building at the DOT street address stated in the ADDRESSES section. Comments will be available in the AD docket shortly after the Docket Management System receives them.
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 AD will not have federalism implications under Executive Order 13132. This AD 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.
For the reasons discussed above, I certify that the 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 AD and placed it in the AD docket. See the ADDRESSES section for a location to examine the regulatory evaluation.
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 FAA amends 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.
Sec. 39.13 [Amended]
2. The Federal Aviation Administration (FAA) amends Sec. 39.13 by adding the following new airworthiness directive (AD):