Discussion
What events have caused this AD? The FAA has received several reports of improper engine fuel flow settings on Cessna Models 172R and 172S airplanes. These improper settings could prevent the engine from operating at idle speed when the pilot reduces power (i.e., landing approach, power off stalls, etc.). An over-rich fuel mixture is a reason why the engine may not operate at idle speed. This over-rich fuel mixture also contributes to the engine not restarting during flight when using published in-flight restart procedures.
The current pilot operating handbook (POH) and FAA-approved airplane flight manual (AFM) procedures for the Cessna Models 172R and 172S airplanes do not address the pilot bringing the throttle back to the hard idle stop (throttle full aft). The POH/AFM also does not address emergency engine restart procedures to enable engine startup if a rich fuel mixture exists.
What are the consequences if the condition is not corrected? This condition, if not corrected, could result in rough engine operation or engine stoppage. The over-rich fuel mixture also contributes to the engine not restarting during flight when using published in-flight restart procedures.
FAA's Determination and an Explanation of the Provisions of this AD
What has FAA decided? The FAA has reviewed all available information and determined that:
- the unsafe condition referenced in this document exists or could develop on other Cessna Models 172R and 172S airplanes of the same type design;
- these airplanes should be inspected for proper engine idle speed and fuel control mixture setting, the engine idle speed or fuel control mixture setting should be adjusted as necessary, and engine operating procedures should be incorporated into the POH/AFM; and
- AD action should be taken in order to correct this unsafe condition.
Is there service information that applies to this subject? Cessna has issued Service Bulletin SB01-11- 02, dated March 5, 2001. This service bulletin:
- includes procedures for inspecting the engine idle speed; and
- specifies pilot operating procedure changes.
What does this AD require? This AD requires a one-time inspection for proper engine idle speed and fuel control mixture setting and adjustment, as necessary. This AD also requires incorporating engine operating procedures into the POH/AFM.
Procedures for accomplishing the inspection are included in the AD. We are not utilizing the procedures included in Cessna Service Bulletin SB01-11-02, dated March 5, 2001.
Why is FAA not requiring the actions specified in the service bulletin? The inspection procedures in Cessna Service Bulletin SB01-11-02 agree with the service manual procedures. The procedures we are including in this AD agree with the Cessna factory production procedures. After examining these procedures, FAA has determined that:
- the procedures in the service bulletin and service manual procedures are too restrictive for a pilot to accomplish in the field without using specialized equipment (portable electric tachometer);
- the pilot should be able to accomplish the inspection for proper engine idle speed and fuel control mixture setting; and
- the inspection procedures in this AD allow the pilot to both easily accomplish the inspection and address the safety intent of this AD.
Will I have the opportunity to comment prior to the issuance of the rule? Because the unsafe condition described in this could result in rough engine operation or engine stoppage, FAA finds that notice and opportunity for public prior comment are impracticable. Therefore, good cause exists for making this amendment effective in less than 30 days.
Comments Invited
How do I comment on this AD? Although this action is in the form of a final rule and was not preceded by notice and opportunity for public comment, we invite your comments on the rule. You may submit whatever written data, views, or arguments you choose. You need to include the rule's docket number and submit your comments in triplicate to the address specified under the caption "ADDRESSES." We will consider all comments received on or before the closing date specified above. We may amend this rule in light of comments received. Factual information that supports your ideas and suggestions is extremely helpful in evaluating the effectiveness of the AD action and determining whether we need to take additional rulemaking action.
Are there any specific portions of the AD that FAA wants me to address? The FAA specifically invites comments on the overall regulatory, economic, environmental, and energy aspects of the rule that might suggest a need to modify the rule. You may examine all comments we receive before and after the closing date of the rule in the Rules Docket. We will file a report in the Rules Docket that summarizes each FAA contact with the public that concerns thesubstantive parts of this AD.
We are reviewing the writing style we currently use in regulatory documents, in response to the Presidential memorandum of June 1, 1998. That memorandum requires federal agencies to communicate more clearly with the public. We are interested in your comments on whether the style of this document is clear, and any other suggestions you might have to improve the clarity of FAA communications that affect you. You can get more information about the Presidential memorandum and the plain language initiative at http://www.plainlanguage.gov.
How can I be sure FAA receives my comment? If you want us to acknowledge the receipt of your comments, you must include a self-addressed, stamped postcard. On the postcard, write "Comments to Docket No. 2001-CE-14-AD." We will date stamp and mail the postcard back to you.
Regulatory Impact
Does this AD impact various entities? These regulations will not have a substantial direct effect on the States, onthe relationship between the national Government and the States, or on the distribution of power and responsibilities among the various levels of government. Therefore, FAA has determined that this final rule does not have federalism implications under Executive Order 13132. Does this AD involve a significant rule or regulatory action? The FAA has determined that this regulation is an emergency regulation that must be issued immediately to correct an unsafe condition in aircraft, and is not a significant regulatory action under Executive Order 12866. It has been determined further that this action involves an emergency regulation under DOT Regulatory Policies and Procedures (44 FR 11034, February 26, 1979). If it is determined that this emergency regulation otherwise would be significant under DOT Regulatory Policies and Procedures, a final regulatory evaluation will be prepared and placed in the Rules Docket (otherwise, an evaluation is not required). A copy of it, if filed, maybe obtained from the Rules Docket.
List of Subjects in 14 CFR Part 39
Air transportation, Aircraft, Aviation safety, 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. 39.13 [Amended]
2. FAA amends 39.13 by adding a new airworthiness directive (AD) to read as follows: