On June 23, 1994, the Federal Aviation Administration (FAA) issued priority letter airworthiness directive (AD) 94-14-11, applicable to Franklin Model 6A4-150-B3 and 6A4-165-B3 reciprocating engines, installed on the following U.S. registered aircraft: N6209M, N74231, and N752C. That action requires teardown and analytical inspection for engines certified to operate on 91 or higher octane aviation gasoline (avgas), and differential compression test and examination of the oil filter for engines certified to operate on 80 octane avgas. That action was prompted by reports of reports of aviation gasoline (avgas) being contaminated by Jet A fuel. After investigation, the source of the contamination has been determined to be the refiner of the avgas. Through its distribution system, the refiner inadvertently caused Jet A fuel to be loaded into distribution tanks intended for avgas. Contaminated avgas from these distribution tanks was then shipped to localfuel distributors. The FAA has determined that aircraft with certain Franklin engines installed were fueled with this contaminated mixture between May 22 and June 2, 1994, at Sacramento Executive (SAC) airport, or between May 18 and June 2, 1994, at Sacramento Metro (SMF) airport. The list of U.S. registered aircraft specified in the applicability paragraph of this AD is based on investigation of fueling records secured from the two affected airports, which the FAA has determined to represent the population of affected engines. That condition, if not corrected, could result in detonation due to low octane, which can result in severe engine damage and subsequent failure.
This AD requires engines certified to operate on 91 octane or higher avgas to undergo a teardown and analytical inspection for detonation damage, and engines certified to operate on 80 octane avgas to undergo inspection for evidence of possible internal engine damage. Engineering analysis of operating these engines with avgas contaminated with Jet A fuel indicates that actual damage to the engine may range from unnoticeable to very severe, according to the duration of run, engine power level, and level of contamination. Damage may be characterized by increased operating temperatures resulting in damaged intake valves and burned pistons, and excessive loads imposed by detonation. Since internal damage may not be assessed by any other method, engines certified to operate on 91 octane or higher avgas must undergo a teardown and analytical inspection and any parts showing signs of detonation damage must be replaced. Investigation revealed the lowest octane level of the contaminated fuel to be 83 octane, therefore engines certified to operate on 80 octane avgas need not undergo a teardown and analytical inspection unless evidence of internal engine damage is present by the required differential compression test and examination of the oil filter for metal particles. The refiner has advised the FAA that it may pay for any reasonable expense associated with the inspection and/or disassembly in accordance with the mechanic's and manufacturer's recommendations.
Since an unsafe condition has been identified that is likely to exist or develop on other engines of this same type design, this AD supersedes priority letter AD 94-14-11 to revise incorrect engine model numbers listed in the priority letter AD.
Since a situation exists that requires the immediate adoption of this regulation, it is found that notice and opportunity for prior public comment hereon are impracticable, and that good cause exists for making this amendment effective in less than 30 days. Comments Invited
Although this action is in the form of a final rule that involves requirements affecting flight safety and, thus, was not preceded by notice and an opportunity for public comment, comments are invited on this rule. Interested persons are invited to comment on this rule by submitting such written data,views, or arguments as they may desire. Communications should identify the Rules Docket number and be submitted in triplicate to the address specified under the caption "ADDRESSES." All communications received on or before the closing date for comments will be considered, and this rule may be amended in light of the comments received. Factual information that supports the commenter's ideas and suggestions is extremely helpful in evaluating the effectiveness of the AD action and determining whether additional rulemaking action would be needed.
Comments are specifically invited on the overall regulatory, economic, environmental, and energy aspects of the rule that might suggest a need to modify the rule. All comments submitted will be available, both before and after the closing date for comments, in the Rules Docket for examination by interested persons. A report that summarizes each FAA-public contact concerned with the substance of this AD will be filed in the Rules Docket.Commenters wishing the FAA to acknowledge receipt of their comments submitted in response to this notice must submit a self-addressed, stamped postcard on which the following statement is made: "Comments to Docket Number 95-ANE-70." The postcard will be date stamped and returned to the commenter.
The regulations adopted herein will not have substantial direct effects 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, in accordance with Executive Order 12612, it is determined that this final rule does not have sufficient federalism implications to warrant the preparation of a Federalism Assessment.
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. A copy of it, if filed, may be obtained from 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, pursuant to 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 USC 106(g), 40101, 40113, 44701. 39.13 - [AMENDED]
2. Section 39.13 is amended by adding the following new airworthiness directive: