AD 96-12-08

The FAA has recently received an accident report on a certain Twin Commander Model 690B airplane. The accident was caused by the failure of the nose landing gear (NLG) after the NLG drag link bolt, part number (P/N) ED 10055, broke. Further investigation revealed that the bolt had not been heat treated properly during manufacture, thus making it weak and the NLG susceptible to collapse during landing or taxiing operations. Additional bolts in two other manufactured lots also failed the Rockwell Hardness test, resulting in the need to replace all of these NLG drag link bolts.

Twin Commander has issued service bulletin (SB) 224, Revision A, dated April 24, 1996 which specifies replacing the NLG drag link bolt with an approved heat treated bolt. (NOTE: Although it is not required by this AD, the FAA recommends that the owner/operator return the removed bolt to the factory for testing.)

After examining the circumstances and reviewing all available information related to the incidents described above, the FAA has determined that AD action should be taken to prevent the NLG from failing, which if not corrected, could result in loss of the airplane.

Since an unsafe condition has been identified that is likely to exist or develop in other Twin Commander 500, 680, and 690 series airplanes of the same type design, this AD requires replacing the NLG drag link bolt with an approved heat treated bolt which has the manufacturer's serial number, manufacture date, and the last three digits of the drawing number, 055, on the bolt head. The actions are to be done in accordance with the instructions in Twin Commander SB 224, Revision A, dated April 24, 1996.

Since a situation exists that requires the immediate adoption of this regulation, it is found that notice and opportunity for public prior comment hereon are impracticable, and that good cause exists for making this amendment effective in less than 30 days. Comments InvitedAlthough this action is in the form of a final rule that involves requirements affecting immediate flight safety and, thus, was not preceded by notice and opportunity to 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 above. 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 No. 96-CE-22-AD." 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 and 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, may be obtained from the Rules Docket.

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), 40113, 44701.

Section 39.13 - [AMENDED]

2. Section 39.13 is amended by adding a new airworthiness directive (AD) to read as follows: