AD 96-12-08

This amendment adopts a new airworthiness directive (AD) that applies to Twin Commander Aircraft Corporation (Twin Commander) 500, 680, and 690 series airplanes that do not have a nose landing gear drag link bolt with the manufacturer s serial number, manufacture date, and the last three digits of the drawing number, 055, on the bolt head. This action requires replacing the nose landing gear (NLG) drag link bolt with one that has been manufactured with the proper heat treatment. This action was prompted by the failure of an improperly heat treated NLG drag link bolt causing collapse of the nose landing gear on a certain Twin Commander Model 690B airplane while taxiing. The actions specified by this AD are intended to prevent the NLG from collapsing, which if not corrected, could result in loss of the airplane.

Final rule; request for comments.

96-12-08 TWIN COMMANDER AIRCRAFT CORPORATION: Amendment 39-9650; Docket No. 96-CE-22-AD.

Applicability: The following Model and serial number airplanes, certificated in any category.

Models
Serial Numbers
500S
3185, 3228, 3230, 3262, and 3291
500U
1765
680F
1195
681
6027
690
11035, 11053, 11068, and 11074
690A
11111, 11134, 11146, 11173, 11177, 11205, 11215, 11237, 11271, 11273, and 11282
690B
11360, 11382, 11409, 11424, 11451, 11455, 11463, 11491, 11513, 11535, 11536, and 11539
690C
11638, 11676, 11689, and 11719
690D
15041
695
95010, 95033, and 96066
695A
69010, 69041, 69056, and 69061

NOTE 1: This AD applies to each airplane identified in the preceding applicability provision, regardless of whether it has been modified, altered, or repaired in the area subject to the requirements of this AD. For airplanes that have been modified, altered, or repaired so that the performance of the requirements of this AD is affected, the owner/operator mustrequest approval for an alternative method of compliance in accordance with paragraph (e) of this AD. The request should include an assessment of the effect of the modification, alteration, or repair on the unsafe condition addressed by this AD; and, if the unsafe condition has not been eliminated, the request should include specific proposed actions to address it.

Compliance: Required within the next 10 hours time-in-service (TIS), unless already accomplished.

To prevent the nose landing gear (NLG) from collapsing, which if not corrected, could result in loss of the airplane, accomplish the following:

(a) Replace the NLG drag link bolt, part number (P/N) ED 10055, with a new bolt in accordance with the INSTRUCTIONS section of Twin Commander Service Bulletin 224, Revision A, dated April 24, 1996.

(b) The new replacement bolt must be marked with the manufacturer s serial number, the date of manufacture, and the last three digits of the drawing number, 055, on the bolthead.

NOTE 2: Although not required by this AD, it is highly recommended that the removed bolt (P/N ED 10055) be returned to Twin Commander for Rockwell Hardness testing.

(c) As of the effective date of this AD, no person shall install an NLG drag link bolt that does not have the manufacturer's serial number, manufacture date, and the last three digits of the drawing number, 055, on the bolt head.

(d) Special flight permits may be issued in accordance with sections 21.197 and 21.199 of the Federal Aviation Regulations (14 CFR 21.197 and 21.199) to operate the airplane to a location where the requirements of this AD can be accomplished.

(e) An alternative method of compliance (which would include Rockwell Hardness test) or adjustment of the compliance time that provides an equivalent level of safety may be approved by the Manager, Seattle Aircraft Certification Office, 1601 Lind Ave. S.W., Renton, Washington, 98055-4056. The request shall be forwarded through an appropriate FAA Maintenance Inspector, who may add comments and then send it to the Manager, Seattle Aircraft Certification Office.

NOTE 3: Information concerning the existence of approved alternative methods of compliance with this AD, if any, may be obtained from the Seattle Aircraft Certification Office.

(f) The replacement required by this AD shall be done in accordance with Twin Commander Aircraft Corporation Service Bulletin 224, Revision A, dated April 24, 1996. This incorporation by reference was approved by the Director of the Federal Register in accordance with 5 U.S.C. 552(a) and 1 CFR part 51. Copies may be obtained from Twin Commander Aircraft Corporation, 19010 59th Dr. NE, Arlington, Washington, 98223-7832; telephone (360) 435-9797; facsimile (360) 435-1112. Copies may be inspected at the FAA, Central Region, Office of the Assistant Chief Counsel, Room 1558, 601 E. 12th Street, Kansas City, Missouri, or at the Office of the Federal Register, 800 North Capitol Street, NW., suite 700, Washington, DC.

(g) This amendment becomes effective on June 27, 1996.

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: