# AGENCY:

 Federal Aviation Administration, DOT. 

# ACTION:

 Final rule; request for comments. 

# SUMMARY:

 This amendment adopts a new airworthiness directive (AD) applicable to Eurocopter Deutschland GMBH (ECD) Model EC 135 P1 and EC 135 T1 helicopters. This action requires inspecting main rotor expansion bolt safety wires, bolt heads, and bolt nuts; replacing any unairworthy expansion bolt with a hexagon bolt; and, as necessary, replacing any bolt nut before further flight. This AD also requires replacing each expansion bolt, regardless of condition, no later than January 31, 2000. This amendment is prompted by reports of main rotor blade expansion bolt nuts becoming loose. This condition, if not corrected, could result in severe vibration during flight and subsequent loss of control of the helicopter. 

# DATES:

 Effective February 4, 2000.

The incorporation by reference of certain publications listed in the regulations is approved by the Director of the Federal Register as of February 4, 2000.

Comments for inclusion in the Rules Docket must be received on or before March 27, 2000.

# ADDRESSES:

 Submit comments in triplicate to the Federal Aviation Administration (FAA), Office of the Regional Counsel, Southwest Region, Attention: Rules Docket No. 99-SW-74-AD, 2601 Meacham Blvd., Room 663, Fort Worth, Texas. 

The service information referenced in this AD may be obtained from American Eurocopter Corporation, 2701 Forum Drive, Grand Prairie, Texas 75053-4005, telephone (972) 641-3460, fax (972) 641-3527. This information may be examined at the FAA, Office of the Regional Counsel, Southwest Region, Room 663, Fort Worth, Texas. 

# FOR FURTHER INFORMATION CONTACT:

 Richard A. Monschke, Aerospace Engineer, FAA, Rotorcraft Directorate, Rotorcraft Standards Staff, Fort Worth, Texas 76193-0110, telephone (817) 222-5116, fax (817) 222-5961. 

# SUPPLEMENTARY INFORMATION:

 Luftfahrt-Bundesamt (LBA), the airworthiness authority for the Federal Republic of Germany, notified the FAA that an unsafe condition may exist on Model EC 135 P1 and EC 135 T1 helicopters. The LBA advises that severe vibrations occurred during a helicopter flight due to an expansion bolt nut becoming loose. 

ECD has issued Alert Service Bulletin EC135-62A-005, Revision 1, dated November 16, 1999 (ASB). The ASB specifies inspecting the safety wire, bolt head, and bolt nut for the extent of thread protrusion of the expansion bolt through the end of the nut; replacing the expansion bolt by a hexagon bolt as necessary; and replacing the nut as necessary. In addition, all hexagon bolts must replace all expansion bolts no later than January 31, 2000. The LBA classified this ASB as mandatory and issued AD 1999-264, dated July 2, 1999, to ensure the continued airworthiness of these helicopters in the Federal Republic of Germany. 

These helicopter models are manufactured in the Federal Republic of Germany and are type certificated for operation in the United States under the provisions of section 21.29 of the Federal Aviation Regulations (14 CFR 21.29) and the applicable bilateral airworthiness agreement. Pursuant to this bilateral airworthiness agreement, the LBA has kept the FAA informed of the situation described above. The FAA has examined the findings of the LBA, reviewed all available information, and determined that AD action is necessary for products of this type design that are certificated for operation in the United States. 

Since an unsafe condition has been identified that is likely to exist or develop on other ECD Model EC 135 P1 and EC 135 T1 helicopters of the same type designs registered in the United States, this AD is being issued to prevent a main rotor blade expansion bolt from becoming loose, severe vibration during flight, and subsequent loss of control of the helicopter. This AD requires, before further flight and at intervals not to exceed 15 hours time-in-service (TIS), inspecting the main rotor blade expansion bolt safety wire, bolt head, and bolt nut for the extent of thread protrusion of the expansion bolt through the end of the nut; replacing any unairworthy expansion bolt with a hexagon bolt; and replacing the nut as necessary. The AD also requires replacing all expansion bolts, part number (P/N) L621M1010 223, with hexagon bolts, P/N L621M1010 222, before further flight after January 31, 2000. The actions are required to be accomplished in accordance with the ASB described previously. The short compliance time involved is required because the previously described critical unsafe condition can adversely affect the structural integrity of the helicopter. Therefore, inspecting the main rotor blade expansion bolt safety wire, bolt head, and bolt nut; replacing any unairworthy expansion bolt with a hexagon bolt; and replacing the nut as necessary is required before further flight and this AD must be issued immediately. 

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. 

                    The FAA estimates that 14 helicopters will be affected by this AD, that it will take approximately 10 work hours to                     Start Printed Page 3797                    accomplish inspecting and replacing the parts, and that the average labor rate is $60 per work hour. The ECD ASB states that the replacement parts kit, P/N EC 135-62A-005-2.C, will be provided on request to ECD at no cost. Based on these figures, the total cost impact of the AD on U.S. operators is estimated to be $8,400.                 

## 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 rule must submit a self-addressed, stamped postcard on which the following statement is made: “Comments to Docket No. 99-SW-74-AD.” The postcard will be date stamped and returned to the commenter. 

The regulations adopted herein 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. Therefore, it is determined that this proposal does not have federalism implications under Executive Order 13132. 

                    The FAA has determined that this regulation is an emergency regulation that must be issued immediately to correct an unsafe condition in aircraft, and that it 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 U.S.C. 106(g), 40113, 44701. 

§ 39.13 

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

**AD 2000-01-19 Eurocopter Deutschland GMBH:**                        Amendment 39-11517. Docket No. 99-SW-74-AD.                     

*Applicability:*                        Model EC 135 P1 and EC 135 T1 helicopters, with main rotor blades up to and including serial number 834, installed, certificated in any category.                     

# Note 1:

 This AD applies to each helicopter identified in the preceding applicability provision, regardless of whether it has been otherwise modified, altered, or repaired in the area subject to the requirements of this AD. For helicopters that have been modified, altered, or repaired so that the performance of the requirements of this AD is affected, the owner/operator must request approval for an alternative method of compliance in accordance with paragraph (d) 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 as indicated, unless accomplished previously.                     

To prevent a main rotor blade expansion bolt nut becoming loose, causing severe vibration during flight, and subsequent loss of control of the helicopter, accomplish the following: 

(a) Before further flight and thereafter at intervals not to exceed 15 hours time-in-service, visually inspect the main rotor blade expansion bolt safety wire, bolt head, and bolt nut in accordance with the Accomplishment Instructions, paragraph 3.A., steps (1), (2), (3), (4), and (6) of Eurocopter Deutschland GMBH (ECD) Alert Service Bulletin EC 135-62A-005, Revision 1, dated November 16, 1999 (ASB). If the safety wire is improperly fitted, the bolt head is worn, the expansion bolt thread does not protrude through the end of the nut, the bolt head has metallic abrasions, the nut is loose, or the nut has metallic abrasions, before further flight, replace the expansion bolt, part number (P/N) L621M1010 223, with a hexagon bolt, P/N L621M1010 222, and, as necessary, replace the nut in accordance with paragraph 3.B. of the ASB. 

(b) Replace all expansion bolts, P/N L621M1010 223, with hexagon bolts, P/N L621M1010 222, and, as necessary, replace the nuts before flight after January 31, 2000. 

(c) Replacing the expansion bolts with hexagon bolts and replacing the nuts, as necessary, constitutes terminating action for the requirements of this AD. 

(d) An alternative method of compliance or adjustment of the compliance time that provides an acceptable level of safety may be used if approved by the Manager, Regulations Group, Rotorcraft Directorate, FAA. Operators shall submit their requests through an FAA Principal Maintenance Inspector, who may concur or comment and then send it to the Manager, Regulations Group. 

# Note 2:

 Information concerning the existence of approved alternative methods of compliance with this AD, if any, may be obtained from the Regulations Group. 

(e) Special flight permits will not be issued. 

(f) The inspection and replacement of the main rotor blade bolts shall be done in accordance with the Accomplishment Instructions, paragraph 3.A., Eurocopter Deutschland GMBH Alert Service Bulletin EC 135-62A-005, Revision 1, dated November 16, 1999. 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 American Eurocopter Corporation, 2701 Forum Drive, Grand Prairie, Texas 75053-4005, telephone (972) 641-3460, fax (972) 641-3527. Copies may be inspected at the FAA, Office of the Regional Counsel, Southwest Region, Room 663, Fort Worth, Texas; or at the Office of the Federal Register, 800 North Capitol Street, NW., suite 700, Washington, DC. 

(g) This amendment becomes effective on February 4, 2000.

# Note 3:

 The subject of this AD is addressed in Luftfahrt-Bundesamt (the Federal Republic of Germany) AD 1999-264, dated July 2, 1999. 

Issued in Fort Worth, Texas, on January 11, 2000.

Eric Bries,

Acting Manager, Rotorcraft Directorate, Aircraft Certification Service.

[FR Doc. 00-1369 Filed 1-24-00; 8:45 am] 

BILLING CODE 4910-13-U