01-22946. Airworthiness Directives; Eurocopter Deutschland GmbH Model EC135 P1 and EC135 T1 Helicopters

AGENCY:

Federal Aviation Administration, DOT.

ACTION:

Final rule; request for comments.

SUMMARY:

This amendment adopts a new airworthiness directive (AD) for Eurocopter Deutschland GmbH (Eurocopter) Model EC135 P1 and EC135 T1 helicopters. This action requires, before further flight, adding a copy of this AD or a statement to the Emergency Procedures section of the Rotorcraft Flight Manual (RFM) to inform the pilot to reduce power and land as soon as practicable if a thump-like sound followed by unusual vibration occurs during flight. This action also requires visually inspecting for a crack or a break in certain main rotor drive torque strut (strut) assemblies at specified time intervals and recording details of the inspections in the historical or equivalent record. This AD also requires re-marking and relocating the strut as appropriate and replacing any unairworthy strut assembly with an airworthy strut assembly before further flight. Also, this AD establishes a life limit of 1000 hours time-in-service (TIS) for certain struts with an additional 1000 hours TIS for struts re-marked right-hand (RH) or left-hand (LH) before installing in the new location. This amendment is prompted by a report of a thump-like sound heard during flight followed by unusual vibrations due to failure of the RH strut between the main transmission and the fuselage. The actions specified in this AD are intended to prevent failure of a strut, failure of a worn or ineffective back-up emergency stop, and subsequent loss of control of the helicopter.

DATES:

Effective October 1, 2001.

The incorporation by reference of certain publications listed in the regulations is approved by the Director of the Federal Register as of October 1, 2001.

Comments for inclusion in the Rules Docket must be received on or before November 13, 2001.

ADDRESSES:

Submit comments in triplicate to the Federal Aviation Administration (FAA), Office of the Regional Counsel, Southwest Region, Attention: Rules Docket No. 2001-SW-19-AD, 2601 Meacham Blvd., Room 663, Fort Worth, Texas 76137. You may also send comments electronically to the Rules Docket at the following address: [e-mail].

The service information referenced in this AD may be obtained from American Eurocopter Corporation, 2701 Forum Drive, Grand Prairie, Texas 75053-4005, telephone [phone], fax [phone]. This information may be examined at the FAA, Office of the Regional Counsel, Southwest Region, 2601 Meacham Blvd., Room 663, Fort Worth, Texas; or at the Office of the Federal Register, 800 North Capitol Street, NW., suite 700, Washington, DC.

FOR FURTHER INFORMATION CONTACT:

Richard Monschke, Aviation Safety Engineer, FAA, Rotorcraft Directorate, Rotorcraft Standards Staff, Fort Worth, Texas 76193-0110, telephone [phone], fax [phone].

SUPPLEMENTARY INFORMATION:

The Luftfahrt-Bundesamt (LBA), the airworthiness authority for the Federal Republic of Germany, notified the FAA that an unsafe condition may exist on Eurocopter Model EC 135 helicopters. The LBA advises of an isolated thump-like sound heard during flight followed by unusual vibrations. The inspection following this incident revealed that the attachment between the tensile stress-loaded strut on the RH side of the main transmission and the fuselage structure had ruptured. For such cases, the emergency stop, fitted to the fuselage structure to provide redundancy backup, takes over or will have already taken over the function of the strut. Under such conditions, however, there is a danger that the emergency stop could become worn and ineffective if it is kept in operation for a long period of time with an unairworthy strut.

Eurocopter has issued Alert Service Bulletin EC135-63A-002, Revision 1, dated March 12, 2001 (ASB), which specifies notifying the pilots of Model EC 135 helicopters about the contents of the ASB. The ASB also specifies inspecting the strut for a crack, marking the strut location and serial number (S/N) in the vicinity of the part number (P/N), and transferring location side of the struts at certain intervals. The LBA classified this ASB as mandatory and issued AD 2001-107, dated March 13, 2001 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 14 CFR 21.29 and the applicable bilateral agreement. Pursuant to this bilateral 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.

We have identified an unsafe condition that is likely to exist or develop on other Eurocopter Model EC135 P1 and EC135 T1 helicopters of the same type designs registered in the United States. Therefore, this AD is being issued to prevent failure of a strut and subsequent loss of control of the helicopter.

This AD requires the following for each strut, P/N L633M1001 103 and L633M1001 105:

• Before further flight, insert a copy of this AD or a statement into the Emergency Procedures section of the RFM to inform the pilot to reduce power and land as soon as practicable if a thump-like sound followed by unusual vibration occurs during flight.
• Within 10 hours TIS, visually inspect each strut with 950 or more hours TIS for a crack or a break.
• Before accumulating 1000 hours TIS for each strut with less than 950 TIS and within 50 hours TIS for each strut with 950 or more hours TIS, inspect for a crack or a break using a 6-power or higher magnifying glass.
• Replace any cracked or broken strut with an airworthy strut before further flight.
• Enter the details of each inspection in the helicopter's historical or equivalent record.

This AD revises the Airworthiness Limitations section of the maintenance manual by establishing a life limit of 1000 hours TIS for each strut in its original location, with an additional 1000 hours TIS if properly re-marked and relocated (2000 hours total TIS) to the opposite side of the transmission. The additional 1000 hours TIS life is possible because the loading mode is changed by relocating the tension loaded RH strut to the LH position, which is loaded in compression. The actions are required to be accomplished in accordance with the service bulletin described previously.

The short compliance time involved is required because the previously described critical unsafe condition can adversely affect the controllability and structural integrity of the helicopter. Therefore, before further flight, insert a copy of this AD or a statement into the Emergency Procedures section of the RFM to inform the pilot to reduce power and land as soon as practicable if a thump-like sound followed by unusual vibration occurs during flight. Also, because visually inspecting each strut with 950 or more hours TIS for a crack or break is required within 10 hours TIS, and, if a cracked or broken part is found, replacing any unairworthy part with an airworthy part is required before further flight, 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 38 helicopters will be affected by this AD. The FAA also estimates approximately 1/2 work hour to do a flashlight and mirror inspection and 2.5 work hours to re-mark, relocate, inspect with a 6-power or higher magnifying glass, and replace each strut as necessary. The average labor rate is $60 per work hour. Required parts will cost approximately $2400 per helicopter. Based on these figures, the total cost impact of the AD on U.S. operators is estimated to be $98,040.

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 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 mailed 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. 2001-SW-19-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 final rule 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

[Amended]

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

2001-18-13 Eurocopter Deutschland GmbH Amendment 39-12439. Docket No. 2001-SW-19-AD.

Applicability: Model EC135 P1 and EC135 T1 helicopters, with main rotor drive torque strut assembly (strut), part number (P/N) L633M1001 103 or L633M1001 105, 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 (f) 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 failure of the strut and subsequent loss of control of the helicopter, accomplish the following:

(a) Before further flight, insert a copy of this AD or a statement into the Emergency Procedures Section of the Rotorcraft Flight Manual (RFM) to inform the pilot to reduce power and land as soon as practicable if a thump-like sound followed by unusual vibration occurs during flight.

(b) Within 10 hours time-in-service (TIS), visually inspect each strut with 950 or more hours TIS for a crack or a break using a flashlight and a mirror in accordance with the Accomplishment Instructions, paragraph 3.B.(1) and 3.B.(2), of Eurocopter Deutschland GmbH Alert Service Bulletin EC135-63A-002, Revision 1, dated March 12, 2001 (ASB). Replace any cracked or broken strut with an airworthy strut before further flight.

(c) Inspect the following struts for a crack or a break, using a 6-power or higher magnifying glass, and re-mark and relocate each strut in accordance with the Accomplishment Instructions, paragraph 3.C., of the ASB. This AD does not require you to return any part to the manufacturer.

(1) For a strut with less than 950 hours TIS, inspect before accumulating 1000 hours TIS.

(2) For a strut with 950 or more hours TIS, inspect within 50 hours TIS.

(3) Replace any cracked or broken strut with an airworthy strut before further flight.

(d) This AD revises the Airworthiness Limitations section of the maintenance manual by establishing a life limit of 1000 hours TIS for each strut, P/N L633M1001 103 and L633M1001 105, in its original location, with an additional 1000 hours TIS if properly re-marked and relocated (2000 hours total TIS) in accordance with the Accomplishment Instructions, paragraph 3.C.(3) of the ASB.

(e) Record details of the inspections in the historical or equivalent records in accordance with the Accomplishment Instructions, paragraph 3.C.(4) of the ASB.

(f) 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.

(g) Special flight permits may be issued in accordance with 14 CFR 21.197 and 21.199 to operate the helicopter to a location where the requirements of this AD can be accomplished.

(h) The inspections, re-marking, relocation, and entry in the historical or equivalent record of each strut, P/N L633M1001 103 and L633M1001 105, shall be done in accordance with the Accomplishment Instructions, paragraphs 3.B.(1), 3.B.(2), and 3.C., of Eurocopter Deutschland GmbH Alert Service Bulletin EC135-63A-002, Revision 1, dated March 12, 2001. 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 [phone], fax [phone]. Copies may be inspected at the FAA, Office of the Regional Counsel, Southwest Region, 2601 Meacham Blvd., Room 663, Fort Worth, Texas; or at the Office of the Federal Register, 800 North Capitol Street, NW., suite 700, Washington, DC.

(i) This amendment becomes effective on October 1, 2001.

Note 3:

The subject of this AD is addressed in Luftfahrt-Bundesamt (Federal Republic of Germany) AD 2001-107, dated March 13, 2001.

Issued in Fort Worth, Texas, on September 4, 2001.

David A. Downey,

Manager, Rotorcraft Directorate, Aircraft Certification Service.