AD 99-01-02

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AD Number:
99-01-02
Document Type:
AD Final Rules
Docket Number:
97-SW-40-AD
Subject Heading:
Airworthiness Directives; Westland Helicopters Ltd. 30 Series 100 and 100-60 Helicopters
Subject:
Conformal Pinion Quill Shafts in Main Rotor Gearboxes
Status:
Current
Citation:
Federal Register: December 30, 1998 (Volume 63, Number 250)
Citation Publish Date:
12/30/1998
Effective Date:
01/14/1999
Make:
Westland Helicopters Limited
Model:
Westland 30 Series 100 | Westland 30 Series 100-60
Product Type:
Aircraft
Product Subtype:
Rotorcraft
Affected AD:
Superseded AD:
Affected By:
Superseded By:
Service/Office:
Office of Primary Responsibility:
CFR Part Reference:
Part 39 [63 FR 71741 NO. 250 12/30/98]
Comments:
AIRWORTHINESS DIRECTIVES FINAL RULES: 99-01-02
CITATION:   [Federal Register: December 30, 1998 (Volume 63, Number 250)]

PAGE NUMBER:   [Page 71741]

DOCKET NUMBER:   97-SW-40-AD

AMENDMENT:   39-10969

AD NUMBER:   99-01-02

SUBJECT HEADING:   Airworthiness Directives; Westland Helicopters Ltd. 30 Series 100 and 100-60 Helicopters

ACTION:   Final rule; request for comments

SUMMARY:   This amendment adopts a new airworthiness directive (AD) that is applicable to Westland Helicopters Ltd. (Westland) 30 Series 100 and 100-60 helicopters. This action requires the removal and replacement of conformal pinion quill shafts installed in certain main rotor gearboxes that fail to pass a magnetic drain plug inspection. This amendment is prompted by a report of a forced landing that occurred when a single conformal pinion quill shaft failed in a main rotor gearbox (MRGB). This condition, if not corrected, could result in the failure of a MRGB, and a subsequent forced landing or loss of control of the helicopter.

DATES:   Effective January 14, 1999. Comments for inclusion in the Rules Docket must be received on or before March 1, 1999.

ADDRESSES:   Submit comments in triplicate to the Federal Aviation Administration (FAA), Office of the Regional Counsel, Southwest Region, Attention: Rules Docket No. 97-SW-40, 2601 Meacham Blvd., Room 663, Fort Worth, Texas 76137.
The service information referenced in this AD may be obtained from Westland Helicopters Ltd., Customer Support Division, Yeovil, Somerset BA20 2YB, England, telephone (01935) 703884, fax (01935) 703905. 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:   Mr. Shep Blackman, Aerospace Engineer, FAA, Rotorcraft Directorate, Fort Worth, Texas 76193-0111, telephone (817) 222-5296, fax (817) 222-5961.

SUPPLEMENTARY INFORMATION:  
The Civil Aviation Authority (CAA), which is the airworthiness authority for the United Kingdom (UK), notified the FAA that an unsafe condition may exist on Westland 30 series helicopters. The UK CAA advised that an incident of a conformal pinion quill shaft failure within an MRGB occurred, resulting in a forced landing. Further investigation revealed that this MRGB had a history of shock loading, defined as a slam engagement of the No. 1 engine free wheeling unit that can occur when the No. 1 engine condition lever is at "GND" or "FLT" position and the engine is driving accessories but the main rotor is not turning. If the No. 1 engine free wheel is slam engaged, the No. 1 engine power turbine will abruptly stop, causing potential damage to the MRGB and other drive system components. Westland has issued Westland Helicopters Ltd. Service Bulletin W30-63-75, dated November 29, 1995 (SB), that requires the removal and replacement of the conformal pinion quill shafts within a MRGB identified by serial number or with a history of shock loading. The UK CAA classified this SB as mandatory and issued UK CAA AD 012-11-95, dated January 31, 1996, to ensure the continued airworthiness of these helicopters in the UK.
These helicopter models are manufactured in Yeovil, England, and are type certificated for operation in the United States under the provisions of Sec. 21.29 of the Federal Aviation Regulations (14 CFR 21.29) and the applicable bilateral airworthiness agreement. Pursuant to this bilateral airworthiness agreement, the UK CAA has kept the FAA informed of the situation described above. The FAA has examined the findings of the UK CAA, 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.
This AD is being issued to prevent a forced landing or possible loss of control of the helicopter due to failure of the conformal pinion quill shafts installed in the MRGB in certain Westland 30 series helicopters. This AD requires, prior to further flight, a magnetic drain plug inspection of an installed MRGB with a serial number listed in this AD or with a history of shock loading. If the magnetic drain plug passes inspection, the MRGB may remain in service a maximum of 100 additional hours time-in-service (TIS) after the effective date of this AD. If the magnetic drain plug fails inspection, the MRGB must be removed from service prior to further flight and the conformal pinion quill shaft has to be replaced with an airworthy conformal pinion shaft in accordance with the Westland Maintenance Manual.
None of the Westland 30 series helicopters affected by this action are on the U.S. Register. All helicopters included in the applicability of this rule are currently operated by non-U.S. operators under foreign registry; therefore, they are not directly affected by this AD action. However, the FAA considers this rule necessary to ensure that the unsafe condition is addressed in the event that any of these subject helicopters are imported and placed on the U.S. Register in the future.
Should an affected helicopter be imported and placed on the U.S. Register in the future, it would require approximately 1.5 work hours to inspect the magnetic drain plug and 20 work hours to replace, if necessary, the MRGB. The average labor rate is $60 per work hour. A replacement MRGB, if needed, costs $350,000. Based on these figures, the cost impact of this AD would be $350,090 per helicopter; $90 for the inspection and $350,000 for the replacement, if necessary, of the MRGB.
Since this AD action does not affect any helicopter that is currently on the U.S. Register, it has no adverse economic impact and imposes no additional burden on any person. Therefore, 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 rule must submit a self-addressed, stamped postcard on which the following statement is made: "Comments to Docket No. 97-SW-40-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 notice and prior public comment are unnecessary in promulgating this regulation and therefore, it can be issued immediately to correct an unsafe condition in aircraft since none of these model helicopters are registered in the United States, 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, 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.

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

REGULATORY TEXT:  
99-01-02 WESTLAND HELICOPTERS LTD (WESTLAND): Amendment 39-10969. Docket No. 97-SW-40-AD.
Applicability: Westland 30 Series 100 and 100-60 Helicopters, certificated in any category.
NOTE 1: This AD applies to each helicopter 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 helicopters that have been modified, altered, or repaired so that the performance of the requirements of this AD is affected, the owner/operator must use the authority provided in paragraph (c) to request approval from the FAA. This approval may address either no action, if the current configuration eliminates the unsafe condition, or different actions necessary to address the unsafe condition described in this AD. Such a request should include an assessment of the effect of the changed configuration on the unsafe condition addressed by this AD. In no case does the presence of any modification, alteration, or repair remove any rotorcraft from the applicability of this AD.
Compliance: Required as indicated unless accomplished previously.
To prevent failure of the conformal pinion quill shafts installed in certain Westland 30 series helicopters main rotor gearboxes that could result in a subsequent forced landing or loss of control of the helicopter, accomplish the following:
(a) Prior to further flight, determine if the installed main rotor gearbox (MRGB) has a serial number included in the following list or has a history of shock loading. Shock loading is defined as a slam engagement of the No. 1 engine free wheeling unit that can occur when the No. 1 engine condition lever is at "GND" or "FLT" position and the engine is driving accessories but the main rotor is not turning. If the No. 1 engine freewheel is then engaged, the No. 1 engine power turbine will abruptly stop, causing potential damage to the MRGB and other drive system components.


AAT 4440	ABL 5602	ACD 2875
AAX 4726	ABN 8930	ACN 7996
ABC 9438	ABP 3947	ADE 6100
ABD 7294	ABP 9028	WAG 397
ABG 5056	ABT 3965	WAG 410
ABH 5075	ABW 0547	WAK 525
ABJ 9595	ACA 3707	WAK 561
ABK 9484		
(b) If the installed MRGB has a serial number listed in paragraph (a) of this AD or has a history of shock loading, perform a magnetic drain plug inspection.

(1) If the magnetic drain plug passes inspection, the MRGB may remain in service a maximum of 100 additional hours time in service (TIS) after the effective date of this AD with a repetitive magnetic drain plug inspection at intervals not to exceed 25 hours TIS. The MRGB must then be removed from service and the conformal pinion quill shafts replaced.

(2) If the magnetic drain plug fails inspection, remove the MRGB from service prior to further flight and replace the conformal pinion quill shafts.

NOTE 2: Westland Helicopters, Ltd. Service Bulletin No. W30-63-75, dated November 29, 1995 (SB) pertains to the subject of this AD.

(c) 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, Rotorcraft Standards Staff, Rotorcraft Directorate. Operators shall submit their requests through an FAA Principal Maintenance Inspector who may concur or comment and then send it to the Manager, Rotorcraft Standards Staff, Rotorcraft Directorate.

NOTE 3: Information concerning the existence of approved alternative methods of compliance with this AD, if any, may be obtained from the Rotorcraft Standards Staff.

(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 helicopter to a location where the requirements of this AD can be accomplished.

NOTE 4: The subject of this AD is addressed in Civil Aviation Authority (United Kingdom) AD 012-11-95.

(e) This amendment becomes effective on January 14, 1999.

FOOTER: