Airworthiness Directives; Eurocopter Deutschland GmbH Model EC 135 Helicopters

[Federal Register Volume 63, Number 123 (Friday, June 26, 1998)]
[Rules and Regulations]
[Pages 34796-34798]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 98-17023]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 98-SW-18-AD; Amendment 39-10632; AD 98-09-11]
RIN 2120-AA64


Airworthiness Directives; Eurocopter Deutschland GmbH Model EC 
135 Helicopters

AGENCY: Federal Aviation Administration, DOT.

ACTION: Final rule; request for comments.

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SUMMARY: This document publishes in the Federal Register an amendment 
adopting Airworthiness Directive (AD) 98-09-11 which was sent 
previously to all known U.S. owners and operators of Eurocopter 
Deutschland GmbH (Eurocopter) Model EC 135 helicopters by individual 
letters. This AD requires, before further flight, a review of aircraft 
records to determine if a tail rotor drive shaft vibration survey and 
installation of a Fenestron Shaft Retrofit Kit have been accomplished; 
before further flight, and thereafter at intervals not to exceed 15 
hours time-in-service, inspecting the tail rotor drive shaft bearing 
(bearing) attaching lock plates for bent-open tabs, and broken or 
missing slippage marks; and visually inspecting each bearing support 
for cracks. This amendment is prompted by three reports of loose 
bearings and attachment bolts, and one report of a cracked bearing 
support. Excessive vibrations in the tail rotor drive shaft can loosen 
attachment bolts or cause cracking in the bearing supports. This 
condition, if not corrected, could result in loss of drive to the tail 
rotor and subsequent loss of control of the helicopter.

DATES: Effective July 13, 1998, to all persons except those persons to 
whom it was made immediately effective by priority letter AD 98-09-11, 
issued on April 17, 1998, which contained the requirements of this 
amendment.
    Comments for inclusion in the Rules Docket must be received on or 
before August 25, 1998.

ADDRESSES: Submit comments in triplicate to the Federal Aviation 
Administration (FAA), Office of the Regional Counsel, Southwest Region, 
Attention: Rules Docket No. 98-SW-18-AD, 2601 Meacham Blvd., Room 663, 
Fort Worth, Texas 76137.

FOR FURTHER INFORMATION CONTACT: Mr. Scott Horn, Aerospace Engineer, 
FAA, Rotorcraft Directorate, Rotorcraft Standards Staff, 2601 Meacham 
Blvd., Fort Worth, Texas 76137, telephone (817) 222-5125, fax (817) 
222-5961.

SUPPLEMENTARY INFORMATION: On April 17, 1998, the FAA issued priority 
letter AD 98-09-11, applicable to Eurocopter Model EC 135 helicopters, 
which requires, before further flight, a review of aircraft records to 
determine if a tail rotor drive shaft vibration survey and installation 
of a Fenestron Shaft Retrofit Kit L 535M3002 882 have been 
accomplished. If a tail rotor vibration survey has not been 
accomplished or if a Fenestron Shaft Retrofit Kit has not been 
installed, the FAA must be contacted. Also, before further flight, and 
thereafter at intervals not to exceed 15 hours time-in-service, the AD 
requires inspecting the bearing attaching lock plates at each bearing 
support for bent-open tabs, and inspecting for broken or missing 
slippage marks. If a bearing attaching lock plate tab is bent open, or 
if a slippage mark is broken or missing, the FAA must be notified. 
Finally, the AD requires visually inspecting each bearing support for 
cracks, and if a crack is found, replacing the bearing support with an 
airworthy bearing support. That action was prompted by three reports of 
loose bearings and attachment bolts, and one report of a cracked 
bearing support. Excessive vibrations in the tail rotor drive shaft can 
loosen attachment bolts or cause cracking in the bearing supports. This 
condition, if not corrected, could result in loss of drive to the tail 
rotor and subsequent loss of control of the helicopter.
    The Luttfahrt-Bundesamt (LBA), which is the airworthiness authority 
for the Federal Republic of Germany, recently notified the FAA that an 
unsafe condition may exist on Eurocopter Deutschland GmbH (ECD) Model 
EC 135 helicopters. The LBA advises that the loosening of bolt 
connections at the bearing supports may lead to a tail rotor failure 
and thus to the loss of the helicopter. The LBA issued AD 1998-033/5, 
dated April 6, 1998, applicable to ECD Model EC 135 helicopters.
    The FAA has reviewed Eurocopter EC 135 Alert Service Bulletin No. 
EC 135-53A-002, dated December 12, 1997, which describes procedures for 
visually inspecting the bearing supports, and Eurocopter EC 135 Alert 
Service Bulletin No. EC 135-53A-005, Revision 1, dated April 6, 1998, 
which describes procedures for measuring vibrations on the tail rotor 
drive shaft and replacement of roller bearing attaching hardware at 
bearing locations.
    This helicopter model is manufactured in the Federal Republic of 
Germany and is type certificated for operation in the United States 
under the provision 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 operations in the United States.
    Since the unsafe condition described is likely to exist or develop 
on other Eurocopter Model EC 135 helicopters of the same type design, 
the FAA issued priority letter AD 98-09-11 to detect loose bearing 
attachment bolts, or cracked bearing supports, which could result in 
loss of drive to the tail rotor and subsequent loss of control of the 
helicopter. The AD requires, before

[[Page 34797]]

further flight, a review of aircraft records to determine if a tail 
rotor drive shaft vibration survey and installation of a Fenestron 
Shaft Retrofit Kit L 535M3002 882 have been accomplished. If a tail 
rotor vibration survey has not been accomplished or if a Fenestron 
Shaft Retrofit Kit has not been installed, the FAA must be contacted. 
Also, before further flight, and thereafter at intervals not to exceed 
15 hours time-in-service, the AD requires inspecting the bearing 
attaching lock plates at each bearing support for bent-open tabs, and 
inspecting for broken or missing slippage marks. If a bearing attaching 
lock plate tab is bent open, or if a slippage mark is broken or 
missing, the FAA must be notified. Finally, the AD requires visually 
inspecting each bearing support for cracks, and if a crack is found, 
replacing the bearing support with an airworthy bearing support.
    The short compliance time involved is required because the 
previously described critical unsafe condition can adversely affect the 
controllability of the helicopter. Therefore, reviewing aircraft 
records, inspecting the bearing attaching lock plates, and visually 
inspecting each bearing support for cracks are required before further 
flight and this AD must be issued immediately.
    Since it was found that immediate corrective action was required, 
notice and opportunity for prior public comment thereon were 
impracticable and contrary to the public interest, and good cause 
existed to make the AD effective immediately by individual letters 
issued on April 17, 1998 to all known U.S. owners and operators of 
Eurocopter Model EC 135 helicopters. These conditions still exist, and 
the AD is hereby published in the Federal Register as an amendment to 
section 39.13 of the Federal Aviation Regulations (14 CFR 39.13) to 
make it effective to all persons.
    The FAA estimates that 6 helicopters of U.S. registry will be 
affected by this AD, that it will take approximately .5 work hour per 
helicopter to review aircraft records and 1 work hour per helicopter to 
conduct the required inspections, and that the average labor rate is 
$60 per work hour. Required parts will be provided at no cost by the 
manufacturer. Based on these figures, the total cost impact of the AD 
on U.S. operators is estimated to be $540 to review the aircraft 
records and perform the inspections once on each helicopter in the U.S. 
fleet.

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. 98-SW-18-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 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, 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.


Sec. 39.13  [Amended]

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

AD 98-09-11  Eurocopter Deutschland GmbH: Amendment 39-10632. Docket 
No. 98-SW-18-AD.

    Applicability: Model EC 135 helicopters, serial numbers 0005 
through 0048, 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 (d) 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 helicopter from the applicability of this AD.

    Compliance: Required as indicated, unless accomplished 
previously.
    To detect loose tail rotor drive shaft bearing (bearing) 
attachment bolts, or cracked bearing supports, which could result in 
loss of drive to the tail rotor and subsequent loss of control of 
the helicopter, accomplish the following:
    (a) Before further flight, review the helicopter's historical 
records to determine if a tail rotor drive shaft vibration survey 
and the installation of Fenestron Shaft Retrofit Kit L 535M3002 882 
have been accomplished. If either action has not been accomplished, 
contact the Manager, Rotorcraft Standards Staff, FAA, telephone 
(817) 222-5110, fax (817) 222-5961.

[[Page 34798]]

    (b) Before further flight, and thereafter at intervals not to 
exceed 15 hours time-in-service (TIS), at each bearing support:
    (1) Inspect each bearing attaching lock plate that was installed 
with the Fenestron Shaft Retrofit Kit L 535M3002 882 for bent-open 
tabs.
    (2) Inspect for broken or missing slippage marks that may 
indicate looseness or rotation of attaching hardware.
    (3) If a lock plate tab is bent open on bearing supports A, B, 
or C (shown in Figure 1), or if slippage marks are broken or 
missing, contact the Manager, Rotorcraft Standards Staff.

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[GRAPHIC] [TIFF OMITTED] TR26JN98.001

BILLING CODE 4910-13-C

    (c) Before further flight, and thereafter at intervals not to 
exceed 15 hours TIS, using a 6-power or higher magnifying glass and 
a bright light, visually inspect bearing supports B and C as shown 
in Figure 1 for cracks. If a crack is found, replace the bearing 
support with an airworthy bearing support.
    (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, Rotorcraft Standards Staff, FAA. 
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.

    Note 2: Information concerning the existence of approved 
alternative methods of compliance with this AD, if any, may be 
obtained from the Rotorcraft Standards Staff.

    (e) Special flight permits will not be issued.
    (f) This amendment becomes effective on July 13, 1998, to all 
persons except those persons to whom it was made immediately 
effective by Priority Letter AD 98-09-11, issued April 17, 1998, 
which contained the requirements of this amendment.

    Note 3: The subject of this AD is addressed in Luftfahrt-
Bundesamt (Federal Republic of Germany) AD 1998-033/5, dated April 
6, 1998.

    Issued in Fort Worth, Texas, on June 18, 1998.
Eric Bries,
Acting Manager, Rotorcraft Directorate, Aircraft Certification Service.
[FR Doc. 98-17023 Filed 6-25-98; 8:45 am]
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