Airworthiness Directives; Eurocopter Deutschland GMBH Model MBB-BK 117 Helicopters

[Federal Register Volume 65, Number 58 (Friday, March 24, 2000)]
[Rules and Regulations]
[Pages 15858-15859]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 00-7336]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 98-SW-77-AD; Amendment 39-11647; AD 2000-06-07]
RIN 2120-AA64


Airworthiness Directives; Eurocopter Deutschland GMBH Model MBB-
BK 117 Helicopters

AGENCY: Federal Aviation Administration, DOT.

ACTION: Final rule.

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SUMMARY: This amendment adopts a new airworthiness directive (AD), 
applicable to Eurocopter Deutschland GMBH (ECD) Model MBB-BK 117 
helicopters, that requires changing the retirement life for the tail 
rotor (output) drive bevel gear (bevel gear). This amendment is 
prompted by a fatigue analysis of the bevel gear conducted by the 
manufacturer due to installation of different tail rotor blades. The 
actions specified by this AD are intended to prevent fatigue failure of 
the bevel gear, loss of tail rotor drive, and subsequent loss of 
control of the helicopter.

EFFECTIVE DATE: April 28, 2000.

FOR FURTHER INFORMATION CONTACT: Shep Blackman, Aerospace Engineer, 
FAA, Rotorcraft Directorate, Rotorcraft Standards Staff, 2601 Meacham 
Blvd., Fort Worth, Texas 76137, telephone (817) 222-5296, fax (817) 
222-5961.

SUPPLEMENTARY INFORMATION: A proposal to amend part 39 of the Federal 
Aviation Regulations (14 CFR part 39) to include an airworthiness 
directive (AD) that is applicable to ECD Model MBB-BK 117 helicopters 
was published in the Federal Register on December 10, 1999 (64 FR 
69208). That action proposed to require changing the retirement life 
for the bevel gear.
    Interested persons have been afforded an opportunity to participate 
in the making of this amendment. No comments were received on the 
proposal or the FAA's determination of the cost to the public. The FAA 
has determined that air safety and the public interest require the 
adoption of the rule as proposed except that the part number of the 
affected bevel gear has been added to the applicability paragraph and 
the limitations paragraph to more specifically identify the affected 
part. The FAA has determined that these changes will neither increase 
the economic burden on any operator nor increase the scope of the AD.
    The FAA estimates that 130 helicopters of U.S. registry will be

[[Page 15859]]

affected by this AD, that it will take approximately 0.5 work hour per 
helicopter to change the retirement life in the records, and 36 work 
hours to replace the bevel gear. Required parts will cost approximately 
$14,092 per helicopter. Based on these figures, the total cost impact 
of the AD on U.S. operators is estimated to be $2,116,660 to change the 
retirement life entry and to replace the bevel gear upon reaching 
18,500 hours TIS for the entire fleet.
    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.
    For the reasons discussed above, I certify that this action (1) is 
not a ``significant regulatory action'' under Executive Order 12866; 
(2) is not a ``significant rule'' under DOT Regulatory Policies and 
Procedures (44 FR 11034, February 26, 1979); and (3) will not have a 
significant economic impact, positive or negative, on a substantial 
number of small entities under the criteria of the Regulatory 
Flexibility Act. A final evaluation has been prepared for this action 
and it is contained in the Rules Docket. A copy of it may be obtained 
from the Rules Docket at the FAA, Office of the Regional Counsel, 
Southwest Region, 2601 Meacham Blvd., Room 663, Fort Worth, Texas.

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 2000-06-07  Eurocopter Deutschland: Amendment 39-11647. Docket 
No. 98-SW-77-AD.
    Applicability: Model MBB-BK 117 helicopters, serial numbers 7001 
through 7250 and 7500 through 7509, with tail rotor (output) drive 
bevel gear (bevel gear), part number (P/N) 117-12215-01, 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 fatigue failure of the bevel gear, loss of tail rotor 
drive, and subsequent loss of control of the helicopter, accomplish 
the following:
    (a) Within 100 hours time-in-service (TIS):
    (1) Record in the accessory replacement record and historical 
record ``Main Transmission'' section the retirement life of 18,500 
hours TIS for the bevel gear.
    (2) Determine the total hours TIS of the bevel gear. If the 
total hours TIS cannot be determined, use the operating time of the 
main transmission.
    (b) If the bevel gear's total hours TIS is equal to or greater 
than 18,400 hours TIS, remove the bevel gear within the next 100 
hours TIS and replace it with an airworthy bevel gear. If the bevel 
gear's total hours TIS is less than 18,400 hours TIS, remove the 
bevel gear on or before 18,500 hours TIS and replace it with an 
airworthy bevel gear.
    (c) This AD revises the helicopter Airworthiness Limitations 
section of the maintenance manual by establishing a new retirement 
life for the bevel gear, P/N 117-12215-01, of 18,500 hours TIS.
    (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 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.
    (f) This amendment becomes effective on April 28, 2000.

    Note 3: The subject of this AD is addressed in Luftfahrt-
Bundesamt (Federal Republic of Germany) AD No. 97-350, dated 
December 18, 1997.


    Issued in Fort Worth, Texas, on March 17, 2000.
Eric Bries,
Acting Manager, Rotorcraft Directorate, Aircraft Certification Service.
[FR Doc. 00-7336 Filed 3-23-00; 8:45 am]
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