[Federal Register Volume 62, Number 124 (Friday, June 27, 1997)]
[Rules and Regulations]
[Pages 34621-34623]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 97-16695]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 96-ANE-38; Amendment 39-10057; AD 97-13-10]
RIN 2120-AA64


Airworthiness Directives; General Electric Aircraft Engines CF700 
Series Turbofan Engines

AGENCY: Federal Aviation Administration, DOT.

ACTION: Final rule.

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SUMMARY: This amendment adopts a new airworthiness directive (AD), 
applicable to General Electric Aircraft Engines CF700 series turbofan 
engines, that requires replacement of existing fan guards with new, 
improved fan guards. This amendment is prompted by a report of 
uncontained fan blades which separated from the engine during an 
overspeed. The actions specified by this AD are intended to prevent an 
overspeed of the aft fan disk from resulting in an uncontained engine 
failure and damage to the aircraft.

DATES: Effective August 26, 1997.
    The incorporation by reference of certain publications listed in 
the regulations is approved by the Director of the Federal Register as 
of August 26, 1997.

ADDRESSES: The service information referenced in this AD may be 
obtained from GE Aircraft Engines, 1000 Western Ave., Lynn, MA 01910; 
telephone (617) 594-3140, fax (617) 594-4805. This information may be 
examined at the Federal Aviation Administration (FAA), New England 
Region, Office of the Assistant Chief Counsel, 12 New England Executive 
Park, Burlington, MA; or at the Office of the Federal Register, 800 
North Capitol Street, NW., suite 700, Washington, DC.

FOR FURTHER INFORMATION CONTACT: Dave Keenan, Aerospace Engineer, 
Engine Certification Office, FAA, Engine and Propeller Directorate, 12 
New England Executive Park, Burlington, MA 01803-5299; telephone (617) 
238-7139, fax (617) 238-7199.

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 General Electric Aircraft Engines 
(GE) CF700 series turbofan engines was published in the Federal 
Register on February 19, 1997 (62 FR 7387). That action proposed to 
require, within two years after the effective date of this AD, 
replacement of existing fan guards with new, improved fan guards in 
accordance with GE Service Bulletin (SB) No. (CF700) 72-154, dated 
December 20, 1996.
    Interested persons have been afforded an opportunity to participate 
in the making of this amendment. Due consideration has been given to 
the comments received.
    Eight commenters state that the AD should be withdrawn, since there 
has only been one fan guard related uncontained failure event in 30 
years with 10 million operating hours fleet-wide. The FAA does not 
concur. Implicit in the comment is the assumption that since there has 
been only one such event to date, that necessarily means that there can 
be no other like events until the fleet has operated for another 30 
years and 10 million hours. As a result of the uncontained failure and 
subsequent crash, the FAA has identified a new critical failure mode in 
the GE CF700 engine. This mode, exacerbated by the CF700 having a 
passive aft fan without overspeed protection, can result in an unsafe 
condition that needs addressing through an AD. The FAA has, therefore, 
determined that safety in air commerce requires that this new failure 
mode is addressed through the issuance of this AD.
    Seven commenters state that the AD should be withdrawn due to the 
excessive financial burden of compliance. The FAA does not concur. The 
FAA is aware of the high cost of the improved containment guards; 
however, the basis for the AD is that an unsafe condition has been 
identified and needs to be addressed. During the certification of the 
affected engine's type design, the FAA determined that the design met 
applicable airworthiness requirements that established a cost 
beneficial level of safety. The FAA's current finding, that an unsafe 
condition exists requiring an AD, reflects only that in order to 
maintain the level of safety already established by the regulations at 
the time of type certification operators must perform certain required 
actions. Since these requirements do not add an additional regulatory 
burden, but merely return the affected engines to that level of safety, 
a full cost-benefit analysis is not required. The FAA has provided a 
cost analysis, and General Electric has reduced the cost of these fan 
guards for early orders to help offset this burden on operators.
    Six commenters state that the AD should be withdrawn since the FAA 
and NTSB did not directly participate in the accident investigation. 
The FAA does not concur. Although the FAA and NTSB did not participate 
directly in the investigation, the FAA worked closely with 
representatives from GE's Flight Safety office, who were involved in 
the investigation with the French Authorities. This investigation 
involved hardware inspections, witness reports, and cockpit voice 
recorder information.
    Two commenters state that the AD should be withdrawn since the 
increased weight of containment hardware would reduce the payload 
capacity and range of the aircraft. The FAA does not concur. The FAA 
has determined that the actions required in this AD are necessary to 
maintain the level of safety established by the certification basis at 
the time of type certification. This action is consistent with the 
FAA's statutory mandate to ensure safety in air commerce. While the FAA 
need not consider indirect costs, such as any reduction in the payload 
capacity or range of aircraft on

[[Page 34622]]

which the affected engines are installed, the FAA finds that the 
increase of 80 pounds of aircraft weight is more than offset by the 
need to address this unsafe condition, which could result in an 
overspeed of the aft fan disk, an uncontained engine failure, and 
damage to the aircraft.
    One commenter states that the AD should be withdrawn since the new 
aft fan guard will not prevent an overspeed of the engine in a similar 
circumstance. The FAA does not concur. The new fan guard is not 
intended to prevent an overspeed for occurring, but to prevent 
uncontained debris resulting from an overspeed of the fan from damaging 
the aircraft. While preventing fan overspeed might constitute one 
method of addressing this unsafe condition, the FAA finds that 
requiring the installation of a new fan guard offers the best method 
for addressing this problem on this engine, considering the required 
design changes, availability of parts, difficulty of making the 
necessary engine modifications, and timeliness of completion.
    One commenter states that this containment requirement should be 
imposed on every turbofan engine currently in service, as every 
turbofan engine in service has the same probability of experiencing a 
similar event. The FAA does not concur. The GE CF700 engine is a unique 
design in that it has a passive aft fan module without any overspeed 
protection. The FAA is not aware of any other similar type design 
engine that could exhibit such a failure condition.
    One commenter states that the correct name for the Marcel Avions 
Dassault Falcon 20 aircraft listed in the applicability paragraph 
should be Dassault-Aviation Fan Jet Falcon 20. The FAA concurs and has 
revised this AD accordingly.
    Since issuance of the NPRM, the FAA has received updated economic 
information from the manufacturer, decreasing the cost of parts to 
reflect current pricing. The FAA has revised the economic analysis of 
this final rule accordingly.
    After careful review of the available data, including the comments 
noted above, the FAA has determined that air safety and the public 
interest require the adoption of the rule with the changes described 
previously. The FAA has determined that these changes will neither 
increase the economic burden on any operator nor increase the scope of 
the AD.
    There are approximately 826 engines of the affected design in the 
worldwide fleet. The FAA estimates that 414 engines installed on 
aircraft of U.S. registry will be affected by this AD, that it will 
take approximately 20 work hours per engine to accomplish the required 
actions, and that the average labor rate is $60 per work hour. Required 
parts will cost approximately $40,000 per engine. Based on these 
figures, the total cost impact of the AD on U.S. operators is estimated 
to be $17,056,800.
    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.
    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 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.


Sec. 39.13  [Amended]

    2. Section 39.13 is amended by adding the following new 
airworthiness directive:

99-13-10  General Electric Aircraft Engines: Amendment 39-10057. 
Docket 96-ANE-38.

    Applicability: General Electric Aircraft Engines (GE) CF700 
series turbofan engines, installed on but not limited to Dassault-
Aviation Fan Jet Falcon 20, and Sabreliner NA265 series aircraft.

    Note 1: This airworthiness directive (AD) applies to each engine 
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 engines 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 (b) 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 an overspeed of the aft fan disk from resulting in an 
uncontained engine failure and damage to the aircraft, accomplish 
the following:
    (a) Within 2 years after the effective date of this AD, replace 
existing fan guards with new, improved fan guards, in accordance 
with GE Service Bulletin (SB) No. (CF700) 72-154, dated December 20, 
1996.
    (b) 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, Engine Certification Office. 
Operators shall submit their requests through an appropriate FAA 
Principal Maintenance Inspector, who may add comments and then send 
it to the Manager, Engine Certification Office.

    Note 2: Information concerning the existence of approved 
alternative methods of compliance with this airworthiness directive, 
if any, may be obtained from the Engine Certification Office.

    (c) 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 aircraft to a location where 
the requirements of this AD can be accomplished.
    (d) The actions required by this AD shall be done in accordance 
with the following GE SB:

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            Document No.              Pages              Date           
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(CF700) 72-154.....................      1-9  Dec. 20, 1996.            
    Total Pages: 9.                                                     
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    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 GE Aircraft Engines, 1000 
Western Ave., Lynn, MA 01910; telephone (617) 594-3140, fax (617) 
594-4805. Copies may be inspected at the FAA, New England Region, 
Office of the Assistant Chief Counsel, 12 New England Executive 
Park, Burlington, MA; or at the Office of the Federal Register, 800 
North Capitol Street NW., suite 700, Washington, DC.

[[Page 34623]]

    (e) This amendment becomes effective on August 26, 1997.

    Issued in Burlington, Massachusetts, on June 11, 1997.
Jay J. Pardee,
Manager, Engine and Propeller Directorate, Aircraft Certification 
Service.
[FR Doc. 97-16695 Filed 6-26-97; 8:45 am]
BILLING CODE 4910-13-U