[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]
-----------------------------------------------------------------------
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.
-----------------------------------------------------------------------
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:
------------------------------------------------------------------------
Document No. Pages Date
------------------------------------------------------------------------
(CF700) 72-154..................... 1-9 Dec. 20, 1996.
Total Pages: 9.
------------------------------------------------------------------------
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
