[Federal Register Volume 72, Number 193 (Friday, October 5, 2007)]
[Proposed Rules]
[Pages 56945-56947]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: E7-19684]


=======================================================================
-----------------------------------------------------------------------

DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2007-29092; Directorate Identifier 2007-NE-30-AD]
RIN 2120-AA64


Airworthiness Directives; Honeywell International Inc. ATF3-6 and 
ATF3-6A Series Turbofan Engines

AGENCY: Federal Aviation Administration (FAA), Department of 
Transportation (DOT).

ACTION: Notice of proposed rulemaking (NPRM).

-----------------------------------------------------------------------

SUMMARY: The FAA proposes to adopt a new airworthiness directive (AD) 
for Honeywell International Inc. ATF3-6 and ATF3-6A series turbofan 
engines equipped with a certain part number (P/N) low pressure 
compressor (LPC) aft shaft. This proposed AD would require removing 
from service those LPC aft shafts and installing a serviceable LPC aft 
shaft. This proposed AD results from reports of eight LPC aft shafts 
found cracked during fluorescent penetrant inspection (FPI). We are 
proposing this AD to prevent uncoupling and overspeed of the low 
pressure turbine, which could result in uncontained engine failure and 
damage to the airplane.

DATES: We must receive any comments on this proposed AD by December 4, 
2007.

ADDRESSES: Use one of the following addresses to comment on this 
proposed AD.
     Federal eRulemaking Portal: Go to http://www.regulations.gov. Follow the online instructions for sending your 
comments electronically.
     Mail: Docket Management Facility: U.S. Department of 
Transportation, 1200 New Jersey Avenue, SE., West Building Ground 
Floor, Room W12-140, Washington, DC 20590-0001.
     Hand Delivery: Deliver to Mail address above between 9 
a.m. and 5 p.m., Monday through Friday, except Federal holidays.
     Fax: (202) 493-2251.
    You can get the service information identified in this proposed AD 
from Honeywell International Inc., 111 S. 34th St., Phoenix, AZ 85034-
2802; Web

[[Page 56946]]

site: http://portal.honeywell.com/wps/portal/aero; telephone (800) 601-
3099.

FOR FURTHER INFORMATION CONTACT: Joseph Costa, Aerospace Engineer, Los 
Angeles Aircraft Certification Office, FAA, Transport Airplane 
Directorate, 3960 Paramount Blvd., Lakewood, CA 90712-4137; e-mail: 
[email protected]; telephone: (562) 627-5246; fax: (562) 627-5210.

SUPPLEMENTARY INFORMATION: 

Comments Invited

    We invite you to send us any written relevant data, views, or 
arguments regarding this proposal. Send your comments to an address 
listed under ADDRESSES. Include ``Docket No. FAA-2007-29092; 
Directorate Identifier 2007-NE-30-AD'' in the subject line of your 
comments. We specifically invite comments on the overall regulatory, 
economic, environmental, and energy aspects of the proposed AD. We will 
consider all comments received by the closing date and may amend the 
proposed AD in light of those comments.
    We will post all comments we receive, without change, to http://www.regulations.gov, including any personal information you provide. We 
will also post a report summarizing each substantive verbal contact 
with FAA personnel concerning this proposed AD. Anyone is able to 
search the electronic form of all comments received into any of our 
dockets by the name of the individual submitting the comment (or 
signing the comment, if submitted on behalf of an association, 
business, labor union, etc.) You may review the DOT's complete Privacy 
Act Statement in the Federal Register published on April 11, 2000 (65 
FR 19477-78).

Examining the AD Docket

    You may examine the AD docket on the Internet at http://www.regulations.gov; or in person at the Docket Operations office 
between 9 a.m. and 5 p.m., Monday through Friday, except Federal 
holidays. The AD docket contains this proposed AD, the regulatory 
evaluation, any comments received, and other information. The street 
address for the Docket Operations office (telephone (800) 647-5527) is 
the same as the Mail address provided in the ADDRESSES section. 
Comments will be available in the AD docket shortly after receipt.

Discussion

    During routine fluorescent penetrant inspection of P/N 3002070-1 
LPC aft shafts, eight LPC aft shafts were found with cracks in the root 
radii of the curvic teeth. Five of eight cracked aft shafts were found 
to have fillet root radii of the curvic teeth below the manufacturing 
minimum limit. We have determined that curvic teeth machined to a small 
root radii increases local stresses and contributes to cracking. This 
condition, if not corrected, could result in uncoupling and overspeed 
of the low pressure turbine, uncontained engine failure, and damage to 
the airplane.

Relevant Service Information

    We have reviewed and approved the technical contents of Honeywell 
International Inc. Service Bulletin (SB) No. ATF3-72-6240, Revision 1, 
dated May 14, 2007, that describes procedures for removing P/N 3002070-
1 LPC aft shafts from service and installing a serviceable LPC aft 
shaft.

Differences Between the Proposed AD and the Manufacturer's Service 
Information

    The compliance schedule in this proposed AD differs from the SB 
compliance schedule by improving format, by removing the hourly and 
calendar ``at access'' compliance time requirements, and by relaxing 
the compliance schedule.

FAA's Determination and Requirements of the Proposed AD

    We have evaluated all pertinent information and identified an 
unsafe condition that is likely to exist or develop on other products 
of this same type design. We are proposing this AD, which would require 
removing LPC aft shafts, P/N 3002070-1 from service and installing a 
serviceable LPC aft shaft. The proposed AD would require you to use the 
service information described previously to perform these actions.

Costs of Compliance

    We estimate that this proposed AD would affect 32 ATF3-6 and ATF3-
6A series turbofan engines installed on airplanes of U.S. registry. We 
also estimate that it would take about 40 work-hours per engine to 
perform the proposed actions if unscheduled, 20 work-hours per engine 
if during scheduled major periodic inspection (MPI), and 1 work-hour 
per engine during scheduled core zone inspection (CZI). We estimate 
that 4 engines would be unscheduled, 14 engines would be scheduled at 
MPI, and 14 engines would be scheduled at CZI. The average labor rate 
is $80 per work-hour. Required parts would cost about $15,000 per 
engine. Based on these figures, we estimate the total cost of the 
proposed AD to U.S. operators to be $516,320.

Authority for This Rulemaking

    Title 49 of the United States Code specifies the FAA's authority to 
issue rules on aviation safety. Subtitle I, Section 106, describes the 
authority of the FAA Administrator. Subtitle VII, Aviation Programs, 
describes in more detail the scope of the Agency's authority.
    We are issuing this rulemaking under the authority described in 
Subtitle VII, Part A, Subpart III, Section 44701, ``General 
requirements.'' Under that section, Congress charges the FAA with 
promoting safe flight of civil aircraft in air commerce by prescribing 
regulations for practices, methods, and procedures the Administrator 
finds necessary for safety in air commerce. This regulation is within 
the scope of that authority because it addresses an unsafe condition 
that is likely to exist or develop on products identified in this 
rulemaking action.

Regulatory Findings

    We have determined that this proposed AD would not have federalism 
implications under Executive Order 13132. This proposed AD would 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.
    For the reasons discussed above, I certify that the proposed AD:
    1. Is not a ``significant regulatory action'' under Executive Order 
12866;
    2. Is not a ``significant rule'' under the DOT Regulatory Policies 
and Procedures (44 FR 11034, February 26, 1979); and
    3. Would not have a significant economic impact, positive or 
negative, on a substantial number of small entities under the criteria 
of the Regulatory Flexibility Act.
    We prepared a regulatory evaluation of the estimated costs to 
comply with this proposed AD. You may get a copy of this summary at the 
address listed under ADDRESSES.

List of Subjects in 14 CFR Part 39

    Air transportation, Aircraft, Aviation safety, Safety.

The Proposed Amendment

    Under the authority delegated to me by the Administrator, the 
Federal Aviation Administration proposes to amend 14 CFR part 39 as 
follows:

PART 39--AIRWORTHINESS DIRECTIVES

    1. The authority citation for part 39 continues to read as follows:


[[Page 56947]]


    Authority: 49 U.S.C. 106(g), 40113, 44701.


Sec.  39.13  [Amended]

    2. The FAA amends Sec.  39.13 by adding the following new 
airworthiness directive:
Honeywell International Inc. (formerly AlliedSignal Inc. and Garrett 
Turbine Engine Co.): Docket No. FAA-2007-29092; Directorate 
Identifier 2007-NE-30-AD.

Comments Due Date

    (a) The Federal Aviation Administration (FAA) must receive 
comments on this airworthiness directive (AD) action by December 4, 
2007.

Affected ADs

    (b) None.

Applicability

    (c) This AD applies to Honeywell International Inc. ATF3-6-4C, 
ATF3-6A-3C, and ATF3-6A-4C turbofan engines equipped with part 
number (P/N) 3002070-1 low pressure compressor (LPC) aft shaft. 
These engines are installed on, but not limited to, Dassault 
Aviation Fan Jet Falcon Series G (Falcon 20G/HU25), and Dassault 
Aviation Mystere-Falcon 200 airplanes.

Unsafe Condition

    (d) This AD results from reports of eight LPC aft shafts found 
cracked during fluorescent penetrant inspection (FPI). We are 
issuing this AD to prevent uncoupling and overspeed of the low 
pressure turbine, which could result in uncontained engine failure 
and damage to the airplane.

Compliance

    (e) You are responsible for having the actions required by this 
AD performed within the compliance times specified in Table 1 and 
Table 2 of this AD, unless the actions have already been done.

              Table 1.--ATF3-6A-4C Turbofan Engines, LPC Aft Shaft Replacement Compliance Schedule
----------------------------------------------------------------------------------------------------------------
For ATF3-6A-4C turbofan engines, if the cycles-since-new (CSN) on
                the effective date of this AD are:                        Then replace the LPC aft shaft:
----------------------------------------------------------------------------------------------------------------
(1) 6,500 or more CSN............................................  Within an additional 100 cycles-in-service
                                                                    (CIS).
(2) 5,000 to 6,499 CSN...........................................  Within an additional 800 CIS, but not more
                                                                    than 6,600 CSN, whichever occurs first.
(3) 4,000 to 4,999 CSN...........................................  Within an additional 1,500 CIS, but not more
                                                                    than 5,800 CSN, whichever occurs first.
(4) Fewer than 4,000 CSN.........................................  Within an additional 2,000 CIS, but not more
                                                                    than 5,500 CSN, whichever occurs first.
----------------------------------------------------------------------------------------------------------------


       Table 2.--ATF3-6-4C and ATF3-6A-3C Turbofan Engines, LPC Aft Shaft Replacement Compliance Schedule
----------------------------------------------------------------------------------------------------------------
 For ATF3-6-4C and ATF3-6A-3C turbofan engines, if the CSN on the
                  effective date of this AD are:                          Then replace the LPC aft shaft:
----------------------------------------------------------------------------------------------------------------
(1) 4,400 or more CSN............................................  Within an additional 100 CIS.
(2) 3,600 to 4,399 CSN...........................................  Within an additional 500 CIS, but not more
                                                                    than 4,500 CSN, whichever occurs first.
(3) 3,300 to 3,599 CSN...........................................  Within an additional 700 CIS, but not more
                                                                    than 4,100 CSN, whichever occurs first.
(4) Fewer than 3,300 CSN.........................................  Within an additional 1,000 CIS, but not more
                                                                    than 4,000 CSN, whichever occurs first.
----------------------------------------------------------------------------------------------------------------

LPC Aft Shaft Replacement

    (f) Using the compliance schedule in Table 1 or Table 2 of this 
AD as applicable, remove the LPC aft shaft P/N 3002070-1, from 
service, and install a serviceable LPC aft shaft.

Definition

    (g) For the purpose of this AD, a serviceable LPC aft shaft is 
an aft shaft with a P/N not referenced in this AD.

Alternative Methods of Compliance

    (h) The Manager, Los Angeles Aircraft Certification Office, has 
the authority to approve alternative methods of compliance for this 
AD if requested using the procedures found in 14 CFR 39.19.

Related Information

    (i) Honeywell International Inc. Service Bulletin No. ATF3-72-
6240, Revision 1, dated May 14, 2007, pertains to the subject of 
this AD.
    (j) Contact Joseph Costa, Aerospace Engineer, Los Angeles 
Aircraft Certification Office, FAA, Transport Airplane Directorate, 
3960 Paramount Blvd., Lakewood, CA 90712-4137; e-mail: 
[email protected]; telephone: (562) 627-5246; fax: (562) 627-
5210.

    Issued in Burlington, Massachusetts, on October 1, 2007.
Peter A. White,
Acting Manager, Engine and Propeller Directorate, Aircraft 
Certification Service.
[FR Doc. E7-19684 Filed 10-4-07; 8:45 am]
BILLING CODE 4910-13-P