[Federal Register Volume 68, Number 173 (Monday, September 8, 2003)]
[Proposed Rules]
[Pages 52868-52870]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 03-22713]


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

DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 99-NE-48-AD]
RIN 2120-AA64


Airworthiness Directives; General Electric Aircraft Engines CT7 
Series Turboprop Engines

AGENCY: Federal Aviation Administration (FAA), DOT.

ACTION: Notice of proposed rulemaking (NPRM).

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

SUMMARY: The FAA proposes to supersede an existing airworthiness 
directive (AD) for certain General Electric Aircraft Engines (GEAE) CT7 
series turboprop engines. That AD currently requires propeller gearbox 
(PGB) oil filter impending bypass button (IBB) inspections, oil filter 
inspections, replacement of left-hand and right-hand idler gears at 
time of PGB overhaul, and replacement of certain SN PGBs before 
accumulating 2,000 flight hours. This proposed AD would require the 
same actions, and adds additional SNs of affected PGBs. This proposed 
AD is prompted by reports of PGBs equipped with certain gears that do 
not meet design specifications, resulting in the same failure addressed 
in the existing AD. We are proposing this AD to prevent separation of 
PGB left-hand and right-hand idler gears, which could result in 
uncontained PGB failure and internal bulkhead damage, possibly 
prohibiting the auxiliary feathering system from fully feathering the 
propeller on certain PGBs.

DATES: We must receive any comments on this proposed AD by November 7, 
2003.

ADDRESSES: Use one of the following addresses to submit comments on 
this proposed AD:
    [sbull] By mail: Federal Aviation Administration (FAA), New England 
Region, Office of the Regional Counsel, Attention: Rules Docket No. 99-
NE-48-AD, 12 New England Executive Park, Burlington, MA 01803-5299.
    [sbull] By fax: (781) 238-7055.
    [sbull] By e-mail: [email protected].
    You can get the service information identified in this proposed AD 
from General Electric Aircraft Engines, CT7 Series Turboprop Engines, 
1000 Western Ave, Lynn, MA 01910; telephone (781) 594-3140, fax (781) 
594-4805.
    You may examine the AD docket at the FAA, New England Region, 
Office of the Regional Counsel, 12 New England Executive Park, 
Burlington, MA.

FOR FURTHER INFORMATION CONTACT: Eugene Triozzi, Aerospace Engineer, 
Engine Certification Office, FAA, Engine and Propeller Directorate, 12 
New England Executive Park, Burlington, MA 01803-5299; telephone (781) 
238-7148; fax (781) 238-7199.

SUPPLEMENTARY INFORMATION:

Comments Invited

    We invite you to submit any written relevant data, views, or 
arguments regarding this proposal. Send your comments to an address 
listed under ADDRESSES. Include ``AD Docket No. 99-NE-48-AD'' in the 
subject line of your comments. If you want us to acknowledge receipt of 
your mailed comments, send us a self-addressed, stamped postcard with 
the docket number written on it; we will date-stamp your postcard and 
mail it back to you. We specifically invite comments on the overall 
regulatory, economic, environmental, and energy aspects of the proposed 
AD. If a person contacts us verbally, and that contact relates to a 
substantive part of this proposed AD, we will summarize the contact and 
place the summary in the docket. We will consider all comments received 
by the closing date and may amend the proposed AD in light of those 
comments.
    We are reviewing the writing style we currently use in regulatory 
documents. We are interested in your comments on whether the style of 
this document is clear, and your suggestions to improve the clarity of 
our communications that affect you. You may get more information about 
plain language at http://www.faa.gov/language and http://www.plainlanguage.gov.

Examining the AD Docket

    You may examine the AD Docket (including any comments and service 
information), by appointment, between 8 a.m. and 4:30 p.m., Monday 
through Friday, except Federal holidays. See ADDRESSES for the 
location.

Discussion

    On March 12, 2003, the FAA issued AD 2003-06-03 (Amendment 39-
13090, 68 FR 13618, March 20, 2003). That AD requires initial and 
repetitive inspections of the PGB oil filter IBB for extension 
(popping), and follow-on inspections, maintenance, and replacement 
actions if the PGB oil filter IBB is popped, and if necessary, 
replacement of the PGB with a serviceable PGB. In addition, that 
amendment requires replacement of certain left-hand and right-hand 
idler gears at time of overhaul of PGBs, and the replacement of certain 
SN PGBs before accumulating 2,000 flight hours. That AD was prompted by 
an on-going investigation that concluded that low-time PGB removals are 
due to accelerated wear of the PGB idler gears, rather than improperly 
hardened PGB input pinions. That condition, if not corrected, could 
result in uncontained PGB failure and internal bulkhead damage, 
possibly prohibiting the auxiliary feathering system from fully 
feathering the propeller on certain PGBs.

Actions Since AD 2003-06-03 was Issued

    Since that AD was issued, the FAA has learned that a certain 
population of PGBs have been discovered equipped with certain gears 
that do no meet design specifications. This can result in the same PGB 
failure described in AD 2003-06-03.

Relevant Service Information

    For AD 2003-06-03, the FAA previously reviewed and approved the 
technical contents of:
    [sbull] GEAE CT7 Turboprop Service Bulletin (SB) CT7-TP S/B 72-
0453, dated July 27, 2001, that describes procedures for inspections of 
the PGB oil filter IBB for extension, and if the oil filter IBB is 
extended, follow-on inspections, maintenance, and replacement actions. 
This SB also identifies PGBs by SN that require inspection; and
    [sbull] GEAE CT7 Turboprop SB CT7-TP S/B 72-0452, dated July 27, 
2001, that requires replacement of certain SNs of left-hand and right-
hand idler gears

[[Page 52869]]

with serviceable gears. This SB also identifies affected PGBs by SN.
    [sbull] For this proposal, the FAA has reviewed and approved the 
technical contents of GEAE CT7 Turboprop Alert Service Bulletin CT7-TP 
S/B 72-A0466, dated April 17, 2003, that lists the population of SNs of 
PGBs susceptible to gears not meeting design specifications.

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. Therefore, we are proposing this AD, which 
would require:
    [sbull] Initial and repetitive inspections of the propeller gearbox 
(PGB) oil filter IBB for extension (popping).
    [sbull] Follow-on inspections, maintenance, and replacement actions 
if the PGB oil filter IBB is popped, and if necessary, replacement of 
the PGB with a serviceable PGB.
    [sbull] Replacement of certain left-hand and right-hand idler gears 
at time of overhaul of PGBs, and the replacement of certain SN PGBs 
before accumulating 2,000 flight hours after April 24, 2003, the 
effective date of AD 2003-06-03.
    The proposed AD would require that you do these actions using the 
service information described previously.

Changes to 14 CFR Part 39--Effect on the Proposed AD

    On July 10, 2002, we published a new version of 14 CFR part 39 (67 
FR 47997, July 22, 2002), which governs the FAA's AD system. This 
regulation now includes material that relates to altered products, 
special flight permits, and alternative methods of compliance. This 
material previously was included in each individual AD. Since this 
material is included in 14 CFR part 39, we will not include it in 
future AD actions.

Costs of Compliance

    There are about 667 GEAE CT7 series turboprop engines of the 
affected design in the worldwide fleet. We estimate that 400 engines 
installed on airplanes of U.S. registry would be affected by this 
proposed AD. We also estimate that each IBB inspection would take 
approximately 0.25 work hours per engine, and the average labor rate is 
$65 per work hour. Inspection and replacement of idler gears would take 
approximately four work hours per engine at time of PGB overhaul. 
Replacement cost for idler gears per PGB is estimated to be $140,670. 
Therefore, the total cost on U.S. operators would be approximately 
$56,378,500.

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 
regulation:
    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 summary of the costs to comply with this proposal and 
placed it in the AD Docket. You may get a copy of this summary by 
sending a request to us at the address listed under ADDRESSES. Include 
``AD Docket No. 99-NE-48-AD'' in your request.

List of Subjects in 14 CFR Part 39

    Air transportation, Aircraft, Aviation safety, Safety.

The Proposed Amendment

    Accordingly, 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:


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


Sec.  39.13  [Amended]

    2. The FAA amends Sec.  39.13 by removing Amendment 13090, 68 FR 
13618, March 20, 2003, and by adding a new airworthiness directive, 
Amendment 39-XXXXX, to read as follows:

General Electric Aircraft Engines: Docket No. 99-NE-48-AD. 
Supersedes AD 2003-06-03, Amendment 39-13090.

Comments Due Date

    (a) The Federal Aviation Administration (FAA) must receive 
comments on this airworthiness directive (AD) action by November 7, 
2003.

Affected ADs

    (b) This AD supersedes AD 2003-06-03, Amendment 39-13090.

Applicability

    (c) This AD applies to General Electric Aircraft Engines (GEAE) 
CT7 series turboprop engines, with propeller gearboxes (PGBs) 
identified by serial number (SN) in Table 1 of GEAE CT7 Turboprop 
Service Bulletin (SB) CT7-TP S/B 72-0452, dated July 27, 2001, and 
Table 1 of GEAE CT7 Turboprop Alert Service Bulletin (ASB) CT7-TP S/
B 72-A0466, dated April 17, 2003. These engines are installed on but 
not limited to SAAB 340 series airplanes.

Unsafe Condition

    (d) This AD is prompted by reports of additional PGBs equipped 
with certain gears that do not meet design specifications, resulting 
in the same failure addressed in the AD being superseded. We are 
issuing this AD to prevent separation of PGB left-hand and right-
hand idler gears, which could result in uncontained PGB failure and 
internal bulkhead damage, possibly prohibiting the auxiliary 
feathering system from fully feathering the propeller on certain 
PGBs.

Compliance

    (e) You are responsible for having the actions required by this 
AD performed within the compliance times specified unless the 
actions have already been done.
    (f) Inspect the PGB oil filter impending bypass button (IBB) for 
extension using the following schedule:
    (1) Initially inspect within 50 hours time-in-service (TIS) 
after the effective date of this AD.
    (2) Thereafter, inspect each operational day.
    (g) If the PGB oil filter IBB is extended, replace the oil 
filter and perform follow-on inspections, using paragraph 3.A of the 
Accomplishment Instructions of GEAE CT7 Turboprop SB CT7-TP S/B 72-
0453, dated July 27, 2001.
    (h) At the next return of the PGB to a CT7 turboprop overhaul 
facility after the effective date of this AD, replace left-hand and 
right-hand idler gears. Use the Accomplishment Instructions of GEAE 
CT7 Turboprop SB CT7-TP S/B 72-0452, dated July 27, 2001 to replace 
the gears.
    (i) If the PGB is mated to a Hamilton Standard propeller and the 
left-hand and right-hand idler gears have not been replaced in 
accordance with the Accomplishment Instructions of GEAE CT7 
Turboprop SB CT7-TP S/B 72-0452, dated July 27, 2001, replace the 
PGB before accumulating an additional 2,000 engine flight hours 
after April 24, 2003, the effective date of AD 2003-06-03.

Terminating Action

    (j) Replacement of left-hand and right-hand idler gears in 
accordance with paragraph (h) of this AD, or replacement of the PGB 
in accordance with paragraph (i) of this AD constitutes terminating 
action to the repetitive inspections required by paragraph (f) of 
this AD.

[[Page 52870]]

Alternative Methods of Compliance

    (k) The Manager, Engine 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.

Special Flight Permits

    (l) Special flight permits may be issued only for an airplane 
that does not have more than one engine with a PGB oil filter IBB 
extended, to operate the airplane to allocation where the 
requirements of this AD can be done.

Material Incorporated by Reference

    (m) You must use the service information specified in Table 1 to 
perform the inspections and replacements required by this AD. 
Approval of incorporation by reference from the Office of the 
Federal Register is pending for GEAE CT7 Turboprop ASB CT7-TP S/B 
72-A0466, dated April 17, 2003. Table 1 follows:

                                      Table 1.--Incorporation by Reference
----------------------------------------------------------------------------------------------------------------
         Service bulletin no.                    Page                   Revision                   Date
----------------------------------------------------------------------------------------------------------------
SB CT7-TP S/B 72-0452................  ALL....................  Original...............  July 27, 2001.
Total Pages: 12
SB CT7-TP S/B 72-0453................  ALL....................  Original...............  July 27, 2001.
Total Pages: 5
ASB CT7-TP S/B 72-A0466..............  ALL....................  Original...............  April 17, 2003.
Total Pages: 8
----------------------------------------------------------------------------------------------------------------

Related Information

    (n) None.

    Issued in Burlington, Massachusetts, on September 2, 2003.
Jay J. Pardee,
Manager, Engine and Propeller Directorate, Aircraft Certification 
Service.
[FR Doc. 03-22713 Filed 9-5-03; 8:45 am]
BILLING CODE 4910-13-P