Airworthiness Directives; GE Aircraft Engines CT7-9B Turboprop Engines

[Federal Register Volume 68, Number 95 (Friday, May 16, 2003)]
[Rules and Regulations]
[Pages 26478-26481]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 03-11972]


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

DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 2003-NE-16-AD; Amendment 39-13145; AD 2003-08-52]
RIN 2120-AA64


Airworthiness Directives; GE Aircraft Engines CT7-9B Turboprop 
Engines

AGENCY: Federal Aviation Administration (FAA), DOT.

ACTION: Final rule; request for comments.

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

SUMMARY: This document publishes in the Federal Register an amendment 
adopting Airworthiness Directive (AD) 2003-08-52 that was sent 
previously to all known U.S. owners and operators of GE Aircraft 
Engines (GEAE) CT7-9B turboprop engines. This AD requires rigging the 
compressor variable geometry (VG) to VG schedule N. This AD is prompted 
by reports of 12 compressor stall events that occurred over a six-month 
period. The actions specified in this AD are intended to prevent a 
dual-engine in-flight shutdown or power loss due to a compressor stall 
during deceleration from takeoff power to climb power.

DATES: Effective June 2, 2003, to all persons except those persons to 
whom it was made immediately effective by emergency AD 2003-08-52, 
issued on April 15, 2003, which contained the requirements of this 
amendment. The Director of the Federal Register approved the 
incorporation by reference of certain publications listed in the 
regulations as of June 2, 2003.
    We must receive any comments on this AD by July 15, 2003.

[[Page 26479]]


ADDRESSES: Use one of the following addresses to submit comments on 
this AD:
    [sbull] By mail: The Federal Aviation Administration (FAA), New 
England Region, Office of the Regional Counsel, Attention: Rules Docket 
No. 2003-NE-16-AD, 12 New England Executive Park, Burlington, MA 01803-
5299.
    [sbull] By fax: (781) 238-7055.
    [sbull] By e-mail: [email protected].
    You may get the service information referenced in this AD from GE 
Aircraft Engines Customer Support Center, M/D 285, 1 Neumann Way, 
Evendale, OH 45215, telephone (513) 552-3272, fax (513) 552-3329, e-
mail [email protected].
    You may examine the AD docket, by appointment, at the FAA, New 
England Region, Office of the Regional Counsel, 12 New England 
Executive Park, Burlington, MA. You may examine the service 
information, by appointment, at the FAA, New England Region, Office of 
the Regional 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: Anthony W. Cerra Jr., Aerospace 
Engineer, Engine Certification Office, FAA, Engine and Propeller 
Directorate, 12 New England Executive Park, Burlington, MA 01803-5299, 
telephone (781) 238-7128; fax (781) 238-7199.

SUPPLEMENTARY INFORMATION: On April 15, 2003, we issued emergency AD 
2003-08-52, that is applicable to GEAE CT7-9B turbofan engines. That 
emergency AD requires rigging the compressor VG to VG schedule N. That 
action was prompted by reports of 12 compressor stall events that 
occurred over a six-month period. This is in contrast to recent 
historical experience of four to six stall events per year. The stall 
events have occurred on deceleration when transitioning from takeoff 
power to climb power. Of the 10 events under investigation, nine had 
the compressor VG rigged to the VG schedule N1. The manufacturer's 
maintenance manuals and related service bulletins permit the compressor 
VG to be rigged to either the VG schedule N or the VG schedule N1. The 
VG schedule N provides a higher stall margin at the expense of a small 
reduction of engine performance margin as compared to the VG schedule 
N1. Since 1992, the manufacturer has recommended that overhaul shops 
use the VG schedule N only. VG schedule N provides more stall margin on 
used engines, which inherently have a lower stall margin due to wear or 
deterioration. Other factors that contribute to lower stall margins 
include dirty compressors and the increased compressor clearances that 
occur during the first takeoff of the day. This condition, if not 
corrected, could result in a dual-engine in-flight shutdown or power 
loss due to a compressor stall during deceleration from takeoff power 
to climb power.

Relevant Service Information

    We have reviewed and approved the technical contents of GEAE Alert 
Service Bulletin (ASB) No. CT7-TP S/B 72-A0328, Revision 1, dated April 
8, 2003. That ASB describes procedures for rigging the compressor VG to 
the VG schedule N.

FAA's Determination and Requirements of This AD

    The unsafe condition described previously is likely to exist or 
develop on other GEAE CT7-9B turboprop engines of the same type design. 
Therefore, we are issuing this AD to prevent a dual-engine in-flight 
shutdown or power loss due to a compressor stall during deceleration 
from takeoff power to climb power. This AD requires:
    [sbull] If both engines on the airplane are rigged to VG schedule 
N1, rigging the compressor VG on one engine to VG schedule N within 30 
flight hours (FH) or 3 days after the effective date of this AD, 
whichever occurs later and,
    [sbull] Rigging the remaining engine compressor VG to VG schedule N 
within 100 FH or 10 days after the effective date of this AD, whichever 
occurs earlier.
    [sbull] If only one engine is rigged to VG schedule N1, rigging the 
compressor VG to VG schedule N within 100 FH or 10 days after the 
effective date of this AD, whichever occurs earlier.

You must do the actions per GEAE ASB No. CT7-TP S/B 72-A0328, Revision 
1, dated April 8, 2003, described previously.

FAA's Determination of the Effective Date

    Since it was found that immediate corrective action was required, 
notice and opportunity for prior public comment were impracticable and 
contrary to the public interest and that good cause existed to make the 
AD effective immediately on April 15, 2003, to all known U.S. owners 
and operators of GEAE CT7-9B turboprop engines. These conditions still 
exist, and we are publishing the AD in the Federal Register as an 
amendment to section 39.13 of part 39 of the Federal Aviation 
Regulations (14 CFR part 39) to make it effective to all persons.

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

    On July 10, 2002, we issued a new version of 14 CFR part 39 (67 FR 
47997, July 22, 2002), which governs our AD system. This regulation now 
includes material that relates to special flight permits, alternative 
methods of compliance, and altered products. 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.

Interim Action

    The investigation to determine the root causes of the decel stall 
events is ongoing. We may take further rulemaking action when we have 
identified the root causes.

Comments Invited

    This AD is a final rule that involves requirements affecting flight 
safety and was not preceded by notice and an opportunity for public 
comment; however, we invite you to submit any written relevant data, 
views, or arguments regarding this AD. Send your comments to an address 
listed under ADDRESSES. Include ``AD Docket No. 2003-NE-16-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 rule 
that might suggest a need to modify it. If a person contacts us through 
a nonwritten communication, and that contact relates to a substantive 
part of this 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 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 with you. You may get more information about plain 
language at http://www.plainlanguage.gov.

Regulatory Findings

    We have determined that this AD will not have federalism 
implications under Executive Order 13132. This AD will not have a 
substantial direct effect on

[[Page 26480]]

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 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. 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.
    We prepared a summary of the costs to comply with this AD 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. 2003-NE-16-AD'' in your request.

List of Subjects in 14 CFR Part 39

    Air transportation, Aircraft, Aviation safety, Incorporation by 
reference, Safety.

Adoption of the Amendment

0
Accordingly, under 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

0
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]

0
2. The FAA amends Sec.  39.13 by adding the following new airworthiness 
directive:

2003-08-52 GE Aircraft Engines: Amendment 39-13145. Docket No. 2003-
NE-16-AD.

Effective Date

    (a) This amendment becomes effective June 2, 2003, to all 
persons except those persons to whom it was made immediately 
effective by emergency AD 2003-08-52, issued April 15, 2003.

Affected ADs

    (b) None.

Applicability

    (c) This AD applies to GEAE CT7-9B turboprop engines. These 
engines are installed on, but not limited to Saab Aircraft AB 340B 
airplanes.

Unsafe Condition

    (d) This AD was prompted by reports of 12 compressor stall 
events that occurred over a six month period. The actions specified 
in this AD are intended to prevent a dual-engine in-flight shutdown 
or power loss due to a compressor stall during deceleration from 
takeoff power to climb power.

Compliance

    (e) Compliance with the requirements of this AD is required as 
indicated unless already done.

Determining Compressor VG Rigging Schedule

    (f) Determine which schedule was used to rig the compressor VG. 
The serial numbers (SNs) contained in Table 1 of this AD are known 
to have been rigged to VG schedule N1. Engines with SNs that are not 
listed in Table 1 might be rigged to VG schedule N1. You must review 
the engine records to determine if the engines are rigged to VG 
schedule N1 using GEAE Service Bulletin (SB) No. CT7-TP S/B 72-0241, 
dated April 6, 1990. Table 1 follows:

                      Table 1.--SNs of Engines Known to Have Been Rigged to VG Schedule N1
----------------------------------------------------------------------------------------------------------------
 
----------------------------------------------------------------------------------------------------------------
         785102             785104             785106             785107             785109             785111
         785112             785113             785117             785118             785125             785128
         785129             785131             785133             785136             785138             785148
         785150             785151             785152             785154             785160             785185
         785188             785211             785231             785232             785234             785235
         785237             785239             785241             785257             785259             785265
         785266             785275             785322             785325             785326             785334
         785375             785391             785400             785459             785460             785462
         785465             785474             785476             785477             785480             785481
         785487             785499             785506             785534             785538             785554
         785569             785591             785592             785598             785603             785700
         785759
----------------------------------------------------------------------------------------------------------------

Rigging the Compressor VG to Schedule N

    (g) If the compressor VGs of both engines on the airplane are 
rigged to VG schedule N using GEAE SB CT7-TP S/B 72-0328 dated June 
9, 1992 or GEAE Alert Service Bulletin (ASB) CT7-TP S/B 72-A0328, 
Revision 1, dated April 8, 2003 no further action is required.
    (h) If the compressor VGs on both engines on the airplane are 
rigged to VG schedule N1, do the following:
    (1) Within 30 flight hours (FH) or 3 days after the effective 
date of this AD, whichever occurs later, rig the compressor VG on 
one engine to VG schedule N in accordance with 3.A.(1) through 
3.A.(12) of the Accomplishment Instructions of GEAE ASB No. CT7-TP 
S/B 72-A0328, Revision 1, dated April 8, 2003.
    (2) Within 100 FH or 10 days after the effective date of this 
AD, whichever occurs earlier, rig the compressor VG on the remaining 
engine to VG schedule N in accordance with 3.A.(1) through 3.A.(12) 
of the Accomplishment Instructions of GEAE ASB No. CT7-TP S/B 72-
A0328, Revision 1, dated April 8, 2003.
    (i) If the compressor VG on one engine on the airplane is rigged 
to VG schedule N1, within 100 FH or 10 days after the effective date 
of this AD, whichever occurs earlier, rig the compressor VG to VG 
schedule N in accordance with 3.A.(1) through 3.A.(12) of the 
Accomplishment Instructions of GEAE ASB No. CT7-TP S/B 72-A0328, 
Revision 1, dated April 8, 2003.

Installation of Engines With VG Schedule N1

    (j) After the effective date of this AD, do not install any CT7-
9B turboprop engine that is rigged to VG schedule N1 on to any Saab 
Aircraft AB 340B airplane.

Alternative Methods of Compliance

    (k) Alternative methods of compliance must be requested in 
accordance with 14 CFR part 39.19, and must be approved by the 
Manager, Engine Certification Office, Federal Aviation 
Administration (FAA).

Material Incorporated by Reference

    (l) The rigging of the compressor VG must be done in accordance 
with GE Aircraft Engines Alert Service Bulletin (ASB) No. CT7-TP S/B 
72-A0328, Revision 1, dated April 8, 2003. The Director of the 
Federal Register approved the incorporation by reference of this 
service bulletin in accordance with 5 U.S.C. 552(a) and 1 CFR part 
51. You may get a copy from GE Aircraft Engines Customer Support 
Center, M/D 285, 1 Neumann Way, Evendale, OH 45215, telephone (513) 
552-3272, fax (513) 552-3329, email [email protected]. You may 
review copies at the FAA, New England Region, Office of the Regional 
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.

Related Information

    (m) Additional information to help minimize the occurrence of 
multiple-engine in-flight shutdowns or power loss may be

[[Page 26481]]

found in GEAE All Operator's Wire CT7-03-02, dated April 3, 2003.

    Issued in Burlington, MA on May 7, 2003.
Jay J. Pardee,
Manager, Engine and Propeller Directorate, Aircraft Certification 
Service.
[FR Doc. 03-11972 Filed 5-15-03; 8:45 am]
BILLING CODE 4910-13-P

The complete text was extracted from the official GovInfo HTML edition for this publication. Acquired 2026-10-09T04:13:33.247173+00:00. Text extraction preserves the recorded source wording; it does not determine current requirements.

Open the captured official edition

Source SHA-256

75d0fd35ae2a5a00927087bb5043f6d9b938bcde8b3be40c064229e9fcdc1628

Text SHA-256

87182a18b4bce6a50228e4ff024e1a03c7bc40bdfcd44377c59bef45dd51a2a7