Document ID: FAA-2016-5307-0002
Agency: faa
Document Type: Proposed Rule
Title: Airworthiness Directives: General Electric Company Turbofan Engines
Posted Date: 2016-04-11T04:00Z

[Federal Register Volume 81, Number 69 (Monday, April 11, 2016)]
[Proposed Rules]
[Pages 21286-21288]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2016-08111]

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

DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2016-5307; Directorate Identifier 2016-NE-08-AD]
RIN 2120-AA64

Airworthiness Directives; General Electric Company Turbofan 
Engines

AGENCY: Federal Aviation Administration (FAA), DOT.

ACTION: Notice of proposed rulemaking (NPRM).

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

SUMMARY: We propose to adopt a new airworthiness directive (AD) for all 
General Electric Company (GE) GE90-76B, GE90-77B, GE90-85B, GE90-90B, 
and GE90-94B turbofan engines with high-pressure compressor (HPC) stage 
8-10 spool, part numbers (P/Ns) 1694M80G04, 1844M90G01, or 1844M90G02, 
installed. This proposed AD was prompted by reports of cracks found on 
the seal teeth of the HPC stage 8-10 spool. This proposed AD would 
require eddy current inspections (ECIs) or fluorescent penetrant 
inspections (FPIs) of the HPC stage 8-10 spool seal teeth and removing 
from service those parts that fail inspection. We are proposing this AD 
to prevent failure of the HPC stage 8-10 spool, uncontained rotor 
release, damage to the engine, and damage to the airplane.

DATES: We must receive comments on this proposed AD by June 10, 2016.

ADDRESSES: You may send comments, using the procedures found in 14 CFR 
11.43 and 11.45, by any of the following methods:
     Federal eRulemaking Portal: Go to http://www.regulations.gov. Follow the instructions for submitting comments.
     Fax: 202-493-2251.
     Mail: U.S. Department of Transportation, Docket 
Operations, M-30, West Building Ground Floor, Room W12-140, 1200 New 
Jersey Avenue SE., Washington, DC 20590.
     Hand Delivery: Deliver to Mail address above between 9 
a.m. and 5 p.m., Monday through Friday, except Federal holidays.
    For service information identified in this proposed AD, contact 
General Electric Company, GE-Aviation, Room 285, 1 Neumann Way, 
Cincinnati, OH 45215, phone: 513-552-3272; email: 
aviation.fleetsupport@ge.com. You may

[[Page 21287]]

view this service information at the FAA, Engine & Propeller 
Directorate, 1200 District Avenue, Burlington, MA. For information on 
the availability of this material at the FAA, call 781-238-7125.

Examining the AD Docket

    You may examine the AD docket on the Internet at http://www.regulations.gov by searching for and locating Docket No. FAA-2016-
5307; or in person at the Docket Management Facility 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 
Office (phone: 800-647-5527) is in the ADDRESSES section. Comments will 
be available in the AD docket shortly after receipt.

FOR FURTHER INFORMATION CONTACT: John Frost, Aerospace Engineer, Engine 
Certification Office, FAA, 1200 District Avenue, Burlington, MA 01803; 
phone: 781-238-7756; fax: 781-238-7199; email: john.frost@faa.gov.

SUPPLEMENTARY INFORMATION: 

Comments Invited

    We invite you to send any written relevant data, views, or 
arguments about this NPRM. Send your comments to an address listed 
under the ADDRESSES section. Include ``Docket No. FAA-2016-5307; 
Directorate Identifier 2016-NE-08-AD'' at the beginning of your 
comments. We specifically invite comments on the overall regulatory, 
economic, environmental, and energy aspects of this NPRM. We will 
consider all comments received by the closing date and may amend this 
NPRM because 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 we 
receive about this NPRM.

Discussion

    We received reports of multiple cracks found on the seal teeth of 
HPC stage 8-10 spools during shop visits. The cracks initiated because 
of degraded surface properties caused by an alloy depletion zone (ADZ). 
The ADZ developed over time due to higher than predicted temperatures 
and reaction with the seal teeth bond coat. GE is developing a 
modification to address the unsafe condition. This condition, if not 
corrected, could result in failure of the HPC stage 8-10 spool, 
uncontained rotor release, damage to the engine, and damage to the 
airplane.

Related Service Information

    We reviewed GE Service Bulletins SB 72-1141, Revision 0, dated 
December 2, 2015 and SB 72-1142, Revision 0, dated November 30, 2015. 
The service information describes procedures for inspecting the HPC 
stage 8-10 spool seal teeth.

FAA's Determination

    We are proposing this NPRM because we evaluated all the relevant 
information and determined the unsafe condition described previously is 
likely to exist or develop in other products of the same type design.

Proposed AD Requirements

    This NPRM would require accomplishing an ECI or FPI of the seal 
teeth of the HPC stage 8-10 spool and removing from service those parts 
that fail inspection.

Costs of Compliance

    We estimate that this proposed AD affects 54 engines installed on 
airplanes of U.S. registry. We also estimate that it will take about 1 
hour per engine to comply with this AD. The average labor rate is $85 
per hour. We estimate 14 parts will fail inspection at a pro-rated cost 
of $400,000 per part. Based on these figures, we estimate the total 
cost of the AD to U.S. operators to be $5,604,590.

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 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 this 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),
    (3) Will not affect intrastate aviation in Alaska to the extent 
that it justifies making a regulatory distinction, and
    (4) 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.

List of Subjects in 14 CFR Part 39

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

The Proposed Amendment

    Accordingly, under the authority delegated to me by the 
Administrator, the FAA proposes to amend 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 (AD):

General Electric Company: Docket No. FAA-2016-5307; Directorate 
Identifier 2016-NE-08-AD.

(a) Comments Due Date

    We must receive comments by June 10, 2016

(b) Affected ADs

    None.

(c) Applicability

    This AD applies to General Electric Company (GE) GE90-76B, GE90-
77B, GE90-85B, GE90-90B, and GE90-94B turbofan engines with a high-
pressure compressor (HPC) stage 8-10 spool, part numbers (P/Ns) 
1694M80G04, 1844M90G01, or 1844M90G02, installed.

(d) Unsafe Condition

    This AD was prompted by reports of cracks found on the seal teeth 
of the

[[Page 21288]]

HPC stage 8-10 spool. We are issuing this AD to prevent failure of the 
HPC stage 8-10 spool, uncontained rotor release, damage to the engine, 
and damage to the airplane.

(e) Compliance

    Comply with this AD within the compliance times specified, unless 
already done.
    (1) Perform an eddy current inspection (ECI) or fluorescent 
penetrant inspection (FPI) of the seal teeth of the HPC stage 8-10 
spool as follows:
    (i) For HPC stage 8-10 spools with fewer than 11,000 cycles since 
new (CSN) on the effective day of this AD, inspect at the next shop 
visit after reaching 6,000 CSN, not to exceed 12,500 CSN.
    (ii) For HPC stage 8-10 spools with 11,000 CSN or more on the 
effective day of this AD, inspect within the next 1,500 cycles in 
service.
    (iii) Thereafter, inspect the seal teeth of the HPC stage 8-10 
spool at each shop visit.
    (2) Remove from service any HPC stage 8-10 spool that fails the ECI 
or FPI required by paragraph (e)(1) of this AD and replace with a part 
eligible for installation.

(f) Definition

    For the purpose of this AD, an engine shop visit is the induction 
of an engine into the shop for maintenance during which the compressor 
discharge pressure seal face is exposed.

(g) Alternative Methods of Compliance (AMOCs)

    The Manager, Engine Certification Office, FAA, may approve AMOCs 
for this AD. Use the procedures found in 14 CFR 39.19 to make your 
request. You may email your request to: ANE-AD-AMOC@faa.gov.

(h) Related Information

    (1) For more information about this AD, contact John Frost, 
Aerospace Engineer, Engine Certification Office, FAA, 1200 District 
Avenue, Burlington, MA 01803; phone: 781-238-7756; fax: 781-238-7199; 
email: john.frost@faa.gov.
    (2) GE Service Bulletins SB 72-1141, Revision 0, dated December 2, 
2015 and SB 72-1142, Revision 0, dated November 30, 2015 can be 
obtained from GE, using the contact information in paragraph (h)(3) of 
this AD.
    (3) For service information identified in this proposed AD, contact 
General Electric Company, GE-Aviation, Room 285, 1 Neumann Way, 
Cincinnati, OH 45215, phone: 513-552-3272; email: 
aviation.fleetsupport@ge.com.
    (4) You may view this service information at the FAA, Engine & 
Propeller Directorate, 1200 District Avenue, Burlington, MA. For 
information on the availability of this material at the FAA, call 781-
238-7125.

    Issued in Burlington, Massachusetts, on April 5, 2016.
Colleen M. D'Alessandro,
Manager, Engine & Propeller Directorate, Aircraft Certification 
Service.
[FR Doc. 2016-08111 Filed 4-8-16; 8:45 am]
 BILLING CODE 4910-13-P