[Federal Register Volume 67, Number 132 (Wednesday, July 10, 2002)]
[Proposed Rules]
[Pages 45675-45677]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 02-17297]


 ========================================================================
 Proposed Rules
                                                 Federal Register
 ________________________________________________________________________
 
 This section of the FEDERAL REGISTER contains notices to the public of 
 the proposed issuance of rules and regulations. The purpose of these 
 notices is to give interested persons an opportunity to participate in 
 the rule making prior to the adoption of the final rules.
 
 ========================================================================
 

  Federal Register / Vol. 67, No. 132 / Wednesday, July 10, 2002 / 
Proposed Rules  

[[Page 45675]]



DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 2002-NE-13-AD]
RIN 2120-AA64


Airworthiness Directives; General Electric Company CF34-8C1 
Turbofan Engines

AGENCY: Federal Aviation Administration, DOT.

ACTION: Notice of proposed rulemaking (NPRM).

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

SUMMARY: The Federal Aviation Administration (FAA) proposes to adopt a 
new airworthiness directive (AD) that is applicable to General Electric 
Company CF34-8C1 turbofan engines, that would require revisions to the 
Airworthiness Limitations Section (ALS) of the manufacturer's 
Instructions for Continued Airworthiness (ICA) to include required 
enhanced inspection of selected critical life-limited parts at each 
piece-part exposure. This proposal would also require an air carrier's 
approved continuous airworthiness maintenance program to incorporate 
these inspection procedures. Air carriers with an approved continuous 
airworthiness maintenance program would be allowed to either maintain 
the records showing the current status of the inspections using the 
record keeping system specified in the air carrier's maintenance 
manual, or establish an acceptable alternate method of record keeping. 
This proposal is prompted by the need to require enhanced inspection of 
selected critical life-limited parts of CF34-8C1 turbofan engines at 
each piece-part exposure. The actions specified by this proposed AD are 
intended to prevent critical life-limited rotating engine part failure, 
which could result in an uncontained engine failure and damage to the 
airplane.

DATES: Comments must be received by September 9, 2002.

ADDRESSES: Submit comments in triplicate to the Federal Aviation 
Administration (FAA), New England Region, Office of the Regional 
Counsel, Attention: Rules Docket No. 2002-NE-13-AD, 12 New England 
Executive Park, Burlington, MA 01803-5299. Comments may be inspected at 
this location, by appointment, between 8 a.m. and 4:30 p.m., Monday 
through Friday, except Federal holidays. Comments may also be sent via 
the Internet using the following address: ``[email protected]''. 
Comments sent via the Internet must contain the docket number in the 
subject line.

FOR FURTHER INFORMATION CONTACT: Barbara Caufield, Aerospace Engineer, 
Engine Certification Office, FAA, Engine and Propeller Directorate, 12 
New England Executive Park, Burlington, MA 01803-5299; telephone (781) 
238-7146; fax (781) 238-7199.

SUPPLEMENTARY INFORMATION:

Comments Invited

    Interested persons are invited to participate in the making of the 
proposed rule by submitting such written data, views, or arguments as 
they may desire. Communications should identify the Rules Docket number 
and be submitted in triplicate to the address specified above. All 
communications received on or before the closing date for comments, 
specified above, will be considered before taking action on the 
proposed rule. The proposals contained in this action may be changed in 
light of the comments received.
    Comments are specifically invited on the overall regulatory, 
economic, environmental, and energy aspects of the proposed rule. All 
comments submitted will be available, both before and after the closing 
date for comments, in the Rules Docket for examination by interested 
persons. A report summarizing each FAA-public contact concerned with 
the substance of this proposal will be filed in the Rules Docket.
    Commenters wishing the FAA to acknowledge receipt of their comments 
submitted in response to this action must submit a self-addressed, 
stamped postcard on which the following statement is made: ``Comments 
to Docket Number 2002-NE-13-AD.'' The postcard will be date stamped and 
returned to the commenter.

Availability of NPRM's

    Any person may obtain a copy of this NPRM by submitting a request 
to the FAA, New England Region, Office of the Regional Counsel, 
Attention: Rules Docket No. 2002-NE-13-AD, 12 New England Executive 
Park, Burlington, MA 01803-5299.

Discussion

    A recent FAA study analyzing 15 years of accident data for 
transport category airplanes identified several failure mode root 
causes that can result in serious safety hazards to transport category 
airplanes. That study identified uncontained failure of critical life-
limited rotating engine parts as the leading engine-related safety 
hazard to airplanes. Uncontained engine failures have resulted from 
undetected cracks in rotating parts that initiated and propagated to 
failure. Cracks can originate from causes such as unintended excessive 
stress from original design or they may initiate from stresses induced 
from material flaws, handling damage, or damage from machining 
operations. Failure of rotating parts presents a significant safety 
hazard to the airplanes by releasing high-energy fragments that could 
injure passengers or crew by penetrating the cabin, damaging flight 
control surfaces, severing flammable fluid lines, or otherwise 
compromising the airworthiness of the airplane.

Intervention Strategy

    The FAA has developed an intervention strategy to significantly 
reduce uncontained engine failures. The intervention strategy was 
developed after consultation with industry and will be used as a model 
for future initiatives. The intervention strategy involves enhanced, 
nondestructive inspections of the rotating parts that could most likely 
result in a safety hazard to the airplane in the event of a fracture.

Future Rulemaking

    The need for additional rule making is also being considered by the 
FAA. Future AD's may be issued introducing additional intervention 
strategies to further reduce or eliminate uncontained engine failures.

[[Page 45676]]

Safety Critical Parts and Inspection Methods

    Properly focused enhanced inspections require identifying the parts 
whose failure presents the highest safety hazard to the airplane, 
identifying the most critical features to inspect on these parts, and 
utilizing inspection procedures and techniques that improve crack 
detection. The FAA, with the close cooperation of the engine 
manufacturers, has completed a detailed analysis identifying the most 
safety significant parts and features, and the most appropriate 
inspection methods.
    Critical life-limited high-energy rotating parts are currently 
subject to some form of recommended crack inspection when exposed 
during engine maintenance or disassembly. As a result of this proposed 
AD, the inspections currently recommended by the manufacturer will 
become mandatory for those parts listed in the compliance section. 
Furthermore, the FAA intends that additional mandatory enhanced 
inspections resulting from this proposed AD will serve as an adjunct to 
the existing inspections. The FAA has determined that the enhanced 
inspections will significantly improve the probability of crack 
detection while the parts are disassembled during maintenance. All 
mandatory inspections must be conducted in accordance with detailed 
inspection procedures prescribed in the manufacturer's Engine Manual.

Part 121 Operators

    This proposed AD would allow for 14 CFR part 121 air carriers 
having an FAA-approved continuous airworthiness maintenance program, 
and for entities that these air carriers use to do this maintenance, to 
verify performance of the enhanced inspections. This is done by 
retaining the maintenance records that include the inspections 
resulting from this proposed AD. However, these records must include 
the date and signature of the person performing the maintenance action. 
These records would be retained with the maintenance records of the 
part, engine module, or engine until the inspection is repeated. This 
will establish a method of record preservation and retrieval typical to 
those in existing continuous airworthiness maintenance programs. 
Instructions would be included in an air carrier's maintenance manual 
providing procedures for implementation and integration of this record 
preservation and retrieval system into the air carrier's record keeping 
system.
    For engines or engine modules that are approved for return to 
service by an authorized FAA-certificated entity and that are acquired 
by an operator after the effective date of the proposed AD, the 
mandatory enhanced inspections would not be required until the next 
piece-part opportunity. For example, there is no need for an operator 
to disassemble to piece-part level an engine or module returned to 
service by an FAA-certificated facility simply because that engine or 
module was previously operated by an entity not required to comply with 
the proposed AD. Furthermore, the FAA intends for operators to perform 
the proposed enhanced inspections of these parts at the next piece-part 
opportunity following the initial acquisition, installation, and 
removal of the part following the effective date of the proposed AD. 
For piece parts that have not been approved for return to service 
before the effective date of the proposed AD, the FAA does intend that 
the mandatory enhanced inspections required by the proposed AD be 
performed before such parts are approved for return to service. Piece 
parts that have been approved for return to service before the 
effective date of the proposed AD could be installed; however, enhanced 
inspection would be required at the next piece-part opportunity.

Proposed Actions

    This proposal would require, within the next 30 days after the 
effective date of the proposed AD, revisions to the Time Limits Section 
(TLS) in the GE CF34-8C1 Turbofan Engine Manual, and, for air carriers, 
revisions to the approved continuous airworthiness maintenance program. 
GE, the manufacturer of CF34-8C1 turbofan engines used on 14 CFR part 
25 airplanes, has provided the FAA with a detailed proposal that 
identifies and prioritizes the critical life-limited rotating engine 
parts with the highest potential to hazard the airplane in the event of 
failure, along with instructions for enhanced, focused inspection 
methods. The enhanced inspections resulting from the proposed AD would 
be conducted at piece-part opportunity, as defined below in the 
compliance section, rather than specific time inspection intervals.

Economic Analysis

    There are approximately 26 engines of the affected design in the 
worldwide fleet. The FAA estimates that 26 engines installed on 
airplanes of U.S. registry would be affected by this proposed AD, that 
it would take approximately 75 work hours per engine to accomplish the 
proposed actions. The average labor rate is $60 per work hour. Using 
average shop visitation rates, 5 engines are expected to be affected 
per year. Based on these figures, the total cost of the proposed AD on 
U.S. operators is estimated to be $22,500 per year.

Regulatory Analysis

    This proposed rule does not have federalism implications, as 
defined in Executive Order 13132, because it 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. 
Accordingly, the FAA has not consulted with state authorities prior to 
publication of this proposed rule.
    For the reasons discussed above, I certify that 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); 
and (3) if promulgated, 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 copy of the draft 
regulatory evaluation prepared for this action is contained in the 
Rules Docket. A copy of it may be obtained by contacting the Rules 
Docket at the location provided under the caption ADDRESSES.

List of Subjects in 14 CFR Part 39

    Air transportation, Aircraft, Aviation safety, Safety.

The Proposed Amendment

    Accordingly, pursuant to the authority delegated to me by the 
Administrator, the Federal Aviation Administration proposes to amend 
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:

General Electric Company: Docket No. 2002-NE-13-AD.

Applicability

    This airworthiness directive (AD) is applicable to General 
Electric Company (GE)

[[Page 45677]]

CF34-8C1 turbofan engines. These engines are installed on, but not 
limited to Bombardier Aerospace CRJ700 airplanes.

    Note 1: This 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 (c) 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

    Compliance with this AD is required as indicated, unless already 
done.
    To prevent critical life-limited rotating engine part failure, 
which could result in an uncontained engine failure and damage to 
the airplane, do the following:
    (a) Within the next 30 days after the effective date of this AD, 
revise the Time Limits Section (TLS) of the manufacturer's Engine 
Manual (EM), GEK 105091 and for air carrier operations revise the 
approved continuous airworthiness maintenance program, by adding the 
following:
    ``MANDATORY INSPECTIONS
    (1) Perform inspections of the parts listed in the following 
Table 805 at each piece-part opportunity in accordance with the 
instructions provided in the applicable manual provisions:

              Table 805.--Mandatory Inspection Requirements
------------------------------------------------------------------------
                                 Manual/Chapter
      Part Nomenclature          Section/Subject    Mandatory Inspection
------------------------------------------------------------------------
Fan Disk....................  72-21-15, INSPECTION  All areas (FPI),1,
                                                     Bores (ECI).2
Fan Drive Shaft.............  72-22-00, INSPECTION  All areas (FPI).1
Stage 1 High Pressure         72-51-06, INSPECTION  All areas (FPI) 1,
 Turbine (HPT) Rotor Disk.                           Bores (ECI) 2,
                                                     Boltholes (ECI) 2,
                                                     Air Holes (ECI).2
HPT Rotor Outer Torque        72-51-10, INSPECTION  All areas (FPI) 1,
 Coupling.                                           Bores (ECI).2
Stage 2 HPT Rotor Disk......  72-51-14, INSPECTION  All areas (FPI) 1,
                                                     Bores (ECI).2
HPT Shaft...................  72-51-03, INSPECTION  All areas (FPI).1
Stage 1 and Stage 2 High      72-33-01, INSPECTION  All areas (FPI).1
 Pressure Compressor (HPC)
 Rotor Blisks.
HPC Forward Shaft...........  72-33-02, INSPECTION  All areas (FPI).1
Stage 3 HPC Rotor Blisk.....  72-33-03, INSPECTION  All areas (FPI).1
HPC Aft Shaft Spool.........  72-33-05, INSPECTION  All areas (FPI).1
HPC Discharge Rotating Seal.  72-33-08, INSPECTION  All areas (FPI).1
Stage 3 Low Pressure Turbine  72-57-10, INSPECTION  All areas (FPI).1
 (LPT) Rotor Disk.
Stage 4 LPT Rotor Disk......  72-57-16, INSPECTION  All areas (FPI).1
Rear LPT Shaft..............  72-57-23, INSPECTION  All areas (FPI).1
Stage 5 LPT Rotor Disk......  72-57-20, INSPECTION  All areas (FPI).1
Stage 6 LPT Rotor Disk......  72-57-28, INSPECTION  All areas (FPI).1
------------------------------------------------------------------------
1 FPI = Fluorescent Penetrant Inspection Method
2 ECI = Eddy Current Inspection Method

    (2) For the purposes of these mandatory inspections, piece-part 
opportunity means:
    (i) The part is considered at ``piece-part opportunity'', when 
it is completely disassembled in accordance with the disassembly 
instructions in the manufacturer's engine manual; and
    (ii) The part has accumulated more than 100 cycles in service 
since the last piece-part opportunity inspection, provided that the 
part was not damaged or related to the cause for its removal from 
the engine.
    (b) Except as provided in paragraph (c) of this AD, and 
notwithstanding contrary provisions in section 43.16 of the Federal 
Aviation Regulations (14 CFR 43.16), these mandatory inspections 
shall be performed only in accordance with the TLS of the GE CF34-
8C1 EM.

Alternative Methods of Compliance

    (c) 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 (ECO). 
Operators must submit their request through an appropriate FAA 
Principal Maintenance Inspector (PMI), who may add comments and then 
send it to the Manager, ECO.

    Note 2: Information concerning the existence of approved 
alternative methods of compliance with this airworthiness directive, 
if any, may be obtained from the ECO.

Special Flight Permits

    (d) Special flight permits may be issued in accordance with 
Secs. 21.197 and 21.199 of the Federal Aviation Regulations (14 CFR 
21.197 and 21.199) to operate the airplane to a location where the 
requirements of this AD can be done.

Continuous Airworthiness Maintenance Program

    (e) FAA-certificated air carriers that have an approved 
continuous airworthiness maintenance program in accordance with the 
record keeping requirement of Sec. 121.369 (c) of the Federal 
Aviation Regulations (14 CFR 121.369 (c)) must maintain records of 
the mandatory inspections that result from revising the CF34 Engine 
Maintenance Program and the air carrier's continuous airworthiness 
program. Alternatively, certificated air carriers may establish an 
approved system of record retention that provides a method for 
preservation and retrieval of the maintenance records that include 
the inspections resulting from this AD, and include the policy and 
procedures for implementing this alternate method in the air 
carrier's maintenance manual required by Sec. 121.369 (c) of the 
Federal Aviation Regulations (14 CFR 121.369 (c)). However, the 
alternate system must be accepted by the appropriate PMI and require 
the maintenance records be maintained either indefinitely or until 
the work is repeated. Records of the piece-part inspections are not 
required under Sec. 121.380 (a) (2) (vi) of the Federal Aviation 
Regulations (14 CFR 121.380 (a) (2) (vi)). All other operators must 
maintain the records of mandatory inspections required by the 
applicable regulations governing their operations.

    Note 3: The requirements of this AD have been met when the 
engine manual changes are made and air carriers have modified their 
continuous airworthiness maintenance plans to reflect the Engine 
Maintenance Program requirements specified in the GE CF34-8C1 Engine 
Manual.


    Issued in Burlington, Massachusetts, on July 1, 2002.
Jay J. Pardee,
Manager, Engine and Propeller Directorate, Aircraft Certification 
Service.
[FR Doc. 02-17297 Filed 7-9-02; 8:45 am]
BILLING CODE 4910-13-P