[Federal Register Volume 66, Number 113 (Tuesday, June 12, 2001)]
[Proposed Rules]
[Pages 31569-31571]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 01-14671]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 99-NE-62-AD]
RIN 2120-AA64


Airworthiness Directives; General Electric Company GE90 Series 
Turbofan Engines

AGENCY: Federal Aviation Administration, DOT.

ACTION: Notice of proposed rulemaking (NPRM).

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SUMMARY: The Federal Aviation Administration (FAA) proposes to 
supersede an existing airworthiness directive (AD), applicable to 
certain General Electric Company (GE) GE90 series turbofan engines. 
That AD currently requires inspecting and purging the P3B and Ps3 lines 
and associated fittings and ports of moisture. This proposal would 
allow the installation of improved hardware as terminating action to 
requirements of the AD, and remove the GE90-92B engine model from the 
AD applicability. This proposal is prompted by the recent FAA approval 
of redesigned P3B and Ps3 sense lines, and the removal of the GE90-92B 
engine from the applicability. The actions described in this proposal 
are intended to prevent loss of thrust control due to corruption of the 
P3B and Ps3 signals to the FADEC, which if it occurs in a critical 
phase of flight, could result in loss of airplane control.

DATES: Comments must be received by August 13, 2001.

ADDRESSES: Submit comments in triplicate to the Federal Aviation 
Administration (FAA), New England Region, Office of the Regional 
Counsel, Attention: Rules Docket No. 99-NE-62-AD, 12 New England 
Executive Park, Burlington, MA 01803-5299. 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. Comments may be inspected at this 
location between 8:00 a.m. and 4:30 p.m., Monday through Friday, except 
Federal holidays. The service information referenced in the proposed 
rule may be obtained from General Electric Company via Lockheed Martin 
Technology Services, 10525 Chester Road, Suite C, Cincinnati, OH 45215; 
telephone: (513) 672-8400, fax: (513) 672-8422. This information may be 
examined at the FAA, New England Region, Office of the Regional 
Counsel, 12 New England Executive Park, Burlington, MA.

FOR FURTHER INFORMATION CONTACT: John E. Golinski, Aerospace Engineer, 
Engine Certification Office, FAA, Engine and Propeller Directorate, 12 
New England Executive Park, Burlington, MA 01803-5299; telephone: (781) 
238-7135; 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 to the address specified above. All communications 
received on or before the closing date for comments, specified above, 
will be considered before we take 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 sent 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 send a self-addressed, 
stamped postcard on which the following statement is made: ``Comments 
to Docket Number 99-NE-62-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. 99-NE-62-AD, 12 New England Executive Park, 
Burlington, MA 01803-5299.

Discussion

    On December 29, 1999, the FAA issued AD 99-27-15, Amendment 39-
11496 (65 FR 692, January 6, 2000), to require visually inspecting P3B 
and Ps3 sense lines and FADEC P3B and Ps3 sensing ports and fittings, 
cleaning P3B and Ps3 fittings and sensing ports, purging the P3B and 
Ps3 systems of moisture, and, if necessary, blending of high metal, 
nicks, burrs, or scratches on P3B and Ps3 fitting threads. That action 
was prompted by seven reports of loss of thrust control due to 
corruption of the signals to the FADEC caused by water freezing in the 
Ps3 sensing system. That condition, if not corrected, could result in 
loss of thrust control due to corruption of the P3B and Ps3 signals to 
the FADEC, which if it occurs in a critical phase of flight, could 
result in loss of airplane control. Since that AD was issued, improved 
hardware has been introduced as terminating action to the visual 
inspections, cleanings, purging, and blending of metal. Also, 
alternative methods of compliance approved for AD 99-27-15 are 
incorporated as conventional methods of compliance in this proposal. 
Also, the GE90-92B engine model has been removed from the AD 
applicability. The FAA recently removed the GE90-92B engine from the 
type certificate at the request of GE.

Service Information

    The FAA has reviewed and approved the technical contents of GE 
Alert Service Bulletin (ASB) GE90 73-A0060, Revision 3, dated September 
14, 2000, that describes procedures for:
     Visually inspecting P3B and Ps3 sense lines and FADEC 
sensing ports and fittings.
     Cleaning P3B and Ps3 fittings and sensor ports, purging 
the P3B and Ps3 systems of moisture.
     Blending of high metal, nicks, burrs, or scratches on Ps3 
and P3B fitting threads.
    The FAA has also reviewed and approved the technical contents of GE 
Service Bulletin (SB) GE90 S/B 75-0031, Revision 3, dated March 30, 
2001, that describes procedures for replacing existing P3B and Ps3 
lines and related brackets and clamping with redesigned hardware.

Differences Between ASB, SB, and Proposal

    This proposal contains provisions for initial actions and GE ASB 
GE90 73-A0060, Revision 3, dated September 14, 2000, assumes that all 
operators have completed the initial actions based on field reports. 
If, however, operators have already accomplished the required initial 
actions, they need not repeat those actions, but may proceed directly 
to accomplishing the repetitive actions,

[[Page 31570]]

or P3B and Ps3 line replacement. Also, GE SB GE90 S/B 75-0031, Revision 
3, dated March 30, 2001, recommends a hardware installation date of not 
later than March 31, 2001, and this proposal requires hardware 
installation at the next shop visit after the effective date of this 
AD, or no later than October 31, 2001. The FAA is aware that almost all 
affected GE90 engines have been retrofitted with the new design 
hardware and, therefore, has established this end date of not later 
than October 31, 2001, to complete the retrofit program before the 
colder temperatures of winter arrive.

Proposed Actions

    Since an unsafe condition has been identified that is likely to 
exist or develop on other engines of the same type design, this 
proposed AD would supersede AD 99-27-15, to require:
     Visual inspections for high metal, nicks, burrs, or 
scratches on P3B and Ps3 fitting threads, and, if necessary, blending 
of these.
     Visual inspections for moisture, debris, or ice in P3B and 
Ps3 FADEC fittings, ports, and open sense lines.
     Cleaning of P3B and Ps3 FADEC fittings and sensing ports.
     Purging of any moisture from the P3B and Ps3 sense system.
     Replacement of existing P3B and Ps3 lines and related 
brackets and clamping with redesigned hardware at the next shop visit 
after the effective date of this AD, or no later than October 31, 2001.
     Engine idle leak check run following the maintenance 
activity to confirm there are no P3B or Ps3 sense system faults 
present, or a dual signoff procedure by a 2nd mechanic.

Economic Impact

    There are about 208 engines of the affected design in the worldwide 
fleet. The FAA estimates that 28 engines installed on aircraft of U.S. 
registry would be affected by this proposed AD, that it would take 
about one work hour per engine to do the proposed inspection and 
purging, and that the average labor rate is $60 per work hour. Based on 
these figures, the total proposed AD cost impact on U.S. operators for 
one inspection is estimated to be $1,680. The FAA also estimates that 
it would take about four work hours per engine to do the proposed P3B/
Ps3 sense line replacement, and that the average labor rate is $60 per 
work hour. The manufacturer has stated that it may provide the 
redesigned hardware at no cost to operators. Based on this information, 
the total proposed AD cost impact on U.S. operators for sense line 
replacement is estimated to be $6,720.

Regulatory Impact

    This proposal 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 before publication of 
this proposal.
    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.

Adoption of the Amendment

    Accordingly, pursuant to the authority delegated to me by the 
Administrator, the Federal Aviation Administration (FAA) 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 removing Amendment 39-11496 (65 FR 
692, January 6, 2000) and by adding a new airworthiness directive:

General Electric Company: Docket No. 99-NE-62-AD.

    Applicability: General Electric Company (GE) Models GE90-76B, -
77B, -85B, and -90B turbofan engines. These engines are installed 
on, but not limited to Boeing 777 series airplanes.

    Note 1: This airworthiness directive (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 (m) 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 the requirements of this AD is 
required as indicated, unless already done.
    To prevent loss of thrust control due to corruption of the P3B 
and Ps3 signals to the full authority digital engine control 
(FADEC), which if it occurs in a critical phase of flight, could 
result in loss of airplane control, do the following:

Determination of Further Action

    (a) If the engine has been configured as specified in one of the 
following service bulletins (SB's), or has one of the following 
serial numbers (SN's), no further action is required.
    (1) SB GE90 S/B 75-0031, Revision 1, dated August 29, 2000.
    (2) SB GE90 S/B 75-0031, Revision 2, dated September 14, 2000.
    (3) SB GE90 S/B 75-0031, Revision 3, dated March 30, 2001.
    (4) Engine SN is 900-326, 900-328, 900-332, 900-333, 900-334, or 
higher.

Initial Inspection, Cleaning, Moisture Purging, and Blending

    (b) For engines that are not configured or listed by SN as 
specified in paragraph (a) of this AD, do the following:
    (1) Inspect, clean, moisture purge, and if necessary, blend any 
high metal, nicks, or burrs on fitting threads, on one engine 
installed on Boeing 777 series aircraft, within 10 cycles-in-service 
(CIS) after the effective date of this AD in accordance with the 
Accomplishment Instructions, Section 3 of GE Alert Service Bulletin 
(ASB) No. GE90 73-A0060, Revision 3, dated September 14, 2000.
    (2) Inspect, clean, moisture purge, and if necessary, blend any 
high metal, nicks, or burrs on fitting threads, on the other engine 
installed on the Boeing 777 series aircraft, within 20 CIS after the 
effective date of this AD in accordance with the Accomplishment 
Instructions, Section 3 of GE ASB No. GE90 73-A0060, Revision 3, 
dated September 14, 2000.

Credit for Previous Inspections, Cleaning, and Moisture Purging

    (c) For engines that have complied with the initial and 
repetitive inspections of AD 99-27-15, GE ASB No. GE90 73-A0060, 
Revision 1, dated March 1, 2000; GE ASB No. GE90 73-A0060, Revision 
2, dated May 12, 2000; GE ASB No. GE90 73-A0060, Revision 3, dated 
September 14, 2000; or with an FAA approved alternative method of 
compliance, perform repetitive inspections as specified in paragraph 
(d) of this AD.

[[Page 31571]]

Repetitive Inspections

    (d) Thereafter, inspect, clean, and moisture purge, and if 
necessary, blend any high metal, nicks, or burrs on fitting threads 
of each engine in accordance with the Accomplishment Instructions, 
Section 3, of GE ASB No. GE90 73-A0060, Revision 3, dated September 
14, 2000, within:
    (1) 30 CIS since-last-inspection, or,
    (2) If applicable, 125 CIS since-last-inspection for one-engine-
only per airplane.

Replacement Engines

    (e) For replacement engines, perform the initial inspection, 
cleaning, and moisture purging, and if necessary, blend any high 
metal, nicks, or burrs on fitting threads as specified in paragraph 
(b) of this AD, except perform initial inspection before 
accumulating 30 CIS or 125 CIS, depending on the existing inspection 
interval for the engine that was replaced.

Idle Leak Check or Dual Signoff Procedure Check

    (f) After accomplishing the inspection and maintenance actions 
specified in paragraphs (b) through (e) of this AD, and before entry 
into service, do either of the following:
    (1) Perform an idle leak check to confirm no P3B or Ps3 sense 
system faults in accordance with Accomplishment Instructions, 
Section 3, paragraph (15), of GE ASB No. GE90 73-A0060, Revision 3, 
dated September 14, 2000. or,
    (2) Perform a dual signoff procedure check to confirm there are 
no loose fittings that could cause P3B and Ps3 sense system faults, 
in accordance with Accomplishment Instructions, Section 3, paragraph 
(15), of GE ASB No. GE90 73-A0060, Revision 3, dated September 14, 
2000. Idle leak checks that were performed using GE ASB No. GE90 73-
A0060, dated December 23, 1999, and idle leak checks or dual signoff 
procedure checks that were performed using GE ASB No. GE90 73-A0060, 
Revision 1, dated March 1, 2000, or GE ASB No. GE90 73-A0060, 
Revision 2, dated May 12, 2000, may be considered as alternative 
methods of compliance for this requirement.

Installation of Redesigned Hardware

    (g) At the next engine shop visit after the effective date of 
this AD, but not later than October 31, 2001, install the redesigned 
P3B and Ps3 tubes, hoses, clamps, and bracket assembly in accordance 
with Accomplishment Instructions, Section 3.A. through 3.H. of GE 
ASB No. GE90 S/B 75-0031, Revision 3, dated March 30, 2001.

Definition

    (h) For the purposes of this AD, an engine shop visit is defined 
as any time an engine has maintenance performed that involves 
separation of a major flange, such as removal of the low pressure 
turbine module, or high pressure compressor top case half.

Credit for Installation of Redesigned Hardware

    (i) Hardware installation that was performed using GE ASB No. 
GE90 S/B 75-0031, Revision 2, dated September 14, 2000; or GE ASB 
No. GE90 S/B 75-0031, Revision 1, dated August 29, 2000, may be 
considered as alternative methods of compliance for this 
requirement.

No Simultaneous Actions

    (j) Do not perform the actions required by this AD concurrently 
on both engines installed on Boeing 777 series aircraft.

Old Configuration Hardware

    (k) After the effective date of this AD, do not install any of 
the old configuration hardware listed in the following table.

             Old Configuration Hardware Not To Be Installed
------------------------------------------------------------------------
                         Part                               Part No.
------------------------------------------------------------------------
Ps3 Tube..............................................     350-151-505-0
                                                           350-184-806-0
                                                           350-114-005-0
Ps3 Hose..............................................     649-794-573-0
P3B Tube..............................................     350-151-604-0
                                                           350-184-904-0
                                                           350-114-105-0
P3B Hose..............................................     649-794-572-0
Single Tube Clamp.....................................       2151M51P107
Double Tube Clamp.....................................       2151M52P102
Bracket Assembly......................................     350-178-309-0
                                                           350-178-311-0
------------------------------------------------------------------------

Terminating Action

    (l) Installation of redesigned hardware as specified in 
paragraph (g) of this AD constitutes terminating action for 
requirements of paragraph (d) and paragraph (e) of this AD.

Alternative Methods of Compliance

    (m) 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 shall submit their requests through an appropriate FAA 
Principal Maintenance Inspector, 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

    (n) Special flight permits may be issued in accordance with 
sections 21.197 and 21.199 of the Federal Aviation Regulations (14 
CFR 21.197 and 21.199) to operate the aircraft to a location where 
the requirements of this AD can be accomplished.

    Issued in Burlington, Massachusetts, on June 4, 2001.
Francis A. Favara,
Acting Manager, Engine and Propeller Directorate, Aircraft 
Certification Service.
[FR Doc. 01-14671 Filed 6-11-01; 8:45 am]
BILLING CODE 4910-13-P