Document ID: FAA-2008-0589-0001
Agency: faa
Document Type: Rule
Title: Airworthiness Directives; Pratt and Whitney (P&W) PW4000 Series 94- Inch Fan Turbofan Engines
Posted Date: 2008-08-14T04:00Z

[Federal Register: August 14, 2008 (Volume 73, Number 158)]
[Proposed Rules]               
[Page 47561-47563]
From the Federal Register Online via GPO Access [wais.access.gpo.gov]
[DOCID:fr14au08-12]                         

========================================================================
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.

========================================================================

[[Page 47561]]

DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2008-0589; Directorate Identifier 2008-NE-17-AD]
RIN 2120-AA64

 
Airworthiness Directives; Pratt & Whitney (P&W) PW4000 Series 94-
Inch Fan Turbofan Engines

AGENCY: Federal Aviation Administration (FAA), Department of 
Transportation (DOT).

ACTION: Notice of proposed rulemaking (NPRM).

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

SUMMARY: The FAA proposes to adopt a new airworthiness directive (AD) 
for P&W PW4052, PW4056, PW4060, PW4062, PW4152, PW4156A, PW4158, 
PW4460, and PW4462 turbofan engines. This proposed AD would require a 
onetime visual inspection of all EEC-131 model electronic engine 
controls (EECs). This proposed AD would require the EECs to be 
identified, categorized by group number, marked, and replaced using a 
fleet management plan. This proposed AD results from a report of an 
uncommanded engine in-flight shutdown due to defective EEC pulse width 
modulator (PWM) microcircuits. We are proposing this AD to prevent 
uncommanded in-flight engine shutdowns which could result in loss of 
thrust and prevent continued safe flight or landing.

DATES: We must receive any comments on this proposed AD by September 
15, 2008.

ADDRESSES: Use one of the following addresses to comment on this 
proposed AD.
     Federal eRulemaking Portal: Go to http://
www.regulations.gov and follow the instructions for sending your 
comments electronically.
     Mail: Docket Management Facility, U.S. Department of 
Transportation, 1200 New Jersey Avenue, SE., West Building Ground 
Floor, Room W12-140, Washington, DC 20590-0001.
     Hand Delivery: Deliver to Mail address above between 9 
a.m. and 5 p.m., Monday through Friday, except Federal holidays.
     Fax: (202) 493-2251.
    You can get the service information identified in this proposed AD 
from Pratt & Whitney, 400 Main St., East Hartford, CT 06108; telephone 
(860) 565-8770; fax (860) 565-4503.

FOR FURTHER INFORMATION CONTACT: V. Rose Len, Aerospace Engineer, 
Engine Certification Office, FAA, Engine & Propeller Directorate, 12 
New England Executive Park, Burlington, MA 01803; e-mail: 
rose.len@faa.gov; telephone (781) 238-7772; fax (781) 238-7199.

SUPPLEMENTARY INFORMATION:

Comments Invited

    We invite you to send us any written relevant data, views, or 
arguments regarding this proposal. Send your comments to an address 
listed under ADDRESSES. Include ``Docket No. FAA-2008-0589; Directorate 
Identifier 2008-NE-17-AD'' in the subject line of your comments. We 
specifically invite comments on the overall regulatory, economic, 
environmental, and energy aspects of the proposed AD. We will consider 
all comments received by the closing date and may amend the proposed AD 
in light 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 
with FAA personnel concerning this proposed AD. Using the search 
function of the Web site, anyone can find and read the comments in any 
of our dockets, including, if provided, the name of the individual who 
sent the comment (or signed the comment on behalf of an association, 
business, labor union, etc.). You may review the DOT's complete Privacy 
Act Statement in the Federal Register published on April 11, 2000 (65 
FR 19477-78).

Examining the AD Docket

    You may examine the AD docket on the Internet at http://
www.regulations.gov; or in person at the Docket Operations office 
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 Operations office (telephone (800) 647-5527) is 
the same as the Mail address provided in the ADDRESSES section. 
Comments will be available in the AD docket shortly after receipt.

Discussion

    In May of 2006 we received a report of an uncommanded engine in-
flight shutdown of a P&W PW4152 turbofan engine. The investigation of 
this event determined that certain EECs were built with defective PWM 
microcircuits. The defective microcircuits degrade over time as a 
result of thermal cycling while operating within their certified 
temperature range. In operation, the EEC system tests the functional 
capability of the PWM in Channel A. If the Channel A PWM fails the 
test, the EEC automatically switches to the Channel B PWM. In this 
case, both of the EEC PWMs are degrading similarly and the Channel B 
PWM is also likely to fail, at which time the EEC automatically shuts 
down the engine. Based on a risk analysis provided by P&W which we 
reviewed and concurred, this condition, if not corrected, could result 
in uncommanded in-flight engine shutdowns, which could result in loss 
of thrust and prevent continued safe flight or landing.
    The defective PWMs are the result of a change from the original PWM 
design introduced by a single microcircuit supplier before 1993. Our 
investigation showed that the supplier returned to the original PWM 
design between 1993 and 1994. The EEC supplier determined the 
population of affected EECs by testing model EEC-131 EECs built after 
the introduction of the PWM design change. The EEC supplier performed 
destructive testing of the PWMs, and identified four distinct groups of 
EECs by serial number:
    Group 1: EECs with a high concentration of PWMs that failed during 
testing.
    Group 2: EECs with a low concentration of PWMs that failed during 
testing.
    Group 3: All EECs not in Group 1 or Group 2 but may contain suspect 
PWMs due to board swapping during the repair or refurbishment of the 
EEC.

[[Page 47562]]

    Group 4: EECs have been inspected for defective PWMs and repaired 
if required.
    To facilitate the timely removal of the defective PWMs from the 
fleet, all of the EECs must first be identified, categorized, and 
marked by their group number so that the higher risk EECs will be 
replaced before the lower risk EECs are replaced. Group 4 EECs have 
been inspected or repaired, so they are not subject to the same PWM 
problem. However, they still require further internal and external 
labeling for tracking purposes. Labeling will be done using P&W Alert 
Service Bulletin (ASB) No. PW4ENG 73-216, dated April 8, 2008.

Relevant Service Information

    We have reviewed and approved the technical contents of P&W ASB No. 
PW4ENG A73-214, Revision 2, dated May 23, 2008. That ASB describes 
procedures for inspecting, identifying, categorizing, and marking all 
EEC-131 model EECs that are identified by part number and serial number 
into four groups. The Group 1 EECs have a high probability of having 
defective PWM microcircuits, while the other groups have a lower 
probability of having defective PWM microcircuits.

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. We are proposing this AD, which would require 
a onetime visual inspection of all EEC-131 model EECs. The proposed AD 
would also require the EECs to be identified, categorized by group 
number, marked, and replaced using a fleet management plan. The 
proposed AD would require you to use the service information described 
previously to perform these actions.

Costs of Compliance

    We estimate that this proposed AD would affect 730 P&W PW4000 
series 94-inch fan turbofan engines installed on airplanes of U.S. 
registry. We also estimate that it would take about 1 work-hour per 
engine to inspect, categorize, and mark each of the 730 EECs, and 1 
work-hour per engine to replace up to 730 EECs. The average labor rate 
is $80 per work-hour. Required replacement parts would cost about $400 
per engine. Based on these figures, we estimate the total cost of the 
proposed AD to U.S. operators to be $467,200.

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 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 AD:
    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 regulatory evaluation of the estimated costs to 
comply with this proposed AD. You may get a copy of this summary at the 
address listed under ADDRESSES.

List of Subjects in 14 CFR Part 39

    Air transportation, Aircraft, Aviation safety, Safety.

The Proposed Amendment

    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 adding the following new 
airworthiness directive:

Pratt & Whitney: Docket No. FAA-2008-0589; Directorate Identifier 
2008-NE-17-AD.

Comments Due Date

    (a) The Federal Aviation Administration (FAA) must receive 
comments on this airworthiness directive (AD) action by September 
15, 2008.

Affected ADs

    (b) None.

Applicability

    (c) This AD applies to Pratt & Whitney (P&W) PW4052, PW4056, 
PW4060, PW4062, PW4152, PW4156A, PW4158, PW4460, and PW4462 turbofan 
engines. These engines are installed on, but not limited to, Airbus 
A300-600 and A310-300, and Boeing 747-400, Boeing 767-200, 767-300, 
and MD-11 series airplanes.

Unsafe Condition

    (d) This AD results from a report of an uncommanded engine in-
flight shutdown due to defective electronic engine control (EEC) 
pulse width modulator (PWM) microcircuits. We are issuing this AD to 
prevent uncommanded in-flight engine shutdowns which could result in 
loss of thrust and prevent continued safe flight or landing.

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.

Onetime Visual Inspection and Reporting Requirements

    (f) Within 600 operating hours after the effective date of this 
AD:
    (1) Perform a onetime visual inspection of the EEC-131 model 
EECs to identify, categorize, and mark them as a Group 1, Group 2, 
Group 3, or Group 4 EEC.
    (2) Use paragraphs 1 through 7 in the Accomplishment 
Instructions of P&W Alert Service Bulletin No. PW4ENG A73-214, 
Revision 2, dated May 23, 2008, to inspect, categorize, and mark the 
EECs.
    (3) Within 30 calendar days of completing paragraph (f)(1) of 
this AD, report all inspection findings to V. Rose Len, Engine 
Certification Office, Engine & Propeller Directorate, 12 New England 
Executive Park, Burlington, MA 01803.
    (4) The Office of Management and Budget (OMB) has approved the 
reporting requirements and assigned OMB control number 2120-0056.

Replacement of Group 1 EECs

    (g) Replace Group 1 EECs with a serviceable EEC before reaching 
2,000 cycles-in-service (CIS) since new, but not later than one year 
from the effective date of this AD.

[[Page 47563]]

Replacement of Groups 2, 3, and 4 EECs

    (h) Replace the following groups of EECs with a serviceable EEC, 
or any EEC that does not violate the EEC installation procedure as 
provided by paragraphs (k), (l), and (m) of this AD, as follows:
    (1) Group 2 EECs, before reaching 4,000 CIS since new, but not 
later than 2 years after the effective date of this AD.
    (2) Group 3 EECs, before reaching 14,000 CIS since new, but not 
later than 6 years after the effective date of this AD.

Definition of Serviceable EECs

    (i) A serviceable EEC is an EEC that does not violate the EEC 
installation procedure as provided by paragraphs (k), (l), and (m) 
of this AD, or is marked as Group 4 per P&W ASB No. PW4ENG 73-214, 
Revision 2, dated May 23, 2008, or has been repaired per P&W Service 
Bulletin (SB) No. PW4ENG 73-216, dated April 8, 2008. Once an EEC 
has been repaired, it is viewed as a Group 4 EEC.
    (j) Information on obtaining a serviceable EEC can be found in 
P&W SB No. PW4ENG 73-216, dated April 8, 2008.

EEC Installation Prohibition

    (k) Do not install any Group 1 EEC after 1 year from the 
effective date of this AD or any Group 1 EEC that has reached 2,000 
CIS since new.
    (l) Do not install any Group 2 EEC after 2 years from the 
effective date of this AD or any Group 2 EEC that has reached 4,000 
CIS since new.
    (m) Do not install any Group 3 EEC after 6 years from the 
effective date of this AD or any Group 3 EEC that has reached 14,000 
CIS since new.

Alternative Methods of Compliance

    (n) 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.

Related Information

    (o) Contact V. Rose Len, Aerospace Engineer, Engine 
Certification Office, FAA, Engine & Propeller Directorate, 12 New 
England Executive Park, Burlington, MA 01803; e-mail: 
rose.len@faa.gov; telephone (781) 238-7772; fax (781) 238-7199, for 
more information about this AD.

    Issued in Burlington, Massachusetts, on August 8, 2008.
Peter A. White,
Assistant Manager, Engine and Propeller Directorate, Aircraft 
Certification Service.
 [FR Doc. E8-18811 Filed 8-13-08; 8:45 am]

BILLING CODE 4910-13-P