[Federal Register Volume 71, Number 196 (Wednesday, October 11, 2006)]
[Rules and Regulations]
[Pages 59651-59653]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: E6-16670]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2006-26028; Directorate Identifier 2006-NM-222-AD; 
Amendment 39-14786; AD 2006-20-51]
RIN 2120-AA64


Airworthiness Directives; Boeing Model 777-200LR Series Airplanes 
Powered by General Electric (GE) Model GE90-110B Engines, and Model 
777-300ER Series Airplanes Powered by GE Model GE90-115B Engines

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

ACTION: Final rule; request for comments.

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SUMMARY: This document publishes in the Federal Register an amendment 
adopting airworthiness directive (AD) 2006-20-51 that was sent 
previously to all known U.S. owners and operators of certain Boeing 
Model 777-200LR and -300ER series airplanes by individual notices. This 
AD requires revising the Airplane Flight Manual to prohibit takeoffs at 
less than full-rated thrust. This AD is prompted by a report of two 
occurrences of engine thrust rollback (reduction) during takeoff. We 
are issuing this AD to prevent dual-engine thrust rollback, which could 
result in the airplane failing to lift off before reaching the end of 
the runway or failing to clear obstacles below the takeoff flight path.

DATES: This AD becomes effective October 16, 2006 to all persons except 
those persons to whom it was made immediately effective by emergency AD 
2006-20-51, issued September 30, 2006, which contained the requirements 
of this amendment.
    We must receive comments on this AD by December 11, 2006.

ADDRESSES: Use one of the following addresses to submit comments on 
this AD.
     DOT Docket Web site: Go to http://dms.dot.gov and follow 
the instructions for sending your comments electronically.
     Government-wide rulemaking Web site: Go to http://www.regulations.gov and follow the instructions for sending your 
comments electronically.
     Mail: Docket Management Facility; U.S. Department of 
Transportation, 400 Seventh Street, SW., Nassif Building, Room PL-401, 
Washington, DC 20590.
     Fax: (202) 493-2251.
     Hand Delivery: Room PL-401 on the plaza level of the 
Nassif Building, 400 Seventh Street, SW., Washington, DC, between 9 
a.m. and 5 p.m., Monday through Friday, except Federal holidays.

FOR FURTHER INFORMATION CONTACT: Margaret Langsted, Aerospace Engineer, 
Propulsion Branch, ANM-140S, FAA, Seattle Aircraft Certification 
Office, 1601 Lind Avenue, SW., Renton, Washington 98057-3356; telephone 
(425) 917-6500; fax (425) 917-6590.

SUPPLEMENTARY INFORMATION: On September 30, 2006, we issued emergency 
AD 2006-20-51, which applies to all Boeing Model 777-200LR series 
airplanes powered by General Electric (GE) Model GE90-110B engines, and 
Model 777-300ER series airplanes powered by GE Model GE90-115B engines.

Background

    We have received a report of two occurrences of engine thrust 
rollback (reduction) during takeoff on Boeing Model 777-300ER series 
airplanes powered by GE Model GE90-115B engines. In both cases, only 
one engine was affected. The N1 (fan speed--the normal thrust setting 
parameter for this engine type) thrust level on the affected engine 
progressively dropped resulting in a thrust loss of 65 to 77% due to an 
erroneous N1 command computed by the Full Authority Digital Engine 
Control (FADEC). In both cases, the engine recovered to the proper N1 
thrust level as the airplane climbed beyond 400 feet above ground 
level. In one case,

[[Page 59652]]

the operator elected to return to the departure airport after reaching 
cruise. In the other case, the operator continued to its destination. 
There were no further anomalies reported during the remainder of the 
flights. No flight deck messages or maintenance indications occurred as 
a result of the event.
    Investigation indicates that these events are the results of a 
software algorithm in the FADEC that was introduced in software version 
A.0.4.5 (GE90-100 Service Bulletin 73-0021). Investigation also 
indicates that a dual-engine thrust rollback could occur just after V1 
(takeoff decision speed after which takeoff is to proceed even after an 
engine failure), which would result in the airplane not having adequate 
thrust to safely complete the takeoff. A de-rated or a reduced thrust 
takeoff, in combination with specific ambient conditions, can result in 
the FADEC commanding a progressive reduction in the engine thrust. 
Airplane takeoffs are often performed with engine thrust levels at less 
than the maximum engine thrust approved for the airplane. This is done 
to reduce wear on the engines, increase fuel efficiency, and maximize 
passenger comfort. Operators are permitted to calculate airplane 
takeoff performance and required engine thrust using two different 
methods referred to as ``derated takeoff thrust'' (also known as fixed 
de-rate) and ``reduced takeoff thrust'' (also known as the assumed 
temperature method). Full-rated thrust takeoffs with the thrust levers 
at the full forward position are not exposed to the potential thrust 
rollback caused by the software anomaly described above.
    A dual-engine thrust rollback, if not corrected, could result in 
the airplane failing to lift off before reaching the end of the runway 
or failing to clear obstacles below the takeoff flight path.
    The FADEC software, version A.0.4.5, on certain Model 777-200LR 
powered by GE Model 90-110B engines is identical to that on the 
affected Model 777-300ER series airplanes powered by GE Model GE90-115B 
engines. Therefore, both of these airplane models may be subject to the 
same unsafe condition.
    Although the software anomaly was introduced by this version of 
software, the affected operators have a mixed fleet of airplanes with 
and without the affected software version. To avoid reliance on flight 
crews determining which software version is installed as they operate 
different airplanes, we have determined that this AD should apply to 
all airplanes equipped with the affected engines. If operators develop 
an acceptable method to ensure flight crews will consistently perform 
the correct procedure on affected airplanes, they may request approval 
for an alternative method of compliance in accordance with paragraph 
(h) of this AD.

FAA's Determination and Requirements of This AD

    Since the unsafe condition described is likely to exist or develop 
on other airplanes of the same type design, we issued emergency AD 
2006-20-51 to prevent dual-engine thrust rollback, which could result 
in the airplane failing to lift off before reaching the end of the 
runway or failing to clear obstacles below the takeoff flight path. The 
AD requires revising the Airplane Flight Manual to prohibit takeoffs at 
less than full-rated thrust.
    We found that immediate corrective action was required; therefore, 
notice and opportunity for prior public comment thereon were 
impracticable and contrary to the public interest, and good cause 
existed to make the AD effective immediately by individual notices 
issued on September 30, 2006, to all known U.S. owners and operators of 
all Boeing Model 777-200LR series airplanes powered by General Electric 
(GE) Model GE90-110B engines, and Model 777-300ER series airplanes 
powered by GE Model GE90-115B engines. These conditions still exist, 
and the AD is hereby published in the Federal Register as an amendment 
to section 39.13 of the Federal Aviation Regulations (14 CFR 39.13) to 
make it effective to all persons.

Interim Action

    This is considered to be interim action. The engine manufacturer 
has advised that it currently is developing a modification that will 
eliminate the unsafe condition addressed by this AD. Once this 
modification is developed, approved, and available, we may consider 
additional rulemaking.

Comments Invited

    This AD is a final rule that involves requirements that affect 
flight safety and was not preceded by notice and an opportunity for 
public comment; however, we invite you to submit any relevant written 
data, views, or arguments regarding this AD. Send your comments to an 
address listed in the ADDRESSES section. Include ``Docket No. FAA-2006-
26028; Directorate Identifier 2006-NM-222-AD'' at the beginning of your 
comments. We specifically invite comments on the overall regulatory, 
economic, environmental, and energy aspects of the AD that might 
suggest a need to modify it.
    We will post all comments we receive, without change, to http://dms.dot.gov, including any personal information you provide. We will 
also post a report summarizing each substantive verbal contact with FAA 
personnel concerning this AD. Using the search function of that Web 
site, anyone can find and read the comments in any of our dockets, 
including 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), or you may visit 
http://dms.dot.gov.

Examining the Docket

    You may examine the AD docket on the Internet at http://dms.dot.gov, or in person at the Docket Management Facility office 
between 9 a.m. and 5 p.m., Monday through Friday, except Federal 
holidays. The Docket Management Facility office (telephone (800) 647-
5227) is located on the plaza level of the Nassif Building at the DOT 
street address stated in the ADDRESSES section. Comments will be 
available in the AD docket shortly after the Docket Management System 
receives them.

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 AD will not have federalism 
implications under Executive Order 13132. This AD will 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.

[[Page 59653]]

    The FAA has determined that this regulation is an emergency 
regulation that must be issued immediately to correct an unsafe 
condition in aircraft, and that it is not a ``significant regulatory 
action'' under Executive Order 12866. It has been determined further 
that this action involves an emergency regulation under DOT Regulatory 
Policies and Procedures (44 FR 11034, February 26, 1979). If this 
emergency regulation is later deemed significant under DOT Regulatory 
Policies and Procedures, we will prepare a final regulatory evaluation 
and place it in the AD Docket. See the ADDRESSES section for a location 
to examine the regulatory evaluation, if filed.

List of Subjects in 14 CFR Part 39

    Air transportation, Aircraft, Aviation safety, Safety.

Adoption of the Amendment

0
Accordingly, under the authority delegated to me by the Administrator, 
the FAA amends 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):

2006-20-51 Boeing: Amendment 39-14786. Docket No. FAA-2006-26028; 
Directorate Identifier 2006-NM-222-AD.

Effective Date

    (a) This AD becomes effective October 16, 2006, to all persons 
except those persons to whom it was made immediately effective by 
emergency AD 2006-20-51, issued on September 30, 2006, which 
contained the requirements of this amendment.

Affected ADs

    (b) None.

Applicability

    (c) This AD applies to airplanes in Table 1 of this AD 
certificated in any category.

                         Table 1.--Applicability
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                                       Powered by General Electric (GE)
            Boeing model                             model
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(1) 777-200LR series airplanes......  GE90-110B engines.
(2) 777-300ER series airplanes......  GE90-115B engines.
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Unsafe Condition

    (d) This AD results from a report of two occurrences of engine 
thrust rollback during takeoff. The Federal Aviation Administration 
is issuing this AD to prevent dual-engine thrust rollback, which 
could result in the airplane failing to lift off before reaching the 
end of the runway or failing to clear obstacles below the takeoff 
flight path.

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.

Revision of the Airplane Flight Manual (AFM)

    (f) Within 24 hours after the effective date of this AD, revise 
the Certificate Limitations Section of the AFM to include the 
following statement. This may be done by inserting a copy of this AD 
into the AFM.

    ``Use of reduced thrust takeoff ratings determined by either the 
assumed temperature method or the fixed de-rate method or a 
combination of both, is prohibited. Full-rated thrust must be used 
for takeoff.''


    Note 1: When a statement identical to that in paragraph (f) of 
this AD has been included in the general revisions of the AFM, the 
general revisions may be inserted into the AFM, and the copy of this 
AD may be removed from the AFM.

Special Flight Permit

    (g) Special flight permits, as described in Section 21.197 and 
Section 21.199 of the Federal Aviation Regulations (14 CFR 21.197 
and 21.199), are not allowed.

Alternative Methods of Compliance (AMOCs)

    (h)(1) The Manager, Seattle Aircraft Certification Office (ACO), 
FAA, has the authority to approve AMOCs for this AD, if requested in 
accordance with the procedures found in 14 CFR 39.19.
    (2) Before using any AMOC approved in accordance with Sec.  
39.19 on any airplane to which the AMOC applies, notify the 
appropriate principal inspector in the FAA Flight Standards 
Certificate Holding District Office.

    Issued in Renton, Washington, on October 2, 2006.
Kalene C. Yanamura,
Acting Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. E6-16670 Filed 10-10-06; 8:45 am]
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