[Federal Register Volume 60, Number 108 (Tuesday, June 6, 1995)]
[Proposed Rules]
[Pages 29795-29797]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 95-13784]



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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 94-NM-133-AD]


Airworthiness Directives; Boeing Model 757 Series Airplanes

AGENCY: Federal Aviation Administration, DOT.

ACTION: Notice of proposed rulemaking (NPRM).

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SUMMARY: This document proposes the adoption of a new airworthiness 
directive (AD) that is applicable to Boeing Model 757 series airplanes. 
This proposal would require modifying the engine fuel indication 
circuits. This proposal is prompted by numerous reports of false 
indications of engine fuel valve faults, which have led to the flight 
crew conducting rejected takeoffs (RTO). The actions specified by the 
proposed AD are intended to prevent such false indications and the 
flight crew's consequent execution of an RTO at high speed during 
takeoff roll, which could result in the airplane overrunning the 
runway, damage to the airplane, and injury to airplane occupants.

DATES: Comments must be received by August 2, 1995.

ADDRESSES: Submit comments in triplicate to the Federal Aviation 
Administration (FAA), Transport Airplane Directorate, ANM-103, 
Attention: Rules Docket No. 94-NM-133-AD, 1601 Lind Avenue, SW., 
Renton, Washington 98055-4056. Comments may be inspected at this 
location between 9:00 a.m. and 3:00 p.m., Monday through Friday, except 
Federal holidays.
    The service information referenced in the proposed rule may be 
obtained from Boeing Commercial Airplane Group, P.O. Box 3707, Seattle, 
Washington 98124-2207. This information may be examined at the FAA, 
Transport Airplane Directorate, 1601 Lind Avenue, SW., Renton, 
Washington.

FOR FURTHER INFORMATION CONTACT: Jeff Duven, Aerospace Engineer, 
Propulsion Branch, ANM-140S, Seattle Aircraft Certification Office, 
FAA, Transport Airplane Directorate, 1601 Lind Avenue, SW., Renton, 
Washington 98055-4065; telephone (206) 227-2688; fax (206) 227-1181.

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 shall 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 notice 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 notice must submit a self-addressed, 
stamped postcard on which the following statement is made: ``Comments 
to Docket Number 94-NM-133-AD.'' The postcard will be date stamped and 
returned to the commenter.

Availability of NPRMs

    Any person may obtain a copy of this NPRM by submitting a request 
to the FAA, Transport Airplane Directorate, ANM-103, Attention: Rules 
Docket No. 94-NM-133-AD, 1601 Lind Avenue, SW., Renton, Washington 
98055-4056.
Discussion

    The FAA has received reports of at least fifteen incidents of false 
indications of engine fuel valve faults that have occurred on Boeing 
Model 757 series airplanes. The purpose of the engine fuel valve fault 
indication is to alert the flight crew that the engine-mounted fuel 
valve is not in the commanded position. In all of the reported 
incidents, the engine fuel valve was in the commanded position, but the 
indication system indicated that the valve was not in that position.
    In nine of these incidents, the flight crew's response to the false 
indication was to initiate a rejected takeoff (RTO). The other six 
incidents resulted in various flight schedule interruptions. There have 
been no reports of airplane damage or passenger injuries resulting from 
any of these particular incidents.
    Rejected takeoffs that are initiated at high speed should be 
executed only in response to conditions that preclude the continued 
safe takeoff of the airplane. False indications of an engine fuel valve 
fault, such as those that occurred in the [[Page 29796]] reported 
incidents, are not a hazard to the continued safe operation of the 
engines or the airplane and, therefore, should not result in RTO's. The 
current service history of Model 757 series airplanes has shown, 
however, that when these false indications occur during the takeoff 
roll, flight crews are concerned to such a level that they believe an 
RTO is necessary.
    Transport category airplanes, such as the Model 757, are designed 
to allow an RTO to be safely executed, provided that the maneuver is 
initiated at or below established airplane speeds. When RTO's are 
initiated at speeds in excess of the established speeds, or when the 
established flight crew procedures are not followed, there may not be 
sufficient distance remaining on the runway to bring the airplane to a 
safe stop. Service history has documented numerous accidents and 
incidents in which various models of transport category airplanes have 
overrun the available stopping area; this has led to consequent damage 
or destruction of the airplane, and injuries to airplane occupants.
    The FAA has reviewed and approved the following two Boeing service 
bulletins:
    1. Boeing Service Bulletin 757-76-0010, dated August 12, 1993, 
which pertains to Model 757 series airplanes equipped with Pratt & 
Whitney (P&W) PW2000 engines; and
    2. Boeing Service Bulletin 757-76-0011, dated December 2, 1993, 
which pertains to Model 757 series airplanes equipped with Rolls-Royce 
RB211-535 engines.
    These service bulletins describe procedures for modifying the 
engine fuel indication circuits to decrease the number of false fault 
indications of the engine fuel valve. Decreasing the number of these 
false indications will thereby decrease the number of RTO's initiated 
for this reason. This modification will not affect correct indications 
of an engine fuel valve fault.
    For Model 757 series airplanes equipped with Rolls-Royce RB211-535 
engines, the successful installation of this modification of the engine 
fuel indication circuits requires that an additional modification of 
the engine fuel shutoff valve control be installed previously or 
concurrently. Boeing Service Bulletin 757-76-0007, Revision 2, dated 
January 23, 1992, describes procedures for modifying the engine fuel 
shutoff valve control on these airplanes by installing six blocking 
diodes in the P36 and P37 panels, and modifying the airplane's wiring 
to accommodate the diode installation. (This modification will reduce 
the possibility of engine shutdown due to uncommanded closing of the 
engine fuel shutoff valve.) The FAA has reviewed and approved this 
service bulletin.
    Since an unsafe condition has been identified that is likely to 
exist or develop on other products of this same type design, the 
proposed AD would require modifying the engine fuel indication circuits 
to decrease the number of false fault indications of the engine fuel 
valve. This proposed AD would also require that modification of the 
engine fuel shutoff valve control be accomplished on airplanes equipped 
with the subject Rolls Royce engines prior to or concurrently with the 
modification of the engine fuel indication circuits. The actions would 
be required to be accomplished in accordance with the service bulletins 
described previously.
    Operators of airplanes equipped with Rolls Royce engines would be 
provided a longer compliance time for modification, since the 
modifications required for those airplanes necessitate more work hours 
to complete than for the modification of airplanes equipped with P&W 
engines.
    As a result of recent communications with the Air Transport 
Association (ATA) of America, the FAA has learned that, in general, 
some operators may misunderstand the legal effect of AD's on airplanes 
that are identified in the applicability provision of the AD, but that 
have been altered or repaired in the area addressed by the AD. The FAA 
points out that all airplanes identified in the applicability provision 
of an AD are legally subject to the AD. If an airplane has been altered 
or repaired in the affected area in such a way as to affect compliance 
with the AD, the owner or operator is required to obtain FAA approval 
for an alternative method of compliance with the AD, in accordance with 
the paragraph of each AD that provides for such approvals. A note has 
been included in this notice to clarify this long-standing requirement.
    There are approximately 272 Model 757 series airplanes equipped 
with P&W PW2000 engines in the worldwide fleet. The FAA estimates that 
219 of these airplanes are currently of U.S. registry and would be 
affected by this proposed AD. It would take approximately 4 work hours 
per airplane to accomplish the proposed modification of the engine fuel 
indication circuits, at an average labor rate of $60 per work hour. The 
cost of required parts would be negligible. Based on these figures, the 
total cost impact of the proposed AD on U.S. operators of these 
airplanes is estimated to be $52,560, or $240 per airplane.
    There are approximately 302 Model 757 series airplanes equipped 
with Rolls Royce RB211-535 engines in the worldwide fleet. The FAA 
estimates that 119 of these airplanes are currently of U.S. registry 
and would be affected by this proposed AD. It would take approximately 
4 work hours per airplane to accomplish the proposed modification of 
the engine fuel indication circuits, at an average labor rate of $60 
per work hour. The cost of required parts would be $194 per airplane. 
Based on these figures, the total cost impact of this proposed 
modification on U.S. operators of these airplanes is estimated to be 
$51,646, or $434 per airplane.
    Additionally, for airplanes equipped with Rolls Royce RB211-535 
engines, it would take approximately 28 work hours to accomplish the 
proposed modification of the engine fuel shutoff valve control, at an 
average labor rate of $60 per work hour. The cost of required parts 
would be $470 per airplane. Based on these figures, the total cost 
impact of this proposed modification on U.S. operators of these 
airplanes is estimated to be $255,850, or $2,150 per airplane.
    The total cost impact figures discussed above are based on 
assumptions that no operator has yet accomplished any of the proposed 
requirements of this AD action, and that no operator would accomplish 
those actions in the future if this AD were not adopted. However, the 
FAA is aware that the modification of the engine fuel shutoff valve 
control has already been accomplished on several affected Model 757 
series airplanes equipped with Rolls Royce RB211-535 engines; 
therefore, the future total cost impact of this proposed AD is reduced 
by that amount.
    The regulations proposed herein would not have substantial direct 
effects 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. Therefore, in 
accordance with Executive Order 12612, it is determined that this 
proposal would not have sufficient federalism implications to warrant 
the preparation of a Federalism Assessment.
    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 
[[Page 29797]] 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. App. 1354(a), 1421 and 1423; 49 U.S.C. 
106(g); and 14 CFR 11.89.


Sec. 39.13  [Amended]

    2. Section 39.13 is amended by adding the following new 
airworthiness directive:

Boeing: Docket 94-NM-133-AD.

    Applicability: Model 757 series airplanes equipped with Pratt & 
Whitney PW2000 engines, as listed in Boeing Service Bulletin 757-76-
0010, dated August 12, 1993; and Model 757 series airplanes equipped 
with Rolls-Royce RB211-535 engines, as listed in Boeing Service 
Bulletin 757-76-0011, dated December 2, 1993; certificated in any 
category.

    Note 1: This AD applies to each airplane 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 airplanes that have been modified, 
altered, or repaired so that the performance of the requirements of 
this AD is affected, the owner/operator must use the authority 
provided in paragraph (c) to request approval from the FAA. This 
approval may address either no action, if the current configuration 
eliminates the unsafe condition; or different actions necessary to 
address the unsafe condition described in this AD. Such a request 
should include an assessment of the effect of the changed 
configuration on the unsafe condition addressed by this AD. In no 
case does the presence of any modification, alteration, or repair 
remove any airplane from the applicability of this AD.

    Compliance: Required as indicated, unless accomplished 
previously.
    To prevent false indications of engine fuel valve faults, 
accomplish the following:
    (a) For airplanes equipped with Pratt & Whitney PW2000 engines: 
Within 6 months after the effective date of this AD, modify the 
engine fuel valve indication circuits in accordance with Boeing 
Service Bulletin 757-76-0010, dated August 12, 1993.
    (b) For airplanes equipped with Rolls-Royce RB211-535 engines: 
Within 18 months after the effective date of this AD, accomplish the 
modifications specified in paragraphs (b)(1) and (b)(2) of this AD. 
The modification specified in paragraph (b)(1) must be accomplished 
either prior to or concurrently with the modification specified in 
paragraph (b)(2). In any case, both modifications must be completed 
within 18 months after the effective date of this AD.
    (1) Modify the engine fuel shutoff valve control in accordance 
with Boeing Service Bulletin 757-76-0007, Revision 2, dated January 
23, 1992.

    Note 2: Accomplishment of this modification prior to the 
effective date of this AD in accordance with Boeing Service Bulletin 
757-76-0007 (original issue), dated February 22, 1990, or Revision 
1, dated October 31, 1991, is considered acceptable for compliance 
with paragraph (b)(1) of this AD.

    (2) Modify the engine fuel valve indication circuits in 
accordance with Boeing Service Bulletin 757-76-0011, dated December 
2, 1993.
    (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, Seattle Aircraft Certification 
Office (ACO), FAA, Transport Airplane Directorate. Operators shall 
submit their requests through an appropriate FAA Principal 
Maintenance Inspector, who may add comments and then send it to the 
Manager, Seattle ACO.

    Note 3: Information concerning the existence of approved 
alternative methods of compliance with this AD, if any, may be 
obtained from the Seattle ACO.

    (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 accomplished.

    Issued in Renton, Washington, on May 30, 1995.
Darrell M. Pederson,
 Acting Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. 95-13784 Filed 6-5-95; 8:45 am]
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