[Federal Register Volume 60, Number 83 (Monday, May 1, 1995)]
[Proposed Rules]
[Pages 21054-21056]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 95-10585]
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DEPARTMENT OF TRANSPORTATION
14 CFR Part 39
[Docket No. 95-NM-26-AD]
Airworthiness Directives; Boeing Model 757 and 767 Series
Airplanes Equipped With Sundstrand Ram Air Turbine (RAT)/Hydraulic
Pumps
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 certain Boeing Model 757 and 767
series airplanes. This proposal would require replacement of the
hydraulic pressure transfer tube of the ram air turbine (RAT) system
with a new hose assembly. This proposal is prompted by reports that,
during flight tests, the hydraulic pressure transfer tube of the RAT
cracked when the RAT was extended on a Model 767 series airplane. The
actions specified by the proposed AD are intended to prevent such
cracking, which could result in the loss of hydraulic fluid of the
center system and the inability of the RAT to pressurize the center
system; this situation could lead to loss of all hydraulic system power
in the event that power is lost in both engines.
DATES: Comments must be received by June 26, 1995.
ADDRESSES: Submit comments in triplicate to the Federal Aviation
Administration (FAA), Transport Airplane Directorate, ANM-103,
Attention: Rules Docket No. 95-NM-26-AD, 1601 Lind Avenue, SW.,
[[Page 21055]] 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: Kathi Ishimaru, Aerospace Engineer,
Systems and Equipment Branch, ANM-130S, FAA, Transport Airplane
Directorate, Seattle Aircraft Certification Office, 1601 Lind Avenue,
SW., Renton, Washington, 98055-4056; telephone (206) 227-2674; 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 95-NM-26-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. 95-NM-26-AD, 1601 Lind Avenue, SW., Renton, Washington
98055-4056.
Discussion
The FAA has received reports that, during two flight tests, the
pressure transfer tube of the ram air turbine (RAT) cracked when the
RAT was extended on a Model 767 series airplane. Investigation revealed
that the cause of such cracking has been attributed to overload due to
mishandling or improper installation of the pressure transfer tubes on
the strut of the RAT system. Such overloads are likely to have occurred
on other tubes because it is extremely difficult to shim the tubes
properly. Cracking of the hydraulic pressure transfer tube of the RAT,
if not corrected, could result in the loss of hydraulic fluid of the
center system and the inability of the RAT to pressurize the center
hydraulic system; this situation could lead to loss of all hydraulic
system power in the event that power is lost in both engines.
The subject RAT hydraulic pump and pressure transfer tube
installations on Model 757 series airplanes are identical to those
installed on Model 767 series airplanes. Therefore, both models may be
subject to the same unsafe condition revealed on the Model 767.
The FAA has reviewed and approved Boeing Alert Service Bulletin
757-29A0046, dated October 6, 1994 (for Model 757 series airplanes),
and Boeing Alert Service Bulletin 767-29A0077, dated October 6, 1994
(for Model 767 series airplanes), which describe procedures for
replacement of the hydraulic pressure transfer tube of the RAT system
with a new hose assembly. Accomplishment of this replacement will
prevent over stressing of the pressure line during installation.
The RAT/hydraulic pumps addressed in these service bulletins are
manufactured by Sundstrand. For Model 757 series airplanes, these pumps
have part number 730814 series, serial numbers 0001 through 0735
inclusive. For Model 767 series airplanes, these pumps have part number
729548 series, serial numbers 0001 through 0620 inclusive.
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 replacement of the hydraulic pressure
transfer tube of the RAT system with a new hose assembly. The actions
would be required to be accomplished in accordance with the alert
service bulletins described previously.
There are approximately 1,215 Model 757 and 767 series airplanes of
the affected design in the worldwide fleet. The FAA estimates that 582
airplanes of U.S. registry would be affected by this proposed AD, that
it would take approximately 2 work hours per airplane to accomplish the
proposed actions, and that the average labor rate is $60 per work hour.
Required parts would be supplied by the manufacturer at no cost to the
operators. Based on these figures, the total cost impact of the
proposed AD on U.S. operators is estimated to be $69,840, or $120 per
airplane.
The total cost impact figure discussed above is 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.
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 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. [[Page 21056]]
Sec. 39.13 [Amended]
2. Section 39.13 is amended by adding the following new
airworthiness directive:
Boeing: Docket 95-NM-26-AD.
Applicability: Model 757 series airplanes having line positions
1 through 650 inclusive, and equipped with Sundstrand ram air
turbine (RAT)/hydraulic pumps having part number (P/N) 730814
series, serial numbers 0001 through 0735 inclusive; and Model 767
series airplanes having line positions 1 through 565 inclusive, and
equipped with Sundstrand RAT/hydraulic pumps having P/N 729548
series, serial numbers 0001 through 0620 inclusive; 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 (b) 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 cracking of the hydraulic pressure transfer
tube of the ram air turbine (RAT), which could result in the loss of
all center systems hydraulic fluid and the inability of the RAT to
pressurize the center hydraulic system, accomplish the following:
(a) Within 24 months after the effective date of this AD,
replace the hydraulic pressure transfer tube of the RAT system with
a new hose assembly, in accordance with Boeing Alert Service
Bulletin 757-29A0046, dated October 6, 1994 (for Model 757 series
airplanes); or Boeing Alert Service Bulletin 767-29A0077, dated
October 6, 1994 (for Model 767 series airplanes), as applicable.
Note 2: Boeing Alert Service Bulletin 757-29A0046 references
Sundstrand Service Bulletin 730814-29-11, dated November 3, 1994;
and Boeing Alert Service Bulletin 767-29A0077 references Sundstrand
Service Bulletin 729548-29-14, dated November 3, 1994; as additional
sources of service information for procedures to replace the
pressure tube.
Note 3: Modification of the hydraulic pressure transfer tube of
the RAT system in accordance with Sundstrand Service Bulletin
730814-29-9, Revision 1, dated November 3, 1994 (for Model 757
series airplanes); or Sundstrand Service Bulletin 729548-29-12,
Revision 2, dated November 3, 1994 (for Model 767 series airplanes);
is considered acceptable for compliance with the modification
requirements of paragraph (a) of this AD.
(b) 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 4: Information concerning the existence of approved
alternative methods of compliance with this AD, if any, may be
obtained from the Seattle ACO.
(c) 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 April 25, 1995.
James V. Devany,
Acting Manager, Transport Airplane Directorate, Aircraft Certification
Service.
[FR Doc. 95-10585 Filed 4-28-95; 8:45 am]
BILLING CODE 4910-13-U
