[Federal Register Volume 61, Number 152 (Tuesday, August 6, 1996)]
[Proposed Rules]
[Pages 40758-40760]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 96-19893]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 96-NM-12-AD]
RIN 2120-AA64


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 all Boeing Model 757 series 
airplanes. This proposal would require the replacement of certain 
discrepant ram air turbine (RAT) deployment actuator assemblies with 
units that have been modified and shipped in a specific fashion prior 
to installation. This proposal is prompted by reports that the RAT 
deployment actuators have failed to deploy upon command, due to 
interference in the actuator locking mechanism, which was caused by 
damage incurred during shipping of the actuator assembly. The actions 
specified by the proposed AD are intended to ensure that the RAT is 
deployed when commanded to do so. Failure of the RAT to deploy, 
specifically during a dual engine failure, would result in loss of 
hydraulic power, which would adversely affect the continued safe flight 
and landing of the airplane.

DATES: Comments must be received by September 16, 1996.

ADDRESSES: Submit comments in triplicate to the Federal Aviation 
Administration (FAA), Transport Airplane Directorate, ANM-103, 
Attention: Rules Docket No. 96-NM-12-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

[[Page 40759]]

Airplane Directorate, 1601 Lind Avenue, SW., Renton, Washington.

FOR FURTHER INFORMATION CONTACT: Sheila Kirkwood, Aerospace Engineer, 
Systems and Equipment Branch, ANM-130S, FAA, Seattle Aircraft 
Certification Office, 1601 Lind Avenue, SW., Renton, Washington; 
telephone (206) 227-2675; 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 96-NM-12-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. 96-NM-12-AD, 1601 Lind Avenue, SW., Renton, Washington 
98055-4056.

Discussion

    During maintenance tests on in-service Boeing Model 757 series 
airplanes, two ram air turbine (RAT) deployment actuators failed to 
deploy upon command. Additionally, during functional testing of 
airplanes in production, several actuators failed to deploy when 
commanded to do so. Investigation revealed that the lock pins and the 
piston head of the actuator unit were deformed at the point where the 
two come into contact with each other. The failure of the actuator to 
deploy was traced to the lock pins, which were peened at the ends, 
causing them to drag against the traveling cylinder and the piston head 
(lock rod), and prohibiting the movement of the lock rod.
    The damage to the lock pins apparently occurred from impact loads 
on the rod or head end of the actuator during shipping. Since the 
actuator is shipped in the extended position, the locking mechanism is 
susceptible to damage from dropping or from other types of improper 
handling. This was confirmed by laboratory testing.
    Additionally, a tolerance study showed that, under adverse 
conditions, the latch subassembly has the potential to interfere with 
the fixed end cap assembly. This situation can cause unlocking 
abnormalities.
    Failure of the RAT to deploy upon command, specifically during a 
dual engine failure, could result in loss of hydraulic power. This 
condition, if not corrected, would adversely affect the continued safe 
flight and landing of the airplane.

Explanation of Relevant Service Information

    The FAA has reviewed and approved Arkwin Industries Service 
Bulletin 1211233-29-21-3, Revision 2, dated June 17, 1994. (Arkwin 
Industries, Inc., is the manufacturer of the subject RAT deployment 
actuator assemblies.) This service bulletin describes procedures for 
conducting a check to identify discrepant actuator assemblies. If a 
discrepant assembly is found, the service bulletin provides procedures 
for removal, repair, and reidentification of it. The service bulletin 
recommends that the repair and reidentification of the discrepant 
assemblies be performed by Arkwin Industries, since specialized 
equipment is needed to perform the work.
    The FAA also has reviewed and approved Arkwin Industries Service 
Bulletin 1211233-29-21-4, Revision 2, dated June 17, 1994. This service 
bulletin describes procedures for proper identification of the 
necessary reusable shipping container and shipping sleeve assembly that 
should be used when transporting or shipping the RAT deployment 
actuator assembly. Use of this container and sleeve will prevent damage 
to the actuators during shipping.

Explanation of the Requirements of the Proposed Rule

    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 the replacement of discrepant RAT deployment 
actuator assemblies with units that have been modified (repaired and 
reidentified) and shipped in a specific fashion prior to installation. 
The actions would be required to be accomplished in accordance with the 
service bulletins described previously.

Cost Impact

    There are approximately 631 Boeing Model 757 series airplanes of 
the affected design in the worldwide fleet. The FAA estimates that 389 
airplanes of U.S. registry would be affected by this proposed AD, that 
it would take approximately 4 work hours per airplane to accomplish the 
proposed actions, and that the average labor rate is $60 per work hour. 
Required parts would cost approximately $4,832 per airplane. (If the 
unit is under warranty, the required parts would be provided by the 
actuator manufacturer at no cost to the operator.) Based on these 
figures, the cost impact of the proposed AD on U.S. operators is 
estimated to be $1,973,008, or $5,072 per airplane.
    The 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. However, the FAA has been 
advised that the proposed requirements of this AD already have been 
accomplished on approximately 13 airplanes of U.S. registry. Therefore, 
the future cost impact of this proposed AD on U.S. operators would be 
$1,907,072.

Regulatory Impact

    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

[[Page 40760]]

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:
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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 adding the following new 
airworthiness directive:

Boeing: Docket 96-NM-12-AD.

    Applicability: Model 757 series airplanes; equipped with ram air 
turbine (RAT) deployment actuators having Boeing part number (P/N) 
1211233-04 (Arkwin P/N 1211233-004) or Boeing P/N S271N102-5 (Arkwin 
P/N 1211233-005), and serial number 00001 and subsequent; 
certificated in any category.

    Note 1: This AD applies to each airplane identified in the 
preceding applicability provision, regardless of whether it has been 
otherwise 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 request approval for an 
alternative method of compliance in accordance with paragraph (d) 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: Required as indicated, unless accomplished 
previously.
    To prevent the failure of the RAT to deploy when commanded to do 
so, accomplish the following:
    (a) For airplanes equipped with a ram air turbine (RAT) 
deployment actuator, having serial number 00001 through 00631, 
inclusive, and without a suffix letter ``B'': Within 30 months after 
the effective date of this AD, remove the RAT deployment actuator 
and replace it with an actuator that meets the conditions specified 
in paragraphs (a)(1) and (a)(2) of this AD:
    (1) The actuator has been modified (repaired and reidentified) 
in accordance with Arkwin Industries Service Bulletin 1211233-19-21-
3, Revision 2, dated June 17, 1994; and

    Note 2: Arkwin Industries Service Bulletin 1211233-19-21-3, 
Revision 2, dated June 17, 1994, recommends that the actuator unit 
be returned to Arkwin Industries for repair, since specialized 
equipment is needed to perform the rework of the unit.

    (2) Prior to installation, the modified replacement actuator was 
shipped (i.e., to the place where installation is accomplished) in 
accordance with Arkwin Industries Service Bulletin 1211233-29-21-4, 
Revision 2, dated June 17, 1994.

    Note 3: Shipping records or tags may be reviewed to determine 
whether the actuator was shipped in accordance with Arkwin 
Industries Service Bulletin 1211233-29-1-4, Revision 2.
    Note 4: Arkwin Industries Service Bulletin 1211233-29-21-4, 
Revision 2, dated June 17, 1994, provides procedures for proper 
identification of the necessary reusable shipping container and 
shipping sleeve assembly that is to be used when transporting or 
shipping the RAT deployment actuator assembly. Use of this container 
and sleeve will prevent damage to the assembly during shipping.

    (b) For airplanes equipped with a RAT deployment actuator, 
having serial number 00632 and subsequent, which, prior to 
installation, was shipped in the extended position and not in 
accordance with Arkwin Industries Service Bulletin 1211233-29-21-4, 
Revision 2, dated June 17, 1994: Within 30 months after the 
effective date of this AD, remove that RAT deployment actuator and 
replace it with an actuator that meets the conditions specified in 
paragraphs (b)(1) and (b)(2) of this AD:
    (1) The actuator has been modified (repaired and reidentified) 
in accordance with Arkwin Industries Service Bulletin 1211233-19-21-
3, Revision 2, dated June 17, 1994; or the actuator is a new 
actuator from Arkwin Industries, Inc.; and
    (2) Prior to installation, the actuator was shipped (i.e., to 
the place where installation is accomplished) in accordance with 
Arkwin Industries Service Bulletin 1211233-29-21-4, Revision 2, 
dated June 17, 1994.
    (c) As of a date 30 months after the effective date of this AD, 
no person shall install on any airplane a RAT deployment actuator 
assembly, Boeing P/N 1211233-04 (Arkwin P/N 1211233-004) or Boeing 
P/N S271N102-5 (Arkwin P/N 1211233-005), serial number 00001 and 
subsequent; unless the conditions specified in both paragraphs 
(c)(1) and (c)(2) of this AD apply:
    (1) The actuator assembly has been modified (repaired and 
reidentified) in accordance with Arkwin Industries Service Bulletin 
1211233-19-21-3, Revision 2, dated June 17, 1994; or the actuator is 
replaced with a new actuator from Arkwin Industries, Inc.; and
    (2) Prior to installation, the actuator was shipped (i.e., to 
the place where installation is accomplished) in accordance with 
Arkwin Industries Service Bulletin 1211233-29-21-4, Revision 2, 
dated June 17, 1994.
    (d) 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 5: Information concerning the existence of approved 
alternative methods of compliance with this AD, if any, may be 
obtained from the Seattle ACO.

    (e) 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 airplane to a location where 
the requirements of this AD can be accomplished.

    Issued in Renton, Washington, on July 30, 1996.
Darrell M. Pederson,
Acting Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. 96-19893 Filed 8-5-96; 8:45 am]
BILLING CODE 4910-13-U