[Federal Register Volume 61, Number 56 (Thursday, March 21, 1996)]
[Proposed Rules]
[Pages 11593-11594]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 96-6808]



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


DEPARTMENT OF TRANSPORTATION
14 CFR Part 39

[Docket No. 95-NM-203-AD]


Airworthiness Directives; Boeing Model 767 Series Airplanes

AGENCY: Federal Aviation Administration, DOT.

ACTION: Notice of proposed rulemaking (NPRM).

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

SUMMARY: This document proposes the adoption of a new airworthiness 
directive (AD) that is applicable to all Boeing Model 767 series 
airplanes. This proposal would require repetitive operational tests to 
verify proper deployment of the ram air turbine (RAT), and replacement 
of the rotary actuator motor with a new or serviceable rotary actuator 
motor, if necessary. This proposal is prompted by reports of corroded 
rotary actuator motors of the RAT found on in-service airplanes. The 
actions specified by the proposed AD are intended to prevent such 
corrosion, which could result in failure of the RAT to deploy and 
subsequent loss of emergency hydraulic power to the flight controls in 
the event that power is lost in both engines.

DATES: Comments must be received by May 14, 1996.

ADDRESSES: Submit comments in triplicate to the Federal Aviation 
Administration (FAA), Transport Airplane Directorate, ANM-103, 
Attention: Rules Docket No. 95-NM-203-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: 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 95-NM-203-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-203-AD, 1601 Lind Avenue, SW., Renton, Washington 
98055-4056.

Discussion

    -The FAA has received several reports of corroded rotary actuator 
motors of the ram air turbine (RAT) found on in-service Boeing Model 
767 series airplanes during ground testing. In these incidents, the 
effects of such corrosion prevented deployment of the RAT. 
Investigation has revealed that the rotary actuator motor of the RAT is 
not hermetically sealed. The motor is located in the right aft fairing 
of the airplane where it is susceptible to moisture accumulation when 
exposed to high cycling or humid conditions; such moisture accumulation 
can produce or accelerate the identified corrosion conditions. 
Corrosion of the rotary actuator motors, if not detected and corrected 
in a timely manner, could result in failure of the RAT to deploy and 
subsequent loss of emergency hydraulic power to the flight controls in 
the event that power is lost in both engines.
    -The FAA has reviewed and approved Boeing Alert Service Bulletin 
767-29A0080, dated October 12, 1995, which describes procedures for 
repetitive operational tests to verify

[[Page 11594]]
proper deployment of the ram air turbine (RAT) system, and replacement 
of the rotary actuator motor with a new or serviceable rotary actuator 
motor, if necessary. The alert service bulletin recommends that the 
repetitive operational tests be accomplished at intervals not to exceed 
3,000 flight hours.
    -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 repetitive operational tests to verify proper 
deployment of the ram air turbine (RAT) system, and replacement of the 
rotary actuator motor with a new or serviceable rotary actuator motor, 
if necessary. The actions would be required to be accomplished in 
accordance with the alert service bulletin described previously.
    -Operators should note that, although the alert service bulletin 
recommends a repetitive interval of 3,000 flight hours for the 
operational tests, the proposed AD would require that the operational 
tests be accomplished at intervals not to exceed 1,000 flight hours. In 
developing an appropriate compliance time for this action, the FAA 
considered not only the degree of urgency associated with addressing 
the subject unsafe condition, but the susceptibility of the rotary 
actuator motor to moisture accumulation when exposed to high cycling or 
humid conditions, which could lead corrosion of the rotary actuator 
motor. In consideration of these items, the FAA finds that operational 
tests conducted at intervals of 1,000 flight hours will better ensure 
that any detrimental effects associated with corrosion will be 
identified and corrected prior to the time that they could adversely 
affect the actuator motor.
    -This is considered to be interim action until final action is 
identified, at which time the FAA may consider further rulemaking.
    -There are approximately 583 Boeing Model 767 series airplanes of 
the affected design in the worldwide fleet. The FAA estimates that 197 
airplanes of U.S. registry would be affected by this proposed AD, that 
it would take approximately 1 work hour per airplane to accomplish the 
proposed actions, and that the average labor rate is $60 per work hour. 
Based on these figures, the cost impact of the proposed AD on U.S. 
operators is estimated to be $11,820, or $60 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.
    -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 USC 106(g), 40113, 44701.


Sec. 39.13   [Amended]

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

Boeing: Docket 95-NM-203-AD.

    -Applicability: All Model 767 series airplanes, 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 (b) 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 corrosion of the rotary actuator motors, which could 
result in failure of the RAT to deploy and subsequent loss of 
emergency hydraulic power to the flight controls in the event that 
power is lost in both engines, accomplish the following:
    (a) Within 6 months after the effective date of this AD, perform 
an operational test to verify proper deployment of the ram air 
turbine (RAT) in accordance with Boeing Alert Service Bulletin 767-
29A0080, dated October 12, 1995.
    (1) If the RAT deploys properly, repeat the operational test 
thereafter at intervals not to exceed 1,000 flight hours.
    (2) If the RAT deploys improperly, prior to further flight, 
replace the rotary actuator motor with a new or serviceable rotary 
actuator motor, in accordance with the service bulletin. Repeat the 
operational test thereafter at intervals not to exceed 1,000 flight 
hours.
    (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 2: 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 
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 March 15, 1996.
James V. Devany,
Acting Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. 96-6808 Filed 3-20-96; 8:45 am]
BILLING CODE 4910-13-P