[Federal Register Volume 60, Number 149 (Thursday, August 3, 1995)]
[Rules and Regulations]
[Pages 39631-39633]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 95-18435]



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


DEPARTMENT OF TRANSPORTATION
14 CFR Part 39

[Docket No. 95-NM-06-AD; Amendment 39-9321; AD 95-16-02]


Airworthiness Directives; Boeing Model 747 SP, SR, -100, -200, 
and -300 Series Airplanes Equipped with Pratt & Whitney Model JT9D 
Series Engines (Excluding Model JT9D-70 Engines)

AGENCY: Federal Aviation Administration, DOT.

ACTION: Final rule.

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

SUMMARY: This amendment adopts a new airworthiness directive (AD), 
applicable to certain Boeing Model 747 SP, SR, -100, -200, and -300 
series airplanes, that requires repetitive operational tests of the 
reversible gearbox pneumatic drive unit (PDU) or the reversing air 
motor PDU to ensure that the unit can restrain the thrust reverser 
sleeve, and correction of any discrepancy found. This amendment is 
prompted by the results of an investigation, which revealed that, in 
the event of thrust reverser deployment during high-speed climb or 
during cruise, these airplanes could experience control problems. The 
actions specified by this AD are intended to ensure the integrity of 
the fail safe features of the thrust reverser system by preventing 
possible failure modes in the thrust reverser control system that can 
result in inadvertent deployment of a thrust reverser during flight.

DATES: Effective September 5, 1995.

    The incorporation by reference of certain publications listed in 
the regulations is approved by the Director of the Federal Register as 
of September 5, 1995.

ADDRESSES: The service information referenced in this AD may be 
obtained from Boeing Commercial Airplane Group, P.O. Box 3707, Seattle, 
Washington 98124-2207. This information may be examined at the Federal 
Aviation Administration (FAA), Transport Airplane Directorate, Rules 

[[Page 39632]]
Docket, 1601 Lind Avenue, SW., Renton, Washington; or at the Office of 
the Federal Register, 800 North Capitol Street, NW., suite 700, 
Washington, DC.

FOR FURTHER INFORMATION CONTACT: G. Michael Collins, Aerospace 
Engineer, Propulsion Branch, ANM-140S, FAA, Transport Airplane 
Directorate, Seattle Aircraft Certification Office, 1601 Lind Avenue, 
SW., Renton, Washington 98055-4056; telephone (206) 227-2689; fax (206) 
227-1181.

SUPPLEMENTARY INFORMATION: A proposal to amend part 39 of the Federal 
Aviation Regulations (14 CFR part 39) to include an airworthiness 
directive (AD) that is applicable to certain Boeing Model 747 SP, SR, -
100, -200, and -300 series airplanes was published in the Federal 
Register on March 30, 1995 (60 FR 16392). [A correction of the proposal 
was published in the Federal Register on April 5, 1995 (60 FR 17385).] 
That action proposed to require repetitive operational tests of the 
reversible gearbox pneumatic drive unit (PDU) or the reversing air 
motor PDU to ensure that the unit can restrain the thrust reverser 
sleeve, and correction of any discrepancy found during the test.
    Interested persons have been afforded an opportunity to participate 
in the making of this amendment. Due consideration has been given to 
the comments received.
    Two commenters support the proposed rule.
    One commenter requests an extension of the intervals for repeating 
the operational tests from 2,000 flight hours to 2,200 flight hours so 
that the tests can be performed during regularly scheduled maintenance 
visits. The commenter indicates that it has performed the initial test 
and one repetitive test on all of its aircraft, and no anomalies have 
been found. The FAA does not concur. The FAA established the repetitive 
test interval of 2,000 flight hours to provide an acceptable level of 
safety and to allow the majority of affected operators to schedule the 
tests during normal maintenance intervals at a maintenance base where 
special equipment and trained maintenance personnel will be available, 
if necessary. In addition, the interval is consistent with the interval 
recommended by the manufacturer in the alert service bulletin cited in 
this AD. However, under the provisions of paragraph (d) of the final 
rule, operators may apply for the approval of an adjustment of the 
compliance time if sufficient justification is presented to the FAA.
    After careful review of the available data, including the comments 
noted above, the FAA has determined that air safety and the public 
interest require the adoption of the rule as proposed.
    This AD is considered to be interim action until final action is 
identified, at which time the FAA may consider additional rulemaking.
    There are approximately 456 Model 747 SP, SR, -100, -200, and -300 
series airplanes of the affected design in the worldwide fleet. The FAA 
estimates that 173 airplanes of U.S. registry will be affected by this 
AD, that it will take approximately 16 work hours per airplane to 
accomplish the required actions, and that the average labor rate is $60 
per work hour. Based on these figures, the total cost impact of the AD 
on U.S. operators is estimated to be $166,080, or $960 per airplane.
    The total cost impact figure discussed above is based on 
assumptions that no operator has yet accomplished any of the 
requirements of this AD action, and that no operator would accomplish 
those actions in the future if this AD were not adopted.
    The regulations adopted herein will 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 final 
rule does not have sufficient federalism implications to warrant the 
preparation of a Federalism Assessment.
    For the reasons discussed above, I certify that this action (1) is 
not a ``significant regulatory action'' under Executive Order 12866; 
(2) is not a ``significant rule'' under DOT Regulatory Policies and 
Procedures (44 FR 11034, February 26, 1979); and (3) 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 final evaluation has been prepared for this action 
and it is contained in the Rules Docket. A copy of it may be obtained 
from the Rules Docket at the location provided under the caption 
ADDRESSES.

List of Subjects in 14 CFR Part 39

    Air transportation, Aircraft, Aviation safety, Incorporation by 
reference, Safety.

Adoption of the Amendment

    Accordingly, pursuant to the authority delegated to me by the 
Administrator, the Federal Aviation Administration amends 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.


39.13  [Amended]

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

95-16-02  Boeing: Amendment 39-9321. Docket 95-NM-06-AD.

    Applicability: Model 747 SP, SR, -100, -200, and -300 series 
airplanes equipped with Pratt & Whitney Model JT9D series engines 
(excluding Model JT9D-70 engines), 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 (d) of this AD 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 ensure the integrity of the fail safe features of 
the thrust reverser system, accomplish the following:
    (a) Within 90 days after the effective date of this AD, perform 
an operational test of the reversible gearbox pneumatic drive unit 
(PDU) or the reversing air motor PDU to ensure that the unit can 
restrain the thrust reverser sleeve, in accordance with Boeing Alert 
Service Bulletin 747-78A2131, dated September 15, 1994. Repeat the 
test thereafter at intervals not to exceed 2,000 flight hours.
    (b) If any of the tests required by this AD cannot be 
successfully performed, or if any discrepancy is found during those 
tests, accomplish either paragraph (b)(1) or (b)(2) of this AD.
    (1) Prior to further flight, correct the discrepancy found, in 
accordance with Boeing Alert Service Bulletin 747-78A2131, dated 
September 15, 1994. Or
    (2) The airplane may be operated in accordance with the 
provisions and limitations specified in an operator's FAA-approved 
Minimum Equipment List (MEL), provided that no more than one thrust 
reverser on the airplane is inoperative.
    (c) Within 30 days after performing each initial test required 
by this AD, submit a report of the test results, both positive and 
negative, to the FAA, Seattle Aircraft 

[[Page 39633]]
Certification Office (ACO), ANM-100S, 1601 Lind Avenue, SW., Renton, 
Washington 98055-4056; fax (206) 227-1181. Information collection 
requirements contained in this regulation have been approved by the 
Office of Management and Budget (OMB) under the provisions of the 
Paperwork Reduction Act of 1980 (44 U.S.C. 3501 et seq.) and have 
been assigned OMB Control Number 2120-0056.
    (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 2: 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.
    (f) The actions shall be done in accordance with Boeing Alert 
Service Bulletin 747-78A2131, dated September 15, 1994. This 
incorporation by reference was approved by the Director of the 
Federal Register in accordance with 5 U.S.C. 552(a) and 1 CFR part 
51. Copies may be obtained from Boeing Commercial Airplane Group, 
P.O. Box 3707, Seattle, Washington 98124-2207. Copies may be 
inspected at the FAA, Transport Airplane Directorate, 1601 Lind 
Avenue, SW., Renton, Washington; or at the Office of the Federal 
Register, 800 North Capitol Street, NW., suite 700, Washington, DC.
    (g) This amendment becomes effective on September 5, 1995.

    Issued in Renton, Washington, on July 21, 1995.
Darrell M. Pederson,
Acting Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. 95-18435 Filed 8-2-95; 8:45 am]
BILLING CODE 4910-13-U