[Federal Register Volume 59, Number 152 (Tuesday, August 9, 1994)]
[Unknown Section]
[Page 0]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 94-19351]


[[Page Unknown]]

[Federal Register: August 9, 1994]


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DEPARTMENT OF TRANSPORTATION
14 CFR Part 39

[Docket No. 94-NM-72-AD]

 

Airworthiness Directives; Boeing Model 757 Series Airplanes 
Equipped With Pratt and Whitney Engines

AGENCY: Federal Aviation Administration, DOT.

ACTION: Notice of proposed rulemaking (NPRM).

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SUMMARY: This document proposes the supersedure of an existing 
airworthiness directive (AD), applicable to certain Boeing Model 757 
series airplanes, that currently requires repetitive inspections to 
detect cracking in the midspar fuse pins and replacement of certain 
fuse pins. This action would require inspecting straight fuse pins and 
replacing cracked straight fuse pins with either new corrosion-
resistant steel fuse pins or like pins, replacing bulkhead fuse pins 
with new corrosion-resistant steel fuse pins, and repetitively 
inspecting newly installed fuse pins. This proposal is prompted by the 
development of new corrosion-resistant steel fuse pins. The actions 
specified by the proposed AD are intended to prevent cracking of the 
midspar fuse pins, which may lead to separation of the strut and engine 
from the wing of the airplane.

DATES: Comments must be received by October 3, 1994.

ADDRESSES: Submit comments in triplicate to the Federal Aviation 
Administration (FAA), Transport Airplane Directorate, ANM-103, 
Attention: Rules Docket No. 94-NM-72-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: Carrie Sumner, Aerospace Engineer, 
Airframe Branch ANM-120S, FAA, Transport Airplane Directorate , Seattle 
Aircraft Certification Office, 1601 Lind Avenue, SW., Renton, 
Washington 98055-4056; telephone (206) 227-2778; 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-72-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-72-AD, 1601 Lind Avenue, SW., Renton, Washington 
98055-4056.

Discussion

    On August 17, 1993, the FAA issued AD 93-16-09, amendment 39-8666 
(58 FR 45044, August 26, 1993), applicable to certain Boeing Model 757 
series airplanes, to require repetitive inspections to detect cracking 
in the midpsar fuse pins and replacement of certain fuse pins with new 
or refinished fuse pins. That action was prompted by reports of cracked 
fuse pins found on in-service airplanes. The requirements of that AD 
are intended to prevent separation of the strut and engine from the 
wing of the airplane.
    Since the issuance of that AD, the manufacturer has developed new 
15-5PH corrosion-resistant steel fuse pins. Test data have shown that 
these new fuse pins have a longer service life. Therefore, the FAA has 
determined that the inspection interval for these new pins can be 
increase significantly without compromising safety.
    Further, the FAA has reviewed the service experience of affected 
in-service airplanes and has found that consistent quality of the fuse 
pins cannot be ensured during the refinishing process of the fuse pins. 
Consequently, refinished straight fuse pins, currently allowed by AD 
93-16-09 as suitable replacement fuse pins, are no longer considered to 
be suitable replacements.
    Cracked fuse pins, if not corrected, could result in separation of 
the strut and engine from the wing of the airplane.
    The FAA has reviewed and approved Boeing Service Bulletin 757-
54A0019, Revision 5, dated March 17, 1994, which describes procedures 
for eddy current inspection to detect cracking in straight fuse pins, 
replacement of cracked straight fuse pins with either new 15-5PH pins 
or like pins, replacement of bulkhead fuse pins with new 15-5PH 
corrosion-resistant steel fuse pins, and repetitive eddy current 
inspections to detect cracking in the newly installed fuse pins.
    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 supersede AD 93-16-09 to require inspection of 
straight fuse pins, replacement of cracked straight fuse pins with 
either new 15-5PH corrosion-resistant steel fuse pins or like pins, 
replacement of bulkhead fuse pins with new 15-5PH corrosion-resistant 
steel fuse pins, and repetitive inspections of newly installed fuse 
pins. Installation of the steel fuse pins would allow a longer 
repetitive inspection interval than was previously provided by AD 93-
16-09. The actions would be required to be accomplished in accordance 
with the service bulletin described previously.
    There are approximately 273 Model 757 series airplanes equipped 
with Pratt and Whitney engines of the affected design in the worldwide 
fleet. The FAA estimates that 237 airplanes of U.S. registry would be 
affected by this proposed AD.
    The inspections that were previously required by AD 93-16-09, and 
retained in this proposal take approximately 8 work hours per fuse pin 
at an average labor rate of $55 per work hour. There are 4 fuse pins 
per airplane. Based on these figure, the total cost impact of these 
inspections on U.S. operators is estimated to be $417,120, or $1,760 
per airplane, per cycle. However, since the integrity and strength of 
the new steel fuse pins permit longer inspection intervals, the cost 
impact for these inspections would actually be lessened because the 
proposed inspections are not required to be performed as frequently as 
currently required by AD 93-16-09.
    The proposed replacement would take approximately 56 work hours per 
fuse pin at an average labor rate of $55 per work hour. Required parts 
would be provided by the manufacturer at no cost to the operator. Based 
on these figures, the total cost impact of the proposed replacement on 
U.S. operators is estimated to be $2,919,840, or $12,320 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 FAA recognizes that the obligation to maintain aircraft in an 
airworthy condition is vital, but sometimes expensive. Because AD's 
require specific actions to address specific unsafe conditions, they 
appear to impose costs that would not otherwise be borne by operators. 
However, because of the general obligation of operators to maintain 
aircraft in an airworthy condition, this appearance is deceptive. 
Attributing those costs solely to the issuance of this AD is 
unrealistic because, in the interest of maintaining safe aircraft, most 
prudent operators would accomplish the required actions even if they 
were not required to do so by the AD.
    A full cost-benefit analysis has not been accomplished for this 
proposed AD. As a matter of law, in order to be airworthy, an aircraft 
must conform to its type design and be in a condition for safe 
operation. The type design is approved only after the FAA makes a 
determination that it complies with all applicable airworthiness 
requirements. In adopting and maintaining those requirements, the FAA 
has already made the determination that they establish a level of 
safety that is cost-beneficial. When the FAA, as in this proposed AD, 
makes a finding of an unsafe condition, this means that this cost-
beneficial level of safety is no longer being achieved and that the 
proposed actions are necessary to restore that level of safety. Because 
this level of safety has already been determined to be cost-beneficial, 
a full cost-benefit analysis for this proposed AD would be redundant 
and unnecessary.
    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.


Sec. 39.13--[Amended] -

    2. Section 39.13 is amended by removing amendment 39-8666 (58 FR 
45044, August 26, 1993), and by adding a new airworthiness directive 
(AD), to read as follows:

    Boeing: Docket 94-NM-72-AD. Supersedes AD 93-16-09, Amendment 
39-8666. -
    Applicability: Model 757 series airplanes equipped with Pratt 
and Whitney engines, certificated in any category. -
    Compliance: Required as indicated, unless accomplished 
previously.
    Note 1: Inspections accomplished prior to the effective date of 
this amendment in accordance with the procedures described in Boeing 
Service Bulletin 757-54A0019, Revision 4, dated May 27, 1993, 
Revision 3, dated March 26, 1992, or Revision 2, dated October 11, 
1989, are considered acceptable for compliance with the applicable 
inspection specified in this amendment. -
    To prevent cracking of the midspar fuse pins, which may lead to 
separation of the strut and engine from the wing of the airplane, 
accomplish the following:
    (a) For airplanes equipped with straight fuse pins, part number 
(P/N) 311N5067-1: Prior to the accumulation of 3,800 total flight 
cycles on the straight fuse pin, perform an eddy current inspection 
to detect cracking in those fuse pins, in accordance with Boeing 
Service Bulletin 757-54A0019, Revision 5, dated March 17, 1994.
    (1) If no cracking is detected, repeat the inspection thereafter 
at intervals not to exceed 1,000 flight cycles on the straight fuse 
pin.
    (2) If any cracking is detected, prior to further flight, 
accomplish the requirements of either paragraph (a)(2)(i) or 
(a)(2)(ii) of this AD.
    (i) Replace the cracked straight fuse pins with new straight 
fuse pin, P/N 311N5067-1, and prior to the accumulation of 3,800 
total flight cycles on the newly installed straight fuse pin, 
perform an eddy current inspection, in accordance with the service 
bulletin. Repeat the inspection thereafter at intervals not to 
exceed 1,000 flight cycles on the newly installed straight fuse pin. 
Or
    (ii) Replace the cracked straight fuse pin with new 15-5PH fuse 
pin, P/N 311N5217-1, and prior to the accumulation of 14,000 total 
flight cycles on the newly installed 15-5PH fuse pin, perform an 
eddy current inspection to detect cracking in the newly installed 
pin, in accordance with the service bulletin. Repeat the inspection 
thereafter at intervals not to exceed 3,000 flight cycles on the 
newly installed fuse pin.
    (b) For airplanes equipped with bulkhead fuse pins, P/N 
311N5211-1: Within 90 days after the effective date of this AD, 
replace bulkhead fuse pins with 15-5PH fuse pins, P/N 311N5217, in 
accordance with Boeing Service bulletin 757-54A0019, Revision 5, 
dated March 17, 1994, and accomplish the requirements of paragraph 
(c) of this AD.
    (c) For airplanes equipped with 15-5PH fuse pins: Prior to the 
accumulation of 14,000 total flight cycles on the 15-5PH fuse pins, 
perform an eddy current inspection to detect cracking in those fuse 
pins, in accordance with Boeing Service Bulletin 757-54A0019, 
Revision 5, dated March 17, 1994.
    (1) If no cracking is detected, repeat the inspection thereafter 
at intervals not to exceed 3,000 flight cycles on the fuse pin.
    (2) If any cracking is detected, accomplish the requirements of 
paragraphs (c)(2)(i) and (c)(2)(ii) of this AD.
    (i) Prior to further flight, replace any cracked 15-5PH fuse pin 
with a new 15-5PH fuse pin, P/N 311N5217-1, in accordance with the 
service bulletin.
    (ii) Prior to the accumulation of 14,000 total flight cycles on 
the newly installed 15-5PH fuse pin, perform an eddy current 
inspection to detect cracking in the newly installed pin, in 
accordance with the service bulletin. Repeat the inspection 
thereafter at intervals not to exceed 3,000 flight cycles on the 
newly installed fuse pin.
    (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.

    Issued in Renton, Washington, on August 2, 1994.
James V. Devany,
Acting Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. 94-19351 Filed 8-8-94; 8:45 am]
BILLING CODE 4910-13-U