[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
