[Federal Register Volume 60, Number 96 (Thursday, May 18, 1995)]
[Proposed Rules]
[Pages 26696-26700]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 95-12207]



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[[Page 26697]]

DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 94-NM-71-AD]


Airworthiness Directives; Boeing Model 757 Series Airplanes 
Equipped with Rolls Royce Engines

AGENCY: Federal Aviation Administration, DOT.

ACTION: Supplemental notice of proposed rulemaking; reopening of 
comment period.

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SUMMARY: This document revises an earlier proposed airworthiness 
directive (AD), applicable to certain Boeing Model 757 series 
airplanes, that would have required inspection of certain fuse pins, 
and replacement of certain fuse pins with certain other fuse pins. That 
proposal was prompted by the development of new corrosion-resistant 
steel fuse pins. This action revises the proposed rule by including 
requirements for inspections of refinished straight fuse pins, and 
replacement of cracked refinished straight fuse pins with certain other 
straight fuse pins. The actions specified by this 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 June 9, 1995.
ADDRESSES: Submit comments in triplicate to the Federal Aviation 
Administration (FAA), Transport Airplane Directorate, ANM-103, 
Attention: Rules Docket No. 94-NM-71-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-71-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-71-AD, 1601 Lind Avenue, SW., Renton, Washington 
98055-4056.

Discussion

    A proposal to amend part 39 of the Federal Aviation Regulations (14 
CFR part 39) to add an airworthiness directive (AD), applicable to 
certain Boeing Model 757 series airplanes, was published as a notice of 
proposed rulemaking (NPRM) in the Federal Register on August 9, 1994 
(59 FR 40488). That NPRM would have superseded AD 93-16-08, amendment 
39-8665 (58 FR 45041, August 26, 1993), 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 new 15-5PH corrosion-resistant steel fuse 
pins would allow a longer interval for repetitive inspection than was 
previously provided by AD 93-16-08. That NPRM was prompted by the 
development of new 15-5PH corrosion-resistant steel fuse pins. Cracking 
of the midspar fuse pins, if not detected and corrected in a timely 
manner, could result in separation of the strut and engine from the 
wing of the airplane.
    Interested persons have been afforded an opportunity to participate 
in the making of this amendment. Due consideration has been given to 
the comments received.
    One commenter requests that the proposal be revised to include 
repetitive inspections of refinished straight fuse pins. The commenter 
asserts that these pins should be inspected repetitively until cracking 
is found, at which time they should be replaced with the new 15-5PH 
fuse pins. The FAA concurs. The FAA's intent was to continue the 
requirements of AD 93-16-08 to inspect repetitively currently installed 
refinished straight fuse pins. However, this requirement was 
inadvertently excluded; therefore, a new paragraph (b) has been added 
to this supplemental NPRM.
    [All paragraphs subsequent to paragraph (b) have been redesignated 
in this supplemental NPRM to accommodate the new paragraph (b); see 
discussion, above.]
    One commenter requests that the proposed requirement in paragraph 
(b) to replace the bulkhead fuse pins within 90 days be extended to 
3,000 flight cycles. The commenter notes that there have been no 
reports of cracking or corrosion on 68 bulkhead fuse pins that had 
accumulated between 4,500 and 6,000 flight cycles. Further, the 
commenter states that its suggested 3,000-flight cycle compliance time 
will not adversely affect safety, since test results indicate that 
these fuse pins will maintain limit load beyond 5,000 flight cycles 
after the detection of an initial crack. Additionally, the commenter 
asserts that the fail-safe capability of the strut on Model 757 series 
airplanes can withstand full limit load with a total failure (i.e., 
failure of both shear planes) of the midspar fuse pin. Finally, the 
commenter points out that the proposed 90-day compliance time is 
inconsistent with that of a similar AD that requires inspections/
replacement of the bulkhead fuse pins on Model 747 series airplanes.
    The FAA concurs. The FAA has reviewed the test data submitted by 
this commenter and has determined that extending the compliance time of 
paragraph (c) of the supplemental NPRM to 3,000 flight cycles will not 
[[Page 26698]] adversely affect safety. The FAA finds that the strut of 
Model 757 series airplanes has fail-safe capability and can withstand 
full limit load, even with total failure of a midspar fuse pin.
    Since issuance of the proposal, the FAA has found that the proposed 
repetitive inspection interval of 3,000 flight cycles for inspection of 
the new 15-5PH fuse pins may not coincide with operators' regularly 
scheduled maintenance visits. The FAA finds that extending the 
compliance time by 500 additional flight cycles will not adversely 
affect safety, and will allow the modification to be performed at a 
base during regularly scheduled maintenance where special equipment and 
trained maintenance personnel will be available if necessary. 
Therefore, paragraphs (a)(2)(ii), (d)(1), and (d)(2)(ii) of the 
supplemental notice have been revised to specify a repetitive 
inspection interval of 3,500 flight cycles for inspection of the new 
15-5PH corrosion-resistant steel fuse pins. Additionally, the newly 
added paragraph (b)(2)(iii) of this supplemental NPRM, specifies a 
repetitive interval of 3,500 flight cycles for inspection of refinished 
straight fuse pins. [Paragraph (c) of the proposal has been 
redesignated as paragraph (d) of this supplemental NPRM; see 
discussion, above.]
    Further, since issuance of the proposal, the FAA has found that 
Boeing Service Bulletin 757-54A0020, Revision 5, dated March 17, 1994 
(which is referenced in the proposal as the appropriate source of 
service information), does not describe procedures for eddy current 
inspections of the new 15-5PH corrosion-resistant steel fuse pins. 
However, that service bulletin does describe eddy current inspection 
procedures for the old style fuse pins, part number 311N5067-1, and the 
FAA finds that these procedures are also applicable to the new 15-5PH 
fuse pins. Therefore, paragraphs (a)(2)(ii), (b)(2)(iii), and 
(d)(2)(ii) of this supplemental NPRM have been revised to reference the 
procedures described in the service bulletin to perform the eddy 
current inspections of the new 15-5PH corrosion-resistant steel fuse 
pins.
    The FAA has reviewed and reconsidered the replacement requirements 
that were proposed in the original NPRM. The FAA finds that confusion 
may exist concerning whether straight fuse pins may be replaced 
independently of the other fuse pin on the same strut when only one 
fuse pin is cracked. It is not the FAA's intent to require replacement 
of uncracked fuse pins. However, the FAA has determined that it is 
unacceptable to mix the types of fuse pins on the same strut, since 
double shear load of the fuse pin depends upon the type of fuse pin. 
Therefore, a steel fuse pin having part number (P/N) 311N5067-1 may not 
be installed on the same strut that has a corrosion-resistant steel 
(CRES) fuse pin having P/N 311N5217-1 installed on that strut. However, 
each strut must have fuse pins of the same type, which may differ from 
fuse pins on another strut. A new paragraph (e) has been added to this 
supplemental notice to clarify the proposed replacement requirement.
    The FAA has recently reviewed the figures it has used over the past 
several years in calculating the economic impact of AD activity. In 
order to account for various inflationary costs in the airline 
industry, the FAA has determined that it is necessary to increase the 
labor rate used in these calculations from $55 per work hour to $60 per 
work hour. The economic impact information, below, has been revised to 
reflect this increase in the specified hourly labor rate.
    As a result of recent communications with the Air Transport 
Association (ATA) of America, the FAA has learned that, in general, 
some operators may misunderstand the legal effect of AD's on airplanes 
that are identified in the applicability provision of the AD, but that 
have been altered or repaired in the area addressed by the AD. The FAA 
points out that all airplanes identified in the applicability provision 
of an AD are legally subject to the AD. If an airplane has been altered 
or repaired in the affected area in such a way as to affect compliance 
with the AD, the owner or operator is required to obtain FAA approval 
for an alternative method of compliance with the AD, in accordance with 
the paragraph of each AD that provides for such approvals. A note has 
been included in this supplemental notice to clarify this long-standing 
requirement.
    Since these changes expand the scope of the originally proposed 
rule, the FAA has determined that it is necessary to reopen the comment 
period to provide additional opportunity for public comment.
    There are approximately 306 Model 757 series airplanes equipped 
with Rolls Royce engines of the affected design in the worldwide fleet. 
The FAA estimates that 119 airplanes of U.S. registry would be affected 
by this proposed AD.
    The inspections that were previously required by AD 93-16-08, and 
retained in this supplemental proposal take approximately 8 work hours 
per fuse pin at an average labor rate is $60 per work hour. There are 4 
fuse pins per airplane. Based on these figures, the total cost impact 
of these inspections on U.S. operators is estimated to be $228,480, or 
$1,920 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 93-16-08.
    The proposed replacement would take approximately 56 work hours per 
fuse pin at an average labor rate of $60 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 $1,599,360, or $13,440 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 [[Page 26699]] 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 39-8665 (58 FR 
45041, August 26, 1993), and by adding a new airworthiness directive 
(AD), to read as follows:

Boeing: Docket 94-NM-71-AD. Supersedes AD 93-16-08, Amendment 39-
8665.

    Applicability: Model 757 series airplanes equipped with Rolls 
Royce 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 (f) 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.

    Note 2: Inspections accomplished prior to the effective date of 
this amendment in accordance with the procedures described in Boeing 
Service Bulletin 757-54A0020, Revision 4, dated May 27, 1993; 
Revision 3, dated March 26, 1992; or Revision 2, dated October 31, 
1991; 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 5,000 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 757-54A0020, Revision 5, dated March 17, 1994.
    (1) If no cracking is detected, repeat the inspection thereafter 
at intervals not to exceed 1,500 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 pin with a new straight 
fuse pin, P/N 311N5067-1, and prior to the accumulation of 5,000 
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 1,500 flight cycles on the newly installed straight fuse pin. 
Or
    (ii) Replace the cracked straight fuse pin with a 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 procedures described in the service 
bulletin. Repeat the inspection thereafter at intervals not to 
exceed 3,500 flight cycles on the newly installed fuse pin.
    (b) For airplanes equipped with refinished straight fuse pins, 
P/N 311N5067-1: Perform an eddy current inspection to detect 
cracking in those fuse pins at intervals not to exceed 1,500 flight 
cycles on the refinished fuse pins, in accordance with Boeing 
Service Bulletin 757-54A0020, Revision 5, dated March 17, 1994.
    (1) If no cracking is detected, repeat the inspection thereafter 
at intervals not to exceed 1,500 flight cycles on the refinished 
straight fuse pin.
    (2) If any cracking is detected, prior to further flight, 
accomplish the requirements of paragraph (b)(2)(i), (b)(2)(ii), or 
(b)(2)(iii) of this AD, in accordance with the service bulletin.
    (i) Replace the cracked refinished straight fuse pin with a 
crack-free refinished straight fuse pin, P/N 311N5067-1, and perform 
an eddy current inspection to detect cracking in the refinished 
straight fuse pin at intervals not to exceed 1,500 flight cycles, in 
accordance with the procedures described in the service bulletin. Or
    (ii) Replace the cracked refinished straight fuse pin with a new 
straight fuse pin, P/N 311N5067-1, and prior to the accumulation of 
5,000 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 1,500 flight cycles on the newly installed straight fuse pin. 
Or
    (iii) Replace the cracked refinished straight fuse pin with a 
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 procedures described in 
the service bulletin. Repeat the inspection thereafter at intervals 
not to exceed 3,500 flight cycles on the newly installed fuse pin.
    (c) For airplanes equipped with bulkhead fuse pins, P/N 
311N5211-1: Within 3,000 flight cycles after the effective date of 
this AD, replace the bulkhead fuse pins with 15-5PH fuse pins, P/N 
311N5217-1, in accordance with Boeing Service Bulletin 757-54A0020, 
Revision 5, dated March 17, 1994, and accomplish the requirements of 
paragraph (d) of this AD.
    (d) 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 the procedures described in Boeing Service 
Bulletin 757-54A0020, Revision 5, dated March 17, 1994.
    (1) If no cracking is detected, repeat the inspection thereafter 
at intervals not to exceed 3,500 flight cycles on the fuse pin.
    (2) If any cracking is detected, accomplish the requirements of 
paragraphs (d)(2)(i) and (d)(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 
procedures described in the service bulletin. And
    (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 procedures described in the service bulletin. 
Repeat the inspection thereafter at intervals not to exceed 3,500 
flight cycles on the newly installed fuse pin.
    (e) Fuse pins must be of the same type on the same strut. For 
example, a steel fuse pin [[Page 26700]] having P/N 311N5067-1 may 
not be installed on the same strut that has a corrosion-resistant 
steel (CRES) fuse pin having P/N 311N5217-1 installed on that strut. 
However, fuse pins on one strut may differ from those on another 
strut, provided the fuse pins are not of mixed types on the same 
strut.
    (f) 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 3: Information concerning the existence of approved 
alternative methods of compliance with this AD, if any, may be 
obtained from the Seattle ACO.

    (g) Special flight permits may be issued in accordance with 
Secs. 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 May 12, 1995.
Darrell M. Pederson,
Acting Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. 95-12207 Filed 5-17-95; 8:45 am]
BILLING CODE 4910-13-U