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

[Federal Register Volume 62, Number 169 (Tuesday, September 2, 1997)]
[Rules and Regulations]
[Pages 46186-46189]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 97-23176]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 97-NM-130-AD; Amendment 39-10115; AD 97-18-05]
RIN 2120-AA64


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

AGENCY: Federal Aviation Administration, DOT.

ACTION: Final rule; request for comments.

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SUMMARY: This amendment supersedes an existing airworthiness directive 
(AD), applicable to certain Boeing Model 757

[[Page 46187]]

series airplanes, that currently requires repetitive inspections to 
detect cracking in the midspar fuse pins; replacement with new or 
refinished fuse pins, if necessary; and repetitive inspections of newly 
installed fuse pins. This AD requires earlier initial inspections and 
replacements; more frequent repetitive inspections of certain fuse 
pins; and replacement with new fuse pins, if necessary. This amendment 
is prompted by reports of fatigue cracking of the midspar fuse pins and 
by fatigue test data indicating that current inspection thresholds and 
intervals for repetitive inspections are inadequate to detect fatigue 
cracking in a timely manner. The actions specified in this AD are 
intended to detect and correct such fatigue cracking, which could lead 
to separation of the strut and engine from the wing of the airplane.

DATES: Effective September 17, 1997.
    The incorporation by reference of Boeing Alert Service Bulletin 
757-54A0019, Revision 6, dated July 18, 1997, as listed in the 
regulations, is approved by the Director of the Federal Register as of 
September 17, 1997.

    The incorporation by reference of Boeing Service Bulletin 757-
54A0019, Revision 5, dated March 17, 1994, as listed in the 
regulations, was approved previously by the Director of the Federal 
Register as of April 10, 1996 (61 FR 9599, March 11, 1996).
    Comments for inclusion in the Rules Docket must be received on or 
before November 3, 1997.

ADDRESSES: Submit comments in triplicate to the Federal Aviation 
Administration (FAA), Transport Airplane Directorate, ANM-103, 
Attention: Rules Docket No. 97-NM-130-AD, 1601 Lind Avenue, SW., 
Renton, Washington 98055-4056.
    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 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.

FOR FURTHER INFORMATION CONTACT: Todd Martin, Aerospace Engineer, 
Airframe Branch, ANM-120S, FAA, Transport Airplane Directorate, Seattle 
Aircraft Certification Office, 1601 Lind Avenue, SW., Renton, 
Washington; telephone (425) 227-2781; fax (425) 227-1181.

SUPPLEMENTARY INFORMATION: On March 1, 1996, the FAA issued AD 96-05-
07, amendment 39-9533 (61 FR 9599, March 11, 1996), applicable to 
certain Boeing Model 757 series airplanes. That AD requires repetitive 
inspections to detect cracking in the midspar fuse pins, regardless of 
whether they are straight, bulkhead, or 15-5PH fuse pins, and 
replacement of discrepant pins with new straight fuse pins, refinished 
straight fuse pins, or new corrosion-resistant steel (15-5PH) fuse 
pins, depending on the type of cracked pin. The actions required by 
that 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.

Actions Since Issuance of Previous Rule

    Since the issuance of AD 96-05-07, the FAA has received two reports 
indicating the detection of damaged straight fuse pins (one broken pin 
and one cracked pin) on Model 757 series airplanes equipped with Pratt 
& Whitney engines. In these instances, damage to the fuse pins was 
detected before reaching the threshold specified in AD 96-05-07 for 
conducting an initial inspection of the fuse pins. In addition, since 
the issuance of that AD, the FAA was informed by Boeing that refinished 
straight fuse pins have a shorter fatigue life than new straight fuse 
pins.
    Based on data from fatigue testing by the manufacturer and reports 
of early cracking, the FAA finds that the current inspection thresholds 
and intervals for repetitive inspections are inadequate to detect 
cracking in a timely manner. Consequently, it is necessary to lower the 
threshold for the initial inspection and conduct repetitive inspections 
of these fuse pins more frequently than currently required by AD 96-05-
07. In addition, the FAA has determined that the action specified in 
paragraph (b)(2)(i) of AD 96-05-07, which requires the replacement of 
cracked refinished straight fuse pins with crack-free refinished 
straight fuse pins, is no longer acceptable. The FAA concludes that, 
because of the safety implications and consequences associated with the 
fatigue cracking of fuse pins, the replacement of refinished straight 
fuse pins must be made with either new straight fuse pins or new 15-5PH 
fuse pins. However, the FAA has determined that the existing refinished 
straight fuse pins, which are already installed on Boeing Model 757 
series airplanes and do not have cracks, may continue in use in 
accordance with the requirements of this AD.
    The FAA is considering a separate rulemaking action to address the 
same unsafe condition on certain Model 757 airplanes equipped with 
Rolls Royce engines.

Explanation of Relevant Service Information

    Since the issuance of AD 96-05-07, the FAA has reviewed and 
approved Boeing Alert Service Bulletin 757-54A0019, Revision 6, dated 
July 18, 1997, which continues specifications similar to those in 
Boeing Service Bulletin 757-54A0019, Revision 5, dated March 17, 1994 
(which was referenced in AD 96-05-07 as the appropriate source of 
service information). The relevant changes in Revision 6 are procedures 
for earlier initial inspections and replacements; more frequent 
repetitive inspections of certain fuse pins; and replacement with new 
fuse pins, if necessary. In addition, Revision 6 specifies the 
replacement of cracked refinished straight fuse pins with new straight 
fuse pins or 15-5PH fuse pins.

Explanation of Requirements of Rule

    Since an unsafe condition has been identified that is likely to 
exist or develop on other airplanes of this same type design, this AD 
supersedes AD 96-05-07 to continue to require repetitive inspections to 
detect cracking in the midspar fuse pins; replacement with new or 
refinished fuse pins, if necessary; and repetitive inspections of newly 
installed fuse pins. This AD requires earlier initial inspections and 
replacements; more frequent repetitive inspections of certain fuse 
pins; and replacement with new fuse pins, if necessary. This AD also 
requires the replacement of cracked refinished straight fuse pins with 
new straight fuse pins or 15-5PH fuse pins. These actions are required 
to be accomplished in accordance with Revision 6 of the alert service 
bulletin described previously.

Differences Between the AD and the Relevant Service Bulletin

    Operators should note that, although Boeing Alert Service Bulletin 
757-54A0019, Revision 6, dated July 18, 1997, specifies that a cracked 
bulkhead fuse pin may be replaced with either a new straight fuse pin 
or a new 15-5PH fuse pin, this AD requires a bulkhead fuse pin to be 
replaced only with a new 15-5PH fuse pin. The FAA has determined that 
because 15-5PH fuse pins are made from corrosion-resistant steel, 15-
5PH fuse pins are less likely to be subject to fatigue cracking and 
stress corrosion cracking, and, as a result, have a longer service life 
than straight fuse pins or bulkhead fuse pins. The FAA also considers 
that this action is necessary to support the continued airworthiness of 
Boeing Model 757

[[Page 46188]]

series airplanes equipped with Pratt & Whitney engines.
    Operators also should note that Revision 6 of the previously 
described alert service bulletin specifies the replacement of bulkhead 
fuse pins within 6,000 total flight cycles on the bulkhead fuse pins. 
However, this AD requires the replacement of bulkhead fuse pins within 
3,000 flight cycles on the bulkhead fuse pins after April 10, 1996, the 
effective date of AD 96-05-07. The FAA has determined that continuing 
the requirement for such replacement, which was required in AD 96-05-
07, is sufficient to detect and correct the initiation and propagation 
of fatigue cracking in the midspar fuse pins.
    In addition, operators should note that the applicability of this 
AD differs from the effectivity listing in Revision 6 of the previously 
referenced alert service bulletin. The FAA has determined that to 
adequately address the problem of fatigue cracking in the midspar fuse 
pins, this AD should include Model 757 series airplanes (all serial 
numbers) equipped with Pratt & Whitney engines, as previously specified 
in AD 96-05-07.

Interim Action

    This is considered to be interim action until final action is 
identified, at which time the FAA may consider further rulemaking.

Determination of Rule's Effective Date

    Since a situation exists that requires the immediate adoption of 
this regulation, it is found that notice and opportunity for prior 
public comment hereon are impracticable, and that good cause exists for 
making this amendment effective in fewer than 30 days.

Comments Invited

    Although this action is in the form of a final rule that involves 
requirements affecting flight safety and, thus, was not preceded by 
notice and an opportunity for public comment, comments are invited on 
this rule. Interested persons are invited to comment on this 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 under the caption ADDRESSES. All 
communications received on or before the closing date for comments will 
be considered, and this rule may be amended in light of the comments 
received. Factual information that supports the commenter's ideas and 
suggestions is extremely helpful in evaluating the effectiveness of the 
AD action and determining whether additional rulemaking action would be 
needed.
    Comments are specifically invited on the overall regulatory, 
economic, environmental, and energy aspects of the rule that might 
suggest a need to modify the 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 that 
summarizes each FAA-public contact concerned with the substance of this 
AD will be filed in the Rules Docket.
    Commenters wishing the FAA to acknowledge receipt of their comments 
submitted in response to this rule must submit a self-addressed, 
stamped postcard on which the following statement is made: ``Comments 
to Docket Number 97-NM-130-AD.'' The postcard will be date stamped and 
returned to the commenter.

Regulatory Impact

    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.
    The FAA has determined that this regulation is an emergency 
regulation that must be issued immediately to correct an unsafe 
condition in aircraft, and that it is not a ``significant regulatory 
action'' under Executive Order 12866. It has been determined further 
that this action involves an emergency regulation under DOT Regulatory 
Policies and Procedures (44 FR 11034, February 26, 1979). If it is 
determined that this emergency regulation otherwise would be 
significant under DOT Regulatory Policies and Procedures, a final 
regulatory evaluation will be prepared and placed in the Rules Docket. 
A copy of it, if filed, 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. 106(g), 40113, 44701.


Sec. 39.13  [Amended]

    2. Section 39.13 is amended by removing amendment 39-9533 (61 FR 
9599, March 11, 1996), and by adding a new airworthiness directive 
(AD), amendment 39-10115, to read as follows:

97-18-05  Boeing: Amendment 39-10115. Docket 97-NM-130-AD. 
Supersedes AD 96-05-07, Amendment 39-9533.

    Applicability: Model 757 series airplanes equipped with Pratt & 
Whitney 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 
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 (f) 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.

    Note 2: Inspections accomplished prior to the effective date of 
this amendment in accordance with the procedures described in Boeing 
Service Bulletin 757-54A0019, Revision 5, dated March 17, 1994; 
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 inspections specified in this 
amendment.

    To detect and correct fatigue cracking of the midspar fuse pins, 
which could 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 1,000 total flight 
cycles on the straight fuse pin, or within 60 days after the 
effective date of this AD, whichever occurs later, perform an eddy 
current inspection to detect fatigue cracking in the fuse pin, in 
accordance with Boeing Alert Service Bulletin 757-54A0019, Revision 
6, dated July 18, 1997.
    (1) If no cracking is detected, repeat the inspection thereafter 
at intervals not to exceed 500 flight cycles on the straight fuse 
pin.
    (2) If any cracking is detected, prior to further flight, 
accomplish the requirements of

[[Page 46189]]

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 1,000 
total flight cycles on the newly installed straight fuse pin, 
perform an eddy current inspection to detect fatigue cracking in the 
fuse pin, in accordance with the alert service bulletin. Repeat the 
inspection thereafter at intervals not to exceed 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 fatigue cracking in the fuse 
pin, in accordance with the procedures described in the alert 
service bulletin. Repeat the inspection thereafter at intervals not 
to exceed 3,500 flight cycles on the newly installed 15-5PH fuse 
pin.
    (b) For airplanes equipped with refinished straight fuse pins, 
P/N 311N5067-1: Prior to the accumulation of 500 total flight cycles 
on the refinished straight fuse pin, or within 60 days after the 
effective date of this AD, whichever occurs later, perform an eddy 
current inspection to detect fatigue cracking in the fuse pin, in 
accordance with Boeing Alert Service Bulletin 757-54A0019, Revision 
6, dated July 18, 1997.
    (1) If no cracking is detected, repeat the inspection thereafter 
at intervals not to exceed 500 flight cycles on the refinished 
straight fuse pin.
    (2) If any cracking is detected, prior to further flight, 
accomplish the requirements of either paragraph (b)(2)(i) or 
(b)(2)(ii) of this AD.
    (i) Replace the cracked fuse pin with a new straight fuse pin, 
P/N 311N5067-1, and prior to the accumulation of 1,000 total flight 
cycles on the newly installed straight fuse pin, perform an eddy 
current inspection to detect fatigue cracking in the new straight 
fuse pin, in accordance with the procedures described in the alert 
service bulletin. Repeat this inspection thereafter at intervals not 
to exceed 500 flight cycles on the newly installed straight fuse 
pin. Or
    (ii) Replace the cracked 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 fatigue cracking in the fuse pin, in 
accordance with the procedures described in the alert service 
bulletin. Repeat the inspection thereafter at intervals not to 
exceed 3,500 flight cycles on the newly installed 15-5PH fuse pin.
    (c) For airplanes equipped with bulkhead fuse pins, P/N 
311N5211-1: Within 3,000 flight cycles on the bulkhead fuse pins 
after April 10, 1996 (the effective date of AD 96-05-07, amendment 
39-9533), replace the bulkhead fuse pin with a new 15-5PH fuse pin, 
P/N 311N5217-1, in accordance with Boeing Service Bulletin 757-
54A0019, Revision 5, dated March 17, 1994, or Boeing Alert Service 
Bulletin 757-54A0019, Revision 6, dated July 18, 1997, 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 pin, 
perform an eddy current inspection to detect fatigue cracking in 
those fuse pins, in accordance with the procedures described in 
Boeing Alert Service Bulletin 757-54A0019, Revision 6, dated July 
18, 1997.
    (1) If no cracking is detected, repeat the inspection thereafter 
at intervals not to exceed 3,500 flight cycles on the 15-5PH fuse 
pin.
    (2) If any cracking is detected, prior to further flight, 
replace the cracked 15-5PH 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 fatigue cracking in the newly installed 
15-5PH fuse pin; in accordance with the procedures described in the 
alert service bulletin. Repeat this inspection thereafter at 
intervals not to exceed 3,500 flight cycles on the newly installed 
15-5PH fuse pin.
    (e) Fuse pins must be of the same type on the same strut. For 
example, a steel fuse pin having P/N 311N5067-1 may not be installed 
on the same strut that has a 15-5PH 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 
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.
    (h) The inspections and replacements shall be done in accordance 
with Boeing Service Bulletin 757-54A0019, Revision 5, dated March 
17, 1994, or Boeing Alert Service Bulletin 757-54A0019, Revision 6, 
dated July 18, 1997.
    (1) The incorporation by reference of Boeing Alert Service 
Bulletin 757-54A0019, Revision 6, dated July 18, 1997, was approved 
by the Director of the Federal Register in accordance with 5 U.S.C. 
552(a) and 1 CFR part 51.
    (2) The incorporation by reference of Boeing Service Bulletin 
757-54A0019, Revision 5, dated March 17, 1994, was approved 
previously by the Director of the Federal Register in accordance 
with 5 U.S.C. 552(a) and 1 CFR part 51 as of April 10, 1996 (61 FR 
9599, March 11, 1996).
    (3) 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.
    (i) This amendment becomes effective on September 17, 1997.

    Issued in Renton, Washington, on August 21, 1997.
Darrell M. Pederson,
Acting Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. 97-23176 Filed 8-29-97; 8:45 am]
BILLING CODE 4910-13-U

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