27008 Federal Register / Vol. 60, No. 98 / Monday, May 22, 1995 / Rules and Regulations

provided in paragraph (b) 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 prevent

multiple faults in the thrust reverser position

indication, and subsequent uncontrolled

reduction of engine power, accomplish the

following:

(a) Within 3,000 flight hours after the

effective date of this AD, modify the junction

box, connector backshells, and the electrical

harness assembly of the thrust reverser, in

accordance with Airbus Service Bulletin

A320–71–1011, dated November 17, 1993, or

Revision 1, dated June 27, 1994.

(b) 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,

Standardization Branch, ANM–113, 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, Standardization

Branch, ANM–113.

Note 2: Information concerning the

existence of approved alternative methods of

compliance with this AD, if any, may be

obtained from the Standardization Branch,

ANM–113.

(c) 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.

(d) The modification shall be done in

accordance with Airbus Service Bulletin

A320–71–1011, dated November 17, 1993; or

in accordance with Airbus Service Bulletin

A320–71–1011, Revision 1, dated June 27,

1994, which contains the following list of

effective pages:

Page No.

Revision

level

shown

on page

Date shown on

page

1, 4–6 ............. 1 ........... June 27, 1994.

2, 3, 7–11 ....... Original . Nov. 17, 1993.

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 Airbus Industrie, 1 Rond Point Maurice

Bellonte, 31707 Blagnac Cedex, France.

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.

(e) This amendment becomes effective on

June 21, 1995.

Issued in Renton, Washington, on May 9,

1995.

Darrell M. Pederson,

Acting Manager, Transport Airplane

Directorate, Aircraft Certification Service.

[FR Doc. 95–11908 Filed 5–19–95; 8:45 am]

BILLING CODE 4910–13–U

14 CFR Part 39

[Docket No. 94–NM–187–AD; Amendment

39–9233; AD 95–10–16]

Airworthiness Directives; Boeing

Model 747 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

series airplanes, that requires

modification of the nacelle strut and

wing structure, inspections and checks

to detect discrepancies, and correction

of discrepancies. This amendment is

prompted by the development of a

modification of the strut and wing

structure that improves the damage

tolerance capability and durability of

the strut-to-wing attachments, and

reduces reliance on inspections of those

attachments. The actions specified by

this AD are intended to prevent failure

of the strut and subsequent loss of the

engine.

DATES: Effective June 21, 1995.

The incorporation by reference of

certain publications listed in the

regulations is approved by the Director

of the Federal Register as of June 21,

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

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: Tim

Backman, Aerospace Engineer, Airframe

Branch, ANM–120S, FAA, Transport

Airplane Directorate, Seattle Aircraft

Certification Office, 1601 Lind Avenue,

SW., Renton, Washington 98055–4056;

telephone (206) 227–2776; 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 series airplanes was

published in the Federal Register on

December 21, 1994 (59 FR 65733). That

action proposed to require modification

of the nacelle strut and wing structure,

inspections and checks to detect

discrepancies in the adjacent structure,

and correction of discrepancies.

Interested persons have been afforded

an opportunity to participate in the

making of this amendment. Due

consideration has been given to the

comments received.

Revision of Descriptive Language

One commenter notes that the

description of the unsafe condition that

appeared in the Discussion section of

the preamble to the notice refers to ‘‘the

structural fail-safe capability of the

strut-to-wing attachment.’’ The

commenter states that this description is

inaccurate, since it implies that the

strut-to-wing attachment is inadequate.

The commenter suggests that a more

accurate description would be ‘‘damage

tolerance capability of the strut-to-wing

attachment.’’ The FAA acknowledges

that the commenter’s wording is more

accurate. The pertinent wording this

preamble to the final rule has been

revised to reflect this change.

Furthermore, the FAA considers the

new structure of the strut as meeting the

damage tolerance requirements of

amendment 45 of section 25.571,

‘‘Damage—tolerance and fatigue

evaluation of structure’’ of the Federal

Aviation Regulations (14 CFR 25.571,

amendment 45), which provides an

even higher level of safety than simply

fail-safe requirements.

One commenter provides further

information to describe the purpose of

the proposed modification of the nacelle

strut and wing structure. This

commenter suggests that the rule should

specify that the modification not only

significantly improves the load-carrying

and durability of the strut-to-wing

attachments, but ‘‘reduces the reliance

on non-routine inspections,’’ as well.

The FAA concurs with this suggestion

and has revised the Summary section of

the preamble to this final rule to include

wording relevant to this aspect.

One commenter provides clarification

of the description in the Explanation of

Service Information section of the

preamble to the proposal. That section

of the preamble described the various

terminating actions specified in the

service bulletins listed in paragraph I.C.,

Table 2, Prior or Concurrent Service
Federal Register / Vol. 60, No. 98 / Monday, May 22, 1995 / Rules and Regulations 27009

Bulletins,’’ on page 13 of Boeing Alert

Service Bulletin 747–54A2159, dated

November 3, 1994 (which was

referenced in the notice as the

appropriate source of service

information). The commenter notes that

it is replacement of the ‘‘diagonal brace

strut lower spar fitting’’ which is

specified as a terminating action in that

listing. The notice, however,

incompletely described that particular

terminating action as the replacement of

‘‘the diagonal brace strut and wing and

attachment fittings.’’ The FAA

acknowledges that the commenter

provides a more complete description of

that terminating action. However, since

the Explanation of Service Information

section is not restated in this rule, no

change to the final rule is necessary.

Clarification of Note 1

One commenter requests that Note 1

of the proposal be clarified since it is

too vague to determine exactly when

FAA approval of alternative methods of

compliance (AMOC) is necessary. The

FAA concurs. Although every effort is

made to keep the language simple and

clear, it is apparent that some additional

explanation is necessary to clarify the

intent of Note 1. Performance of the

requirements of this final rule is

‘‘affected’’ if an operator is unable to

perform those requirements in the

manner described in this AD. For

example, if an AD requires a visual

inspection in accordance with a certain

service bulletin, and the operator cannot

perform that inspection because of the

placement of a repair doubler over the

structure to be inspected, then

‘‘performance of the AD is affected.’’

In addition, performance of the

requirements is ‘‘affected’’ if it is

physically possible to perform the

requirements, but the results achieved

are different from those specified in the

AD. For example, if the AD requires a

non-destructive test (NDT) inspection in

accordance with a certain service

bulletin, and the operator is able to

move the NDT probe over the specified

area in the specified manner, but the

results are either meaningless or

inaccurate because of a repair doubler

placed over that area, then

‘‘performance of the AD is affected.’’

While Note 1 itself is not capable of

addressing every possible situation,

‘‘affected’’ is normally an easy standard

to apply: either it is possible to perform

the requirements as specified in the AD

and achieve the specified results, or it

is not possible. Therefore, if the

requirements of this AD cannot be

performed, then operators must submit

a request for an approval of an AMOC

from the FAA, in accordance with the

provision of paragraph (d) of this final

rule.

Accomplishment of any modification

requirement of an AD, such as the

modification of the nacelle strut and

wing structure required by this final

rule, does not ‘‘affect performance of the

AD;’’ it is performance of the AD. Every

AD includes a provision, with which

operators are familiar, that states,

‘‘Compliance required as indicated,

unless accomplished previously .’’ If an

operator performs such a requirement

before the AD is issued, the FAA is

confident that the operator will

recognize that it has already complied

with the AD and no further action

(including obtaining approval of an

AMOC) is required. This is consistent

with current law and practice, which

Note 1 is not intended to change.

Compliance Time for Modification

One commenter requests that the

compliance times of proposed

paragraph (a), which requires

modification of the nacelle strut and

wing structure, be extended by 4

months. The commenter notes that a 4-

month extension of the compliance

times would coincide with the times

recommended in the referenced Boeing

Alert Service Bulletin 747–54A2159 for

that modification. Furthermore, the

commenter states that the referenced

alert service bulletin contains numerous

errors, and a 4-month extension would

allow the manufacturer sufficient time

to publish a revision to that alert service

bulletin to correct those errors.

The FAA does not concur with the

commenter’s request. In developing an

appropriate compliance time for this

action, the FAA considered not only the

degree of urgency associated with

addressing the subject unsafe condition,

but the manufacturer’s recommendation

as to an appropriate compliance time,

the availability of required parts, and

the practical aspect of installing the

required modification within a

maximum interval of time allowable for

all affected airplanes to continue to

operate without compromising safety.

Further, the FAA took into account the

3-year and 5-year compliance times

recommended by the manufacturer, as

well as the number of days required for

the rulemaking process; in

consideration of these factors, the FAA

finds that 32 months and 56 months

after the effective date of this final rule

will fall approximately at the same time

for compliance as recommended by the

manufacturer. Furthermore, the FAA

does not consider that delaying this

action until after the release of the

manufacturer’s planned revision to the

alert service bulletin is warranted, since

the changes in the revised alert service

bulletin are mostly minor and clarifying

in nature and do not affect the

procedures to accomplish the

modification of the nacelle strut and

wing structure.

However, under the provisions of

paragraph (d) of the final rule, any

operator may submit requests for

adjustments to the compliance time

along with data demonstrating that such

requests will not compromise safety. In

evaluating such requests for adjustments

to the compliance time, the FAA will

closely examine the operator’s

explanation of why an extension is

needed. The FAA will also consider the

operator’s good faith attempt at

complying within the compliance times

contained in this final rule, which can

be demonstrated by accomplishing the

modification on a significant percentage

of the airplanes in the operator’s fleet

prior to submitting a request for

adjustments to the compliance times.

The FAA will take into consideration

the number of airplanes in the

operator’s fleet on which the

modification has been accomplished

and the number of unmodified airplanes

remaining in the operator’s fleet.

Additionally, the operator may be asked

to submit a schedule for accomplishing

the modification on the airplanes

remaining in its fleet.

Calculation of Age of Affected

Airplanes

Several commenters request that the

age of the airplanes be measured as of

the date of issuance of Boeing Alert

Service Bulletin 747–54A2159, rather

than as of the effective date of the AD,

as proposed in paragraphs (a)(1) and

(a)(2). Some of these commenters state

that this change would coincide with

the thresholds recommended in that

alert service bulletin. One of these

commenters notes that this change

would move three of the airplanes in its

fleet from the applicability provisions of

paragraph (a)(2) (which would allow it

32 months) to paragraph (a)(1) (which

would allow it the maximum amount of

time of 56 months) to accomplish the

modification of the nacelle strut and

wing structure.

The FAA concurs. As discussed

above, the FAA’s intent was to align the

compliance times as closely as possible

with those recommended by the

manufacturer in the referenced alert

service bulletin. Therefore, paragraphs

(a)(1) and (a)(2) of the final rule have

been revised to specify that the age of

the airplane is to be measured as of

November 3, 1994, which is the date of

issuance of the alert service bulletin.
27010 Federal Register / Vol. 60, No. 98 / Monday, May 22, 1995 / Rules and Regulations

Service Bulletins Listed in Note 2

Several commenters request that Note

2, which follows proposed paragraph

(a)(2)(i), be revised either to exclude or

to add service bulletins to the list of

bulletins that describe modifications

that must be accomplished in order to

gain the maximum time allowable (56

months) in which to accomplish the

modification of the nacelle strut and

wing structure. One of these

commenters requests that the list be

revised to exclude all Boeing service

bulletins, with the exception of the

following two:

1. Boeing Alert Service Bulletin 747–

54A2155, dated September 23, 1993,

which specifies inspection of the

midspar fittings; and

2. Boeing Alert Service Bulletin 747–

54A2152, Revision 2, dated September

16, 1993, which specifies installation of

(third generation fuse pins) upper link

diagonal brace and midspar fuse pins

[required by AD 93–17–07, amendment

39–8678 (58 FR 45827, August 31,

1993)].

This commenter states that, if the

other service bulletins are excluded

from the list, safety would not be

compromised since various repetitive

inspections already are required by

numerous other AD’s that are intended

to ensure the structural integrity of the

strut-to-wing attachments and the failsafe capability of the strut structure.

The FAA does not concur. As stated

in the preamble to the proposal, one of

the purposes of this rulemaking action

is to reduce reliance on inspections of

the strut-to-wing attachments. The FAA

has determined that long term

continued operational safety will be

better assured by actual modification of

the airframe to remove the source of the

problem, rather than by repetitive

inspections. Long term inspections may

not be providing the degree of safety

assurance necessary for the transport

airplane fleet. This, coupled with a

better understanding of the human

factors associated with numerous

repetitive inspections, has led the FAA

to consider placing less emphasis on

special procedures and more emphasis

on design improvements. The

modification requirement of this final

rule is in consonance with these

considerations.

Modification of Engine Mounts

Two commenters request that the list

of service bulletins be revised to

exclude Boeing Alert Service Bulletin

747–71A2269, Revision 1, dated July 7,

1994, which describes procedures for

modification of the engine mounts.

These commenters state that

modification of the engine mounts is an

entirely separate subject that is not

related to the unsafe condition

addressed by the proposed rule. One of

these commenters believes that

modification of the engine mounts is

addressed more appropriately in AD 94–

10–05.

The FAA does not concur. The FAA

finds that the unsafe conditions

addressed in both AD 94–10–05

[amendment 39–8912 (59 FR 25288,

May 16, 1994)] and this AD are closely

related. AD 94–10–05 requires

replacement of the existing nut with a

new castellated nut, and references

Boeing Alert Service Bulletin 747–

71A2269 as the appropriate source of

service information. That AD addresses

migration of the bolts out of the engine

lug joint, which may lead to loss of the

engine from the strut. Therefore, the

FAA has determined that accomplishing

the requirements of AD 94–10–05, prior

to accomplishing the requirements of

this final rule, reduces reliance on

repetitive inspections, and decreases the

likelihood of the engine separating from

the airplane.

Replacement of Diagonal Braces

Certain commenters request that the

list of service bulletins be revised to

exclude Boeing Service Bulletin 747–

54–2123, which describes procedures

for replacement of the diagonal braces.

One of these commenters notes that it

has found no significant discrepancies

on any of the airplanes in its fleet while

performing the inspections of this area

that are required by AD 90–20–20.

Therefore, this commenter contends that

replacement of the diagonal braces prior

to accomplishment of the proposed

modification of nacelle strut and wing

structure is unnecessary if the brace lugs

have been modified in accordance with

Boeing Service Bulletin 747–54–2126

and the diagonal braces have been

inspected in accordance with Boeing

Service Bulletin 747–54–2123.

Further, these commenters contend

that temporarily replacing the diagonal

braces is cost-prohibitive: one of these

commenters estimates the cost at

$50,000 per airplane, while the other

commenter estimates the cost at $60,000

per airplane. These commenters also

point out that these costs are

unreasonable, especially in light of the

fact that the diagonal braces must be

replaced once more as part of the

proposed modification of the nacelle

strut and wing structure.

Additionally, one of these

commenters suggests that there is

potential for a parts availability problem

if all operators choose to replace these

diagonal braces. Consequently, these

commenters request the removal of

Boeing Service Bulletin 747–54–2123

from the list of service bulletins.

The FAA does not concur. In

addressing these particular comments,

the FAA points out that there are three

types of diagonal braces currently

available:

1. ‘‘Type 1 Braces’’ have been

addressed previously by two AD’s:

—AD 89–07–15, amendment 39–6167

(54 FR 11693, March 22, 1989),

references Boeing Service Bulletin

747–54–2126. That AD requires the

lugs of Type 1 Braces to ultrasonically

inspected every 1,000 flight cycles.

That AD was prompted by reports of

cracking in the lugs that had initiated

at corrosion pits in the lug bores and

was propagated by fatigue.

Terminating action for those

inspections consists of removing

bushings, oversizing of the hole to

eliminate corrosion, and installing

high interference fit bushings. There

have been reports of 11 cracked braces

found during the inspections required

by this AD.

—AD 90–20–20, amendment 39–6725

(55 FR 37859, September 14, 1990),

references Boeing Service Bulletin

747–54–2123. That AD requires Type

1 Braces to be either visually

inspected every 1,000 flight cycles, or

ultrasonically inspected every 3,000

flight cycles; any cracked brace is

required to be replaced with either a

serviceable Type 1 Brace or a ‘‘Type

2 Brace’’ (see below). That AD was

prompted by the finding of a

completely separated brace in service.

Separation was attributed to

circumferential cracks initiating from

a tool mark in the brace’s inner

surface. (There also has been one

additional report of a crack found, but

separation did not occur.)

Terminating action for these

inspections consists of replacing Type

1 Braces with ‘‘Type 2 Braces.’’

2. ‘‘Type 2 Braces’’ are not susceptible

to the cracking conditions of the brace’s

inner surface (as was found on the Type

1 Braces) because of their revised

internal and external surface finish.

Additionally, during production, the

lugs associated with these Type 2 Braces

were modified in accordance with the

terminating action specified in AD 89–

07–15; with this modification, the

ultrasonic inspections required by that

AD are not necessary on this type of

brace.

3. ‘‘Type 3 Braces’’ are those that are

required to be installed as part of the

full strut modification program on

which this AD is based. These braces

are optimal because they have increased
Federal Register / Vol. 60, No. 98 / Monday, May 22, 1995 / Rules and Regulations 27011

strength and are not susceptible to the

type of cracking found in Type 1 Braces.

The FAA points out that this final

rule provides operators 32 months in

which to accomplish the full strut

modification if Type 1 Braces are

currently installed. Likewise, this final

rule provides operators 56 months in

which to accomplish the full strut

modification if Type 2 Braces are

currently installed, or if Type 2 Braces

are installed within 32 months (and the

additional modifications specified in

the service bulletins listed in Note 2 are

accomplished, as well).

Optimally, the FAA would prefer that

all affected airplanes be modified within

32 months. However, when developing

the compliance time for this AD, the

FAA recognized the high costs (down

time) that would be imposed on

operators when accomplishing the full

strut modification program. In so doing,

the FAA looked for ways to lessen that

economic burden, while still ensuring

that a higher level of safety would exist

than that currently provided. Based on

analyses following relevant accidents

involving failure of the strut-to-wing

attachment and subsequent separation

of the engine from the airplane during

flight, the FAA determined that the

Type 1 Brace, with its extensive history

of service difficulties, is not adequate

for long term assurance of safety. Even

with repetitive inspections, these Type

1 Braces have inadequate damage

tolerance. In light of this and the

catastrophic consequences of fatigue

cracking and/or corrosion in the strutto-wing attachments, the FAA has

determined that Type 1 Braces must be

removed from the fleet sooner than the

other braces that have a better service

record.

As for the costs of replacement of the

braces, the FAA finds that the figures

quoted by the commenters need

clarification. The manufacturer has

provided the following figures relative

to costs:

—Installation of Type 2 Braces requires

from 88 to 116 work hours per

airplane, at an average labor rate of

$60 per work hour. The cost of each

brace is, at most, $13,282 (in 1990

dollars) per brace; there are 4 braces

on each airplane. Using these figures,

the cost to install four Type 2 Braces

on an airplane would be, at most,

$53,128 in parts and $6,960 in labor

charges.

—Parts and labor costs for the

installation of Type 3 Braces, as part

of the full strut modification kit, will

be absorbed by the manufacturer.

Regardless of these costs, the FAA has

determined that the safety benefit

justifiably outweighs the economic cost

of replacing diagonal braces. Further,

the replacement of the Type 1 Brace

with a Type 2 Brace is required only if

the operator wants the longer

compliance time of 56 months for

accomplishing the full strut

modification. This extended compliance

time lessens the economic impact on

operators in terms of the costs of special

scheduling and down time. The FAA

notes that certain operators have already

accomplished the full strut

modification; these operators have

found it to be more cost effective to do

so, since they incur no charges for parts.

A full discussion of the cost impact of

this rule on U.S. operators is discussed

later in this preamble.

As for the availability of parts, the

manufacturer has advised that there

would be a problem with parts

availability only if many of the affected

operators elected to install the Type 2

Braces as an interim measure. However,

as a matter of fact, both the

manufacturer and the FAA expect that

many operators will not elect to do this,

but will opt to install the full strut

modification, which includes the Type

3 Brace. The manufacturer has indicated

that there are ample numbers of the full

strut modification kits available.

Rework of Midspar Fitting Lugs

One commenter requests that the list

of service bulletins be revised to add

Boeing Service Bulletin 747–54–2100 as

an alternative to Boeing Alert Service

Bulletin 747–54A2152 (original or

Revision 1). The commenter believes

that procedures for rework of the

midspar fitting lugs, which is described

Service Bulletin 747–54–2100, is

equivalent to that specified in Service

Bulletin 747–54A2152.

The FAA does not concur, since it

does not find that the two procedures

described in the referenced service

bulletins are equivalent. For example,

the rework procedure described in

Boeing Service Bulletin 747–54–2100

does not include an ‘‘insurance’’ cut

that is included in the rework procedure

described in Boeing Alert Service

Bulletin 747–54A2152 (original issue

and Revision 1). Further, Revision 2 of

Boeing Alert Service Bulletin 747–

54A2152 has refined the procedure even

further: this revision [which is

referenced in paragraphs (a)(2)(iii) and

(a)(2)(iv) of the final rule] describes a

magnetic particle inspection to detect

cracking of the midspar fitting lugs.

Consequently, the FAA finds the

procedures described in Revision 2 of

Boeing Alert Service Bulletin 747–

54A2152 to be significantly better in

detecting and removing undetected

cracks than those described in the

earlier versions of that alert service

bulletin or in Boeing Service Bulletin

747–54–2100.

Clarification of Requirements for

Modified Airplanes

One commenter requests that the

requirements of proposed paragraph

(a)(2)(i) be clarified. The commenter

notes that Boeing Service Bulletin 747–

54–2062, Revision 5, which is

referenced in the list of modifications

under Note 2 of the proposal, must be

accomplished to obtain the maximum

amount of time allowable (56 months)

in which to accomplish the proposed

modification of the nacelle strut and

wing structure. (These modifications are

described in the service bulletins listed

in paragraph I.D., ‘‘Compliance,’’ on

page 17 of Boeing Alert Service Bulletin

747–54A2159, dated November 3, 1994.)

However, the commenter notes that

Revision 7 of that service bulletin,

which is referenced in the list of

terminating actions for the proposed

rule, must be accomplished prior to or

concurrently with the proposed

modification of the nacelle strut and

wing structure. (These terminating

actions are described in the service

bulletins listed in paragraph I.C., Table

2, ‘‘Prior or Concurrent Service

Bulletins,’’ on page 13 of Boeing Alert

Service Bulletin 747–54A2159, dated

November 3, 1994.)

The FAA concurs that clarification is

warranted. Although Note 2 following

paragraph (a)(2)(i) clearly states that

subsequent revisions of the service

bulletins ‘‘are acceptable and preferred

for accomplishment of the

modifications,’’ a footnote has been

added to the final rule following that list

to point out specifically that additional

actions described in a subsequent

revision of that service bulletin are

required to be accomplished prior to or

concurrently with the modification of

the nacelle strut and wing structure,

required by paragraph (a) of the final

rule.

Shortening the Compliance Times of

Other Related AD’s

One commenter considers it

inappropriate to use the proposed rule

to shorten the 4,000-landing compliance

time of AD 87–04–13 R1, amendment

39–5546 (52 FR 3421, February 4, 1987).

That AD requires repetitive ultrasonic

inspections of the fastener holes of the

midspar fittings. The commenter states

that, if the 1,000-landing compliance

time specified in proposed paragraphs

(a)(2)(ii)(B) and (a)(2)(iv)(B) is

appropriate to accomplish the

requirements of the proposal, then it
27012 Federal Register / Vol. 60, No. 98 / Monday, May 22, 1995 / Rules and Regulations

should also be appropriate for

accomplishing the inspection

requirements of AD 87–04–13 R1.

Similarly, the commenter states that it

is equally inappropriate to use the

proposal to shorten the 5,000-landing

compliance time of AD 93–17–07. That

AD requires repetitive ultrasonic

inspections of the inboard midspar

fitting lugs and references Boeing Alert

Service Bulletin 747–54A2152 (original

issue or Revision 1) as the appropriate

source of service information. The

commenter states that if the 2,500-

landing compliance time specified in

proposed paragraphs (a)(2)(iii)(B) and

(a)(2)(iv)(C) is appropriate to accomplish

the requirements of the proposal, then it

should also be appropriate for

accomplishing the requirements of AD

93–17–07. The commenter believes that

the appropriate means to effect a change

to the compliance times of AD 87–04–

13 R1 and AD 93–17–07 should be by

revising those AD’s.

The FAA concurs with the

commenter’s observations.

As for AD 87–04–13 R1, the FAA will

consider re-examining its compliance

time to determine if a revision to it is

appropriate. However, any revision to

that AD would be proposed as a

separate rulemaking action. Further, in

re-examining the compliance times of

proposed paragraphs (a)(2)(ii)(B),

(a)(2)(iii)(B), (a)(2)(iv)(B), and

(a)(2)(iv)(C), the FAA finds that

operators may not be afforded the

opportunity to obtain the maximum

amount of time allowable to accomplish

the modification of the nacelle strut and

wing structure if the ‘‘shortened’’

compliance times of AD 87–04–13 R1

(from 4,000 landings to 1,000 landings)

and AD 93–17–07 (from 5,000 landings

or 5 years to 2,500 landings or 3 years)

have already been exceeded. Therefore,

the FAA has revised those paragraphs of

the final rule to include a ‘‘grace

period.’’

As for AD 93–17–07, Note 4 of this

final rule explains that the compliance

time of 2,500 landings or 3 years since

rework of the lugs, whichever occurs

earlier, coincides with the compliance

time recommended in Revision 2 of

Boeing Alert Service Bulletin 747–

54A2152, dated September 15, 1993,

which the FAA has approved as an

alternative method of compliance for

accomplishment of the requirements of

AD 93–17–07. However, the FAA will

consider re-examining the compliance

time of AD 93–17–07 to determine if

further rulemaking is warranted. In the

interim, the compliance time of

paragraphs (a)(2)(iii)(B) and (a)(2)(iv)(C)

of this final rule will remain unchanged.

Any revision to the compliance time of

AD 93–17–07, if deemed necessary,

must be proposed in a separate

rulemaking action.

Inspection Interval for the Inboard

Midspar Fitting Lugs

One commenter requests that

proposed paragraph (a)(2)(iii)(B) be

revised to require the reduced 2,500-

cycle compliance time only for the

ultrasonic inspection of the inboard

midspar fitting lugs. This change would

make this requirement consistent with

that of AD 93–17–07, amendment 39–

8678 (58 FR 45827, August 31, 1993).

This commenter also notes that

outboard struts do not have spring

beams.

The FAA concurs. Further, the FAA

finds that this change is also applicable

to paragraph (a)(2)(iv)(C) of the final

rule. Therefore, paragraphs (a)(2)(iii)(B)

and (a)(2)(iv)(C) of the final rule have

been revised accordingly.

Correction of Typographical Error in

Note 6

Three commenters request that a

typographical error that appeared in

Note 6 [which follows proposed

paragraph (a)(2)(v)] be corrected. The

commenters note that the Table in Note

6 erroneously referred to Boeing Alert

Service Bulletin 747–54A2159. The

correct reference should have been

Boeing Alert Service Bulletin 747–

54A2152, as it correctly appeared in

paragraphs (a)(2)(iii) and (a)(2)(iv) of the

proposal. The FAA concurs and has

made the correction accordingly.

Additionally, the FAA has reformatted

the Table in Note 6 for purposes of

clarification: the column headed

‘‘Revision Level’’ has been removed,

and the revision level of the service

bulletin has been inserted adjacent to

the service bulletin number itself.

Requirements Redundant to Part 121

One commenter requests that

proposed paragraph (b) be deleted since

the proposed inspection and repair of

components (referenced in Notes 8, 9,

and 10 of the Accomplishment

Instructions on page 150 of Boeing Alert

Service Bulletin 747–54A2159, dated

November 3, 1994) are redundant to the

requirements of part 121 of the Federal

Aviation Regulations (14 CFR 121).

Furthermore, the commenter believes

that the proposed torque check of the

fasteners of the diagonal brace fittings

(referenced in Note 11 of the alert

service bulletin) should be incorporated

as part of the Accomplishment

Instructions of the Boeing Alert Service

Bulletin 747–54A2159, rather than as

merely a Note in the Accomplishment

Instructions.

The FAA does not concur with the

commenter that the requirements of

paragraph (b) should be deleted from

the final rule. According to section 39.1

of the Federal Aviation Regulations (14

CFR 39.1), the issuance of an AD is

based on the finding that an unsafe

condition exists or is likely to develop

in aircraft of a particular type design.

Further, it is within the FAA’s authority

to issue an AD to require actions to

address unsafe conditions that are not

otherwise being addressed (or addressed

adequately) by normal maintenance

procedures. The FAA points out that

fatigue cracking and corrosion in the

strut-to-wing attachments have resulted

in several incidents and catastrophic

accidents. Although 14 CFR 121

addresses damage found on components

during other maintenance activities, the

FAA has determined that the

catastrophic consequences of the unsafe

condition are such that reiterating the

necessity of performing inspections and

repairs when any damage or corrosion is

found while performing the

modification of the nacelle strut and

wing structure is warranted and

necessary. The AD is the appropriate

vehicle for mandating such actions.

AD’s Terminated by This Final Rule

One commenter notes that the AD’s

listed in proposed paragraph (c) as those

that are terminated once the actions of

the proposal are accomplished, differs

from those listed in Table 1 of Boeing

Alert Service Bulletin 747–54A2159.

The FAA concurs that a difference

does exist. However, several of the AD’s

included in the listing contained in the

Boeing alert service bulletin have been

superseded by new AD’s. The FAA

points out that, when an AD is

superseded, it is deleted from the

system, and as such, no longer exists,

since it has been replaced with a ‘‘new’’

AD that has a new (different) AD

number and amendment number. The

FAA considers that referencing

nonexistent AD’s would serve no

meaningful purpose, and may result in

some confusion for affected operators.

Consequently, no change to paragraph

(c) of the final rule is necessary.

Clarification of Cost Estimate

Information

Two commenters request that the cost

estimate be revised to include the cost

of out-of-service time for each aircraft

during the time that the modification is

accomplished, and the additional fuel

costs that would be incurred due to the

additional weight added to each aircraft

by the modification hardware.

The FAA does not concur that a

revision is necessary. The appropriate
Federal Register / Vol. 60, No. 98 / Monday, May 22, 1995 / Rules and Regulations 27013

number of hours required to accomplish

the required actions, specified as

between 7,700 and 8,892 work hours in

the economic impact information,

below, was developed with data

provided by the manufacturer. This

number represents the time required to

gain access, remove parts, inspect,

modify, install, and close up. The cost

analysis in AD rulemaking actions

typically does not include out-of-service

time for each aircraft or additional fuel

costs, as was suggested by the

commenter. These costs would be

impossible to calculate accurately due

the differences in out-of-service time for

each operator. Furthermore, the increase

in fuel costs due to the weight added by

the modification, would vary greatly

from operator to operator, depending

upon airplane utilization.

The Air Transport Association of

America (ATA) requests that the FAA

include costs ‘‘beyond just parts and

labor costs’’ when calculating the

estimated costs to accomplish the

proposed actions. The ATA points out

that the FAA should consider such costs

to avoid requiring actions that the ATA

considers inconsequential.

The FAA does not concur. Contrary to

the ATA’s assertion, in establishing the

requirements of all AD’s, the FAA does

consider cost impact to operators

beyond the estimates of parts and labor

costs contained in AD preambles. For

example, where safety considerations

allow, the FAA attempts to impose

compliance times that generally

coincide with operators’ maintenance

schedules. However, because operators’

schedules vary substantially, the FAA is

unable to accommodate every operator’s

optimal scheduling in each AD. Each

AD does allow individual operators to

obtain approval for extensions of

compliance times, based on a showing

that the extension will not affect safety

adversely. Therefore, the FAA does not

consider it appropriate to attribute to

the AD, the costs associated with the

type of special scheduling that might

otherwise be required.

Furthermore, because the FAA

generally attempts to impose

compliance times that coincide with

operators’ scheduled maintenance, the

FAA considers it inappropriate to

attribute the costs associated with

aircraft ‘‘downtime’’ to the cost of the

AD, because, normally, compliance with

the AD will not necessitate any

additional downtime beyond that of a

regularly scheduled maintenance hold.

Even if, in some cases, additional

downtime is necessary for some

airplanes, the FAA does not possess

sufficient information to evaluate the

number of airplanes that may be so

affected or the amount of additional

downtime that may be required.

Therefore, attempting to estimate such

costs would be futile.

The FAA points out that this AD is an

excellent example of the fact that costs

to operators are fully considered

beginning at the earliest possible stages

of AD development. In this case, the

service bulletin that is referenced in this

final rule was developed by Boeing only

after extensive and detailed

consultations with large numbers of

operators of Model 747’s. The

compliance times and various optional

means of compliance presented in this

AD are based on those consultations,

and were developed in order to

minimize the economic impacts on

operators to the extent possible

consistent with the service bulletin’s

and this AD’s safety objectives.

Therefore, the costs that the ATA asserts

were not considered by the FAA have,

in fact, been a major consideration

throughout this AD process; the fact that

the FAA has not attempted to quantify

speculative costs does not diminish the

extent of this consideration.

Conclusion

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 with the changes

previously described. The FAA has

determined that these changes will

neither increase the economic burden

on any operator nor increase the scope

of the AD.

Cost Impact

There are approximately 600 Model

747 series airplanes equipped with Pratt

& Whitney Model JT9D series engines

(excluding Model JT9D–70 engines) of

the affected design in the worldwide

fleet. The FAA estimates that 146

airplanes of U.S. registry will be affected

by this AD.

The full strut modification required

by this AD may take as many as 7,700

to 8,892 work hours to accomplish,

depending upon the configuration of the

airplane. The manufacturer will incur

the cost of labor, on a pro-rated basis,

with 20 years being the expected life of

these airplanes. The total cost impact of

this AD on U.S. operators is based on

the median age for the fleet of Model

747 series airplanes equipped with Pratt

& Whitney Model JT9D series engines,

which is estimated to be 15 years. The

average labor rate is estimated to be $60

per work hour. Required parts will be

supplied by the manufacturer at no cost

to the operator. Based on these figures,

the cost impact of this proposal on U.S.

operators is estimated to be between

$50,589,000 ($346,500 per airplane) and

$58,420,440 ($400,140 per airplane).

This cost impact figure does not

reflect the cost of the terminating

actions described in the service

bulletins listed in paragraph I.C., Table

2, ‘‘Prior or Concurrent Service

Bulletins,’’ on page 13 of Boeing Alert

Service Bulletin 747–54A2159, dated

November 3, 1994, that are required to

be accomplished prior to or

concurrently with the modification of

the nacelle strut and wing structure.

Since some operators may have

accomplished certain modifications on

some or all of the airplanes in its fleet,

while other operators may not have

accomplished any of the modifications

on any of the airplanes in its fleet, the

FAA is unable to provide a reasonable

estimate of the cost of accomplishing

the terminating actions described in the

service bulletins listed in Table 2 of the

Boeing alert service bulletin.

The 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. However, the

FAA is aware that some operators have

already installed the strut modification

that is required by this AD; therefore,

the future economic cost impact of this

rule on U.S. operators is reduced by that

amount.

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, 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 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-
27014 Federal Register / Vol. 60, No. 98 / Monday, May 22, 1995 / Rules and Regulations

beneficial. When the FAA, as in this

proposed AD, makes a finding of an

unsafe condition, this means that the

original cost-beneficial level of safety is

no longer being achieved and that the

required 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 AD would be redundant

and unnecessary.

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.

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:

95–10–16 Boeing: Amendment 39–9233.

Docket 94–NM–187–AD.

Applicability: Model 747 series airplanes

having line positions 001 through 814

inclusive, 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) 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 prevent failure of the strut and

subsequent loss of the engine, accomplish the

following:

(a) Accomplish the modification of the

nacelle strut and wing structure in

accordance with Boeing Alert Service

Bulletin 747–54A2159, dated November 3,

1994, at the time specified in either

paragraph (a)(1) or (a)(2) of this AD, as

applicable. All of the terminating actions

described in the service bulletins listed in

paragraph I.C., Table 2, ‘‘Prior or Concurrent

Service Bulletins,’’ on page 13 of Boeing

Alert Service Bulletin 747–54A2159, dated

November 3, 1994, must be accomplished in

accordance with those service bulletins prior

to or concurrently with the accomplishment

of the modification of the nacelle strut and

wing structure required by this paragraph.

(1) For airplanes that are younger than 15

years as of November 3, 1994, within 56

months after the effective date of this AD,

accomplish the modification.

(2) For airplanes that are 15 years or older

as of November 3, 1994, accomplish the

modification, and other required actions, at

the time specified in paragraph (a)(2)(i),

(a)(2)(ii), (a)(2)(iii), (a)(2)(iv), or (a)(2)(v) of

this AD, as applicable.

(i) For airplanes on which all of the

modifications described in the service

bulletins referenced by paragraph I.D.,

‘‘Compliance,’’ on page 17 of Boeing Alert

Service Bulletin 747–54A2159, dated

November 3, 1994, have been accomplished:

Within 56 months after the effective date of

this AD, accomplish the modification of the

nacelle strut and wing structure and perform

the inspections of the adjacent structure that

has not been replaced by the modification.

Note 2: Paragraph I.D., ‘‘Compliance,’’ on

page 17 of Boeing Alert Service Bulletin 747–

54A2159, dated November 3, 1994,

references the following Boeing service

bulletins. Subsequent revisions of the

following service bulletins are acceptable and

preferred for accomplishment of the

modifications described therein:

Service

bulletin No.

Revision

level Date

747–54–2027 1 ........... February 23,

1973.

747–54–2030 Initial release.February 23,

1973.

* 747–54–

2062.

5 ........... June 1, 1984.

747–54A2069 6 ........... October 22, 1982.

747–54–2118 Initial release.July 25, 1986.

747–54–2123 1 ........... March 1, 1990.

747–54A2151 Initial release.October 6, 1992.

747–54A2152 2 ........... September 16,

1993.

747–54A2155 Initial release.September 23,

1993.

747–57A2235 Initial release.June 27, 1986.

747–71A2269 1 ........... July 7, 1994.

*AD 79–17–07, amendment 39–3533, requires inspection of the strut-to-diagonal brace

fittings, which may be terminated by replacing

the aluminum fittings with steel fittings in accordance with Revision 1 (or subsequent revisions) of Boeing Service Bulletin 747–54–

2062. Revision 7 of this service bulletin (referenced in paragraph I.C., Table 2, ‘‘Prior or

Concurrent Service Bulletins,’’ on page 13 of

Boeing Alert Service Bulletin 747–54A2159,

dated November 3, 1994) specifies the replacement of aluminum fittings with steel fittings and sealing the gap between the steel

fitting and the closure web.

(ii) For airplanes on which all of the

modifications described in the service

bulletins referenced by paragraph I.D.,

‘‘Compliance,’’ on page 17 of Boeing Alert

Service Bulletin 747–54A2159, dated

November 3, 1994, have been accomplished,

excluding the modification described in

Boeing Service Bulletin 747–54–2118, dated

July 25, 1986:

(A) Within 56 months after the effective

date of this AD, accomplish the modification

of the nacelle strut and wing structure and

perform the inspections of the adjacent

structure that has not been replaced by the

modification.

(B) Repeat the ultrasonic inspections to

detect cracking of the aft-most two fastener

holes in both strut midspar fittings on the

inboard and outboard nacelle struts, as

required by AD 87–04–13 R1, amendment

39–5546, within 4,000 landings following the

immediately preceding inspection performed

in accordance with AD 87–04–13 R1 or

within 1,000 landings after the effective date

of this AD, whichever occurs earlier, in

accordance with Boeing Service Bulletin

747–54–2118, dated July 25, 1986, until the

modification of the nacelle strut and wing

structure is accomplished in accordance with

Boeing Alert Service Bulletin 747–54A2159,

dated November 3, 1994. Repeat this
Federal Register / Vol. 60, No. 98 / Monday, May 22, 1995 / Rules and Regulations 27015

inspection thereafter at intervals not to

exceed 1,000 landings.

Note 3: These inspections of the fastener

holes are required by AD 87–04–13 R1,

amendment 39–5546, at 4,000-landing

intervals. Accomplishment of the inspections

of the fastener holes, as required by this

paragraph at 1,000-landing intervals,

constitutes compliance with paragraph A. of

AD 87–04–13 R1.

(iii) For airplanes on which all of the

modifications described in the service

bulletins referenced by paragraph I.D.,

‘‘Compliance,’’ on page 17 of Boeing Alert

Service Bulletin 747–54A2159, dated

November 3, 1994, have been accomplished;

except that rework of the midspar fitting lugs

was accomplished in accordance with Boeing

Alert Service Bulletin 747–54A2152, dated

December 23, 1992, or Revision 1, dated July

15, 1993, instead of Revision 2, dated

September 16, 1993:

(A) Within 56 months after the effective

date of this AD, accomplish the modification

of the nacelle strut and wing structure and

perform the inspections of the adjacent

structure that has not been replaced by the

modification.

(B) Prior to the accumulation of 3 years

since rework of the inboard lugs, or within

6 months after the effective date of this AD,

whichever occurs later, perform an ultrasonic

inspection to detect cracking of the midspar

fitting lugs of the inboard struts, in

accordance with Boeing Alert Service

Bulletin 747–54A2152, Revision 2, dated

September 16, 1993. Repeat this inspection

thereafter as required by AD 93–17–07.

Note 4: This ultrasonic inspection is

required by AD 93–17–07, amendment 39–

8678, to be performed prior to the

accumulation of 5,000 landings or 5 years

since accomplishment of the rework of the

lugs, whichever occurs earlier, in accordance

with Boeing Alert Service Bulletin 747–

54A2152, dated December 23, 1992, or

Revision 1, dated July 15, 1993. Repetitive

inspections are required by that AD at

intervals not to exceed 500 landings for

inboard struts and 1,000 landings for

outboard struts. Since the issuance of that

AD, the FAA has approved Revision 2 of

Boeing Alert Service Bulletin 747–54A2152,

dated September 16, 1993, as an alternative

method of compliance for accomplishment of

these ultrasonic inspections and rework of

the lugs. Revision 2 of the alert service

bulletin recommends that inboard lugs that

have been reworked in accordance with the

original issue or Revision 1 of the alert

service bulletin be inspected prior to the

accumulation of 2,500 landings or 3 years

since accomplishment of the rework of the

lugs, whichever occurs earlier. Therefore,

accomplishment of ultrasonic inspections

prior to the accumulation of 2,500 landings

or 3 years since accomplishment of rework of

the lugs, whichever occurs earlier, and

thereafter as required by AD 93–17–07,

constitutes compliance with paragraph

(e)(2)(i)(A) of AD 93–17–07 for the inboard

lugs.

(iv) For airplanes on which all of the

modifications described in the service

bulletins referenced by paragraph I.D.,

‘‘Compliance,’’ on page 17 of Boeing Alert

Service Bulletin 747–54A2152, dated

November 3, 1994, have been accomplished;

except that rework of the midspar fitting lugs

was accomplished in accordance with the

Boeing Alert Service Bulletin 747–54A2152,

dated December 23, 1992, or Revision 1,

dated July 15, 1993, instead of Revision 2,

dated September 16, 1993; and excluding the

modification described in Boeing Service

Bulletin 747–54–2118, dated July 25, 1986:

(A) Within 56 months after the effective

date of this AD, accomplish the modification

of the nacelle strut and wing structure and

perform the inspections of the adjacent

structure that has not been replaced by the

modification.

(B) Repeat the ultrasonic inspections to

detect cracking of the aft-most two fastener

holes in both strut midspar fittings on the

inboard and outboard nacelle struts, as

required by AD 87–04–13 R1, within 4,000

landings following the immediately

preceding inspection performed in

accordance with AD 87–04–13 R1, or within

1,000 landings after the effective date of this

AD, whichever occurs earlier, in accordance

with Boeing Service Bulletin 747–54–2118,

dated July 25, 1986, until the modification of

the nacelle strut and wing structure is

accomplished in accordance with Boeing

Alert Service Bulletin 747–54A2159, dated

November 3, 1994. Repeat this inspection

thereafter at intervals not to exceed 1,000

landings.

(C) Prior to the accumulation of 3 years

since rework of the inboard lugs, or within

6 months after the effective date of this AD,

whichever occurs later, perform an ultrasonic

inspection to detect cracking of the midspar

fitting lugs of the inboard struts, and repeat

the inspection thereafter as required by AD

93–17–07, until the modification of the

nacelle strut and wing structure is

accomplished in accordance with Boeing

Alert Service Bulletin 747–54A2159, dated

November 3, 1994.

Note 5: Notes 3 and 4 are also applicable

to this paragraph.

(v) For all other airplanes not subject to the

requirements of paragraph (a)(2)(i), (a)(2)(ii),

(a)(2)(iii), or (a)(2)(iv) of this AD: Within 32

months after the effective date of this AD,

accomplish the modification of the nacelle

strut and wing structure and perform the

inspections of the adjacent structure that has

not been replaced by the modification.

Note 6: The following table graphically

illustrates the applicability and compliance

times for accomplishing the modification of

the nacelle strut and wing structure as

required by paragraph (a)(2) of this AD.

ParagraphAccomplishment of

service bulletins

Compliance

time

(months)

(i) ......... All in paragraph I.D. 56

(ii) ......... All except 747–54–

2118.

56

(iii) ........ All except 747–

54A2152, Revision 2.

56

(iv) ........ All except 747–54–

2118 and 747–

54A2152, Revision 2.

56

(v) ........ (*) ............................ 32

*Paragraph (a)(2)(v) of this AD is applicable

to all airplanes, other than those addressed in

paragraphs (a)(2)(i), (a)(2)(ii), (a)(2)(iii), and

(a)(2)(iv) of this AD. As such, these airplanes

may have accomplished some or none of the

service bulletins listed in paragraph I.D. of

Boeing Alert Service Bulletin 747–54A2159,

dated November 3, 1994.

(b) Perform the inspections and checks

specified in paragraph III, NOTES 8, 9, 10,

and 11 of the Accomplishment Instructions

on pages 149 and 150 of Boeing Alert Service

Bulletin 747–54A2159, dated November 3,

1994, concurrently with the modification of

the nacelle strut and wing structure required

by paragraph (a) of this AD. Prior to further

flight, correct any discrepancies found, in

accordance with the alert service bulletin.

(c) Accomplishment of the modification of

the nacelle strut and wing structure in

accordance with Boeing Alert Service

Bulletin 747–54A2159, dated November 3,

1994, constitutes terminating action for the

inspections required by the following AD’s:

AD No. Amendment

No.

Federal Register

citation Date of publication

94–17–17 ..................................................................................................................... 39–9012 59 FR 44903 August 31, 1994.

94–10–05 ..................................................................................................................... 39–8912 59 FR 25288 May 16, 1994.

93–17–07 ..................................................................................................................... 39–8678 58 FR 45827 August 31, 1993.

93–03–14 ..................................................................................................................... 39–8518 58 FR 14513 March 18, 1993.

92–24–51 ..................................................................................................................... 39–8439 57 FR 60118 December 18, 1992.

92–07–11 ..................................................................................................................... 39–8207 57 FR 10415 March 26, 1992.

90–20–20 ..................................................................................................................... 39–6725 55 FR 37859 September 14, 1990.

90–17–18 ..................................................................................................................... 39–6702 55 FR 33279 August 15, 1990.

89–07–15 ..................................................................................................................... 39–6167 54 FR 11693 March 22, 1989.

87–04–13 R1 ................................................................................................................ 39–5546 54 FR 3421 February 4, 1987.
27016 Federal Register / Vol. 60, No. 98 / Monday, May 22, 1995 / Rules and Regulations

AD No. Amendment

No.

Federal Register

citation Date of publication

86–08–03 ..................................................................................................................... 39–5289 51 FR 12836 April 16, 1986.

86–07–06 ..................................................................................................................... 39–5270 51 FR 10821 March 31, 1986.

86–05–11 ..................................................................................................................... 39–5255 51 FR 8479 March 12, 1986.

86–23–01 ..................................................................................................................... 39–5450 51 FR 37712 October 24, 1986.

82–22–02 ..................................................................................................................... 39–4476 47 FR 46842 October 21, 1982.

80–08–02 ..................................................................................................................... 39–3738 45 FR 24450 April 10, 1980.

79–17–07 ..................................................................................................................... 39–3533 44 FR 50033 August 27, 1979.

(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 7: 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 modification, inspections, checks,

and correction of discrepancies shall be done

in accordance with Boeing Alert Service

Bulletin 747–54A2159, dated November 3,

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

June 21, 1995.

Issued in Renton, Washington, on May 10,

1995.

James V. Devany,

Acting Manager, Transport Airplane

Directorate, Aircraft Certification Service.

[FR Doc. 95–11968 Filed 5–19–95; 8:45 am]

BILLING CODE 4910–13–U

14 CFR Part 39

[Docket No. 94–NM–163–AD; Amendment

39–9232; AD 95–10–15]

Airworthiness Directives; British

Aerospace Model BAe 146–100A,

–200A, –300A and Model Avro 146–

RJ70A, –RJ85A, and –RJ100A

Airplanes Equipped With Certain Air

Cruisers Evacuation Slides

AGENCY: Federal Aviation

Administration, DOT.

ACTION: Final rule.

SUMMARY: This amendment adopts a

new airworthiness directive (AD),

applicable to certain British Aerospace

Model BAe 146–100A, –200A, –300A

and Model Avro 146–RJ70A, –RJ85A,

and –RJ100A airplanes, that requires

repetitive inspections to verify proper

deployment of the evacuation slide at

each door position, and various followon actions to correct discrepancies. This

amendment is prompted by a report

that, during operational checks of

evacuation slides on in-service

airplanes, the inflation valves failed to

deploy the evacuation slide properly.

The actions specified by this AD are

intended to prevent failure of the

evacuation slide to deploy automatically

on demand, which would necessitate

the flightcrew to manually deploy the

slide; this situation could delay or

impede the evacuation of passengers

during an emergency.

DATES: Effective June 21, 1995.

The incorporation by reference of

certain publications listed in the

regulations is approved by the Director

of the Federal Register as of June 21,

1995.

ADDRESSES: The service information

referenced in this AD may be obtained

from British Aerospace Holdings, Inc.,

Avro International Aerospace Division,

P.O. Box 16039, Dulles International

Airport, Washington DC 20041–6039;

and Air Cruisers Company, P.O. Box

180, Belmar, New Jersey 07719–0180.

This information may be examined at

the Federal Aviation Administration

(FAA), Transport Airplane Directorate,

Rules 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:

William Schroeder, Aerospace Engineer,

Standardization Branch, ANM–113,

FAA, Transport Airplane Directorate,

1601 Lind Avenue, SW., Renton,

Washington 98055–4056; telephone

(206) 227–2148; fax (206) 227–1320.

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 British

Aerospace Model BAe 146–100A,

–200A, –300A and Model Avro 146–

RJ70A, –RJ85A, and –RJ100A airplanes

was published in the Federal Register

on November 7, 1994 (59 FR 55382).

That action proposed to require

repetitive inspections to verify proper

deployment of the evacuation slide at

each door position, and various followon actions to correct discrepancies. That

action also proposed to require

modification of the inflation valve of the

evacuation slide, which would

terminate the repetitive inspection

requirements.

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 questions the need

for the rule since the major U.S.

operators of the affected airplanes have

accomplished the proposed actions. The

commenter also states that for over two

years there have been no reports of inservice deployment or inflation

problems in the field, since the issuance

of Air Cruisers Service Bulletin S.B.

201–25–17, dated June 4, 1992,

referenced in the proposal as the

appropriate source of service

information. However, the commenter

notes that, during an evacuation

demonstration, an isolated incident did

occur in which the inflation valve did

not inflate automatically.

From these comments, the FAA infers

that the commenter is requesting that

the rule be withdrawn. The FAA does

not concur. The FAA has received no

documentation to indicate that all

affected U.S. operators have

accomplished the actions required by

this AD. Even if that were the case,

issuance of this AD is necessary to

ensure that the required actions are

accomplished on any British Aerospace

Model BAe 146–100A, –200A, –300A

and Model Avro 146–RJ70A, –RJ85A,

and –RJ100A airplanes that may be

imported and added to the U.S. Register

in the future. Although the FAA

recognizes that there have been no cases

of failure of the slides in service, the

potential for such failures does exist