20762 Federal Register / Vol. 61, No. 90 / Wednesday, May 8, 1996 / Proposed Rules

greater susceptibility to adverse effects

from HIRF; and laboratory tests, in

general, do not accurately represent the

aircraft installation. Service experience

alone will not be acceptable since such

experience in normal flight operations

may not include an exposure to HIRF.

Reliance on a system with similar

design features for redundancy, as a

means of protection against the effects

of external HIRF, is generally

insufficient because all elements of a

redundant system are likely to be

concurrently exposed to the radiated

fields.

The modulation that represents the

signal most likely to disrupt the

operation of the system under test,

based on its design characteristics,

should be selected. For example, flight

control systems may be susceptible to 3

HZ square wave modulation while the

video signals for electronic display

systems may be susceptible to 400 HZ

sinusoidal modulation. If the worst-case

modulation is unknown or cannot be

determined, default modulations may be

used. Suggested default values are a 1

KHZ sine wave with 80 percent depth of

modulation in the frequency range from

10 KHZ to 500 MHZ and 1 KHZ square

wave with greater than 90 percent depth

of modulation from MHZ to 18 GHZ. For

frequencies where the unmodulated

signal would cause deviations from

normal operation, several different

modulating signals with various

waveforms and frequencies should be

applied.

Acceptable system performance

would be attained by demonstrating that

the critical function components of the

system under consideration continue to

perform their intended function during

and after exposure to required

electromagnetic fields. Deviations from

system specifications may be acceptable

but must be independently assessed by

the FAA on a case-by-case basis.

TABLE 1.—FIELD STRENGTH VOLTS/

METER

Frequency Peak Average

10–100 KHZ 50 50

100–500 60 60

500–2000 70 70

2–30 MHZ 200 200

30–100 30 30

100–200 150 33

200–400 70 70

400–700 4020 935

700–1000 1700 170

1–2 GHZ 5000 990

2–4 6680 840

4–6 6850 310

6–8 3600 670

8–12 3500 1270

12–18 3500 360

TABLE 1.—FIELD STRENGTH VOLTS/

METER—Continued

Frequency Peak Average

18–40 2100 750

As discussed above, these special

conditions are applicable initially to the

Sikorsky Model S76C helicopter.

Should Sikorsky apply at a later date for

a change to the type certificate to

include another model incorporating the

same novel or unusual design feature,

the special conditions would apply to

that model as well, under the provisions

of § 21.101(a)(1).

Conclusion

This action affects only certain

unusual or novel design features on one

model of helicopter. It is not a rule of

general applicability and affects only

the manufacturer who applied to the

FAA for approval of these features on

the affected helicopters.

List of Subjects in 14 CFR Parts 21 and

29

Aircraft, Air transportation, Aviation

safety, Rotorcraft, Safety.

The authority citation for this special

condition is as follows:

Authority: 42 U.S.C. 7572; 49 U.S.C.

106(g), 40105, 40113, 44701, 44702, 44704,

44709, 44711, 44713, 44715, 45303.

The Proposed Special Condition

Accordingly, pursuant to the

authority delegated to me by the

Administrator, the Federal Aviation

Administration (FAA) proposes the

following special condition as a part of

the type certification basis for the

Sikorsky Model S76C helicopter.

Protection for Electrical and Electronic

Systems From High Intensity Radiated

Fields

Each system that performs critical

functions must be designed and

installed to ensure that the operation

and operational capabilities of these

critical functions are not adversely

affected when the helicopters are

exposed to high intensity radiated fields

external to the helicopters.

Issued in Fort Worth, Texas, on April 26,

1996.

Larry M. Kelly,

Acting Manager, Rotorcraft Directorate,

Aircraft Certification Service.

[FR Doc. 96–11496 Filed 5–7–96; 8:45 am]

BILLING CODE 4910–13–M

Federal Aviation Administration

14 CFR Part 39

[Docket No. 95–NM–241–AD]

RIN 2120–AA64

Airworthiness Directives; Airbus Model

A310 Series Airplanes

AGENCY: Federal Aviation

Administration, DOT.

ACTION: Notice of proposed rulemaking

(NPRM).

SUMMARY: This document proposes the

adoption of a new airworthiness

directive (AD) that is applicable to

certain Airbus Model A310 series

airplanes. This proposal would require

repetitive inspections to detect

discrepancies of the slat universal joint

and steady bearing assemblies, and

replacement of any discrepant assembly

with a new, like assembly. The proposal

also would require replacement of all

slat universal joint and steady bearing

assemblies with improved assemblies,

which would terminate the repetitive

inspections. This proposal is prompted

by reports of broken or missing inner

races on the slat universal joint and

steady bearing assemblies of the slat

transmission system. The actions

specified by the proposed AD are

intended to prevent cracking of the

inner race, which could cause it to break

off and, consequently, allow the slat

universal joint and steady bearing

assemblies to become worn; this

situation could result in failure of the

shaft of the slat transmission system,

and subsequent uncommanded

movement of the associated slat.

DATES: Comments must be received by

June 17, 1996.

ADDRESSES: Submit comments in

triplicate to the Federal Aviation

Administration (FAA), Transport

Airplane Directorate, ANM–103,

Attention: Rules Docket No. 95–NM–

241–AD, 1601 Lind Avenue, SW.,

Renton, Washington 98055–4056.

Comments may be inspected at this

location between 9:00 a.m. and 3:00

p.m., Monday through Friday, except

Federal holidays.

The service information referenced in

the proposed rule may be obtained from

Airbus Industrie, 1 Rond Point Maurice

Bellonte, 31707 Blagnac Cedex, France.

This information may be examined at

the FAA, Transport Airplane

Directorate, 1601 Lind Avenue, SW.,

Renton, Washington.

FOR FURTHER INFORMATION CONTACT:

Charles Huber, Aerospace Engineer,

Standardization Branch, ANM–113,

FAA, Transport Airplane Directorate,
Federal Register / Vol. 61, No. 90 / Wednesday, May 8, 1996 / Proposed Rules 20763

1601 Lind Avenue, SW., Renton,

Washington 98055–4056; telephone

(206) 227–2589; fax (206) 227–1149.

SUPPLEMENTARY INFORMATION:

Comments Invited

Interested persons are invited to

participate in the making of the

proposed rule by submitting such

written data, views, or arguments as

they may desire. Communications shall

identify the Rules Docket number and

be submitted in triplicate to the address

specified above. All communications

received on or before the closing date

for comments, specified above, will be

considered before taking action on the

proposed rule. The proposals contained

in this notice may be changed in light

of the comments received.

Comments are specifically invited on

the overall regulatory, economic,

environmental, and energy aspects of

the proposed rule. All comments

submitted will be available, both before

and after the closing date for comments,

in the Rules Docket for examination by

interested persons. A report

summarizing each FAA-public contact

concerned with the substance of this

proposal will be filed in the Rules

Docket.

Commenters wishing the FAA to

acknowledge receipt of their comments

submitted in response to this notice

must submit a self-addressed, stamped

postcard on which the following

statement is made: ‘‘Comments to

Docket Number 95–NM–241–AD.’’ The

postcard will be date stamped and

returned to the commenter.

Availability of NPRMs

Any person may obtain a copy of this

NPRM by submitting a request to the

FAA, Transport Airplane Directorate,

ANM–103, Attention: Rules Docket No.

95–NM–241–AD, 1601 Lind Avenue,

SW., Renton, Washington 98055–4056.

Discussion

The Direction Ge ́ne ́rale de l’Aviation

Civile (DGAC), which is the

airworthiness authority for France,

recently notified the FAA that an unsafe

condition may exist on certain Airbus

Model A310 series airplanes. The DGAC

advises that it has received reports that,

during maintenance inspections, the

inner races were found to be broken or

missing on the slat universal joint and

steady bearing assemblies of the slat

transmission system. The existing

design can cause these inner races to be

susceptible to cracking. If the inner race

cracks, it could break off, and the slat

universal joint and steady bearing

assemblies consequently could become

worn. This condition, if not corrected,

could result in failure of the shaft of the

slat transmission system, and

subsequent uncommanded movement of

the associated slat.

Explanation of Relevant Service

Information

Airbus has issued Service Bulletin

A310–27–2040, Revision 2, dated

January 5, 1995. The service bulletin

describes procedures for repetitive

visual inspections to detect

discrepancies of the slat universal joint

and steady bearing assemblies, and

replacement of any discrepancy

assembly with a new, like assembly.

The DGAC classified this service

bulletin as mandatory and issued

French airworthiness directive (CN) 95–

074–179(B), dated April 26, 1995, in

order to assure the continued

airworthiness of these airplanes in

France.

In addition, Lucas Liebherr has issued

Service Bulletin 523–27–M523–1, dated

April 25, 1986, which describes

procedures for replacement of all slat

universal joint and steady bearing

assemblies with new improved

assemblies. Accomplishment of the

replacement will eliminate the need for

the repetitive inspections. The

replacement will improve the reliability

of the universal joint assemblies.

FAA’s Conclusions

This airplane model is manufactured

in France and is type certificated for

operation in the United States under the

provisions of section 21.29 of the

Federal Aviation Regulations (14 CFR

21.29) and the applicable bilateral

airworthiness agreement. Pursuant to

this bilateral airworthiness agreement,

the DGAC has kept the FAA informed

of the situation described above. The

FAA has examined the findings of the

DGAC, reviewed all available

information, and determined that AD

action is necessary for products of this

type design that are certificated for

operation in the United States.

Explanation of the Proposed

Requirements of the Rule

Since an unsafe condition has been

identified that is likely to exist or

develop on other airplanes of the same

type design, the proposed AD would

require repetitive visual inspections to

detect discrepancies of the slat universal

joint and steady bearing assemblies, and

replacement of any discrepany assembly

with a new, like assembly. The

proposed AD also would require

replacement of all slat universal joint

and steady bearing assemblies with new

assemblies, which would constitute

terminating action for the repetitive

inspection requirements. The actions

would be required to be accomplished

in accordance with the service bulletins

described previously.

Differences Between the Proposal and

the Related French AD

This proposed rule would differ from

the parallel French airworthiness

directive (CN) 95–074–179(B), in that it

would mandate the accomplishment of

the terminating action for the repetitive

inspections. The French airworthiness

directive provides that action as

optional.

Mandating the terminating action is

based on the FAA’s determination that

long term continued operational safety

will be better assured by design changes

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 continual

inspections, has led the FAA to consider

placing less emphasis on inspections

and more emphasis on design

improvements. The proposed

requirement to accomplish the

terminating action is in consonance

with these considerations.

Cost Impact

The FAA estimates that 26 Airbus

Model A310 series airplanes of U.S.

registry would be affected by this

proposed AD.

It would take approximately 5 work

hours per airplane to accomplish the

proposed inspection, at an average labor

rate of $60 per work hour. Based on

these figures, the cost impact of the

proposed inspection on U.S. operators is

estimated to be $7,800, or $300 per

airplane, per inspection.

It would take approximately 9 work

hours per airplane to accomplish the

proposed replacement, at an average

labor rate of $60 per work hour.

Required parts would cost

approximately $48,108 per airplane.

Based on these figures, the cost impact

of the proposed replacement on U.S.

operators is estimated to be $1,264,848,

or $48,648 per airplane.

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.

Regulatory Impact

The regulations proposed herein

would not have substantial direct effects
20764 Federal Register / Vol. 61, No. 90 / Wednesday, May 8, 1996 / Proposed Rules

on the States, on the relationship

between the national government and

the States, or on the distribution of

power and responsibilities among the

various levels of government. Therefore,

in accordance with Executive Order

12612, it is determined that this

proposal would not have sufficient

federalism implications to warrant the

preparation of a Federalism Assessment.

For the reasons discussed above, I

certify that this proposed regulation (1)

is not a ‘‘significant regulatory action’’

under Executive Order 12866; (2) is not

a ‘‘significant rule’’ under the DOT

Regulatory Policies and Procedures (44

FR 11034, February 26, 1979); and (3) if

promulgated, will not have a significant

economic impact, positive or negative,

on a substantial number of small entities

under the criteria of the Regulatory

Flexibility Act. A copy of the draft

regulatory evaluation prepared for this

action is contained in the Rules Docket.

A copy of it may be obtained by

contacting the Rules Docket at the

location provided under the caption

ADDRESSES.

List of Subjects in 14 CFR Part 39

Air transportation, Aircraft, Aviation

safety, Safety.

The Proposed Amendment

Accordingly, pursuant to the

authority delegated to me by the

Administrator, the Federal Aviation

Administration proposes to amend part

39 of the Federal Aviation Regulations

(14 CFR part 39) as follows:

PART 39—AIRWORTHINESS

DIRECTIVES

1. The authority citation for part 39

continues to read as follows:

Authority: 49 USC 106(g), 40101, 40113,

44701.

§ 39.13 [Amended]

2. Section 39.13 is amended by

adding the following new airworthiness

directive:

Airbus Industrie: Docket 95–NM–241–AD

Applicability: Model A310 series airplanes,

on which Airbus Modification 6022 or 6485

has not been installed; 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 (c) 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.

To prevent failure of the shaft of the slat

transmission system, and subsequent

uncommanded movement of the associated

slat, accomplish the following:

(a) Prior to the accumulation of 2,000

landings or 500 flight hours after the effective

date of this AD, whichever occurs later,

perform a visual inspection to detect

discrepancies of the slat universal joint and

steady bearing assemblies, in accordance

with Airbus Service Bulletin A310–27–2040,

Revision 2, dated January 5, 1995.

Note 2: Airbus Service Bulletin A310–27–

2040 inadvertently references Lucas/Liebherr

Service Bulletin 551A–27–6010 as the

appropriate source for accomplishing the

inspection. Lucas/Liebherr Service Bulletin

551A–27–610 is the appropriate source of

information.

(1) If no discrepancy is found, repeat the

inspection thereafter at intervals not to

exceed 2,000 landings.

(2) If any discrepancy is detected and the

groove depth on the shaft is greater than or

equal to 1 mm (0.04 in.), prior to further

flight, replace the discrepant bearing

assembly with a new, like assembly, in

accordance with the service bulletin. After

replacement, repeat the visual inspection

thereafter at intervals not to exceed 2,000

landings.

(3) If any discrepancy is detected and the

groove depth on the shaft is less than 1 mm

(0.04 in.), prior to 50 landings after

accomplishing the initial inspection, replace

the discrepant bearing assembly with a new,

like assembly, in accordance with the service

bulletin. After the replacement, repeat the

visual inspection thereafter at intervals not to

exceed 2,000 landings.

(b) Within 5 years after the effective date

of this AD, replace the slat universal joint

and steady bearing assemblies with new

assemblies, in accordance with Lucas

Liebherr Service Bulletin 523–27–M523–1,

dated April 25, 1986. Accomplishment of the

replacement constitutes terminating action

for the repetitive inspection requirements of

paragraph (a) of this AD.

(c) 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 3: Information concerning the

existence of approved alternative methods of

compliance with this AD, if any, may be

obtained from the Standardization Branch,

ANM–113.

(d) Special flight permits may be issued in

accordance with sections 21.197 and 21.199

of the Federal Aviation Regulations (14 CFR

21.197 and 21.199) to operate the airplane to

a location where the requirements of this AD

can be accomplished.

Issued in Renton, Washington, on May 2,

1996.

Darrell M. Pederson,

Acting Manager, Transport Airplane

Directorate, Aircraft Certification Service.

[FR Doc. 96–11441 Filed 5–7–96; 8:45 am]

BILLING CODE 4910–13–U

14 CFR Part 39

[Docket No. 96–NM–90–AD]

RIN 2120–AA64

Airworthiness Directives; Gulfstream

Model G–1159 (G–II), G–1159A (G–III),

and G–1159B (G–IIB) Series Airplanes

AGENCY: Federal Aviation

Administration, DOT.

ACTION: Notice of proposed rulemaking

(NPRM).

SUMMARY: This document proposes the

adoption of a new airworthiness

directive (AD) that is applicable to all

Gulfstream Model G–1159 (G–II), G–

1159A (G–III), and G–1159B (G–IIB)

series airplanes. This proposal would

require inspections to detect cracking

and/or corrosion at various locations of

the wings, and modification of cracked

and/or corroded parts. This proposal is

prompted by a report indicating that

cracks, caused by stress corrosion, were

found at various locations at buttock

line (BL) 0 to BL 19 of the lower wing

plank. The actions specified by the

proposed AD are intended to prevent

such stress corrosion cracking, which

could result in structural failure of the

wing under certain load conditions.

DATES: Comments must be received by

June 17, 1996.

ADDRESSES: Submit comments in

triplicate to the Federal Aviation

Administration (FAA), Transport

Airplane Directorate, ANM–103,

Attention: Rules Docket No. 96–NM–

90–AD, 1601 Lind Avenue, SW.,

Renton, Washington 98055–4056.

Comments may be inspected at this

location between 9:00 a.m. and 3:00

p.m., Monday through Friday, except

Federal holidays.

The service information referenced in

the proposed rule may be obtained from

Gulfstream Aerospace Corporation,

Technical Operations Department, P.O.

Box 2206, M/S D–10, Savannah, Georgia

31402–2206. This information may be

examined at the FAA, Transport

Airplane Directorate, 1601 Lind

Avenue, SW., Renton, Washington; or at

the FAA, Small Airplane Directorate,

Atlanta Aircraft Certification Office,

Campus Building, 1701 Columbia

Avenue, Suite 2–160, College Park,

Georgia.