22428 Federal Register / Vol. 66, No. 87 / Friday, May 4, 2001 / Rules and Regulations

2. A threat external to the airframe of

the following field strengths for the

frequency ranges indicated. Both peak

and average field strength components

from the Table are to be demonstrated.

Frequency

Field strength (volts per meter)

Peak Average

10 kHz–100 kHz ...................................................................................................................................................... 50 50

100 kHz–500 kHz .................................................................................................................................................... 50 50

500 kHz–2 MHz ....................................................................................................................................................... 50 50

2 MHz–30 MHz ........................................................................................................................................................ 100 100

30 MHz–70 MHz ...................................................................................................................................................... 50 50

70 MHz–100 MHz .................................................................................................................................................... 50 50

100 MHz–200 MHz .................................................................................................................................................. 100 100

200 MHz–400 MHz .................................................................................................................................................. 100 100

400 MHz–700 MHz .................................................................................................................................................. 700 50

700 MHz–1 GHz ...................................................................................................................................................... 700 100

1 GHz–2 GHz .......................................................................................................................................................... 2000 200

2 GHz–4 GHz .......................................................................................................................................................... 3000 200

4 GHz–6 GHz .......................................................................................................................................................... 3000 200

6 GHz–8 GHz .......................................................................................................................................................... 1000 200

8 GHz–12 GHz ........................................................................................................................................................ 3000 300

12 GHz–18 GHz ...................................................................................................................................................... 2000 200

18 GHz–40 GHz ...................................................................................................................................................... 600 200

The field strengths are expressed in terms of peak of the root-mean-square (rms) over the complete modulation period.

The threat levels identified above are

the result of an FAA review of existing

studies on the subject of HIRF, in light

of the ongoing work of the

Electromagnetic Effects Harmonization

Working Group of the Aviation

Rulemaking Advisory Committee.

Applicability

As discussed above, these special

conditions are applicable to Bombardier

Inc. Model CL–600–1A11 airplane

modified by Duncan Aviation, Inc.

Should Duncan apply at a later date for

a supplemental type certificate to

modify any other model included on the

same type certificate to incorporate the

same novel or unusual design feature,

these special conditions would apply to

that model as well under the provisions

of § 21.101(a)(1).

Conclusion

This action affects only certain novel

or unusual design features on

Bombardier Inc. Model CL–600–1A11

airplane modified by Duncan Aviation,

Inc. It is not a rule of general

applicability and affects only the

applicant who applied to the FAA for

approval of these features on the

airplane.

The substance of the special

conditions for this airplane has been

subjected to the notice and comment

period in several prior instances and has

been derived without substantive

change from those previously issued. It

is unlikely that prior public comment

would result in a significant change

from the substance contained herein.

For this reason, and because a delay

would significantly affect the

certification of the airplane, which is

imminent, the FAA has determined that

prior public notice and comment are

unnecessary and impracticable, and

good cause exists for adopting these

special conditions upon issuance. The

FAA is requesting comments to allow

interested persons to submit views that

may not have been submitted in

response to the prior opportunities for

comment described above.

List of Subjects in 14 CFR Part 25

Aircraft, Aviation safety, Reporting

and recordkeeping requirements.

The authority citation for these

special conditions is as follows:

Authority: 49 U.S.C. 106(g), 40113, 44701,

44702, 44704.

The Special Conditions

Accordingly, pursuant to the

authority delegated to me by the

Administrator, the following special

conditions are issued as part of the type

certification basis for Bombardier Inc.

Model CL–600–1A11 airplanes modified

by Duncan.

1. Protection from Unwanted Effects

of High-Intensity Radiated Fields

(HIRF). Each electrical and electronic

system that performs critical functions

must be designed and installed to

ensure that the operation and

operational capability of these systems

to perform critical functions are not

adversely affected when the airplane is

exposed to high intensity radiated

fields.

2. For the purpose of these special

conditions, the following definition

applies: Critical Functions: Functions

whose failure would contribute to or

cause a failure condition that would

prevent the continued safe flight and

landing of the airplane.

Issued in Renton, Washington, on April 25,

2001.

Donald L. Riggin,

Acting Manager, Transport Airplane

Directorate, Aircraft Certification Service.

[FR Doc. 01–11254 Filed 5–3–01; 8:45 am]

BILLING CODE 4910–13–U

DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 25

[Docket No. NM191, Special Conditions No.

25–179–SC]

Special Conditions: Lockheed-Georgia

Model 1329–25; and Models 1329–23A,

–23D and –23E airplanes modified by

STC SA2326SW (JetStar 731); HighIntensity Radiated Fields (HIRF)

AGENCY: Federal Aviation

Administration (FAA), DOT.

ACTION: Final special conditions; request

for comments.

SUMMARY: These special conditions are

issued for the Lockheed-Georgia Model

1329–25, and Models 1329–23A, –23D

and –23E airplanes modified by STC

SA2326SW, for the modifications

installed by Duncan Aviation Inc. These

modified airplanes will have novel and

unusual design features when compared

to the state of technology envisioned in

the airworthiness standards for

transport category airplanes. The

Federal Register / Vol. 66, No. 87 / Friday, May 4, 2001 / Rules and Regulations 22429

modification incorporates the

installation of dual Attitude Heading

Reference Systems (ARHS) that provide

input to both pilot and copilot flight

instruments displaying critical flight

parameters (attitude) to the flightcrew.

The applicable airworthiness standards

do not contain adequate or appropriate

safety standards for the protection of

these systems from the effects of highintensity radiated fields (HIRF). The

special conditions contain the

additional safety standards that the

Administrator considers necessary to

establish a level of safety equivalent to

that provided by the existing

airworthiness standards.

DATES: The effective date of these

special conditions is April 17, 2001.

Comments must be received on or

before June 4, 2001.

ADDRESSES: Comments on these special

conditions may be mailed in duplicate

to: Federal Aviation Administration,

Transport Airplane Directorate, Attn:

Rules Docket (ANM–114), Docket No.

NM191, 1601 Lind Avenue SW.,

Renton, Washington, 98055–4056; or

delivered in duplicate to the Transport

Airplane Directorate at the above

address. Comments must be marked:

Docket No. NM191. Comments may be

inspected in the Rules Docket

weekdays, except Federal holidays,

between 7:30 a.m. and 4 p.m.

FOR FURTHER INFORMATION CONTACT:

Mark Quam, FAA, Standardization

Branch, ANM–113, Transport Airplane

Directorate, Aircraft Certification

Service, 1601 Lind Avenue SW.,

Renton, Washington, 98055–4056;

telephone (425) 227–2145; facsimile

(425) 227–1149.

SUPPLEMENTARY INFORMATION:

Comments Invited

The FAA has determined that good

cause exists for making these special

conditions effective upon issuance;

however, interested persons are invited

to submit such written data, views, or

arguments as they may desire.

Communications should identify the

Docket or Special Conditions number

and be submitted in duplicate to the

address specified above. All

communications received on or before

the closing date for comments will be

considered by the Administrator. These

special conditions may be changed in

light of the comments received. All

comments received will be available in

the Rules Docket for examination by

interested persons, both before and after

the closing date for comments. A report

summarizing each substantive public

contact with FAA personnel concerning

this rulemaking will be filed in the

docket. Commenters wishing the FAA to

acknowledge receipt of their comments

submitted in response to these special

conditions must include a selfaddressed, stamped postcard on which

the following statement is made:

‘‘Comments to Docket No. NM191.’’ The

postcard will be date stamped and

returned to the commenter.

Background

On February 21, 2001, Duncan

Aviation, Inc., P.O. Box 81887, Lincoln,

Nebraska, applied for a supplemental

type certificate (STC) to modify the

Lockheed-Georgia Model 1329–25, and

Models 1329–23A, –23D and –23E

airplanes modified by STC SA2326SW,

listed on Type Certificate 2A15. These

airplanes are four engine transport

category airplanes of the executive type,

capable of carrying two flight

crewmembers and ten passengers. All

models are powered by four aft mount

AiResearch TFD–731 engines. In the

Model 1329–23A, –23D, and –23E

airplanes modified by STC SA232SW,

the Pratt & Whitney turbojet engines

have been replaced with the AiResearch

TFE–731 engines. The modification

incorporates the installation of dual

Rockwell Collins Attitude Heading

Reference Systems (ARHS) that provide

input to both pilot and copilot flight

instruments displaying critical flight

parameters (attitude and heading) to the

flightcrew. The AHRS can be

susceptible to disruption to both

command/response signals as a result of

electrical and magnetic interference.

This disruption of signals could result

in loss of all critical flight displays and

annunciations or present misleading

information to the pilot.

Type Certification Basis

Under the provisions of 14 CFR

21.101, Duncan Aviation, Inc., must

show that the Lockheed-Georgia Model

1329–25, and Models 1329–23A, –23D

and –23E airplanes modified by STC

SA2326SW, as changed, continue to

meet the applicable provisions of the

regulations incorporated by reference in

Type Certificate No. 2A15, or the

applicable regulations in effect on the

date of application for the change. The

regulations incorporated by reference in

the type certificate are commonly

referred to as the ‘‘original type

certification basis.’’ The certification

basis for the modified Lockheed-Georgia

Model 1329–25, and Models 1329–23A,

–23D and –23E airplanes modified by

STC SA2326SW, includes CAR 4b,

dated December 31, 1953, as amended

by Amendments 4b–1 through 4b–9 as

listed in the Type Certificate Data Sheet

(TCDS) 2A15.

If the Administrator finds that the

applicable airworthiness regulations

(i.e., CAR 4b, as amended) do not

contain adequate or appropriate safety

standards for the Lockheed-Georgia

Model 1329–25, and Models 1329–23A,

–23D and –23E airplanes modified by

STC SA2326SW, because of a novel or

unusual design feature, special

conditions are prescribed under the

provisions of § 21.16.

In addition to the applicable

airworthiness regulations and special

conditions, these Lockheed-Georgia

Model 1329–25; and Models 1329–23A,

–23D, and –23E airplanes must comply

with the fuel vent and exhaust emission

requirements of part 34 and the noise

certification requirements of part 36.

Special conditions, as defined in

§ 11.19, are issued in accordance with

§ 11.38 and become part of the type

certification basis in accordance with

§ 21.101(b)(2).

Special conditions are initially

applicable to the model for which they

are issued. Should Duncan apply at a

later date for a supplemental type

certificate to modify any other model

already included on the same type

certificate to incorporate the same novel

or unusual design feature, these special

conditions would also apply to the other

model under the provisions of

§ 21.101(a)(1).

Novel or Unusual Design Features

As noted earlier, the modified

Lockheed-Georgia Model 1329–25, and

Models 1329–23A, –23D and –23E

airplanes modified by STC SA2326SW,

will incorporate dual Attitude and

Heading Reference Systems (AHRS) that

provide input to both pilot and copilot

flight instruments displaying critical

flight parameters (attitude and heading)

to the flightcrew. The AHRS can be

susceptible to disruption to both

command/response signals as a result of

electrical and magnetic interference.

This disruption of signals could result

in loss of all critical flight displays and

annunciations or present misleading

information to the pilot.

Discussion

There is no specific regulation that

addresses protection requirements for

electrical and electronic systems from

HIRF. Increased power levels from

ground-based radio transmitters and the

growing use of sensitive avionic/

electronic and electrical systems to

command and control airplanes have

made it necessary to provide adequate

protection.

To ensure that a level of safety is

achieved equivalent to that intended by

the regulations incorporated by

22430 Federal Register / Vol. 66, No. 87 / Friday, May 4, 2001 / Rules and Regulations

reference, special conditions are needed

for the Lockheed-Georgia Model 1329–

25; and Models 1329–23A, –23D and

–23E. These special conditions require

that new avionic/electronic and

electrical systems, such as the AHRS,

that perform critical functions be

designed and installed to preclude

component damage and interruption of

function due to both the direct and

indirect effects of HIRF.

High-Intensity Radiated Fields (HIRF)

With the trend toward increased

power levels from ground-based

transmitters, plus the advent of space

and satellite communications, coupled

with electronic command and control of

the airplane, the immunity of critical

avionic/electronic and electrical

systems to HIRF must be established.

It is not possible to precisely define

the HIRF to which the airplane will be

exposed in service. There is also

uncertainty concerning the effectiveness

of airframe shielding for HIRF.

Furthermore, coupling of

electromagnetic energy to cockpitinstalled equipment through the cockpit

window apertures is undefined. Based

on surveys and analysis of existing HIRF

emitters, an adequate level of protection

exists when compliance with the HIRF

protection special condition is shown

with either paragraph 1, or paragraph 2,

below:

1. A minimum threat of 100 volts rms

per meter electric field strength from 10

KHz to 18 GHz.

a. The threat must be applied to the

system elements and their associated

wiring harnesses without the benefit of

airframe shielding.

b. Demonstration of this level of

protection is established through system

tests and analysis.

2. A threat external to the airframe of

the following field strengths for the

frequency ranges indicated. Both peak

and average field strength components

from the Table are to be demonstrated.

Frequency

Field strength (volts per meter)

Peak Average

10 kHz–100 kHz ...................................................................................................................................................... 50 50

100 kHz–500 kHz .................................................................................................................................................... 50 50

500 kHz–2 MHz ....................................................................................................................................................... 50 50

2 MHz–30 MHz ........................................................................................................................................................ 100 100

30 MHz–70 MHz ...................................................................................................................................................... 50 50

70 MHz–100 MHz .................................................................................................................................................... 50 50

100 MHz–200 MHz .................................................................................................................................................. 100 100

200 MHz–400 MHz .................................................................................................................................................. 100 100

400 MHz–700 MHz .................................................................................................................................................. 700 50

700 MHz–1 GHz ...................................................................................................................................................... 700 100

1 GHz–2 GHz .......................................................................................................................................................... 2000 20

2 GHz–4 GHz .......................................................................................................................................................... 3000 200

4 GHz–6 GHz .......................................................................................................................................................... 3000 200

6 GHz–8 GHz .......................................................................................................................................................... 1000 200

8 GHz–12 GHz ........................................................................................................................................................ 3000 300

12 GHz–18 GHz ...................................................................................................................................................... 2000 200

18 GHz–40 GHz ...................................................................................................................................................... 600 200

The field strengths are expressed in terms of peak of the root-mean-square (rms) over the complete modulation period.

The threat levels identified above are

the result of an FAA review of existing

studies on the subject of HIRF, in light

of the ongoing work of the

Electromagnetic Effects Harmonization

Working Group of the Aviation

Rulemaking Advisory Committee.

Applicability

As discussed above, these special

conditions are applicable to LockheedGeorgia Model 1329–25, and Models

1329–23A, –23D and —23E airplanes

modified by STC SA2326SW, with the

modifications installed by Duncan

Aviation. Should Duncan Aviation

apply at a later date for a supplemental

type certificate to modify any other

model included on the same type

certificate to incorporate the same novel

or unusual design feature, these special

conditions would apply to that model as

well under the provisions of

§ 21.101(a)(1).

Conclusion

This action affects only certain novel

or unusual design features on LockheedGeorgia Model 1329–25, and Models

1329–23A, -23D and -23E airplanes

modified by STC SA2326SW, that are

further modified by Duncan Aviation. It

is not a rule of general applicability and

affects only the applicant who applied

to the FAA for approval of these features

on the airplane.

The substance of the special

conditions for this airplane has been

subjected to the notice and comment

period in several prior instances and has

been derived without substantive

change from those previously issued. It

is unlikely that prior public comment

would result in a significant change

from the substance contained herein.

For this reason, and because a delay

would significantly affect the

certification of the airplane, which is

imminent, the FAA has determined that

prior public notice and comment are

unnecessary and impracticable, and

good cause exists for adopting these

special conditions upon issuance. The

FAA is requesting comments to allow

interested persons to submit views that

may not have been submitted in

response to the prior opportunities for

comment described above.

List of Subjects in 14 CFR Part 25

Aircraft, Aviation safety, Reporting

and recordkeeping requirements.

The authority citation for these

special conditions is as follows:

Authority: 49 U.S.C. 106(g), 40113, 44701,

44702, 44704.

The Special Conditions

Accordingly, pursuant to the

authority delegated to me by the

Administrator, the following special

conditions are issued as part of the type

certification basis for Lockheed-Georgia

Model 1329–25, and Models 1329–23A,

–23D and –23E airplanes modified by

STC SA2326SW, that are further

modified by Duncan Aviation, Inc.

1. Protection from Unwanted Effects

of High-Intensity Radiated Fields

(HIRF). Each electrical and electronic

system that performs critical functions

must be designed and installed to

ensure that the operation and

operational capability of these systems

Federal Register / Vol. 66, No. 87 / Friday, May 4, 2001 / Rules and Regulations 22431

to perform critical functions are not

adversely affected when the airplane is

exposed to high intensity radiated

fields.

2. For the purpose of these special

conditions, the following definition

applies:

Critical Functions: Functions whose

failure would contribute to or cause a

failure condition that would prevent the

continued safe flight and landing of the

airplane.

Issued in Renton, Washington, on April 17,

2001.

Ali Bahrami,

Acting Manager, Transport Airplane

Directorate, Aircraft Certification Service.

[FR Doc. 01–11253 Filed 5–3–01; 8:45 am]

BILLING CODE 4910–13–U

DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 2000–SW–40–AD; Amendment

39–12216; AD 94–14–20 R1]

RIN 2120–AA64

Airworthiness Directives; Sikorsky

Aircraft Corporation Model S–76A

Helicopters

AGENCY: Federal Aviation

Administration, DOT.

ACTION: Final rule.

SUMMARY: This amendment revises an

existing airworthiness directive (AD) for

Sikorsky Aircraft Corporation (Sikorsky)

Model S–76A helicopters. That AD

currently requires a one-time inspection

of the tail rotor blade (blade) spar

elliptical centering plug (centering plug)

for disbonding and the addition of a

retaining pad on the pitch change shaft

between the output tail rotor gearbox

flange and the inboard tail rotor spar.

This amendment contains the same

requirements as the existing AD but

clarifies that the 500-hour time-inservice (TIS) repetitive inspections,

which could cause inadvertent damage,

are not required. This AD also

incorporates by reference a revised alert

service bulletin (ASB) that does not

include the 500-hour TIS repetitive

inspections. This amendment is

prompted by operator confusion about

whether the current AD continues to

require the 500-hour TIS repetitive

inspections. The actions specified by

this AD are intended to verify that the

FAA has determined that the 500-hour

TIS repetitive inspections are not

required to prevent the centering plug

from disbonding and moving out of

position, loss of tail rotor control, and

subsequent loss of control of the

helicopter.

DATES: Effective June 8, 2001.

The incorporation by reference of

certain publications listed in the

regulations is approved by the Director

of the Federal Register as of June 8,

2001.

ADDRESSES: The service information

referenced in this AD may be obtained

from Sikorsky Aircraft Corporation,

Attn: Manager, Commercial Tech

Support, 6900 Main Street, Stratford,

Connecticut 06614, phone (203) 386–

3001, fax (203) 386–5983. This 1

information may be examined at the

FAA, Office of the Regional Counsel,

Southwest Region, 2601 Meacham

Blvd., Room 663, Fort Worth, Texas; or

at the Office of the Federal Register, 800

North Capitol Street, NW., suite 700,

Washington, DC.

FOR FURTHER INFORMATION CONTACT:

Richard Noll, Aviation Safety Engineer,

Boston Aircraft Certification Office, 12

New England Executive Park,

Burlington, MA 01803, telephone (781)

238–7160, fax (781) 238–7199.

SUPPLEMENTARY INFORMATION: A

proposal to amend part 39 of the Federal

Aviation Regulations (14 CFR part 39)

by revising AD 94–14–20, Amendment

39–8969 (59 FR 41238, August 11,

1994), which applies to Sikorsky Model

S–76A helicopters, was published in the

Federal Register on January 30, 2001

(66 FR 8184). The action proposed to

require a one-time inspection of the

blade centering plug for disbonding and

the addition of a retaining pad on the

pitch change shaft between the output

tail rotor gearbox flange and the inboard

tail rotor spar. The action also clarified

that 500-hour TIS repetitive inspections,

which could cause inadvertent damage,

are not required and proposed to

incorporate by reference a revised ASB

that does not include the 500-hour TIS

repetitive inspections.

Interested persons have been afforded

an opportunity to participate in the

making of this amendment. No

comments were received on the

proposal or the FAA’s determination of

the cost to the public. The FAA has

determined that air safety and the

public interest require the adoption of

the rule as proposed except for some

editorial changes that are made in

paragraphs (a) and (e). These changes

were made to better identify the service

information that is incorporated by

reference. The FAA has determined that

these changes will neither increase the

economic burden on any operator nor

increase the scope of the AD.

The FAA estimates that this AD will

affect 150 helicopters of U.S. registry.

This revised AD will not impose any

additional burden or costs.

The regulations adopted herein will

not have a substantial direct effect 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, it is

determined that this final rule does not

have federalism implications under

Executive Order 13132.

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. 106(g), 40113, 44701.

§ 39.13 [Amended]

2. Section 39.13 is amended by

removing Amendment 39–8969 (59 FR

41238, August 11, 1994), and by adding

a new airworthiness directive (AD),

Amendment 39–12216, to read as

follows:

94–14–20 R1 Sikorsky Aircraft

Corporation: Amendment 39–12216.

Docket No. 2000–SW–40–AD. Revises

AD 94–14–20, Amendment 39–8969,

Docket No. 93–SW–13–AD.

Applicability: Model S–76A helicopters,

with tail rotor blade (blade) assembly, part

number (P/N) 76101–05001 (all dash

numbers) or 76101–05101 (all dash

numbers), installed with more than 130