24212 Federal Register / Vol. 61, No. 94 / Tuesday, May 14, 1996 / Rules and Regulations

subparagraph (2)(i) of this paragraph.

However, the residual strength level

must not be less than the 1-g flight load,

combined with the loads introduced by

the failure condition, plus two-thirds of

the load increments of the conditions

specified in subparagraph (2)(i) of this

paragraph, applied in both positive and

negative directions (if appropriate). The

residual strength factor (R.S.F.) is

defined in Figure 3.

Qj—Probability of being in failure

condition j

Qj=(Tj)(Pj) where:

Tj=Average time spent in failure

condition j (in hours)

Pj=Probability of occurrence of failure

mode j (per hour)

Note: If Pj is greater than 10¥3 per flight

hour, then a residual strength factor of 1.0

must be used.

(iv) If the loads induced by the failure

condition have a significant effect on

fatigue or damage tolerance, then their

effects must be taken into account.

(v) Freedom from flutter, divergence,

and control reversal must be shown up

to a speed determined from Figure 4.

Flutter clearance speeds V′ and V′′ may

be based on the speed limitation

specified for the remainder of the flight,

using the margins defined by

§ 25.629(b).

Qj=Probability of being in failure

condition j

V′=Clearance speed as defined by

§ 25.629(b)(2).

V′′=Clearance speed as defined by

§ 25.629(b)(1).

Qj=(Tj)(Pj) where:

Tj=Average time spent in failure

condition j (in hours)

Pj=Probability of occurrence of failure

mode j (per hour)

Note: If Pj is greater than 10¥3 per flight

hour, then the flutter clearance speed must

not be less than V′′.

(vi) Freedom from flutter, divergence,

and control reversal must also be shown

up to V′ in Figure 4 above, for any

probable system failure condition

combined with any damage required or

selected for investigation by § 25.571(b).

(vii) If the mission analysis method is

used to account for continuous

turbulence, all the systems failure

conditions associated with their

probability must be accounted for in a

rational or conservative manner in order

to ensure that the probability of

exceeding the limit load is not higher

than the value prescribed in Appendix

G of 14 CFR part 25.

(3) Consideration of certain failure

conditions may be required by other

sections of 14 CFR part 25, regardless of

calculated system reliability. Where

analysis shows the probability of these

failure conditions to be less than 10¥9,

criteria other than those specified in this

paragraph may be used for structural

substantiation to show continued safe

flight and landing.

(d) Warning considerations. For upper

rudder control system failure detection

and warning, the following apply:

(1) The system must be checked for

failure conditions, not extremely

improbable, that degrade the structural

capability below the level required by

part 25 or significantly reduce the

reliability of the remaining system. The

crew must be made aware of these

failures before flight. Certain elements

of the control system, such as

mechanical and hydraulic components,

may use special periodic inspections,

and electronic components may use

daily checks, in lieu of warning systems,

to achieve the objective of this

requirement. These certification

maintenance requirements must be

limited to components that are not

readily detectable by normal warning

systems and where service history

shows that inspections will provide an

adequate level of safety.

(2) The existence of any failure

condition, not extremely improbable,

during flight that could significantly

affect the structural capability of the

airplane, and for which the associated

reduction in airworthiness can be

minimized by suitable flight limitations,

must be signaled to the flight crew. For

example, failure conditions which result

in a factor of safety between the airplane

strength and the loads of 14 CFR part

25, Subpart C, below 1.25, or flutter

margins below V′′, must be signaled to

the crew during the flight.

(3) Dispatch with known failure

conditions. If the airplane is to be

dispatched in a known upper rudder

control system failure condition that

affects structural performance, or affects

the reliability of the remaining system to

maintain structural performance, then

the provisions of this special condition

must be met for the dispatched

condition and for subsequent failures.

Operational and flight limitations may

be taken into account.

Issued in Renton, Washington, on May 1,

1996.

Darrell M. Pederson,

Acting Manager, Transport Airplane

Directorate, Aircraft Certification Service,

ANM–100.

[FR Doc. 96–2086 Filed 5–13–96; 8:45 am]

BILLING CODE 4910–13–M
Federal Register / Vol. 61, No. 94 / Tuesday, May 14, 1996 / Rules and Regulations 24213

14 CFR part 25

[Docket No. NM–124; Special Conditions

No. 25–ANM–114]

Special Conditions: Dassault Aviation,

Mystere Falcon 50 Airplane; HighIntensity Radiated Fields

AGENCY: Federal Aviation

Administration (FAA), DOT.

ACTION: Final special conditions; request

for comments.

SUMMARY: These special conditions are

issued for the Dassault Aviation,

Mystere Falcon 50 airplane modified by

K–C Aviation of Appleton, Wisconsin.

This airplane will be equipped with a

Flight Visions FV–2000 Head-up

Display System that provides critical

data to the flightcrew. The applicable

regulations do not contain adequate or

appropriate safety standards for the

protection of these systems from the

effects of high-intensity radiated fields.

These special conditions contain the

additional safety standards that the

Administrator considers necessary to

establish a level of safety equivalent to

that established by the existing

airworthiness standards.

DATES: The effective date of these

special conditions is May 3, 1996.

Comments must be received on or

before June 28, 1996.

ADDRESSES: Comments on these final

special conditions, request for

comments, may be mailed in duplicate

to: Federal Aviation Administration,

Office of the Assistant Chief Counsel,

Attn: Rules Docket (ANM–7), Docket

No. NM–124, 1601 Lind Avenue SW.,

Renton, Washington, 98055–4056; or

delivered in duplicate to the Office of

the Assistant Chief Counsel at the above

address. Comments must be marked:

Docket No. NM–124. Comments may be

inspected in the Rules Docket

weekdays, except Federal holidays,

between 7:30 a.m. and 4:00 p.m.

FOR FURTHER INFORMATION CONTACT: Dale

Dunford, FAA, Flight Test and Systems

Branch, ANM–111, Transport Airplane

Directorate, Aircraft Certification

Service, 1601 Lind Avenue SW.,

Renton, Washington, 98055–4056;

telephone (206) 227–2239; facsimile

(206) 227–1100.

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

regulatory docket and 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 comments received. All

comments submitted 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. Persons wishing the FAA to

acknowledge receipt of their comments

submitted in response to this request

must be submitted with those comments

a self-addressed, stamped postcard on

which the following statement is made:

‘‘Comments to Docket No. NM–124.’’

The postcard will be date stamped and

returned to the commenter.

Background

On June 27, 1995, K–C Aviation of

Appleton, Wisconsin, applied for a

supplemental type certificate to modify

Dassault Aviation, Mystere Falcon 50

airplanes. The Dassault Aviation,

Mystere Falcon 50 is a business jet with

three aft mounted turbine engines. The

airplane can carry three crew and 19

passengers depending on the

configuration, and is capable of

operating to an altitude of 49,000 feet.

The proposed modification incorporates

the installation of a digital avionics

system that will present critical

functions on the Head-up Display

System (HUD), which are potentially

vulnerable to a high-intensity radiated

fields (HIRF) external to the airplane

Supplemental Type Certification Basis

Under the provisions of § 21.101 of

the Federal Aviation Regulations (FAR),

K–C Aviation must show that the

altered Dassault Aviation, Mystere

Falcon 50 airplane continues to meet

the applicable provisions of § 21.29; and

part 25, effective February 1, 1965, as

amended by Amendments 25–1 through

25–34 and § 25.255 of Amendment 25–

42; § 25.979 (d) and (e) of Amendment

25–38; § 25.1013(b)(1) of Amendment

25–36; § 25.1351(d) of Amendment 25–

41; § 25.1353(c)(6) of Amendment 25–

42; part 36 of the FAR effective

December 1, 1969, as amended through

Amendment 36–9; Special Federal

Aviation Regulations (SFAR) 27

effective February 1, 1974, as amended

through Amendment SFAR 27–1; and

Special Conditions 25–86–EU–24. In

addition, the certification basis may

include other special conditions that are

not relevant to these proposed special

conditions.

If the Administrator finds that the

applicable airworthiness regulations

(i.e., part 25, as amended) do not

contain adequate or appropriate safety

standards for the Dassault Aviation,

Mystere Falcon 50 airplane because of a

novel or unusual design feature, special

conditions are prescribed under the

provisions of § 21.16 to establish a level

of safety equivalent to that established

in the regulations.

Special conditions, as appropriate, are

issued in accordance with § 11.49 of the

FAR after public notice, as required by

§§ 11.28 and 11.29, and become part of

the type certification basis in

accordance with § 21.17(a)(2).

Special conditions are initially

applicable to the model for which they

are issued. Should the type certificate

for that model be amended later to

include any other model that

incorporates the same novel or unusual

design feature, the special conditions

would also apply to the other model

under the provision of § 21.101(a)(1).

Novel or Unusual Design Features

The Dassault Aviation, Mystere

Falcon 50 airplane incorporates a Flight

Visions FV–200 Head-up Display

system that provides critical data to the

flightcrew. These systems may be

vulnerable to HIRF external to the

airplane.

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 electrical and

electronic 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

reference, special conditions are

proposed for the Dassault Aviation,

Mystere Falcon 50, which would require

that new technology electrical and

electronic systems, such as the HUD,

etc., 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
24214 Federal Register / Vol. 61, No. 94 / Tuesday, May 14, 1996 / Rules and Regulations

digital avionics 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 paragraphs 1 or 2 below:

1. A minimum threat of 100 volts per

meter peak 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.

Frequency Peak

(V/M)

Average

(V/M)

10 KHz–100 KHz ...... 50 50

100 KHz–500 KHz .... 60 60

500 KHz–2000 KHz 70 70

2 MHz–30 MHz ......... 200 200

30 MHz–100 MHz ..... 30 30

100 MHz–200 MHz ... 150 33

200 MHz–400 MHz ... 70 70

400 MHz–700 MHz ... 4,020 935

700 MHz–1000 MHz 1,700 170

1 GHz–2 GHz ........... 5,000 990

2 GHz–4 GHz ........... 6,680 840

4 GHz–6 GHz ........... 6,850 310

6 GHz–8 GHz ........... 3,600 670

8 GHz–12 GHz ......... 3,500 1,270

12 GHz–18 GHz ....... 3,500 360

18 GHz–40 GHz ....... 2,100 750

As discussed above, the proposed

special conditions would be applicable

initially to the K–C Aviation modified

Dassault Aviation, Mystere Falcon 50.

Should K–C Aviation apply at a later

date for a change to the supplemental

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 design

features on the Dassault Aviation,

Mystere Falcon 50 airplane. 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 airplane.

The substance of these special

conditions for this airplane has been

subjected to the notice and comment

procedure 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 immediately.

Therefore, these special conditions are

being made effective 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 citiation for these

special conditions is as follows

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

44702, 44704.

The Special Conditions

According, the following special

conditions are issued as part of the

supplemental type certification basis for

the K–C Aviation modified Dassault

Aviation, Mystere Falcon 50 series

airplanes.

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 May 3,

1996.

Stewart R. Miller,

Acting Manager, Transport Airplane

Directorate, Aircraft Certification Service,

ANM–100.

[FR Doc. 96–12085 Filed 5–13–96; 8:45 am]

BILLING CODE 4910–13–M

14 CFR Part 39

[Docket No. 95–NM–127–AD; Amendment

39–9614; AD 92–10–13 R1]

RIN 2120–AA64

Airworthiness Directives; McDonnell

Douglas Model DC–9–80 Series

Airplanes and Model MD–88 Airplanes

AGENCY: Federal Aviation

Administration, DOT.

ACTION: Final rule.

SUMMARY: This amendment revises an

existing airworthiness directive (AD),

applicable to certain McDonnell

Douglas Model DC–9–80 series

airplanes and Model MD–88 airplanes,

that currently requires a revision to the

FAA-approved Airplane Flight Manual

(AFM) to specify that the autothrottles

must be disconnected if engine surge

(stall) is detected during takeoff. That

AD was prompted by results of an

accident investigation, which revealed

that the digital flight guidance computer

(DFGC) on these airplanes can

incorrectly identify an engine surge or

stall as being an engine failure. This can

cause the autothrottles to unclamp and

automatically advance the thrust levers

during takeoff. The actions specified by

that AD are intended to prevent

automatic advance of the thrust lever on

a surging engine during takeoff, which

could cause engine failure. This

amendment provides for an optional

terminating action for the AFM revision.

DATES: Effective June 13, 1996.

The incorporation by reference of

certain publications listed in the

regulations is approved by the Director

of the Federal Register as of June 13,

1996.

ADDRESSES: The service information

referenced in this AD may be obtained

from McDonnell Douglas Corporation,

3855 Lakewood Boulevard, Long Beach,

California 90846, Attention: Technical

Publications Business Administration,

Department C1–L51 (2–60). 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 FAA,

Transport Airplane Directorate, Los

Angeles Aircraft Certification Office,

3960 Paramount Boulevard, Lakewood,

California; or at the Office of the Federal

Register, 800 North Capitol Street, NW.,

suite 700, Washington, DC.

FOR FURTHER INFORMATION CONTACT:

Robert Baitoo, Aerospace Engineer,

Propulsion Branch, ANM–140L, FAA,

Transport Airplane Directorate, Los

Angeles Aircraft Certification Office,

3960 Paramount Boulevard, Lakewood,