Special Conditions; Dassault Aviation Model Falcon 2000 Airplane, High Altitude Operation

DEPARTMENT OF TRANSPORTATION

14 CFR Part 25

[Docket No. NM-100; Final Special Conditions No. 25-ANM-90]

Special Conditions; Dassault Aviation Model Falcon 2000 Airplane,

High Altitude Operation

AGENCY: Federal Aviation Administration, DOT.

ACTION: Final special conditions; request for comments.

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SUMMARY: These special conditions are issued for the Dassault Aviation

Model Falcon 2000 airplane. This new airplane will have an unusual

design feature associated with an unusually high operating altitude

(47,000 feet), for which the applicable airworthiness regulations do

not contain adequate or appropriate safety standards. 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 November 4,

1994.

Comments must be received on or before January 2, 1995.

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-100, 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-100.'' 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: Stephen Slotte, FAA, Standardization

Branch, ANM-113, Transport Airplane Directorate, Aircraft Certification

Service, 1601 Lind Avenue SW., Renton, Washington, 98055-4056,

telephone (206) 227-2797.

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 the 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 submit with those

comments a self-addressed, stamped postcard on which the following

statement is made: ``Comments to Docket No. NM-100.'' The postcard will

be date stamped and returned to the commenter.

Background

On September 13, 1989, Dassault Aviation, B.P. 24, 33701 Merignac

Cedex, France, applied for a new type certificate in the transport

airplane category for the Model Falcon 2000 airplane. The Dassault

Aviation Model Falcon 2000 is a medium-sized transcontinental business

jet powered by two General Electric/Garrett CFE 738 turbofan engines

mounted on pylons extending from the aft fuselage. Each engine will be

capable of delivering 5,600 lbs. thrust. The airplane will be capable

of operating with two flight crewmembers and eight passengers.

The type design of the Model Falcon 2000 contains a number of novel

and unusual design features for an airplane type certificated under the

applicable provisions of part 25 of the Federal Aviation Regulations

(FAR). Those features include the relatively small passenger cabin

volume and a high maximum operating altitude. The applicable

airworthiness requirements do not contain adequate or appropriate

safety standards for the Falcon 2000; therefore, special conditions are

necessary to establish a level of safety equivalent to that established

in the regulations.

Type Certification Basis

Under the provisions of Sec. 21.17 of the FAR, Dassault Aviation

must show that the Falcon 2000 meets the applicable provisions of part

25, effective February 1, 1965, as amended by Amendments 25-1 through

25-69. The certification basis may also include later amendments to

part 25 that are not relevant to these special conditions. In addition,

the certification basis for the Falcon 2000 includes part 34, effective

September 10, 1990, plus any amendments in effect at the time of

certification; and part 36, effective December 1, 1969, as amended by

Amendments 36-1 through the amendment in effect at the time of

certification. These special conditions form an additional part of the

type certification basis. In addition, the certification basis may

include other special conditions that are not relevant to these 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 Falcon 2000 because of a novel or

unusual design feature, special conditions are prescribed under the

provisions of Sec. 21.16 to establish a level of safety equivalent to

that established in the regulations.

Special conditions, as appropriate, are issued in accordance with

Sec. 11.49 of the FAR after public notice, as required by Secs. 11.28

and 11.29, and become part of the type certification basis in

accordance with Sec. 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, or should any other model already included on

the same type certificate be modified to incorporate the same novel or

unusual design feature, the special conditions would also apply to the

other model under the provisions of Sec. 21.101(a)(1).

Novel or Unusual Design Feature

The Dassault Aviation Falcon 2000 will incorporate an unusual

design feature in that it will be certified to operate up to an

altitude of 47,000 feet.

The FAA considers certification of transport category airplanes for

operation at altitudes greater than 41,000 feet to be a novel or

unusual feature because current part 25 does not contain standards to

ensure the same level of safety as that provided during operation at

lower altitudes. Special conditions have therefore been adopted to

provide adequate standards for transport category airplanes previously

approved for operation at these high altitudes, including certain

Learjet models, the Boeing Model 747, Dassault-Breguet Falcon 900,

Canadair Model 600, Cessna Model 650, Israel Aircraft Industries Model

1125, and Cessna Model 560. The special conditions for the Learjet

Model 45 are considered the most applicable to the Falcon 2000 and its

proposed operation and are therefore used as the basis for the special

conditions described below.

Damage tolerance methods are proposed to be used to ensure pressure

vessel integrity while operating at the higher altitudes, in lieu of

the \1/2\-bay crack criterion used in some previous special conditions.

Crack growth data are used to prescribe an inspection program that

should detect cracks before an opening in the pressure vessel would

allow rapid depressurization. Initial crack sizes for detection are

determined under Sec. 25.571, as amended by Amendment 25-72. The

maximum extent of failure and pressure vessel opening determined from

the above analysis must be demonstrated to comply with the

pressurization section of the proposed special conditions, which state

that the cabin altitude after failure must not exceed the cabin

altitude/time curve limits shown in Figures 3 and 4.

In order to ensure that there is adequate fresh air for crewmembers

to perform their duties, to provide reasonable passenger comfort, and

to enable occupants to better withstand the effects of decompression at

high altitudes, the ventilation system must be designed to provide 10

cubic feet of fresh air per minute per person during normal operations.

Therefore, these special conditions require that crewmembers and

passengers be provided with 10 cubic feet of fresh air per minute per

person. In addition, during the development of the supersonic transport

special conditions, it was noted that certain pressurization failures

resulted in hot ram or bleed air being used to maintain pressurization.

Such a measure can lead to cabin temperatures that exceed human

tolerance. Therefore, these special conditions require airplane

interior temperature limits following probable and improbable failures.

Continuous flow passenger oxygen equipment is certificated for use

up to 40,000 feet; however, for rapid decompressions above 34,000 feet,

reverse diffusion leads to low oxygen partial pressures in the lungs,

to the extent that a small percentage of passengers may lose useful

consciousness at 35,000 feet. The percentage increases to an estimated

60 percent at 40,000 feet, even with the use of the continuous flow

system. Therefore, to prevent permanent physiological damage, the cabin

altitude must not exceed 25,000 feet for more than 2 minutes, or 40,000

feet for any time period. The maximum peak cabin altitude of 40,000

feet is consistent with the standards established for previous

certification programs. In addition, at high altitudes the other

aspects of decompression sickness have a significant, detrimental

effect on pilot performance (for example, a pilot can be incapacitated

by internal expanding gases).

Decompression resulting in cabin altitudes above the 37,000-foot

limit depicted in Figure 4 approaches the physiological limits of the

average person; therefore, every effort must be made to provide the

pilots with adequate oxygen equipment to withstand these severe

decompressions. Reducing the time interval between pressurization

failure and the time the pilots receive oxygen will provide a safety

margin against being incapacitated and can be accomplished by the use

of mask-mounted regulators. These special conditions therefore require

pressure demand masks with mask-mounted regulators for the flightcrew.

This combination of equipment will provide the best practical

protection for the failures covered by the special conditions and for

improbable failures not covered by the special conditions, provided the

cabin altitude is limited.

As discussed above, these special conditions are applicable to the

Dassault Aviation Model Falcon 2000. Should Dassault Aviation apply at

a later date for a change to the type certificate to include another

model incorporating the same novel or unusual design feature, these

special conditions would apply to that model as well under the

provisions of Sec. 21.101(a)(1).

Conclusion

This action affects only certain design features on the Dassault

Aviation Model Falcon 2000 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 the 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 citation for these special conditions is as follows:

Authority: 49 U.S.C. app. 1344, 1348(c), 1352, 1354(a), 1355,

1421 through 1341, 1502, 1651(b)(2), 42 U.S.C. 1857f-10, 4321 et

seq.; E.O. 11514; and 49 U.S.C. 106(g).

The Special Conditions

Accordingly, the following special conditions are issued as part of

the type certification basis for the Dassault Aviation Model Falcon

2000:

Operation to 47,000 Feet

1. Pressure Vessel Integrity.

(a) The maximum extent of failure and pressure vessel opening that

can be demonstrated to comply with paragraph 4 (Pressurization) of this

special condition must be determined. It must be demonstrated by crack

propagation and damage tolerance analysis supported by testing that a

larger opening or a more severe failure than demonstrated will not

occur in normal operations.

(b) Inspection schedules and procedures must be established to

ensure that cracks and normal fuselage leak rates will not deteriorate

to the extent that an unsafe condition could exist during normal

operation.

(c) With regard to the fuselage structural design for cabin

pressure capability above 45,000 feet altitude, the pressure vessel

structure, including doors and windows, must comply with

Sec. 25.365(d), using a factor of 1.67 instead of the 1.33 factor

prescribed.

2. Ventilation. In lieu of the requirements of Sec. 25.831(a), the

ventilation system must be designed to provide a sufficient amount of

uncontaminated air to enable the crewmembers to perform their duties

without undue discomfort or fatigue, and to provide reasonable

passenger comfort during normal operating conditions and also in the

event of any probable failure of any system that could adversely affect

the cabin ventilating air. For normal operations, crewmembers and

passengers must be provided with at least 10 cubic feet of fresh air

per minute per person, or the equivalent in filtered, recirculated air

based on the volume and composition at the corresponding cabin pressure

altitude of not more than 8,000 feet.

3. Air Conditioning. In addition to the requirements of

Sec. 25.831, paragraphs (b) through (e), the cabin cooling system must

be designed to meet the following conditions during flight above 15,000

feet mean sea level (MSL):

(a) After any probable failure, the cabin temperature-time history

may not exceed the values shown in Figure 1.

(b) After any improbable failure, the cabin temperature-time

history may not exceed the values shown in Figure 2.

4. Pressurization. In addition to the requirements of Sec. 25.841,

the following apply:

(a) The pressurization system, which includes for this purpose

bleed air, air conditioning, and pressure control systems, must prevent

the cabin altitude from exceeding the cabin altitude-time history shown

in Figure 3 after each of the following:

(1) Any probable malfunction or failure of the pressurization

system. The existence of undetected, latent malfunctions or failures in

conjunction with probable failures must be considered.

(2) Any single failure in the pressurization system, combined with

the occurrence of a leak produced by a complete loss of a door seal

element, or a fuselage leak through an opening having an effective area

2.0 times the effective area that produces the maximum permissible

fuselage leak rate approved for normal operation, whichever produces a

more severe leak.

(b) The cabin altitude-time history may not exceed that shown in

Figure 4 after each of the following:

(1) The maximum pressure vessel opening resulting from an initially

detectable crack propagating for a period encompassing four normal

inspection intervals. Mid-panel cracks and cracks through skin-stringer

and skin-frame combinations must be considered.

(2) The pressure vessel opening or duct failure resulting from

probable damage (failure effect) while under maximum operating cabin

pressure differential due to a tire burst, engine rotor burst, loss of

antennas or stall warning vanes, or any probable equipment failure

(bleed air, pressure control, air conditioning, electrical source(s),

etc.) that affects pressurization.

(3) Complete loss of thrust from all engines.

(c) In showing compliance with paragraphs 4(a) and 4(b) of these

special conditions (Pressurization), it may be assumed that an

emergency descent is made by approved emergency procedure. A 17-second

crew recognition and reaction time must be applied between cabin

altitude warning and the initiation of an emergency descent.

Note: For flight evaluation of the rapid descent, the test

article must have the cabin volume representative of what is

expected to be normal, such that Dassault Aviation must reduce the

total cabin volume by that which would be occupied by the

furnishings and total number of people.

5. Oxygen Equipment and Supply.

(a) A continuous flow oxygen system must be provided for the

passengers.

(b) A quick-donning pressure demand mask with mask-mounted

regulator must be provided for each pilot. Quick-donning from the

stowed position must be demonstrated to show that the mask can be

withdrawn from stowage and donned with 5 seconds.

BILLING CODE 4910-13-M

TR16NO94.000

TR16NO94.001

BILLING CODE 4910-13-C

Issued in Renton, Washington, on November 4, 1994.

Darrell M. Pederson,

Acting Manager, Transport Airplane Directorate, Aircraft Certification

Service, ANM-100.

[FR Doc. 94-28285 Filed 11-15-94; 8:45 am]