[Federal Register: December 20, 2007 (Volume 72, Number 244)]
[Proposed Rules]
[Page 72265-72270]
From the Federal Register Online via GPO Access [wais.access.gpo.gov]
[DOCID:fr20de07-15]
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DEPARTMENT OF TRANSPORTATION
Federal Aviation Administration
14 CFR Part 23
[Docket No. CE275; Notice No. 23-07-04-SC]
Special Conditions: Aviation Technology Group, Inc., Javelin
Model 100; High Altitude Operations
AGENCY: Federal Aviation Administration (FAA), DOT.
ACTION: Notice of proposed special conditions.
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SUMMARY: This action proposes special conditions for the Aviation
Technology Group, Inc., Javelin Model 100 airplane. This airplane will
have a novel or unusual design feature(s) associated with high altitude
operations. The applicable airworthiness regulations do not contain
adequate or appropriate safety standards for these design features.
These proposed 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: We must receive your comments by January 22, 2008.
ADDRESSES: Mail two copies of your comments to: Federal Aviation
Administration, Regional Counsel, ACE-7, 901 Locust, Room 506, Kansas
City, Missouri 64106. You may deliver two copies to the Small Airplane
Directorate at the above address. Mark your comments: Docket No. CE275.
You may inspect comments in the Rules Docket weekdays, except Federal
holidays, between 7:30 a.m. and 4 p.m.
FOR FURTHER INFORMATION CONTACT: Leslie B. Taylor, Regulations & Policy
Branch, ACE-111, Federal Aviation Administration, Small Airplane
Directorate, Aircraft Certification Service, 901 Locust, Kansas City,
MO 64106; telephone (816) 329-4134; facsimile (816) 329-4090, e-mail at
leslie.b.taylor@faa.gov.
SUPPLEMENTARY INFORMATION:
Comments Invited
We invite interested parties to take part in this rulemaking by
sending written comments, data, or views. The most helpful comments
reference a specific portion of the special conditions, explain the
reason for any recommended change, and include supporting data. We ask
that you send us two copies of written comments.
We will file in the docket all comments we receive, as well as a
report summarizing each substantive public contact with FAA personnel
concerning these special conditions. You may inspect the docket before
and after the comment closing date. If you wish to review the docket in
person, go to the address in the ADDRESSES section of this preamble
between 7:30 a.m. and 4 p.m., Monday through Friday, except Federal
holidays.
We will consider all comments we receive on or before the closing
date for comments. We will consider comments filed late if it is
possible to do so without incurring expense or delay. We may change
these special conditions based on the comments we receive.
If you want the FAA to acknowledge receipt of your comments on this
proposal, include with your comments a pre-addressed, stamped postcard
on which the docket number appears. We will stamp the date on the
postcard and mail it back to you.
Background
On February 15, 2005, Aviation Technology Group (ATG), 8001 S.
InterPort Blvd., Englewood, CO 80112 applied for a type certificate for
their new Javelin Model 100 airplane. The Javelin Model 100 is a two-
seat, pressurized, retractable-gear, composite airplane with two
turbofan engines mounted in the aft fuselage.
The Aviation Technology Group, Inc. (ATG) Javelin Model 100 will be
certificated for operations at a maximum altitude of 45,000 feet. This
unusually high operating altitude constitutes a novel or unusual design
feature for which the applicable airworthiness regulations do not
contain adequate or appropriate safety standards. Therefore, it is
necessary to develop special conditions that provide the level of
safety equivalent to that established by the regulations.
ATG indicated they will fully comply with Special Conditions for
a., Pressure Vessel Integrity; b., Ventilation; and c., Air
Conditioning.
However, ATG is unable to fully comply with Special Conditions d.
Pressurization and e. Oxygen equipment and supply. As a result from
these discussions, the Special Conditions d. and e. were revised to
include an alternate means or compensating features that require the
use of an oxygen system and emergency descent procedures that addresses
a rapid decompression event.
Discussion
The 14 CFR part 23 certification basis for the ATG Javelin Model
100 is part 23, Amendment 23-55. The FAA issues high altitude special
conditions for airplanes when the certificated altitude exceeds human
physiological limits.
Crack growth could result in rapid depressurization to cabin
altitudes that exceed human physiological limits. Damage tolerance
methods are proposed to be used to assure pressure vessel integrity
while operating at the higher altitudes. Crack growth data is used to
prescribe an inspection program, which will detect cracks before an
opening in the pressure vessel would allow rapid depressurization.
Initial crack sizes for detection are determined under Sec. 23.571,
Amendment 23-55. The cabin altitude after permissible crack growth may
not exceed specified limits.
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.
Air conditioning special conditions are required because such a measure
can lead to cabin temperatures that exceed human tolerance 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
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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. 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.
Decompression above 37,000 feet can result in cabin altitudes that
approach the physiological limits of the average person; therefore,
every effort must be made to provide the pilot with adequate oxygen
equipment to withstand these severe decompressions. Reducing the time
interval between pressurization failure and the time the pilot receives
oxygen will provide a safety margin against being incapacitated and can
be accomplished by the use of mask-mounted regulators. The proposed
special condition, therefore, requires pressure demand masks with mask-
mounted regulators for the flight crew. This combination of equipment
will provide the best practical protection for the failures covered by
the proposed special conditions and for improbable failures not covered
by the special conditions, provided the cabin altitude is limited.
Type Certification Basis
Under 14 CFR part 21, Sec. 21.17, Aviation Technology Group, Inc.
must show that the Javelin Model 100 meets the applicable provisions of
part 23, as amended by Amendments 23-1 through 23-55 thereto.
If the Administrator finds that the applicable airworthiness
regulations in part 23 do not contain adequate or appropriate safety
standards for the Javelin Model 100 because of a novel or unusual
design feature, special conditions are prescribed under Sec. 21.16.
In addition to the applicable airworthiness regulations and special
conditions, the Javelin Model 100 must comply with the fuel vent and
exhaust emission requirements of 14 CFR part 34 and the noise
certification requirements of 14 CFR part 36, and the FAA must issue a
finding of regulatory adequacy under Sec. 611 of Public Law 92-574,
the ``Noise Control Act of 1972.''
The FAA issues special conditions, as defined in Sec. 11.19, under
Sec. 11.38, and they become part of the type certification basis under
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 or similar
novel or unusual design feature, the special conditions would also
apply to the other model under Sec. 21.101.
Novel or Unusual Design Features
The Javelin Model 100 will incorporate the following novel or
unusual design features:
Part 23 did not envision operation at the service ceiling requested
for this airplane. The methods used to ensure pressure vessel integrity
and to provide ventilation, air conditioning, pressurization, and
supplemental oxygen will be unique due to that operating altitude.
Applicability
As discussed above, these special conditions are applicable to the
Javelin Model 100. Should Aviation Technology Group, Inc., 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 Sec. 21.101.
Conclusion
This action affects only certain novel or unusual design features
on one model of airplane. It is not a rule of general applicability,
and it affects only the applicant who applied to the FAA for approval
of these features on the airplane.
List of Subjects in 14 CFR Part 23
Aircraft, Aviation safety, Signs and symbols.
Citation
The authority citation for these special conditions is as follows:
Authority: 49 U.S.C. 106(g), 40113, and 44701; 14 CFR 21.16 and
21.17; and 14 CFR 11.38 and 11.19.
The Proposed Special Conditions
Accordingly, the Federal Aviation Administration (FAA) proposes the
following special conditions as part of the type certification basis
for Aviation Technology Group, Inc., Javelin Model 100 airplanes.
a. Pressure Vessel Integrity.
1. The maximum extent of failure and pressure vessel opening that
can be demonstrated to comply with paragraph d (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.
2. 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.
b. Ventilation. In lieu of the requirements of Sec. 23.831(b), 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 which 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.
c. Air Conditioning. In addition to the requirements of Sec.
23.831, paragraphs (b), the cabin cooling system must be designed to
meet the following conditions during flight above 15,000 feet mean sea
level (MSL):
1. After any probable failure, the cabin temperature-time history
may not exceed the values shown in Figure 1. (Please see Advisory
Circular (AC) 23.1309-1C, pages 10 and 16.)
2. After any improbable failure, the cabin temperature-time history
may not exceed the values shown in Figure 2. (Please see AC 23.1309-1C,
pages 9 and 16.)
d. Pressurization: In addition to the requirements of Sec. 23.841,
the following revised Special Condition was designed to limit high
altitude exposure by slowing down the depressurization event and to
mitigate or eliminate acute affects of dangerously low atmospheric
pressure on flight crew and passengers.
1. For the purposes of this special condition, the pressurization
system includes bleed air, air conditioning, and pressure control
systems. The pressurization system must prevent the cabin altitude from
exceeding the cabin altitude-time history shown in Figure 3 after each
of the following:
(a) 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.
(b) 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
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having an effective area 2.0 times the effective area, which produces
the maximum permissible fuselage leak rate approved for normal
operation, whichever produces a more severe leak.
Note: The ATG Javelin Model 100 proposes to use a mechanical
canopy seal that is not subject to complete loss of the door seal
element. ATG must still show compliance by analysis and/or test 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.
2. The cabin altitude-time history may not exceed that shown in
Figure 4 after each of the following:
(a) 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.
(b) 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. In showing compliance
with paragraphs d.1 and d.2 of these special conditions
(Pressurization), it may be assumed that an emergency descent is made
by an approved emergency procedure. A 5-second crew recognition and
reaction time must be applied between cabin altitude warning and the
initiation of an emergency descent.
The additional Special Conditions below show full compliance to
paragraphs d.1. and d.2. and are applicable to both aircraft models.
Special Conditions that are aircraft model specific will be noted as
Mk-10 or Mk-20.
4. A decompression event is considered to be a rapid decompression
event; therefore, the following requirements must be met: The airplane
design must include an auto descent feature. The AFM must contain
specific instructions for its use, including considerations for air
traffic conditions, terrain awareness, annunciation, and accessibility
to the control(s) for automatic initiation of the descent sequence by
each occupant.
Note: For the flight evaluation of the rapid descent, the test
article must have the cabin volume representative of what is
expected to be normal, such that ATG must reduce the total cabin
volume by that which would be occupied by the furnishings and total
number of people.
5. ATG must provide flight crew and crewmember training
requirements, including physiological training that covers--
(a) Pressure or reverse cycle breathing,
(b) Rapid decompression training,
(c) Physical condition with respect to the hazards of high altitude
rapid decompression, and
(d) Recognition of decompression sickness symptoms and the need for
medical treatment.
6. The oxygen system must be compatible with paragraph e, Oxygen
Equipment and Supply Special Conditions.
(a) Mk-10: The flight crew and passenger(s) are required to use
oxygen masks for all operating altitudes above 25,000 feet.
(b) Mk-20: The flight crew and crewmember are required to use
oxygen masks for all operating altitudes above 10,000 feet.
7. ATG will show a means of guarding or de-activating the automatic
``auto emergency descent'' mode control in the forward or aft cockpit
to prevent inadvertent descent mode activation. Appropriate placards
will be required for each control device.
8. ATG will show a means of guarding or de-activating the in-flight
jettison canopy control, canopy fracturing system, or any other safety
critical control device in the forward or aft cockpit to prevent
inadvertent activation. Appropriate placards will be required for each
control device.
9. Cabin pressure loss must be annunciated as a warning. (See
Equivalent Level of Safety Findings for Cabin Pressurization.)
10. The AFM will include:
(a) Mk-10: Require a passenger briefing concerning items 4 through
9 above and the following:
(i) Seat belts.
(ii) Emergency exit.
(iii) Use of quick-donning oxygen mask system with a pressure-
demand as described in paragraph e2, Oxygen Equipment and Supply.
(b) Mk-20: Required flight crew and crewmember briefing concerning
items 4 through 10(a) above.
(i) The flight crew is the pilot and crewmember, which means a
person assigned to perform duty in an aircraft during flight time. The
Mk-20 poses safety concerns for a typical passenger since additional
training beyond the pre-flight briefing may be required to use the
emergency egress system (i.e., ejection seat). Each occupant of the Mk-
20 will be considered as a flight crew or crewmember and be required to
complete the minimum requisite training in paragraph d5 before flying
on the airplane.
e. Oxygen equipment and supply. After several follow-on FAA/ATG
discussions, the FAA Position Stage 3 for the Mk-10/Mk-20 Special
Conditions e.1 and e.2 were revised to include quick-donning pressure-
demand oxygen mask or an alternate helmet mounted oxygen mask for both
occupants that complies with TSO-C89 requirements up to 45,000 feet.
Furthermore, Special Condition e.3 was revised to allow a common oxygen
source with a larger capacity as an alternate means or compensating
feature.
1. In addition to the requirements of Sec. 23.1441(d), the
following applies: A quick-donning oxygen mask system with a pressure-
demand, mask mounted regulator that complies with TSO-C89 requirements
up to 45,000 feet must be provided for the flight crew. It must be
shown that each quick-donning mask can, with one hand and within 5
seconds, be placed on the face from its ready position, properly
secured, sealed, and supplying oxygen upon demand. Alternately, a
helmet mounted oxygen mask, panel mounted regulator that complies with
TSO-C89 requirements up to 45,000 feet may be provided to the flight
crew.
2. In addition to the requirements of Sec. 23.1443, the following
applies: A quick-donning oxygen mask system with a pressure-demand,
mask mounted regulator that complies with TSO-C89 requirements up to
45,000 feet must be provided for the passenger or crewmember.
Alternately, a helmet mounted oxygen mask, panel mounted regulator that
complies with TSO-C89 requirements up to 45,000 feet may be provided to
the passenger.
3. In addition to the requirements of Sec. 23.1445, the following
applies: If the flight crew and passenger/crewmember share a common
source of oxygen, a means to separately reserve the minimum supply
required by the flight crew must be provided. Alternately, if the
oxygen system can provide the minimum required for the flight crew as
well as all other occupants, the system can have a common source.
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Issued in Kansas City, Missouri on December 12, 2007.
James E. Jackson,
Acting Manager, Small Airplane Directorate, Aircraft Certification
Service.
[FR Doc. 07-6129 Filed 12-19-07; 8:45 am]
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