[Federal Register: February 28, 2007 (Volume 72, Number 39)]
[Rules and Regulations]
[Page 8882-8887]
From the Federal Register Online via GPO Access [wais.access.gpo.gov]
[DOCID:fr28fe07-2]
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DEPARTMENT OF TRANSPORTATION
Federal Aviation Administration
14 CFR Part 25
[Docket No. NM355; Notice No. 25-346-SC]
Special Conditions: Dassault Aviation Model Falcon 7X Airplane;
Interaction of Systems and Structures, Limit Pilot Forces, and High
Intensity Radiated Fields (HIRF) Protection
AGENCY: Federal Aviation Administration (FAA), DOT.
ACTION: Final special conditions.
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SUMMARY: These special conditions are issued for the Dassault Aviation
Model Falcon 7X airplane. This airplane will have novel or unusual
design features when compared to the state of technology envisioned in
the airworthiness standards for transport category airplanes. These
design features include interaction of systems and structures, limit
pilot forces, and electrical and electronic flight control systems. The
applicable airworthiness regulations do not contain adequate or
appropriate safety standards for these design features. 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.
EFFECTIVE DATE: March 30, 2007.
FOR FURTHER INFORMATION CONTACT: Thomas Rodriguez, FAA, International
Branch, ANM-116, Transport Airplane Directorate, Aircraft Certification
Service, 1601 Lind Avenue SW., Renton, Washington, 98057-3356;
telephone (425) 227-1137; facsimile (425) 227-1149.
SUPPLEMENTARY INFORMATION:
Background
On June 4, 2002, Dassault Aviation, 9 rond Point des Champs
Elys[eacute]es, 75008, Paris, France, applied for a type certificate
for its new Model Falcon 7X airplane. The Model Falcon 7X is a 19
passenger transport category airplane, powered by three aft mounted
Pratt & Whitney PW307A high bypass ratio turbofan engines. The airplane
is operated using a fly-by-wire (FBW) primary flight control system.
This will be the first application of a FBW primary flight control
system in an airplane primarily intended for private/corporate use.
The Dassault Aviation Model Falcon 7X design incorporates equipment
that was not envisioned when part 25 was created. This equipment
affects the interaction of systems and structures, limit pilot forces,
and high intensity radiated fields (HIRF) protection. Therefore,
special conditions are required to provide the level of safety
equivalent to that established by the regulations.
Type Certification Basis
Under the provisions of 14 CFR 21.17, Dassault Aviation must show
that the Model Falcon 7X airplane meets the applicable provisions of
part 25, as amended by Amendments 25-1 through 25-108.
If the Administrator finds that the applicable airworthiness
regulations
[[Page 8883]]
(i.e., 14 CFR part 25) do not contain adequate or appropriate safety
standards for the Model Falcon 7X because of a novel or unusual design
feature, special conditions are prescribed under the provisions of
Sec. 21.16.
In addition to the applicable airworthiness regulations and special
conditions, the Model Falcon 7X 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.
The FAA issues special conditions, as defined in Sec. 11.19, are
issued 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 Model Falcon 7X airplane will incorporate the following novel
or unusual design features: interaction of systems and structures,
limit pilot forces, and electrical and electronic flight control
systems. These special conditions address equipment which may affect
the airplane's structural performance, either directly or as a result
of failure or malfunction; pilot limit forces; and electrical and
electronic systems which perform critical functions that may be
vulnerable to HIRF.
These special conditions are identical or nearly identical to those
previously required for type certification of other Dassault airplane
models. In general, the special conditions were derived initially from
standardized requirements developed by the Aviation Rulemaking Advisory
Committee (ARAC), comprised of representatives of the FAA, Europe's
Joint Aviation Authorities (now replaced by the European Aviation
Safety Agency), and industry.
Additional special conditions will be issued for other novel or
unusual design features of the Dassault Model Falcon 7X airplane. These
additional proposed special conditions will pertain to the following
topics:
Dive Speed Definition With Speed Protection System, Sudden Engine
Stoppage,
High Incidence Protection Function,
Side Stick Controllers,
Lateral-Directional and Longitudinal Stability and Low Energy
Awareness,
Flight Envelope Protection: General Limiting Requirements,
Flight Envelope Protection: Normal Load Factor (g) Limiting,
Flight Envelope Protection: Pitch, Roll and High Speed Limiting
Functions,
Flight Control Surface Position Awareness,
Flight Characteristics Compliance via Handling Qualities Rating Method,
and
Operation Without Normal Electrical Power.
Final special conditions have been issued for the Model Falcon 7X
pertaining to Pilot Compartment View--Hydrophobic Coatings in Lieu of
Windshield Wipers January 10, 2007 (72 FR 1135).
Discussion of Comments
Notice of proposed special conditions no. 26-06-10-SC for Dassault
Aviation Model Falcon 7X airplanes was published in the Federal
Register on October 18, 2006 (FR 71 61427). No comments were received,
and the special conditions are adopted as proposed.
Discussion
Because of these rapid improvements in airplane technology, the
applicable airworthiness regulations do not contain adequate or
appropriate safety standards for these design features. Therefore, in
addition to the requirements of part 25, subparts C and D, the
following three special conditions apply.
Special Condition No. 1. Interaction of Systems and Structures
The Dassault Model Falcon 7X is equipped with systems that may
affect the airplane's structural performance either directly or as a
result of failure or malfunction. The effects of these systems on
structural performance must be considered in the certification
analysis. This analysis must include consideration of normal operation
and of failure conditions with required structural strength levels
related to the probability of occurrence.
Previously, special conditions have been specified to require
consideration of the effects of systems on structures. The special
condition for the Model Falcon 7X is nearly identical to that issued
for other fly-by-wire airplanes.
Special Condition No. 2. Limit Pilot Forces
Like some other certificated transport category airplane models,
the Dassault Model Falcon 7X airplane is equipped with a side stick
controller instead of a conventional wheel or control stick. This kind
of controller is designed to be operated using only one hand. The
requirement of Sec. 25.397(c), which defines limit pilot forces and
torques for conventional wheel or stick controls, is not appropriate
for a side stick controller. Therefore, a special condition is
necessary to specify the appropriate loading conditions for this kind
of controller.
Special Condition No. 3. High Intensity Radiated Fields (HIRF)
Protection
The Dassault Model Falcon X will utilize electrical and electronic
systems which perform critical functions. These systems may be
vulnerable to HIRF external to the airplane. There is no specific
regulation that addresses requirements for protection of electrical and
electronic systems from HIRF. With the trend toward increased power
levels from ground-based transmitters and the advent of space and
satellite communications, coupled with electronic command and control
of the airplane, the immunity of critical avionics/electronics and
electrical systems to HIRF must be established.
To ensure that a level of safety is achieved that is equivalent to
that intended by the regulations incorporated by reference, a special
condition is needed for the Dassault Model Falcon 7X airplane. This
special condition requires that avionics/electronics and electrical
systems that perform critical functions be designed and installed to
preclude component damage and interruption.
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 cockpit-installed
equipment through the cockpit window apertures is undefined. Based on
surveys and analysis of existing HIRF emitters, adequate protection
from HIRF exists when there is compliance with either paragraph 1 OR 2
below:
1. A minimum threat of 100 volts rms (root-mean-square) 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 field strengths
indicated in the table below for the frequency ranges indicated. Both
peak and average field strength components from the table are to be
demonstrated.
[[Page 8884]]
------------------------------------------------------------------------
Field strength
(volts per meter)
Frequency -------------------
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 the
Dassault Model Falcon 7X. 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.
Conclusion
This action affects only certain novel or unusual design features
of the Dassault Model Falcon 7X airplane. It is not a rule of general
applicability.
List of Subjects in 14 CFR Part 25
Aircraft, Aviation safety, Reporting and recordkeeping
requirements.
0
The authority citation for these special conditions is as follows:
Authority: 49 U.S.C. 106(g), 40113, 44701, 44702, 44704.
The Special Conditions
0
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 Dassault Aviation Model Falcon 7X
airplanes.
1. Interaction of Systems and Structures.
In addition to the requirements of part 25, subparts C and D, the
following special conditions apply:
a. For airplanes equipped with systems that affect structural
performance--either directly or as a result of a failure or
malfunction--the influence of these systems and their failure
conditions must be taken into account when showing compliance with the
requirements of part 25, subparts C and D. Paragraph c below must be
used to evaluate the structural performance of airplanes equipped with
these systems.
b. Unless shown to be extremely improbable, the airplane must be
designed to withstand any forced structural vibration resulting from
any failure, malfunction, or adverse condition in the flight control
system. These loads must be treated in accordance with the requirements
of paragraph a above.
c. Interaction of Systems and Structures.
(1) General: The following criteria must be used for showing
compliance with this special condition for interaction of systems and
structures and with Sec. 25.629 for airplanes equipped with flight
control systems, autopilots, stability augmentation systems, load
alleviation systems, flutter control systems, and fuel management
systems. If this special condition is used for other systems, it may be
necessary to adapt the criteria to the specific system.
(a) The criteria defined herein address only the direct structural
consequences of the system responses and performances. They cannot be
considered in isolation but should be included in the overall safety
evaluation of the airplane. These criteria may, in some instances,
duplicate standards already established for this evaluation. These
criteria are applicable only to structures whose failure could prevent
continued safe flight and landing. Specific criteria that define
acceptable limits on handling characteristics or stability requirements
when operating in the system degraded or inoperative modes are not
provided in this special condition.
(b) Depending upon the specific characteristics of the airplane,
additional studies may be required that go beyond the criteria provided
in this special condition in order to demonstrate the capability of the
airplane to meet other realistic conditions, such as alternative gust
or maneuver descriptions for an airplane equipped with a load
alleviation system.
(c) The following definitions are applicable to this paragraph.
Structural performance: Capability of the airplane to meet the
structural requirements of part 25.
Flight limitations: Limitations that can be applied to the airplane
flight conditions following an in-flight occurrence and that are
included in the flight manual (e.g., speed limitations and avoidance of
severe weather conditions).
Operational limitations: Limitations, including flight limitations,
that can be applied to the airplane operating conditions before
dispatch (e.g., fuel, payload, and Master Minimum Equipment List
limitations).
Probabilistic terms: The probabilistic terms (probable, improbable,
and extremely improbable) used in these special conditions are the same
as those used in Sec. 25.1309.
Failure condition: The term failure condition is the same as that
used in Sec. 25.1309. However, this special condition applies only to
system failure conditions that affect the structural performance of the
airplane (e.g., system failure conditions that induce loads, change the
response of the airplane to inputs such as gusts or pilot actions, or
lower flutter margins).
(2) Effects of Systems on Structures.
(a) General. The following criteria will be used in determining the
influence of a system and its failure conditions on the airplane
structure.
(b) System fully operative. With the system fully operative, the
following apply:
(1) Limit loads must be derived in all normal operating
configurations of the system from all the limit conditions specified in
subpart C (or used in lieu of those specified in subpart C), taking
into account any special behavior of such a system or associated
functions or any effect on the structural performance of the airplane
that may occur up to the limit loads. In particular, any significant
non-linearity (rate of displacement of control surface, thresholds or
any other system non-linearities) must be accounted for in a realistic
or conservative way when deriving limit loads from limit conditions.
(2) The airplane must meet the strength requirements of part 25
(static strength, residual strength), using the specified factors to
derive ultimate loads from the limit loads defined above. The effect of
non-linearities must be investigated beyond limit conditions to ensure
that the behavior of the system presents no anomaly compared to the
behavior below limit conditions. However, conditions beyond limit
conditions need not be considered, when it can be shown that the
airplane has design features that will not allow it to exceed those
limit conditions.
(3) The airplane must meet the aeroelastic stability requirements
of Sec. 25.629.
[[Page 8885]]
(c) System in the failure condition. For any system failure
condition not shown to be extremely improbable, the following apply:
(1) At the time of occurrence. Starting from 1g level flight
conditions, a realistic scenario, including pilot corrective actions,
must be established to determine the loads occurring at the time of
failure and immediately after failure.
(i) For static strength substantiation, these loads multiplied by
an appropriate factor of safety that is related to the probability of
occurrence of the failure are ultimate loads to be considered for
design. The factor of safety (FS) is defined in Figure 1.
[GRAPHIC] [TIFF OMITTED] TR28FE07.040
(ii) For residual strength substantiation, the airplane must be
able to withstand two thirds of the ultimate loads defined in paragraph
(c)(1)(i) of this section. For pressurized cabins, these loads must be
combined with the normal operating differential pressure.
(iii) Freedom from aeroelastic instability must be shown up to the
speeds defined in Sec. 25.629(b)(2). For failure conditions that
result in speed increases beyond VC/ MC, freedom
from aeroelastic instability must be shown to increased speeds, so that
the margins intended by Sec. 25.629(b)(2) are maintained.
(iv) Failures of the system that result in forced structural
vibrations (oscillatory failures) must not produce loads that could
result in detrimental deformation of primary structure.
(2) For the continuation of the flight. For the airplane in the
system failed state and considering any appropriate reconfiguration and
flight limitations, the following apply:
(i) The loads derived from the following conditions (or used in
lieu of the following conditions) at speeds up to VC/
MC or the speed limitation prescribed for the remainder of
the flight must be determined:
(A) The limit symmetrical maneuvering conditions specified in
Sec. Sec. 25.331 and in 25.345.
(B) The limit gust and turbulence conditions specified in
Sec. Sec. 25.341 and in 25.345.
(C) The limit rolling conditions specified in Sec. 25.349 and the
limit unsymmetrical conditions specified in Sec. Sec. 25.367 and
25.427(b) and (c).
(D) The limit yaw maneuvering conditions specified in Sec. 25.351.
(E) The limit ground loading conditions specified in Sec. Sec.
25.473 and 25.491.
(ii) For static strength substantiation, each part of the structure
must be able to withstand the loads in paragraph (c)(2)(i) of this
special condition multiplied by a factor of safety, depending on the
probability of being in this failure state. The factor of safety is
defined in Figure 2.
[[Page 8886]]
[GRAPHIC] [TIFF OMITTED] TR28FE07.041
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 1.5 factor of safety must be applied to all
limit load conditions specified in subpart C.
(iii) For residual strength substantiation, the airplane must be
able to withstand two thirds of the ultimate loads defined in paragraph
(c)(2)(ii). For pressurized cabins, these loads must be combined with
the normal operating differential pressure.
(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 aeroelastic instability must be shown up to a
speed determined from Figure 3. 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 Sec. 25.629(b).
[GRAPHIC] [TIFF OMITTED] TR28FE07.042
V' = Clearance speed as defined by Sec. 25.629(b)(2).
V'' = Clearance speed as defined by Sec. 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 aeroelastic instability must also be shown up to
V' in Figure 3 above for any probable system failure condition combined
with any damage required or selected for investigation by Sec.
25.571(b).
(3) Consideration of certain failure conditions may be required by
other sections of this Part, 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 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. As far as reasonably practicable, the flightcrew
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
[[Page 8887]]
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 flightcrew. For example, failure
conditions that result in a factor of safety between the airplane
strength and the loads of part 25, subpart C, below 1.25 or flutter
margins below V'' must be signaled to the crew during flight.
(e) Dispatch with known failure conditions. If the airplane is to
be dispatched in a known 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 conditions must be met, including the provisions of paragraph
(b), for the dispatched condition and paragraph (c) for subsequent
failures. Expected operational limitations may be taken into account in
establishing Pj as the probability of failure occurrence for
determining the safety margin in Figure 1. Flight limitations and
expected operational limitations may be taken into account in
establishing Qj as the combined probability of being in the
dispatched failure condition and the subsequent failure condition for
the safety margins in Figures 2 and 3. These limitations must be such
that the probability of being in this combined failure state and then
subsequently encountering limit load conditions is extremely
improbable. No reduction in these safety margins is allowed, if the
subsequent system failure rate is greater than 1E-3 per flight hour.
2. Limit Pilot Forces. In addition to the requirements of Sec.
25.397(c) the following special condition applies.
The limit pilot forces are:
a. For all components between and including the handle and its
control stops.
------------------------------------------------------------------------
Pitch Roll
------------------------------------------------------------------------
Nose up 200 lbf. (pounds force)........... Nose left 100 lbf.
Nose down 200 lbf......................... Nose right 100 lbf.
------------------------------------------------------------------------
b. For all other components of the side stick control assembly, but
excluding the internal components of the electrical sensor assemblies
to avoid damage as a result of an in-flight jam.
------------------------------------------------------------------------
Pitch Roll
------------------------------------------------------------------------
Nose up 125 lbf........................... Nose left 50 lbf.
Nose down 125 lbf......................... Nose right 50 lbf.
------------------------------------------------------------------------
3. High Intensity Radiated Fields (HIRF) Protection.
a. Protection from Unwanted Effects of High Intensity Radiated
Fields. Each electrical and electronic system which 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.
b. For the purposes of this special condition, 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 February 21, 2007.
Ali Bahrami,
Manager, Transport Airplane Directorate, Aircraft Certification
Service.
[FR Doc. E7-3499 Filed 2-27-07; 8:45 am]
BILLING CODE 4910-13-P