Special Conditions: Dassault Aviation Model Falcon 7X Airplane; Interaction of Systems and Structures, Limit Pilot Forces, and High Intensity Radiated Fields (HIRF) Protection, 8882-8887 [E7-3499]

Agencies

• Federal Aviation Administration
• DEPARTMENT OF TRANSPORTATION

[Federal Register Volume 72, Number 39 (Wednesday, February 28, 2007)]
[Rules and Regulations]
[Pages 8882-8887]
From the Federal Register Online via the Government Printing Office [www.gpo.gov]
[FR Doc No: E7-3499]


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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