Special Conditions: Mitsubishi Aircraft Corporation, Model MRJ-200 Airplane; Operation Without Normal Electrical Power, 26741-26743 [2019-12120]

Agencies

• Federal Aviation Administration
• DEPARTMENT OF TRANSPORTATION

[Federal Register Volume 84, Number 111 (Monday, June 10, 2019)]
[Rules and Regulations]
[Pages 26741-26743]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2019-12120]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 25

[Docket No. FAA-2019-0424; Special Conditions No. 25-748-SC]


Special Conditions: Mitsubishi Aircraft Corporation, Model MRJ-
200 Airplane; Operation Without Normal Electrical Power

AGENCY: Federal Aviation Administration (FAA), DOT.

ACTION: Final special conditions; request for comments.

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SUMMARY: These special conditions are issued for the Mitsubishi 
Aircraft Corporation (MITAC), Model MRJ-200 airplanes. These airplanes 
will have a novel or unusual design feature when compared to the state 
of technology envisioned in the airworthiness standards for transport 
category airplanes. These design features are electrical and electronic 
systems that perform critical functions, the loss of which could be 
catastrophic to the airplane. The applicable airworthiness regulations 
do not contain adequate or appropriate safety standards for this 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.

DATES: This action is effective on MITAC on June 10, 2019. Send 
comments on or before July 25, 2019.

ADDRESSES: Send comments identified by Docket No. FAA-2019-0424 using 
any of the following methods:
     Federal eRegulations Portal: Go to https://www.regulations.gov/ and follow the online instructions for sending 
your comments electronically.
     Mail: Send comments to Docket Operations, M-30, U.S. 
Department of Transportation (DOT), 1200 New Jersey Avenue SE, Room 
W12-140, West Building Ground Floor, Washington, DC, 20590-0001.
     Hand Delivery or Courier: Take comments to Docket 
Operations in Room W12-140 of the West Building Ground Floor at 1200 
New Jersey Avenue SE, Washington, DC, between 9 a.m. and 5 p.m., Monday 
through Friday, except Federal holidays.
     Fax: Fax comments to Docket Operations at 202-493-2251.
    Privacy: The FAA will post all comments it receives, without 
change, to https://www.regulations.gov/, including any personal 
information the commenter provides. Using the search function of the 
docket website, anyone can find and read the electronic form of all 
comments received into any FAA docket, including the name of the 
individual sending the comment (or signing the comment for an 
association, business, labor union, etc.). DOT's complete Privacy Act 
Statement can be found in the Federal Register published on April 11, 
2000 (65 FR 19477-19478).
    Docket: Background documents or comments received may be read at 
https://www.regulations.gov/ at any time. Follow the online instructions 
for accessing the docket or go to Docket Operations in Room W12-140 of 
the West Building Ground Floor at 1200 New Jersey Avenue SE, 
Washington, DC, between 9 a.m. and 5 p.m., Monday through Friday, 
except Federal holidays.

FOR FURTHER INFORMATION CONTACT: Dean Thompson, Airplane and Flight 
Crew Interface Section, AIR-671, Transport Standards Branch, Policy and 
Innovation Division, Aircraft Certification Service, Federal Aviation 
Administration, 2200 South 216th Street, Des Moines, Washington 98198; 
telephone and fax 206-231-3165; email [email protected].

SUPPLEMENTARY INFORMATION: The substance of these special conditions 
has been published in the Federal Register for public comment in 
several prior instances with no substantive comments received. 
Therefore, the FAA has determined that prior public notice and comment 
are unnecessary, and finds that, for the same reason, good cause exists 
for adopting these special conditions upon publication in the Federal 
Register.

Comments Invited

    We invite interested people 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 will consider all comments we receive by the closing date for 
comments. We may change these special conditions based on the comments 
we receive.

Background

    On March 3, 2015, MITAC applied for a type certificate for their 
new Model MRJ-200 airplanes. The MITAC Model MRJ-200 airplane is a low-
wing, conventional-tail design with two wing-mounted turbofan engines. 
The airplane has seating for 92 passengers and a maximum takeoff weight 
of 95,000 lbs.

Type Certification Basis

    Under the provisions of title 14, Code of Federal Regulations (14 
CFR) 21.17, MITAC must show that the Model MRJ-200 airplanes meet the 
applicable provisions of part 25, as amended by amendments 25-1 through 
25-141; and part 26 continued airworthiness certification requirements, 
as amended by Amendments 26-1 through 26-6.
    If the Administrator finds that the applicable airworthiness 
regulations (i.e., 14 CFR part 25) do not contain adequate or 
appropriate safety standards for the MITAC MRJ-200 airplanes because of 
a novel or unusual design feature, special conditions are prescribed 
under the provisions of Sec.  21.16.
    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, these special conditions would also apply to 
the other model under Sec.  21.101.
    In addition to the applicable airworthiness regulations and special 
conditions, the MITAC MRJ-200 airplanes 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 14 CFR 11.19, in 
accordance with Sec.  11.38, and they become part of the type 
certification basis under Sec.  21.17(a)(2).

Novel or Unusual Design Features

    The MITAC Model MRJ-200 airplanes will incorporate the following 
novel or unusual design features:

[[Page 26742]]

    Electrical and electronic systems that perform critical functions, 
the loss of which may result in the loss of flight controls and other 
critical systems and may be catastrophic to the airplane.

Discussion

    The MITAC Model MRJ-200 airplane has a fly-by-wire flight control 
system that requires a continuous source of electrical power to 
maintain an operable flight-control system. Section 25.1351(d), 
Operation without normal electrical power, requires safe operation in 
visual flight rule (VFR) conditions for at least 5 minutes after loss 
of normal electrical power, excluding the battery. This rule was 
structured around a traditional design using mechanical control cables 
and linkages for flight control. These manual controls allow the crew 
to maintain aerodynamic control of the airplane for an indefinite time 
after loss of all electrical power. Under these conditions, a 
mechanical flight control system provided the crew with the ability to 
fly the airplane while attempting to identify the cause of the 
electrical failure, restart engine(s) if necessary, and attempt to re-
establish some of the electrical power generation capability.
    A critical assumption in Sec.  25.1351(d) is that the airplane is 
in VFR conditions at the time of an electrical failure. This is not a 
valid assumption in today's airline operating environment, where 
airplanes fly much of the time in instrument meteorological conditions 
on air traffic control defined flight paths. Another assumption in the 
existing rule is that the loss of all normal electrical power is the 
result of the loss of all engines. The 5-minute period in the rule is 
to allow at least one engine to be restarted following an all-engine 
power loss in order to continue the flight to a safe landing. However, 
service experience on airplanes with similar electrical power system 
architecture as the MITAC Model MRJ-200 airplanes have shown that at 
least the temporary loss of all electrical power for causes other than 
all-engine failure is not extremely improbable.
    To maintain the same level of safety envisioned by the existing 
rule with traditional mechanical flight controls, the MITAC Model MRJ-
200 airplane design must not be time-limited in its operation under all 
reasonably foreseeable conditions, including loss of all normal sources 
of engine or auxiliary power unit (APU)-generated electrical power. 
Unless MITAC can show that the non-restorable loss of the engine and 
APU power sources is extremely improbable, MITAC must demonstrate that 
the airplane can maintain safe flight and landing (including steering 
and braking on the ground for airplanes using steer/brake-by-wire or 
fly-by-wire speed brake panels) with the use of its emergency/alternate 
electrical-power systems. These electrical-power systems, or the 
minimum restorable electrical-power sources, must be able to power 
loads that are essential for continued safe flight and landing, 
including those required for the maximum length of approved flight 
diversion.
    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.

Applicability

    As discussed above, these special conditions are applicable to the 
MITAC Model MRJ-200 airplanes. Should MITAC 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 
on one model of airplanes. It is not a rule of general applicability.

List of Subjects in 14 CFR Part 25

    Aircraft, Aviation safety, Reporting and recordkeeping 
requirements.

Authority Citation

    The authority citation for these special conditions is as follows:

    Authority:  49 U.S.C. 106(f), 106(g), 40113, 44701, 44702, 
44704.

The Special Conditions

    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 MITAC Model MRJ-200 airplanes.
    In lieu of 14 CFR 25.1351(d), the following special conditions 
apply:
    1. The applicant must show by test or a combination of test and 
analysis that the airplane is capable of continued safe flight and 
landing with all normal electrical power sources inoperative, as 
prescribed by paragraphs 1.a. and 1.b., below. For purposes of these 
special conditions, normal sources of electrical power generation do 
not include any alternate power sources such as the battery, ram air 
turbine, or independent power systems such as the flight control 
permanent magnet generating system. In showing capability for continued 
safe flight and landing, the applicant must account for systems 
capability, effects on crew workload and operating conditions, and the 
physiological needs of the flightcrew and passengers for the longest 
diversion time for which the applicant is seeking approval.
    a. In showing compliance with this requirement, the applicant must 
account for common-cause failures, cascading failures, and zonal 
physical threats.
    b. The applicant may consider the ability to restore operation of 
portions of the electrical power generation and distribution system if 
it can be shown that unrecoverable loss of those portions of the system 
is extremely improbable. The design must provide an alternative source 
of electrical power for the time required to restore the minimum 
electrical power generation capability required for safe flight and 
landing. The applicant may exclude unrecoverable loss of all engines 
when showing compliance with this requirement.
    2. Regardless of any electrical generation and distribution system 
recovery capability shown under paragraph 1 of these special 
conditions, sufficient electrical system capability must be provided 
to:
    a. Allow time to descend, with all engines inoperative, at the 
speed that provides the best glide distance, from the maximum operating 
altitude to the top of the engine restart envelope, and
    b. Subsequently allow multiple start attempts of the engines and 
auxiliary power unit (APU). The design must provide this capability in 
addition to the electrical capability required by existing part 25 
requirements related to operation with all engines inoperative.
    3. The airplane emergency electrical power system must be designed 
to supply:
    a. Electrical power required for immediate safety, which must 
continue to operate without the need for crew action following the loss 
of the normal electrical power, for a duration sufficient to allow 
reconfiguration to provide a non-time-limited source of electrical 
power.
    b. Electrical power required for continued safe flight and landing 
for the maximum diversion time.
    4. If the applicant uses APU-generated electrical power to satisfy 
the requirements of these special conditions, and if reaching a 
suitable runway for landing is beyond the capacity of the battery 
systems, then the APU must be able to be started under any foreseeable 
flight condition prior to the depletion of the battery or the 
restoration of normal electrical power, whichever occurs first. Flight 
test must

[[Page 26743]]

demonstrate this capability at the most critical condition.
    a. The applicant must show that the APU will provide adequate 
electrical power for continued safe flight and landing.
    b. The operating limitations section of the airplane flight manual 
(AFM) must incorporate non-normal procedures that direct the pilot to 
take appropriate actions to activate the APU after loss of normal 
engine-driven generated electrical power.
    5. As part of showing compliance with these special conditions, the 
tests to demonstrate loss of all normal electrical power must also take 
into account the following:
    a. The assumption that the failure condition occurs during night 
instrument meteorological conditions (IMC) at the most critical phase 
of the flight, relative to the worst possible electrical power 
distribution and equipment-loads-demand condition.
    b. After the un-restorable loss of normal engine generator power, 
the airplane engine restart capability is provided and operations 
continued in IMC.
    c. The airplane is demonstrated to be capable of continued safe 
flight and landing. The length of time must be computed based on the 
maximum diversion time capability for which the airplane is being 
certified. The applicant must account for airspeed reductions resulting 
from the associated failure or failures.
    d. The airplane must provide adequate indication of loss of normal 
electrical power to direct the pilot to the non-normal procedures, and 
the operating limitations section of the AFM must incorporate non-
normal procedures that will direct the pilot to take appropriate 
actions.

    Issued in Des Moines, Washington, on June 4, 2019.
Paul Siegmund,
Acting Manager, Transport Standards Branch, Policy and Innovation 
Division, Aircraft Certification Service.
[FR Doc. 2019-12120 Filed 6-7-19; 8:45 am]
 BILLING CODE 4910-13-P