[Federal Register Volume 73, Number 185 (Tuesday, September 23, 2008)]
[Rules and Regulations]
[Pages 54675-54677]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: E8-22154]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 23

[Docket No. CE287, Special Conditions No. 23-227-SC]


Special Conditions; Honda Aircraft Company, Model HA-420 HondaJet 
Airplane; Fire Extinguishing

AGENCY: Federal Aviation Administration (FAA), DOT.

ACTION: Final special conditions.

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SUMMARY: This notice issues special conditions for the Honda Aircraft

[[Page 54676]]

Company, Model HA-420 HondaJet Airplane. This new airplane will have 
novel and unusual design features not typically associated with normal, 
utility, acrobatic, and commuter category airplanes. These design 
features include turbofan engines and engine location, for which the 
applicable regulations do not contain adequate or appropriate 
airworthiness standards. These special conditions contain the 
additional airworthiness standards that the Administrator considers 
necessary to establish a level of safety equivalent to that established 
by the existing airworthiness standards.

DATES: Effective Date: September 15, 2008.

FOR FURTHER INFORMATION CONTACT: Leslie B. Taylor, Aerospace Engineer, 
Standards Office (ACE-110), Small Airplane Directorate, Aircraft 
Certification Service, Federal Aviation Administration, Room 301, 901 
Locust Street, Kansas City, Missouri 64106; telephone (816) 329-4134, 
e-mail: [email protected].

SUPPLEMENTARY INFORMATION:

Background

    On October 11, 2006, Honda Aircraft Company, Greensboro, North 
Carolina, made an application to the FAA for a new Type Certificate for 
the Honda Model HA-420 HondaJet. The Honda Model HA-420 HondaJet is an 
all new very light jet, twin engine, high performance, low wing, aft 
overwing mounted turbofan engine powered aircraft in the normal 
category including flight into known icing conditions, Reduced Vertical 
Separation Minima (RVSM) and single pilot operations. The Model HA-420 
HondaJet design criteria includes: 9963 pounds maximum gross weight, 
estimated maximum speed of 258 KIAS/0.72 Mach, cruise speed of 420 KTAS 
at 30,000 feet, and a 43,000 foot maximum altitude.
    Part 23 has historically addressed fire protection through 
prevention, identification, and containment. Prevention has been 
provided through minimizing the potential for ignition of flammable 
fluids and vapors. Identification has traditionally been provided by 
the location of the engines within the pilot's primary field of view 
and/or with the incorporation of fire detection systems. This 
philosophy has provided for both the rapid detection of a fire and 
confirmation when it has been extinguished. Containment has been 
provided through the isolation of designated fire zones through 
flammable fluid shutoff valves and firewalls. The containment 
philosophy also ensures that components of the engine control system 
will function effectively to permit a safe shutdown of the engine. 
However, containment has only been required to be demonstrated for 15 
minutes. In event of a fire in a traditional part 23 airplane, the 
corrective action is to land as soon as possible. For a small, simple 
aircraft originally envisioned by part 23, it is possible to descend 
the aircraft to a suitable landing site within 15 minutes. Thus, if the 
fire is not extinguished, the occupants can safely exit the aircraft 
before the firewall is breached. These simple and traditional aircraft 
normally have the engine located away from critical flight control 
systems and primary structure. This has ensured that, throughout the 
fire event, the pilot can continue safe flight and control. It has also 
made predicting the effects of a fire relatively easy. Other design 
features of these simple and traditional aircraft, such as low stall 
speeds and short landing distances, ensure that, even in the event of 
an off-field landing, the potential for a catastrophic outcome has been 
minimized.
    The certification basis for the Model HA-420 HondaJet does require 
that a fire detection system be installed. However, due to the engine 
location, fire extinguishing is also considered a requirement. A 
sustained fire could result in loss of control of the airplane and 
damage to the primary structure before an emergency landing could be 
made.

Type Certification Basis

    Under the provisions of 14 CFR, part 21, Sec.  21.17, Honda 
Aircraft Company must show that the Model HA-420 HondaJet meets the 
applicable provisions of 14 CFR, part 23, effective February 1, 1965, 
as amended by Amendments 23-1 through Amendment 23-55, effective March 
1, 2002; 14 CFR, part 36, effective December 1, 1969, through the 
amendment effective on the date of type certification; 14 CFR, part 34; 
exemptions, if any; and the special conditions adopted by this 
rulemaking action.

Discussion

    Special conditions, as appropriate, as defined in Sec.  11.19, are 
issued in accordance with Sec.  11.38, and become part of the type 
certification basis in accordance with Sec.  21.17.

Novel or Unusual Design Features

    The Honda Aircraft Company, Model HA-420 HondaJet will incorporate 
the following novel or unusual design features:

Engine Fire Extinguishing System

    The Model HA-420 HondaJet design includes engines mounted aft on 
the top of the wings; therefore, early visual detection of engine fires 
is precluded. The applicable existing regulations do not require fire 
extinguishing systems for engines. Aft mounted engine installations 
were not envisaged in the development of part 23; therefore, special 
conditions for a fire extinguishing system with the applicable agents, 
containers, and materials for the engines of the Model HA-420 HondaJet 
are appropriate.

Discussion of Comments

    A notice of proposed special conditions, Notice No. 23-08-04-SC, 
for the Model HA-420 HondaJet was published on June 25, 2008 (73 FR 
35979). No comments were received, and the special conditions are 
adopted as proposed.

Applicability

    As discussed above, these special conditions are applicable to the 
Model HA-420 HondaJet. Should Honda Aircraft Company 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 identified.

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 Final Special Conditions

    Accordingly, the Federal Aviation Administration (FAA) issues the 
following special conditions as part of the type certification basis 
for the Honda Aircraft Company, Model HA-420 HondaJet airplane:
    SC 23.1195, Fire extinguishing systems--Add the requirements of 14 
CFR Sec.  23.1195 as modified below while deleting, ``For commuter 
category airplanes.''

[[Page 54677]]

    (a) Fire extinguishing systems must be installed and compliance 
must be shown with the following:
    (1) Except for combustor, turbine, and tailpipe sections of 
turbine-engine installations that contain lines or components carrying 
flammable fluids or gases for which a fire originating in these 
sections is shown to be controllable, a fire extinguisher system must 
serve each engine compartment.
    (2) The fire extinguishing system, the quantity of the 
extinguishing agent, the rate of discharge, and the discharge 
distribution must be adequate to extinguish fires. An individual ``one 
shot'' system may be used except for embedded engines where a ``two-
shot'' system is required.
    (3) The fire extinguishing system for a nacelle must be able to 
simultaneously protect each compartment of the nacelle for which 
protection is provided.
    (b) If an auxiliary power unit is installed in any airplane 
certificated to this part, that auxiliary power unit compartment must 
be served by a fire extinguishing system meeting the requirements of 
paragraph (a)(2) of this section.
    SC 23.1197, Fire extinguishing agents--Add the requirement of 14 
CFR Sec.  23.1197 while deleting, ``For commuter category airplanes.''
    (a) Fire extinguishing agents must:
    (1) Be capable of extinguishing flames emanating from any burning 
fluids or other combustible materials in the area protected by the fire 
extinguishing system; and
    (2) Have thermal stability over the temperature range likely to be 
experienced in the compartment in which they are stored.
    (b) If any toxic extinguishing agent is used, provisions must be 
made to prevent harmful concentrations of fluid or fluid vapors (from 
leakage during normal operation of the airplane or as a result of 
discharging the fire extinguisher on the ground or in flight) from 
entering any personnel compartment, even though a defect may exist in 
the extinguishing system. This must be shown by test except for built-
in carbon dioxide fuselage compartment fire extinguishing systems for 
which:
    (1) Five pounds or less of carbon dioxide will be discharged, under 
established fire control procedures, into any fuselage compartment; or
    (2) Protective breathing equipment is available for each flight 
crewmember on flight deck duty.
    SC 23.1199, Extinguishing agent containers--Add the requirements of 
14 CFR Sec.  23.1199 while deleting, ``For commuter category 
airplanes.''
    (a) Each extinguishing agent container must have a pressure relief 
to prevent bursting of the container by excessive internal pressures.
    (b) The discharge end of each discharge line from a pressure relief 
connection must be located so that discharge of the fire extinguishing 
agent would not damage the airplane. The line must also be located or 
protected to prevent clogging caused by ice or other foreign matter.
    (c) A means must be provided for each fire extinguishing agent 
container to indicate that the container has discharged or that the 
charging pressure is below the established minimum necessary for proper 
functioning.
    (d) The temperature of each container must be maintained, under 
intended operating conditions, to prevent the pressure in the container 
from--
    (1) Falling below that necessary to provide an adequate rate of 
discharge, or
    (2) Rising high enough to cause premature discharge.
    (e) If a pyrotechnic capsule is used to discharge the extinguishing 
agent, each container must be installed so that temperature conditions 
will not cause hazardous deterioration of the pyrotechnic capsule.
    SC 23.1201, Fire extinguishing systems materials--Add the 
requirements of Sec.  23.1201 while deleting, ``For commuter category 
airplanes.''
    Fire extinguisher system materials must meet the following 
requirements:
    (a) No material in any fire extinguishing system may react 
chemically with any extinguishing agent so as to create a hazard.
    (b) Each system component in an engine compartment must be 
fireproof.

    Issued in Kansas City, Missouri on September 15, 2008.
John Colomy,
Acting Manager, Small Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. E8-22154 Filed 9-22-08; 8:45 am]
BILLING CODE 4910-13-P