[Federal Register Volume 80, Number 115 (Tuesday, June 16, 2015)]
[Rules and Regulations]
[Pages 34242-34244]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2015-14816]



Federal Aviation Administration

14 CFR Part 23

[Docket No. FAA-2015-0722; Special Conditions No. 23-265-SC]

Special Conditions: Honda Aircraft Company, Model HA-420; Fire 
Extinguishing for Overwing Pylon Mounted Engines

AGENCY: Federal Aviation Administration (FAA), DOT.

ACTION: Final special conditions; request for comments.


SUMMARY: These special conditions are issued for the Honda Aircraft 
Company model HA-420 airplane. This airplane will have a novel or 
unusual design feature associated with mounting the engines on the 
wings in close proximity to the aft fuselage. The applicable 
airworthiness regulations do not contain adequate or appropriate safety 
standards for this design feature. 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: The effective date of these special conditions is June 16, 2015.
    We must receive your comments by July 16, 2015.

ADDRESSES: Send comments identified by docket number FAA-2015-0722 
using any of the following methods:
    [ssquf] Federal eRegulations Portal: Go to http://www.regulations.gov and follow the online instructions for sending your 
comments electronically.
    [ssquf] 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.
    [ssquf] Hand Delivery of 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.
    [ssquf] Fax: Fax comments to Docket Operations at 202-493-2251.
    Privacy: The FAA will post all comments it receives, without 
change, to http://regulations.gov, including any personal information 
the commenter provides. Using the search function of the docket Web 
site, 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), as well as at http://DocketsInfo.dot.gov.
    Docket: Background documents or comments received may be read at  
http://www.regulations.gov at any time. Follow the online instructions 
for accessing the docket or go to the 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.

Administration, Aircraft Certification Service, Small Airplane 
Directorate, ACE-111, 901 Locust, Kansas City, Missouri 64106; 816-329-
3239, fax 816-329-4090, email [email protected].

SUPPLEMENTARY INFORMATION: The FAA has determined, in accordance with 5 
U.S.C. 553(b)(3)(B) and (d)(3), that notice and opportunity for prior 
public comment hereon are unnecessary because the substance of these 
special conditions has been subject to the public comment process in 
several prior instances with no substantive comments received. The FAA 
therefore finds that good cause exists for making these special 
conditions effective upon issuance.

         Special condition No.               Company/Airplane Model
23-210-SC.............................  Adam Aircraft Model A700.
23-245-SC.............................  Cirrus Design Corporation Model
23-221-SC.............................  Embraer S.A. Model EMB-500.

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 ask 
that you send us two copies of written comments.
    We will consider all comments we receive on or before the closing 
date for comments. We will consider comments

[[Page 34243]]

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 


    On October 11, 2006, Honda Aircraft Company applied for a type 
certificate for their new model HA-420. On October 10, 2013, Honda 
Aircraft Company requested an extension with an effective application 
date of October 1, 2013. This extension changed the type certification 
basis to amendment 23-62.
    The HA-420 is a four to five passenger (depending on 
configuration), two crew, lightweight business jet with a 43,000-foot 
service ceiling and a maximum takeoff weight of 9963 pounds. The 
airplane is powered by two GE-Honda Aero Engines (GHAE) HF-120 turbofan 
    The turbofan engines are mounted on a single pylon on each wing 
near the aft fuselage. These types of aft mounted engine installations, 
along with the need to protect such installed engines from fires, were 
not envisioned in the development of the part 23 normal category 
regulations. The performance of the airplane is such that a pilot may 
not be able to locate a suitable landing site and safely land the 
airplane prior to a fire escaping the fire containment capabilities of 
the engine fire zone.

Type Certification Basis

    Under the provisions of 14 CFR 21.17, Honda Aircraft Company must 
show that the model HA-420 meets the applicable provisions of part 23, 
as amended by Amendment 23-1 through Amendment 23-62 thereto.
    If the Administrator finds that the applicable airworthiness 
regulations (i.e., 14 CFR part 23) do not contain adequate or 
appropriate safety standards for the model HA-420 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 HA-420 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. In addition, the FAA must issue a 
finding of regulatory adequacy under section 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 novel or 
unusual design feature, the special conditions would also apply to the 
other model.

Novel or Unusual Design Features

    The model HA-420 will incorporate the following novel or unusual 
design features: Turbofan engines are mounted on a single pylon on each 
wing near the aft fuselage not in the pilot's line of sight.
    This type of configuration was not envisioned in the development of 
part 23 normal category airplanes. Therefore, a special condition for 
the engine fire extinguishing system on the model HA-420 is required.
    As the extinguishing agent is subject to change during the service 
life of the airplane, the certification basis must include SC 23.1195, 
SC 23.1197, SC 23.1199, and SC 23.1201 in their entirety.


    Part 23 has historically addressed fire protection through 
prevention, identification, and containment. Prevention has been 
accomplished by minimizing the potential for ignition of flammable 
fluids and vapors. Identification has traditionally been achieved 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 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 the 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 
isolation means do not extinguish the fire, the occupants can safely 
exit the aircraft prior to breaching the firewall. 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 maintain control and 
continue safe flight. 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.
    Amendment 23-62 applies to the model HA-420 and addresses the 
concerns above by requiring engine fire extinguishing for engines 
embedded in the fuselage or in pylons on the aft fuselage, but do not 
address engines mounted in pylons over the wing as used on the model 
HA-420. The engine fire concerns for engines mounted in overwing pylons 
near the aft fuselage are the same as those associated with engines 
mounted in pylons on the aft fuselage; therefore, the engine fire 
extinguishing requirements included in part 23, amendments 23-1 through 
23-62 apply.


    As discussed above, these special conditions are applicable to the 
model HA-420. Should Honda Airplane 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.


    This action affects only certain novel or unusual design features 
on one model of airplanes. It is not a rule of general applicability 
and affects only the applicant who applied to the FAA for approval of 
these features on the airplane.
    The substance of these special conditions has been subjected to the 
notice and comment period in several prior instances, identified above, 
and has been derived without substantive change from those previously 
issued. It is unlikely that prior public comment would result in a 
significant change from the substance contained herein. Therefore, 
notice and opportunity for prior public comment hereon are unnecessary 
and the FAA finds good cause, in accordance with 5 U.S.C. 553(b)(3)(B) 
and (d)(3), making these special conditions effective upon issuance. 
The FAA is requesting comments to allow interested persons to submit 
views that may not have been submitted in response to the prior 
opportunities for comment described above.

List of Subjects in 14 CFR Part 23

    Aircraft, Aviation safety, Signs and symbols.

[[Page 34244]]


    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 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 Honda Airplane Company model HA-420 

1. Fire Extinguishing for Overwing Pylon Mounted Engines

SC 23.1195 Fire Extinguishing Systems

    (a) Fire extinguishing systems must be installed and compliance 
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 must be used.
    (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

    The following applies:
    (a) Fire extinguishing agents must--
    (1) Be capable of extinguishing flames emanating from any burning 
of 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 
    (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 
member on flight deck duty.

SC 23.1199 Extinguishing Agent Containers

    The following applies:
    (a) Each extinguishing agent container must have a pressure relief 
valve to prevent bursting of the container by excessive internal 
    (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 
    (d) The temperature of each container must be maintained under 
intended operating conditions, to prevent the pressure in the container 
    (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 System Materials

    The following apply:
    (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 

    Issued in Kansas City, Missouri, on June 9, 2015.
Earl Lawrence,
Small Airplane Directorate, Aircraft Certification Service.
[FR Doc. 2015-14816 Filed 6-15-15; 8:45 am]