[Federal Register Volume 63, Number 20 (Friday, January 30, 1998)]
[Rules and Regulations]
[Pages 4563-4564]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 98-2399]

[[Page 4563]]



Federal Aviation Administration

14 CFR Part 23

[Docket No. 143CE; Special Conditions No. SC-23-ACE-93]

Special Conditions: EXTRA Flugzeugbau GmbH, Model EA-400; Heat 
Capability of the Engine Mount and the Fuselage Connection Joint

AGENCY: Federal Aviation Administration (FAA), DOT.

ACTION: Final special conditions.


SUMMARY: These special conditions are issued for the EXTRA Flugzeugbau 
GmbH, Model EA-400 airplane. This airplane will have a novel or unusual 
design feature associated with the Heat Capability of the Engine Mount 
and the Fuselage Connection Joint. 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.

EFFECTIVE DATE: March 2, 1998.

Kenneth W. Payauys, Aerospace Engineer, Standards Office (ACE-110), 
Small Airplane Directorate, Aircraft Certification Service, Federal 
Aviation Administration, 601 East 12th Street, Kansas City, Missouri 
64106; telephone (816) 426-5688.



    On April 6, 1993, EXTRA Flugzeugbau GmbH applied for a type 
certificate for their new Model EA-400. The EA-400 design is a two-
place (side-by-side), all composite material, cantilevered high-wing, 
retractable gear, unpressurized, single reciprocating engine airplane 
with a maximum design weight of 3,974 pounds (1800 kilograms). It is 
intended for 14 CFR part 91 operation as a day-VFR normal category 
    The proposed type design of the EXTRA Flugzeugbau GmbH Model EA-400 
airplane incorporates certain novel and unusual design features for 
which the exiting airworthiness regulations do not contain adequate or 
appropriate safety standards. These features include certain 
performance characteristics necessary for this type of airplane design 
that were not foreseen by the existing regulations.
    This special condition addresses the flight safety of the EA-400 in 
case of an engine compartment fire with resulting heat conduction 
through the engine-mounts to composite structure joints beyond the 
firewall. The type certificate applicant shall demonstrate that the 
airplane structure design, especially the engine-mount attachments to 
the structure beyond the firewall, is able to retain the engine while 
withstanding the following:
    1. An engine compartment fire, the loss of the most highly loaded 
composite joint, and heating of the next most highly loaded composite 
joint from those that remain;
    2. Maximum continuous power for 5 minutes; and
    3. Combined airplane flight maneuver and gust limit loads for at 
least 15 minutes.

    Note: The engine-mount attachments at the firewall are not the 
same as the engine-to-engine-mount attachments, which contain 
vibration dampers.

Type Certification Basis

    Under the provisions of 14 CFR part 21, Sec. 21.17, EXTRA 
Flugzeugbau GmbH must show that the Model EA-400 meets the applicable 
provisions of 14 CFR part 23, effective February 1, 1965, through 
amendment 23-45, effective August 6, 1993; 14 CFR part 36, effective 
December 1, 1969, through amendment 36-21 effective December 28, 1995; 
exemptions, if any; equivalent level of safety findings, if any; and 
the special conditions adopted by this rulemaking action.
    Special conditions are issued, as appropriate, under 14 CFR part 11 
Sec. 11.49 after public notice, as required by Sec. 11.28 and 
Sec. 11.29(b), and become part of the type certification basis in 
accordance with 14 CFR part 21, 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 under the provisions of 14 CFR part 21, Sec. 21.101(a)(1)).

Novel or Unusual Design Features

    The Model EA-400 will incorporate the following novel or unusual 
design features: Heat Capability of the Engine Mount and the Fuselage 
Connection Joint.

Discussion of Comments

    Notice of proposed special conditions No. SC-23-ACE-93 for the 
EXTRA Flugzeugbau GmbH EA-400 airplanes was published on November 20, 
1997 (62 FR 61926). No comments were received and the special 
conditions are adopted as proposed.


    As discussed above, these special conditions are applicable to the 
Model A-400. Should EXTRA Flugzeugbau GmbH apply at a later date for a 
change to the type certificate to include another model incorporating 
the same level or unusual design feature, the special conditions would 
apply to that model as well under the provisions of Sec. 21.101(a)(1).


    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.

List of Subjects in 14 CFR Part 23

    Aircraft, Aviation safety, Signs and symbols.


    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 11.28 and 11.49.

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 EXTRA Flugzeugbau GmbH Model EA-400 

Heat Capability of the Engine Mount and the Fuselage Connection Joint

    (a) Modify the airworthiness standards given in 14 CFR part 23, 
POWERPLANT FIRE PROTECTION, Nacelle areas behind firewalls 
(Sec. 23.1182), by making the most critical composite engine-mount 
attachment ineffective (assumed destroyed by heat). Then, for 15 
minutes, apply an additional flame test of 500 deg. C (932 deg. F) to 
the next most structurally critical engine-mount of those remaining. 
The flame shall encompass the whole engine-mount structural attach 
fitting. Conductive heat will affect the metallic and composite joint 
structural capability beyond the firewall. Test the joint structural 
capability with these simultaneous limit load conditions (under these 
conditions, the engine shall remain attached to the airplane):

[[Page 4564]]

    (1) The combined thrust, torque and gyroscopic loads resulting from 
the engine and propeller at maximum continuous power for the first 5 
minutes, and
    (2) The airplane normal inertial limit loads that result from the 
    (i) A maneuver load factor equal to that obtained from a constant 
altitude 30 deg. bank, combined with
    (ii) The positive and negative vertical design gust load factors 
that occur at the design maneuvering speed and the minimum flying 
weight, and
    (iii) A factor-of-safety equal to one.

    Issued in Kansas City, Missouri on January 22, 1998.
Marvin Nuss,
Assistant Manager, Small Airplane Directorate, Aircraft Certification 
[FR Doc. 98-2399 Filed 1-29-98; 8:45 am]