Special Conditions: Alenia Model C-27J Airplane; Liquid Oxygen System, 54457-54458 [E9-25396]

Agencies

• Federal Aviation Administration
• DEPARTMENT OF TRANSPORTATION

[Federal Register Volume 74, Number 203 (Thursday, October 22, 2009)]
[Rules and Regulations]
[Pages 54457-54458]
From the Federal Register Online via the Government Printing Office [www.gpo.gov]
[FR Doc No: E9-25396]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 25

[Docket No. NM408; Special Conditions No. 25-391-SC]


Special Conditions: Alenia Model C-27J Airplane; Liquid Oxygen 
System

AGENCY: Federal Aviation Administration (FAA), DOT.

ACTION: Final special conditions.

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SUMMARY: These special conditions are issued for the Alenia Model C-27J 
airplane. This airplane will have novel or unusual design features when 
compared to the state of technology described in the airworthiness 
standards for transport-category airplanes. These design features 
include a liquid-oxygen (LOX) system. The applicable airworthiness 
regulations do not contain adequate or appropriate safety standards for 
oxygen systems that use liquid oxygen. 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: Effective Date: November 23, 2009.

FOR FURTHER INFORMATION CONTACT: Tom Groves, FAA, International Branch, 
ANM-116, Transport Airplane Directorate, Aircraft Certification 
Service, 1601 Lind Avenue, SW., Renton, Washington 98057-3356; 
telephone (425) 227-1503, facsimile (425) 227-1149.

SUPPLEMENTARY INFORMATION: 

Background

    On March 27, 2006, the European Aviation Safety Agency (EASA) 
forwarded to the FAA an application from Alenia Aeronautica of Torino, 
Italy, for U.S. type certification of a twin-engine commercial 
transport designated as the Model C-27J. The C-27J is a twin-
turbopropeller, cargo-transport aircraft with a maximum takeoff weight 
of 30,500 kilograms.

Type Certification Basis

    Under the provisions of section 21.17 of Title 14, Code of Federal 
Regulations (14 CFR) and the bilateral agreement between the U.S. and 
Italy, Alenia Aeronautica must show that the C-27J meets the applicable 
provisions of 14 CFR part 25, as amended by Amendments 25-1 through 25-
87. Alenia also elects to comply with Amendment 25-122, effective 
September 5, 2007, for 14 CFR 25.1317.
    If the Administrator finds that existing airworthiness regulations 
do not adequately or appropriately address safety standards for the C-
27J due to a novel or unusual design feature, the FAA prescribes 
special conditions under provisions of 14 CFR 21.16.
    In addition to the applicable airworthiness regulations and special 
conditions, the C-27J 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, and the FAA must issue a finding of 
regulatory adequacy pursuant to Sec.  611 of Public Law 92-574, the 
``Noise Control Act of 1972.''
    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).
    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 also apply to 
the other model under Sec.  21.101.

Novel or Unusual Design Features

    The Alenia Model C-27J incorporates a liquid-oxygen system, 
including a liquid-oxygen converter, valves, evaporating coils, lines, 
regulators, indicators, fittings, etc. The existing airworthiness 
regulations do not adequately or appropriately address safety standards 
for the design and installation of oxygen systems that utilize liquid 
oxygen. These special conditions for the C-27J 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 for these novel or unusual design 
features.

Discussion

    There are no specific regulations that address the design and 
installation of oxygen systems that utilize liquid oxygen for storage. 
Existing requirements, such as Sec. Sec.  25.1309, 25.1441(b) and (c), 
25.1451, and 25.1453, in the Alenia C-27J certification basis, provide 
some design standards for crew and medical-oxygen-system installations. 
However, additional design standards for oxygen systems utilizing 
liquid oxygen are needed to supplement the existing applicable 
requirements. The quantity of liquid oxygen involved in this 
installation and the potential for hazards that may result when the 
oxygen content of an enclosed area becomes too high because of system 
leaks, malfunction, or damage from external sources, make it necessary 
to assure adequate safety standards are applied to the design and 
installation of the system in Alenia C-27J airplanes. These special 
conditions require Alenia to preclude or minimize the risk of these 
potential hazards. These special conditions are also intended to assure 
the safe operation of the liquid-oxygen system, and therefore require 
that:
     Adequate gaseous oxygen is available at temperatures 
appropriate for breathing;
     The liquid-oxygen converter and gaseous-oxygen-
distribution lines are installed in locations that minimize their 
potential for damage;
     The quantity of available oxygen is clearly indicated to 
the flight crew;
     The system is designed to prevent leakage of oxygen into 
the cabin;
     Condensation from the system is collected and drained 
overboard;
     The system must be protected from possible ignition 
sources and structural damage; and
     Appropriate maintenance and operational instructions are 
provided to ensure the system's safe operation.
    Taken together, these requirements would ensure that this liquid-
oxygen system provides an equivalent level of safety to traditional 
oxygen systems.

Discussion of Comments

    Notice of proposed special conditions no. 25-09-04-SC for the 
Alenia model C-27J airplane was published in the Federal Register on 
July 13, 2009. No comments were received, and the special conditions 
are adopted as proposed.

Applicability

    As discussed above, these special conditions are applicable to the 
Alenia C-27J. Should Alenia apply at a later date for a change to the 
type certificate to include another airplane model incorporating the 
same novel or unusual design features, these special conditions apply 
to that model as well under Sec.  21.101.

[[Page 54458]]

Conclusion

    This action affects only certain novel or unusual design features 
of the Alenia C-27J. It is not a rule of general applicability, and it 
affects only the applicant that applied to the FAA for approval of 
these features on the airplane.

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 the C-27J airplane.

General

    1. The liquid-oxygen system must be located to minimize the 
possibility of exposure of occupants to liquid oxygen from a leak or 
condensation.
    2. The liquid-oxygen converter must be located in the airplane so 
that there is no risk of damage to the converter due to an uncontained 
rotor or propeller-blade failure.
    3. The liquid-oxygen system's associated gaseous-oxygen-
distribution lines should be designed and located to minimize the 
hazard from uncontained rotor or propeller-blade debris.
    4. The flight-deck oxygen system must meet the supply requirements 
of part 121 in the event the oxygen-distribution line is severed by a 
rotor or propeller-blade fragment.
    5. The pressure-relief valves on the liquid-oxygen converters must 
be vented overboard. The ventilation means must be configured such that 
liquid and gaseous oxygen will be exhausted so that oxygen will not 
accumulate inside the airplane. Means must be provided to prevent 
hydrocarbon-fluid migration from impinging upon the vent outlet of the 
liquid-oxygen system.
    6. The system must include provisions to ensure complete conversion 
of the liquid oxygen to gaseous oxygen. The resultant oxygen gas must 
be delivered to the first oxygen outlet for breathing such that the 
temperature is no more than 35[deg]F less than the cabin ambient 
temperature or 32[deg]F (whichever is greater), under the conditions of 
the maximum demand or flow of oxygen gas for normal use of the oxygen 
system. A liquid-oxygen shutoff valve must be installed on the main 
oxygen-distribution line prior to any secondary lines. The shutoff 
valve must be both compatible with liquid-oxygen temperatures and 
readily accessible (either directly if manual, or by remote activation 
if automatic).
    7. If multiple converters are used, the design should ensure that a 
leak in one converter does not result in leakage of oxygen from any 
other converter.
    8. Approved flexible hoses must be used for the airplane-systems 
connections to shock-mounted converters, where movement relative to the 
airplane may occur.
    9. Condensation from system components or lines must be collected 
by drip pans, shields, or other suitable collection means, and drained 
overboard through a drain fitting separate from the liquid-oxygen vent 
fitting, as specified in special condition 5, above.
    10. Oxygen-system components must be burst-pressure tested to 3.0 
times, and proof-pressure tested to 1.5 times, the maximum normal 
operating pressure. Compliance with the requirement for burst testing 
may be shown by similarity analysis, or a combination of similarity 
analysis and test.
    11. Oxygen-system components must be electrically bonded to the 
airplane structure.
    12. All gaseous or liquid-oxygen connections located in close 
proximity to an ignition source must be shrouded and vented overboard 
using the system specified in special condition 5, above.
    13. A means must be provided to indicate to the flight crew the 
quantity of available oxygen.
    14. Instructions for Continued Airworthiness (ICA) per Sec.  
25.1529 must be provided for the safe operation and maintenance of the 
liquid-oxygen system.
    15. Emergency procedures must be developed for the aircraft crew to 
address aircraft-safety-related malfunctions of the liquid-oxygen 
system.
    16. The liquid-oxygen-system equipment, including the tank, must be 
retained under all loads up to those specified in Sec.  25.561(b)(3). 
The tank must be able to resist rupture and to retain the liquid 
oxygen, under the inertia forces prescribed for the emergency-landing 
conditions in Sec.  25.561. In addition, the tank must be able to 
withstand, without failure, the vibration, inertia, fluid, and 
structural loads that it may be subjected to in operation. The liquid-
oxygen components, including the tank, must be protected from scraping 
or impact from baggage, cargo, or other contents.

Ali Bahrami,
Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. E9-25396 Filed 10-21-09; 8:45 am]
BILLING CODE 4910-13-P