[Federal Register Volume 66, Number 194 (Friday, October 5, 2001)]
[Notices]
[Pages 51090-51092]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 01-25083]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration


Proposed [Preliminary] Airworthiness Criteria for Airworthiness 
Certification of Transport Category Airships

AGENCY: Federal Aviation Administration, DOT.

ACTION: Notice of availability; request for comments.

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SUMMARY: This notice announces the initiation of a Federal Aviation 
Administration (FAA) proposed airworthiness criteria for transport 
category airships. This notice advises the public, and especially 
manufacturers and potential manufacturers of transport category 
airships, that the FAA intends to develop an airworthiness criteria for 
transport category airships. This notice includes the Transport Airship 
Requirement (TAR) as developed by the Inspectie Verkeer en Waterstaat--
Divisie Luchtvaart (CAA-NL), the civil aviation authority of the 
Netherlands, and the Luftfahrt Bundesamt (LBA), the civil aviation 
authority for Germany. The TAR is based on 14 CFR part 25 transport 
airplane requirements and FAA-P-8110-2 Airship Design Criteria. It is 
intended that the TAR will form the core of a United States 
airworthiness criteria for transport category airships. While 
considering the TAR as the core criteria for the certification of 
transport airships, the FAA may propose alternate or additional 
requirements for some portions of the TAR. This notice is necessary to 
advise the public of the development of this proposed airworthiness 
criteria and give all interested persons an opportunity to present 
their views on it.

DATE: Send your comments by February 5, 2002.
    Discussion: In September 2001, the Small Airplane Directorate 
proposed airworthiness criteria for transport category airships. We are 
making the proposed airworthiness criteria, including ``Transport 
Airship Requirements'' (TAR), dated March 2000, available to the public 
and to all manufacturers for their comments.
    Airships are certificated under the provisions of 14 CFR 21.17(b), 
which

[[Page 51091]]

allows the Administrator to designate appropriate airworthiness 
criteria for special classes of aircraft, including airships. The 
designated criteria should provide a level of safety equivalent to the 
airworthiness regulations contained in 14 CFR parts 23, 25, 27, 29, 31, 
33 and 35. The FAA has decided that airworthiness criteria will be the 
most efficient and flexible method of obtaining an acceptable level of 
safety for transport category airships. The FAA bases this decision on 
the formative state of this industry and the potential for airships to 
develop into a new, viable, and important part of the aerospace 
industry. The FAA may decide to codify airship airworthiness 
requirements at a later time if warranted.
    The criteria will be acceptable airworthiness criteria, but not the 
only acceptable criteria, for certificating a transport category 
airship in the United States. It is intended to utilize the TAR as a 
basis for a harmonized airworthiness standard (criteria) that will 
allow bilateral certification and validation of airships between 
nations that have adopted the TAR as a basis for the certification of 
such airships. This notice is intended to be the first step in 
developing a transport airship airworthiness criteria, public comments 
and subsequent FAA determinations may lead to modifications or 
additions to the proposed criteria as the body of knowledge concerning 
large airship manufacture and operations expands. It is anticipated 
that there will be modification of the criteria from the current 
noticed version as experience and research warrant such changes.
    The proposed airworthiness criteria will apply to rigid, non-rigid, 
and semi-rigid transport category airships that are capable of vertical 
ascent (near equilibrium) operations. The proposed airworthiness 
criteria (and the TAR) does not include provisions for hybrid aircraft/
airships that require or operate with significant dynamic lift. The FAA 
expects modifications and additions to the proposed criteria will be 
necessary for specific airship projects, due to the unique nature of 
each large airship design.
    What is a transport airship? A transport airship is proposed to be 
defined as an airship that has an envelope volume larger than currently 
certificated normal category airships (425,000 cubic feet) or that has 
a combined crew-passenger capacity of 12 or more persons.
    When adopted, the FAA is proposing that the airworthiness criteria 
for transport airships may be used for a fixed time period. The public 
notice of availability for the airworthiness criteria will specify the 
effective period of use to ensure periodic reviews of the criteria.
    While considering the TAR as the core criteria for the 
certification of transport airships, the FAA has specific concerns and 
is interested in proposing alternate or additional requirements for 
some portions of the proposed criteria. The FAA especially desires to 
obtain public comment on the following:
    Flight Tests. 14 CFR part 21, Sec. 21.35, paragraphs (f)(1) and 
(f)(2), provides that a certain number of flight hours must be flown 
before type certification. In addition to the provisions of part 21, 
the FAA proposes that a transport category airship may be required to 
successfully accomplish a certain number of complete mooring, take off, 
and cargo exchange cycles prior to type certification. This may result 
in additional flight hours being required to accomplish this 
requirement, due to the longer mission times of airships.
    Flight in Rough Air, Gust and Turbulence Loads. TAR paragraphs 261, 
341 and other structural and handling requirements are based on 
knowledge of the turbulence and gust environments that the airship will 
encounter. The FAA is concerned that the determination of an 
appropriate gust model for analysis and the determination of the 
maximum gust and gust shape will be a limiting design parameter, 
especially for rigid and semi-rigid airships. Given the extremes of 
weather in the North American landmass (with respect to severity, 
magnitude and front speeds) and the historical experience concerning 
the loss of the Navy airships Shenandoah, Macon and Akron, the FAA 
desires to obtain additional specific comment on these requirements in 
the proposed criteria. The FAA anticipates that both structural and 
controllability issues will be relevant when considering gusts and 
turbulence and the typical operating environment of airships (less than 
1500 feet AGL). There may well be a much greater reliance on 
operational limitations and interrelationship of operational and 
airworthiness requirements to obtain an acceptable level of safety with 
airship operations than has been the past practice with other aircraft.
    Ditching and Emergency Evacuation. TAR paragraphs 801 and 803 
address these concerns. However, additional specific analyses or tests 
will need to be proposed and performed to address these issues. 
Emergency evacuation or ditching of a large airship will entail 
problems that are not encountered with fixed wing aircraft. This could 
include collapse of the airship envelope, lifting, rolling or moving of 
the airship during evacuation, and hazardous effects of leaking lifting 
gas. Additionally, the possibility of removing or adding personnel onto 
the ship for medical or maintenance reasons during operations may need 
to be considered.
    Environmental Issues. The proposed airworthiness requirement does 
not include provisions that may be required due to environmental laws. 
Environmental issues will be evaluated according to applicable 
regulations when an airship is actually certificated in the transport 
category.
    Minimum Flight Crew, Relief Crew and Cargo Handling Crew. Large 
airships have not been operated in the United States for decades, the 
determination of crew duties and complements has never been determined 
by a United States civilian airworthiness authority. The FAA proposes a 
human factors study to be performed to establish acceptable workload, 
tasks, flight crew composition and duty rotation. This study will also 
include ground crew, cargo handling crew and related operations. This 
determination will also affect the flight deck and berth design.
    Electrostatic Charging and Shock Hazards. The FAA proposes that 
additional provisions, similar to those proposed in the Joint 
Airworthiness Authorities (JAA) draft Joint Aviation Requirement (JAR) 
25X899: Electrical Bonding and Protection Against Lightning and Static 
Electricity, be included to address electrostatic charging, shock 
hazards to crew and passengers, and electrical fault returns. For large 
airships that may use a great deal of non-conducting materials there is 
more concern with electrostatic charging and shock hazards.
    Operational Rules. Operational requirements have not yet been 
proposed for the operation of large airships, therefore, the proposed 
airworthiness criteria may not thoroughly address these potential 
operational requirements. When such operational requirements are 
established, there could be additional certification or equipment 
requirements mandated for large airships to allow operation in the 
national airspace.
    Design Standards for Changed Product and Continued Production. 
Transport airships have limited service experience worldwide and are 
anticipated to have extremely long service lives. Because of these 
factors, the FAA foresees a need to review and update the criteria on a 
regular basis. The FAA proposes limiting the useful life of the 
airworthiness criteria in order

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to ensure that this review cycle occurs. As a result, the FAA is 
proposing a different approach to the certification basis of transport 
airships and their modifications and would like comments on the 
following:
    The FAA is proposing that a transport airship type design approval 
be of limited duration. At the end of this duration, aircraft in 
service could continue to be operated, but the airship could not be 
manufactured because the design approval would have lapsed. A new or 
revised type approval would be needed for a manufacturer to continue or 
resume production. The new or revised type approval would then be to 
the most current airworthiness criteria. This could mean that transport 
airships in continuing production may need to be updated to meet the 
most current (updated) airworthiness criteria. Using the most current 
airworthiness criteria would also apply to design approvals granted for 
the modification of transport airships.
    When the criteria are updated, the revision effective date may need 
to define an effective date that includes a reasonable time for 
transport airship manufacturers and modifiers to comply with the 
updated criteria. Changes to the airworthiness criteria for transport 
airships would only be applied retroactively to previously manufactured 
airships if required by the changed criteria to address a safety of 
flight issue by issuance of an airworthiness directive.

ADDRESSES: Copies of the proposed airworthiness criteria for transport 
category airships may be requested from the following: Small Airplane 
Directorate, Standards Office (ACE-110), Aircraft Certification 
Service, Federal Aviation Administration, 901 Locust Street, Room 301, 
Kansas City, MO 64106. The proposed airworthiness criteria will be 
available on the Internet within the next two weeks at the following 
address: http://www.faa.gov/ programs_rsvp2/smart/ faa_home_page /
certification/ aircraft/small_ airplane_directorate 
_news_proposed.html. Send all comments on the proposed airworthiness 
criteria for transport category airships to the individual identified 
under FOR FURTHER INFORMATION CONTACT.

FOR FURTHER INFORMATION CONTACT: Mike Reyer or Karl Schletzbaum, 
Federal Aviation Administration, Small Airplane Directorate, 
Regulations & Policy, ACE-111, 901 Locust Street, Room 301, Kansas 
City, Missouri 64106; telephone: (816) 329-4131 (M. Reyer); or (816) 
329-4146 (K. Schletzbaum); fax: (816) 329-4090; e-mail: 
[email protected] or [email protected].

SUPPLEMENTARY INFORMATION:

Comments Invited

    We invite your comments on the proposed airworthiness criteria for 
transport category airships. Send any data or views as you may desire. 
Identify the proposed transport category airship airworthiness criteria 
on your comments, and if you submit your comments in writing, send two 
copies of your comments to the above address. The Small Airplane 
Directorate will consider all communications received on or before the 
closing date for comments. We may change the proposal referred to in 
this notice because of the comments received.
    You may also send comments to the following Internet address: [email protected]. Comments sent by fax or the Internet must contain 
``Comments to proposed transport category airship airworthiness 
criteria'' in the subject line. You do not need to send two copies if 
you fax your comments or send them through the Internet. If you send 
comments over the Internet as an attached electronic file, format it in 
either Microsoft Word 97 for Windows or ASCII text. State what specific 
change you are seeking to the proposed airworthiness criteria and 
include justification (for example, reasons or data) for each request.

    Issued in Kansas City, Missouri on September 28, 2001.
Michael Gallagher,
Manager, Small Airplane Directorate, Aircraft Certification Service.
[FR Doc. 01-25083 Filed 10-4-01; 8:45 am]
BILLING CODE 4910-13-P