Aerospace Industries Association of America

1000 Wilson Blvd., Suite 1700, Arlington, VA 22209 

Tel (703) 358-1000 Fax (703) 358-1011 

Internet: http://www.aia-aerospace.org 

General Aviation Manufacturers Association

1400 K Street N.W., Suite 801, Washington, DC 20005

Tel (202) 393-1500 Fax (202) 842-4063 

Internet: http://www.GAMA.aero 

August 31, 2010 

Docket Operations, M-30 (Docket# FAA-2010-0636) 

U.S. Department of Transportation 

1200 New Jersey Avenue SE, 

Room W12-140, 

West Building Ground Floor, 

Washington, DC 20590-0001 

SUBJECT: AIA/GAMA Request for Comment Period Extension, NPRM 10-10 

Aerospace Industries Association (AIA) and General Aviation Manufacturers Association (GAMA) are 

requesting an extension to the comment period for NPRM 10-10, Airplane and Engine Certification 

Requirements in Supercooled Large Drop, Mixed Phase, and Ice Crystal Icing Conditions in accordance 

with 14CFR§11.47. AIA and GAMA represent the vast majority of the industry that is affected by this 

proposed regulation. 

The NPRM includes reference to 5-guidance documents which detail how compliance to this rule can be 

achieved. As of this request, only 3 of 5 documents have been released for comment. As the NPRM is 

being published in connection with this new guidance, the requirement does not stand on its own and, 

therefore, it is not possible to determine the complete impact of the proposal. Although the initial 62-day 

comment has been extended by 30 days, the availability of the guidance material remains critical to a 

thorough review and response from the industry. Finally, because the proposed rule differs in some areas 

from the ARAC recommendations, thorough review by the entire industry is necessary. AIA and GAMA 

request the comment period for NPRM 10-10 be extended for 60-days after all guidance referenced in the

proposed rule has been published for public review and comment. 

The FAA is proposing a regulation which will have direct effect on a significant portion of aviation 

manufacturers. The requirements being proposed are not specific and, therefore, the FAA is issuing 

accompanying guidance material along with the regulatory text in the NPRM. Because the requirements of 

the NPRM do not stand on their own, but rather must be understood through companion guidance material,

the industry cannot fully evaluate the impact of this regulation without reviewing all associated guidance. 

The NRPM states that the following guidance documents will be published in support of this proposed 

regulation: 

 

 AC 25-XX, Compliance of Transport Category Airplanes with Certification Requirements for 

Flight in Icing Conditions. (Available for Comment on 7-30-2010) 

 Revision to AC 20-147, Turbojet, Turboprop, and Turbofan Engine Induction System Icing 

and Ice Ingestion. (Not Available for Comment as of 8-30-2010) 

GAMA 10-34 
AIA/GAMA Request for Comment Period Extension, NPRM 10-10 August 31, 2010 

 Revision to AC 25-25, Performance & Handling Characteristics in Icing, Part 25 Appendix C. 

(Not Available for Comment as of 8-30-2010)

 Revision to AC 25.629-1A Aeroelastic Stability Substantiation of Transport Category 

Airplanes. (Available for Comment on 8-11-2010) 

 Revision to AC 25.1329-1B, Approval of Flight Guidance Systems (Available for Comment as 

of 6-6-2010) 

As of August 30th, 2010, several key guidance documents have not been made available for review and 

comment. AIA and GAMA understand some key technical features, which will define the regulations, will

be included in this missing guidance. For instance, there is question as to how radome ice shape ingestion 

for SLD conditions will be addressed. Depending on the guidance material, the regulation will have 

significantly different implications. In order for the affected industry to have a fair opportunity to understand 

the proposed regulation so we can provide appropriate comment, this NPRM referenced material must be 

released with sufficient time remaining in the NPRM comment period. 

Further, this NPRM is being put out for comment near the end of the FAA’s fiscal year, at a time when the 

agency is publishing many other items which impact the same regulated entities. Because of this end of 

year rush to publish policy, guidance and regulatory proposals, the industry resources for review have been 

unreasonably strained. 

As a result of the issues briefed above, AIA and GAMA request the comment period for NPRM 10-10 be 

extended for 60-days after all guidance referenced in the proposed rule has been published for public 

review and comment. 

Sincerely, 

_________________________ ___________________________ 

Todd Sigler Gregory J. Bowles 

Assistant Vice President, Civil Aviation Director, Engineering & Manufacturing 

Aerospace Industries Association General Aviation Manufacturers Association