04-15557. Advisory Circular 25.1419-1A, Certification of Transport Category Airplanes for Flight in Icing Conditions

AGENCY:

Federal Aviation Administration, DOT.

ACTION:

Notice of issuance of advisory circular.

SUMMARY:

The FAA announces the issuance of Advisory Circular 25.1419-1A, “Certification of Transport Category Airplanes in Flight Icing Conditions.” The advisory circular provides guidance for certification of airframe ice detection and protection systems on transport category airplanes, including a revised description of information that an applicant should include in a certification plan.

DATES:

AC 25.1419-1A was issued by the FAA Transport Airplane Directorate in Renton, Washington, on May 7, 2004.

How To Obtain Copies: A copy of Advisory Circular 25.1419-1A can be downloaded from the Internet at http://www.airweb.faa.gov/​rgl. A paper copy will be available in approximately 6-8 weeks from the U.S. Department of Transportation, Subsequent Distribution Office, M-30, Ardmore East Business Center, 3341 Q 75th Avenue, Landover, MD 20795.

FOR FURTHER INFORMATION CONTACT:

Pat Siegrist, FAA Standardization Branch, ANM-113, Transport Airplane Directorate, 1601 Lind Avenue, SW., Renton, Washington 98055-4056; telephone [phone].

Background

Paragraph 3, Analyses, of AC 25.1419-1A, describes information that should be included in a certification plan submitted by the applicant.

Applicants have erroneously thought this note allowed adequate analysis and testing to preclude the requirement for flight test demonstrations. However, 14 CFR 25.1419(b) at amendment level 25-72 requires flight testing in natural icing conditions as a means to verify the analyses required by paragraph (a) to check for icing anomalies, and to demonstrate that the ice protection system and its components are effective. Guidance material may not supersede the rule and, therefore, Note 2 does not preclude the need for flight testing in natural icing conditions.

As part of a new type certification program, flight in natural icing conditions is required to show compliance with § 25.1419(b). In addition to flight in natural icing conditions, additional wind tunnel, laboratory, and other flight tests may be required to verify the analyses required by § 25.1419(a). However, under some circumstances, flight test data acquired on a previous certification program may be found to be applicable to a new or modified airplane (such a derivative model). To use the previous flight test data, the applicant is required to provide supporting data and rationale that show:

a. The original flight test data is applicable (similarity).

b. The applicant possesses the flight test data.

c. The new or modified configuration is safe for flight in icing conditions.

Because of the erroneous interpretations, the AC has been revised to provide further clarification of this issue.

Issued in Renton, Washington, on May 7, 2004.

Ali Bahrami,

Acting Manager, Transport Airplane Directorate, Aircraft Certification Service.