[Federal Register Volume 65, Number 131 (Friday, July 7, 2000)]
[Notices]
[Page 42058]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 00-17244]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration


Proposed Advisory Circular 25.335-1A, Design Dive Speed

AGENCY: Federal Aviation Administration, DOT.

ACTION: Notice of Availability of Proposed Advisory Circular (AC) 
25.335-1A, and request for comments.

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SUMMARY: This notice announces the availability of and requests 
comments on a proposed advisory circular (AC) which sets forth an 
acceptable means, but not the only means, of demonstrating compliance 
with the provisions of part 25 of the Federal Aviation Regulations 
(FAR) related to the minimum speed margin between design cruise speed 
and design dive speed for transport category airplanes.

DATES: Comments must be received on or before September 15, 2000.

ADDRESSES: Send all comments on the proposed AC 25.335-1A to: Federal 
Aviation Administration, Attention: James Haynes, Airframe and Cabin 
Safety Branch, ANM-115, Transport Airplane Directorate, Aircraft 
Certification Service, 1601 Lind Avenue SW, Renton, WA 98055-4056. 
Comments may be inspected at the above address between 7:30 a.m. and 
4:00 p.m. weekdays, except Federal holidays.

FOR FURTHER INFORMATION CONTACT: Jan Thor, Transport Standards Staff, 
at the address above, telephone (425) 227-2127.

SUPPLEMENTARY INFORMATION:

Comments Invited

    Interested persons are invited to comment on the proposed AC by 
submitting such written data, views, or arguments, as they may desire. 
Commenters should identify proposed AC 25.335-1A and submit comments, 
in duplicate, to the address specified above. All communications 
received on or before the closing date for comments will be considered 
by the Transport Standards Staff before issuing the final AC. The 
proposed AC can be found and downloaded from the Internet at http://www.faa.gov/avr/air/airhome.htm, at the link titled ``Draft AC's.'' A 
paper copy of the proposed AC may be obtained by contacting the person 
named above under the caption FOR FURTHER INFORMATION CONTACT.

Discussion

    Section 25.335(b) requires the design dive speed, VD, of 
the airplane to be established so that the design cruise speed is no 
greater than 0.8 times the design dive speed, or that it be based on an 
upset criterion initiated at the design cruise speed, VC At 
altitudes where the cruise speed is limited by compressibility effects, 
Sec. 25.335(b)(2) requires the margin to be not less than 0.05 Mach. 
Furthermore, at any altitude, the margin must be great enough to 
provide for atmospheric variations (such as horizontal gusts and the 
penetration of jet steams), instrument errors, and production 
variations. This AC provides a rational method for considering the 
atmospheric variations.

    Issued in Renton, Washington, on June 27, 2000.
Donald L. Riggin,
Acting Manager, Transport Airplane Directorate, Aircraft Certification 
Service, ANM-100.
[FR Doc. 00-17244 Filed 7-6-00; 8:45 am]
BILLING CODE 4910-13-M