[Federal Register Volume 60, Number 167 (Tuesday, August 29, 1995)]
[Notices]
[Page 45004]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 95-21011]




  Federal Register / Vol. 60, No. 167 / Tuesday, August 29, 1995 / 
Notices  

[[Page 45004]]


DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration


Proposed Advisory Circular 25.335-1, Design Dive Speed

AGENCY: Federal Aviation Administration, DOT.

ACTION: Notice of availability of proposed circular (AC) 25.335-1 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 provides a method 
of compliance with the requirements of Sec. 25.335 of the Federal 
Aviation Regulations (FAR). Section 23.335 contains the certification 
requirements for the minimum speed margin between cruise speed and 
design dive speed for transport category airplanes. This proposed AC 
complements revisions to the airworthiness standards that are being 
proposed by a separate notice. This notice is necessary to give all 
interested persons an opportunity to present their views on the 
proposed AC.

DATES: Comments must be received on or before November 27, 1995.

ADDRESSES: Send all comments on proposed AC to: Federal Aviation 
Administration, Attention: James Haynes, Airframe and Propulsion 
Branch, ANM-112, 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 (206) 227-2127.

SUPPLEMENTARY INFORMATION:

Comments Invited

    A copy of the draft AC may be obtained by contacting the person 
named above under FOR FURTHER INFORMATION CONTACT. 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 AC 25.335-1 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.

Discussion

    Section 25.335(b) requires the design dive speed 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. 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 streams), 
instrument errors, and reduction variations. This proposed AC provides 
a rational method for considering the atmospheric variations This 
proposed AC provides guidance material and one means, but not the only 
means, of complying with the part 25 revisions proposed in Notice No. 
95-14 entitled ``Revised Structural Loads Requirements for Transport 
Category Airplanes,'' published in this same edition of the Federal 
Register. Issuance of AC 25.335-1 is contingent on final adoption of 
the proposed revisions to part 25.

    Issued in Renton, Washington, on July 14, 1995.
James V. Devany,
Acting Manager, Transport Airplane Directorate, Aircraft Certification 
Service, ANM-100.
[FR Doc. 95-21011 Filed 8-28-95; 8:45 am]
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