[Federal Register Volume 60, Number 103 (Tuesday, May 30, 1995)]
[Notices]
[Pages 28200-28201]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 95-13132]



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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration


Airborne Windshear Warning and Escape Guidance Systems for 
Transport Airplanes

AGENCY: Federal Aviation Administration, DOD.

ACTION: Notice of availability.

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SUMMARY: This notice announces the availability of and requests 
comments on a proposed technical standard order (TSO) pertaining to 
airborne windshear warning and escape guidance systems for transport 
airplanes. The proposed TSO prescribes the minimum performance 
standards that airborne windshear warning and escape guidance systems 
for transport airplanes must meet to be identified with the marking 
``TSO-C117a.''.

DATES: Comments must identify the TSO file number and be received on or 
before August 31, 1995.

ADDRESSES: Send all comments on the proposed technical standard order 
to: Technical Analysis Branch, AIR-120, [[Page 28201]] Aircraft 
Engineering Division, Aircraft Certification Service--File No. TSO-
C117a, Federal Aviation Administration (FAA), 800 Independence Avenue, 
SW., Washington, DC 20591. Or deliver comments to: Federal Aviation 
Administration, Room 804, 800 Independence Avenue, SW., Washington, DC 
20591.

FOR FURTHER INFORMATION CONTACT: Ms. Bobbie J. Smith, Technical 
Programs and Continued Airworthiness Branch, AIR-120, Aircraft 
Engineering Division, Aircraft Certification Service, Federal Aviation 
Administration, 800 Independence Avenue, SW., Washington, DC 20591, 
Telephone (202) 267-9546.

Comments Invited

    Interested persons are invited to comment on the proposed TSO 
listed in this notice by submitting such written data, views, or 
arguments as they desire to the above specified address. Comments 
received on the proposed technical standard order may be examined, 
before and after the comment closing date, in Room 804, FAA 
Headquarters Building (FOB-10A), 800 Independence Avenue, SW., 
Washington, DC 20591, weekdays except Federal holidays, between 8:30 
a.m., and 4:30 p.m. All communications received on or before the 
closing date for comments specified above will be considered by the 
Director of the Aircraft Certification Service before issuing the final 
TSO.

Background

    Revised TSO-C117a, Airborne Windshear Warning and Escape Guidance 
Systems for Transport Airplanes, requires the applicant to show by 
analysis, or other suitable means, that the system threshold is above a 
point at which nuisance warnings would be objectionable under 
conditions of severe turbulence, or aircraft change of configuration, 
i.e. flaps and/or gear retraction. If electronics techniques are used 
to reduced nuisance warnings by turbulence or aircraft configuration 
change, it must be shown that the system response to windshear 
detection is acceptable.
    A Douglas DC-9-31 airplane crashed while executing a missed-
approach following an instrument landing system approach. The NTSB 
report identifies the probable contriving factor for the missed-
detection of the presence of a wind shear in the flight path was a 
warning delay designed into the wind shear detection system. This delay 
of warning was designed to reduce nuisance warnings from severe 
turbulence or aircraft configuration change, i.e., change of flap 
setting. This TSO revision will require test to demonstrate that wind 
shear detection is within acceptable limits.

How To Obtain Copies

    A copy of the proposed TSO-C117a may be obtained by contacting the 
individual listed under ``For Further Information Contact.''

    Issued in Washington, DC, on May 23, 1995.
John K. McGrath,
Manager, Aircraft Engineering Division, Aircraft Certification Service.
[FR Doc. 95-13132 Filed 5-26-95; 8:45 am]
BILLING CODE 4910-13-M