[Federal Register Volume 67, Number 225 (Thursday, November 21, 2002)]
[Notices]
[Page 70296]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 02-29659]



[[Page 70296]]

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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

[Policy Statement No. ANM-02-111-05]


Policy Statement With Respect to Part 25 Transport Category 
Airplanes Utilizing Displays With Geometric Altitude Labeled as a Mean 
Sea Level (MSL)

AGENCY: Federal Aviation Administration (FAA), DOT.

ACTION: Notice of proposed policy; request for comments.

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SUMMARY: The Federal Aviation Administration (FAA) announces the 
availability of proposed policy that clarifies current FAA policy with 
respect to part 25 transport category airplanes utilizing displays with 
geometric altitude labeled as a mean sea level (MSL).

DATES: Send your comments on or before December 23, 2002.

ADDRESSES: Address your comments to the individual identified under FOR 
FURTHER INFORMATION CONTACT.

FOR FURTHER INFORMATION CONTACT: Ken Schroer, Federal Aviation 
Administration, Transport Airplane Directorate, Transport Standards 
Staff, Airplane and Flight Crew Interface Branch, ANM-111, 1601 Lind 
Avenue SW., Renton, WA 98055-4056; telephone (425) 227-1154; fax (425) 
227-1320; e-mail: [email protected].

SUPPLEMENTARY INFORMATION: 

Comments Invited

    The proposed policy is available on the Internet at the following 
address: http://www.faa.gov/certification/aircraft/anminfo/devpaper.cfm. If you do not have access to the Internet, you can obtain 
a copy of the policy statement by contacting the person listed under 
FOR FURTHER INFORMATION CONTACT.
    The FAA invites your comments on this proposed policy. We will 
accept your comments, data, views, or arguments by letter, fax, or e-
mail. Send your comments to the person indicated in FOR FURTHER 
INFORMATION CONTACT. Mark your comments, ``Comments to Policy Statement 
ANM-02-111-05.''
    Use the following format when preparing your comments:
    [sbull] Organize your comments issue-by-issue.
    [sbull] For each issue, state what specific change you are 
requesting to the proposed general statement of policy.
    [sbull] Include justification, reasons, or data for each change you 
are requesting.
    We also welcome comments in support of the proposed policy.
    We will consider all communications received on or before the 
closing date for comments. We may change the proposed policy because of 
the comments received.

Background

    This memorandum clarifies Federal Aviation Administration (FAA) 
certification policy with respect to installations that label Global 
Positioning System (GPS) derived geometric altitude as Mean Sea Level 
(MSL) altitude. The issue concerns the Terrain Awareness and Warning 
Systems (TAWS), Global Navigation Systems (GNS), and any other 
installation in which GPS derived altitude is presented as MSL 
altitude.
    Regardless of the higher altitude accuracy that can be derived from 
GPS data, barometric altitude referenced to MSL remains the present 
standard used in the U.S. and internationally for vertical navigation. 
Even though there may be altitude errors while using barometric 
altitude, all aircraft within a particular sector are navigating (in 
principle) with the same error. Since there is a potential for large 
differences between barometric altitude and GPS derived altitude, 
labeling both as MSL may result in confusion and improper vertical 
navigation during high flightcrew workloads.

    Issued in Renton, Washington, on November 13, 2002.
Vi L. Lipski,
Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. 02-29659 Filed 11-20-02; 8:45 am]
BILLING CODE 4910-13-P