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All-Electrical Attitude, Altitude, Direction, and Airspeed Systems Using Battery Standby Power

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Information about this document as published in the Federal Register.

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Federal Aviation Administration (FAA), DOT.


Notice of proposed policy statement; request for comments.


The Federal Aviation Administration (FAA) announces the availability of a proposed policy statement that clarifies current FAA certification policy with respect to all-electrical attitude, altitude, direction, and airspeed systems using battery standby power.


Send your comments on or before July 25, 2001.


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

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Dale Dunford, 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) 227-2239; fax (425) 227-1100; e-mail:

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Comments Invited

The proposed policy statement is available on the Internet at the following address:​avr/​air/​anm/​draftpolicy/​interim.htm. 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 statement. 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-01-111-159.”

Use the following format when preparing your comments:

  • Organize your comments issue-by-issue.
  • For each issue, state what specific change you are requesting to the proposed general statement of policy.
  • 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.


With the advent of highly reliable, low power, liquid crystal display (LCD) electrical indicators, applicants for certification of transport category airplanes and their components are replacing previous pneumatic indicators with electric ones, resulting in an all-electric attitude, altitude, direction, or airspeed configuration. Many of these installations rely on time-limited batteries to power the instruments in the event of loss of generator power on the airplane. Such all-electric configurations must be designed to ensure continued safe flight and landing after any failure or combination of failures not shown to be extremely improbable, including the loss of generated electrical power.

The proposed policy statement provides guidelines that should be used for the certification of flight instrument installations in which

  • All displays of any of the essential flight information (e.g., altitude, attitude, airspeed, or direction) require electrical power,
  • The failure of normal electrical power is not extremely improbable, and
  • The back-up source of electrical power is a time-limited battery.
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Issued in Renton, Washington, on June 19, 2001.

Ali Bahrami,

Acting Manager, Transport Airplane Directorate, Aircraft Certification Service.

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[FR Doc. 01-15898 Filed 6-22-01; 8:45 am]