BTS Navigation Bar

NTL Menu

Use of Portable Electronic Devices Aboard Aircraft - FAA AC 91.21-1

                              ADVISORY CIRCULAR

       AC No: 91.21-1

         Date: 8/20/93


           by:  AFS-350


      1.  PURPOSE.  This advisory circular (AC) provides aircraft
      operators with information and guidance for assistance in the
      compliance of Federal Aviation Regulations (FAR) Section 91.21.
      Because of the potential for portable electronic devices to
      interfere with aircraft communications and navigation equipment,
      FAR Section 91.21 was established.  It prohibits the operation of
      portable electronic devices aboard U.S.-registered civil
      aircraft, operated by the holder of an air carrier operating
      certificate or an operating certificate, or any other aircraft
      while operating under instrument flight rules.  The rule permits
      use of specified portable electronic devices and other devices
      that the operator of the aircraft has determined will not cause
      interference with the safe operation of the aircraft in which it
      is operated.  The recommendations contained herein are one means,
      but not the only means, of complying with the requirements of FAR
      Section 91.21, pertaining to the operation of portable electronic

      2.  CANCELLATION.  AC 91-47, Use of Portable Electronic
      Devices -- Radio Receivers, dated March 23, 1977.

      3.  RELATED FAR SECTIONS.  FAR Section 91.21.

      4.  BACKGROUND.  FAR Section 91.21 (formerly 91.19) was initially
      established in May 1961 to prohibit the operation of portable
      frequency-modulated radio receivers aboard U.S. air carrier
      aircraft and U.S.-registered aircraft when the very high
      frequency omnidirectional range was being used for navigation
      purposes.  The Federal Aviation Administration (FAA) subsequently
      determined that other portable electronic devices could be
      potentially hazardous to aircraft communication and navigation
      equipment if operated aboard aircraft.  Amendment 91-35 amended
      the scope of former FAR Section 91.19 to prohibit the use of
      additional portable electronic devices aboard certain U.S. civil
      aircraft.  Earlier studies conducted by RTCA, Inc. (RTCA),
      Special Committee 156, Document No. RTCA/DO-199, Volumes 1 and 2,
      entitled "Potential Interference To Aircraft Electronic Equipment
      From Devices Carried Aboard," have contributed greatly to an
      understanding of the operational effects of portable electronic
      devices aboard aircraft.  (See paragraph 7b for obtaining

      5.  DISCUSSION.  FAR Section 91.21 allows the operation of
      portable electronic devices which the operator of the aircraft
      has determined will not cause interference with the navigation or
      communication system of that aircraft.  The determination of the
      affect of a particular device on the navigation and communication
      system of the aircraft on which it is to be used or operated can
      be made by the operator and/or the pilot in command.  In some
      cases, the determination may be based on operational tests
      conducted by the operator without sophisticated testing
      equipment.  When safely at cruise altitude, the pilot could allow
      the devices to be operated.  If interference is experienced, the
      types of devices causing interference could be isolated along
      with the applicable conditions recorded.  The device responsible
      for the interference should then be turned off.  If all operators
      collect this type of data with specific information, a large
      enough data base could be generated to identify specific devices
      causing interference.  The operator may elect to obtain the
      services of a person or facility having the capability of making
      the determination for the particular electronic device and
      aircraft concerned.  The rule as adopted was drafted to require
      the air carrier or commercial operator to determine whether a
      particular portable electronic device will cause interference
      when operated aboard its aircraft.  This determination may be
      made by personnel specifically designated by the air carrier or
      commercial operator for this purpose.  For other aircraft, the
      language of the rule expressly permits the determination to be
      made by the pilot in command or operators of the aircraft.  Thus,
      in the case of rental aircraft, the determination could be made
      by the renter-pilot, lessee, or owner-operator.


           a.  If an operator allows the use of portable electronic
      devices aboard its aircraft, procedures should be established
      and spelled out clearly to control their use during passenger-
      carrying operations.  The procedures, when used in conjunction
      with an operator's program, should provide, as a minimum, the
                   (1)  Methods to inform passengers of permissible
      times, conditions, and limitations when various portable
      electronic devices may be used.  This may be accomplished
      through the departure briefing, passenger information cards,
      captain's announcement, and any other method deemed appropriate
      by the operator.  The limitations, as a minimum, should state
      that use of all such devices (except medical) are prohibited
      during any phase of operation when their use could interfere with
      the ability of the flightcrew to give necessary instructions in
      the event of an emergency.

                (2)  Procedures to terminate the operation of portable
      electronic devices suspected of causing interference with
      aircraft systems.

                (3)  Procedures for reporting instances of suspected
      and confirmed interferences by a portable electronic device to
      the local FAA Flight Standards District Office for forwarding to
      the FAA Flight Standards National Field Office, AFS-500.

                (4)  Cockpit to cabin coordination and cockpit flight-
      crew monitoring procedures.

                (5)  Procedures for determining acceptability of those
      portable electronic components to be operated aboard its
      aircraft.  The determination of the affects of a particular
      portable electronic device on the navigation and communication
      systems of the aircraft on which it is to be operated must be
      made by the operator of the aircraft.  The operation of a
      portable electronic device is prohibited unless the device is
      specifically listed in FAR Section 91.21(b)(1) through (4) or
      pursuant to FAR Section 91.21(b)(5), whereby the operator
      determines that the operation of that device will not cause
      interference with the communication or navigation system of the
      aircraft on which it is to be operated.

                (6)  Prohibiting the operation of any portable
      electronic devices during the takeoff and landing phases of
      flight.  It must be recognized that the potential for personal
      injury to passengers is a paramount consideration as well as the
      possibility of missing important safety announcements during
      these important phases of flight.  This is in addition to
      lessening the possible interference that may arise during sterile
      cockpit operations (below 10,000 feet).

                (7)  Prohibiting the operation of any portable
      electronic devices aboard aircraft, unless otherwise authorized,
      which are classified as intentional radiators or transmitters.
         These devices include, but are not limited to:

                     (i)  Citizens band radios.

                     (ii)  Cellular telephones.

                     (iii)  Remote control devices.

           b.  Portable electronic devices designed to transmit have
      considerations in addition to paragraph 6a.  There are certain
      devices which, by their nature and design, transmit
      intentionally.  These include cellular telephones, citizens band
      radios, remote control devices, etc.  These devices are typically
      licensed as land mobile devices by the Federal Communications
      Commission (FCC).  The FCC currently prohibits the use and
      operation of cellular telephones while airborne.  Its primary
      concern is that a cellular telephone, while used airborne, would
      have a much greater transmitting range than a land mobile unit.
      This could result in serious interference to transmissions at
      other cell locations since the system uses the same frequency
      several times within a market.  Since a cellular mobile
      telephone unit is capable of operating on all assignable cellular
      frequencies, serious interference may also occur to cellular
      systems in adjacent markets.  The FAA supports this airborne
      restriction for reasons of potential interference to critical
      aircraft systems.  Currently, the FAA does not prohibit use of
      cellular telephones in aircraft while on the ground if the
      operator has determined that they will not cause interference
      with the navigation or communication system of the aircraft on
      which they are to be used.  An example might be their use at the
      gate or during an extended wait on the ground, while awaiting a
      gate, when specifically authorized by the captain.  A cellular
      telephone must not be authorized for use while the aircraft is
      being taxied for departure after leaving the gate.  The unit
      must be turned off and properly stowed, otherwise it is possible
      that a signal from a ground cell could activate it.  Whatever
      procedures an operator elects to adopt should be clearly spelled
      out in oral departure briefings and by written material provided
      to each passenger to avoid passenger confusion.

           c.  Those telephones which have been permanently installed
      in the aircraft are licensed as air-ground units and are
      operated on the allocated or assigned air-ground radio telephone
      service frequencies.  In addition, they are installed and tested
      in accordance with the appropriate certification and
      airworthiness standards.  These devices are not considered
      portable electronic devices provided they have been installed and
      tested by an FAA-approved repair station or an air carrier's-
         approved maintenance organization and are licensed by the FCC as
      air-ground units.


           a.  Operators should use manufacturers' information, when
      provided, with each device that informs the consumer of the
      conditions and limitations associated with its use aboard

           b.  All portable electronic devices should be designed and
      tested in accordance with appropriate emission control standards.
      Document Nos. RTCA/DO-160C, Environmental Conditions and Test
      Procedures for Airborne Equipment, and RTCA/DO-199, may
      constitute one acceptable method for meeting these requirements.
      These documents may be purchased from:  RTCA Secretariat, 1140
      Connecticut Avenue, Suite 1020, Washington, D.C. 20036.

           c.  The FCC, in conjunction with RTCA, is currently
      evaluating emission standards and appropriate classification
      markings for portable electronic devices that may be used aboard

      /s/ Thomas C. Accardi
          Director, Flight Standards Service

Jump To Top