Dear Mr. Bessette,
The Aircraft Owners and Pilots Association (AOPA), representing the aviation interests of more than 345,000 pilots and aircraft owners, is requesting a clarification of the Federal Aviation Administration (FAA) policy regarding what constitutes the "installation" of a hand-held Global Positioning System (GPS) receiver. AOPA is concerned that the present lack of an official written FAA policy or guidance to FAA operations and airworthiness inspectors in the field is causing confusion and conflicts between these inspectors and users of hand-held GPS units.
AOPA is receiving a steady number of contacts from members across the country who have received incorrect or misleading information from FAA inspectors regarding the "installation" of a hand-held GPS unit in their aircraft. In the majority of these cases an FAA inspector has incorrectly characterized the nature of the mounting of the hand-held GPS unit and its associated antenna, or the connection of a power lead to the cigarette lighter, as installations requiring the filing of a FAA Form 337. Often the inspector states that a suction cup mounted antenna, or a yoke clip mounted with Velcro or thumbscrews qualifies as an installation. Additionally, some inspectors maintain that a power lead connected to the aircraftï¿½s cigarette lighter requires a field approval because the cigarette lighter is not rated to supply continuous power.
Research into this matter has revealed that two publications exist to provide guidance to pilots and FAA inspectors. These documents are AC-91-21 Use of Portable Electronic Devices Aboard Aircraft, and RTCA paper number 379-93/TMC-99 Portable Hand-Held GPS Receivers ï¿½ What You Should Know. Although each document outlines the guidelines for using a handheld GPS unit on board an aircraft from an operational perspective, neither document gives a clear explanation of what constitutes an installation.
Conversations with the FAA Aircraft Certification Service and Aircraft Maintenance Division have revealed that all parties appear to be in agreement regarding what does, or does not, constitute the permanent installation of a hand-held GPS unit. All parties agree that any receiver or antenna mounting device that can be removed from an aircraft without the use of tools or a power lead connected to the cigarette lighter of an aircraft, does not qualify as an installation requiring a field approval. Examples of this include the use of Velcro or suction cups as mounting devices, or brackets that employ clips or thumbscrews to secure them to the aircraft. AOPA agrees that a GPS mounting device that cannot be removed from the aircraft without the use of tools, and an externally mounted GPS antenna would in fact constitute an installation and would require a field approval for that portion of the installation. Unfortunately, the reference documents AC-91-21 and RTCA paper number 379-93/TMC-99 fail to mention any such common-sense guidelines.
As mentioned previously, AOPA regularly receives a large number of communications on this subject from members throughout the United States. These communications serve as a strong indicator that the guidance material currently being used by the FAA is failing to provide adequate guidance to FAA Inspectors in the field. To remedy this problem, AOPA recommends that the FAA reevaluate its use of the above mentioned guidance material and implement the aforementioned common-sense guidelines into an official policy statement that specifically defines what constitutes the installation of a hand-held GPS unit in an aircraft.
We thank you for your time and consideration in this matter, and stand ready to assist the FAA in considering any changes to the current hand-held GPS guidance material.
Dennis E. Roberts Vice President Government and Technical Affairs