Eddie sez:

The Apple iPad has taken over in the world of EFBs and some of the rules seem a bit, well, out of date. But here they are.
Everything here is from the references shown below, with a few comments in an alternate color.
20171220
An EFB used to mean a small tablet computer that was a bit bulky and weighed a few pounds, but of late more and more companies are adopting the use of iPads which are smaller and weigh less.
[AC 120-76D, ¶6.] WHAT IS AN EFB? An EFB is any device, or combination of devices, actively displaying EFB applications. EFBs are characterized by the following:
AC 20-173 describes certification considerations for individual EFB components and for installing EFB aircraft connectivity provisions by addressing the principal elements, or “components." Its provisions are worth examining, see Installation Considerations, below.
[AC 120-76D, ¶7.1] Type A Applications.
Looking at the list, Type A Applications seem to be documents, some of which are required by operational requirements. This seems to be a contradiction.
[AC 120-76D, Appendix A, ¶A.1] Type A EFB Applications.
[AC 120-76D, ¶7.2] Type B Applications.
[AC 120-76D, ¶1.2 Requirements.] This AC describes an acceptable means, but not the only means, foroperators conducting flight operations seeking authorization for the operational use of EFB applications under part 91K, 121, 125, or 135.
If you are operating under one of these parts, you need approval to use an EFB with the following applications.
[AC 120-76D, Appendix B, ¶B.1] Type B EFB Applications.
Note: A depiction of EFB own-ship may be included on this EFB application if the aircraft has a navigation moving map display (navigation display) providing concurrent display of the active flight plan, aircraft position, and aircraft trajectory (for example, heading if a heading is selected). The EFB application may display additional, unique data elements, such as other oceanic routes, but must have sufficient common data to allow the flightcrew member to resolve discrepancies.
Note: A depiction of EFB own-ship may be included on this EFB application if the aircraft has a navigation moving map display (navigation display) providing concurrent display of the active flight plan, aircraft position, and aircraft trajectory (for example, heading is a heading is selected). The EFB application may display additional, unique data elements, such as airspace boundaries, but must have sufficient common data to allow the flightcrew member to resolve discrepancies.
Note: A depiction of EFB own-ship may be included on this EFB application if the aircraft has a weather radar display providing concurrent display of proximate weather hazards. The EFB application may display additional, unique data elements, such as turbulence or data outside the range of the weather radar, but must have sufficient common data to allow the flightcrew member to resolve discrepancies.
It seems the FAA is getting out of the business of telling you how to "install" and use your EFB, but there are a few things to keep in mind.
[AC 20-173, ¶3] This AC addresses installation of EFB components. In the context of this AC, EFB components are “installed” when they are incorporated into aircraft type design under 14 CFR part 21 or as a proper alteration under 14 CFR 43.3. All other EFB components are considered “portable,” regardless of how often they are removed from the aircraft. There are operational restrictions on the use and capability of portable EFB components. Design of portable EFB components is outside the scope of this AC.
While this AC addresses installations incorporated into a type design, it offers things you should think about when using your "portable" EFBs. I was sitting in the right seat of a GV when the left seater's yoke mounted EFB fell between the yoke and the seat just prior to takeoff rotation. The left seater had the presence of mind to pull the EFB from between his legs and was able to rotate. The problem is even broader, as the next paragraph shows.
[AC 20-173, ¶5.a.(4)] Yoke Mounts and Clips. Applicants and operators should be aware of unsafe conditions potentially created when attaching a portable EFB component to the control yoke with an attachment mechanism, mounting device, or clip. For example, the weight of both the EFB and mounting bracket may affect flight control system dynamics or warning indications, such as aerodynamic disturbances or from artificial stall-warning devices (e.g., stick shaker); even though the mount alone may be light enough to be insignificant. The mass, moment of inertia, as well as the physical size of the combined mount and EFB, can all contribute to potential unsafe conditions which may require design changes to flight controls and additional flight testing upon installation. In 14 CFR parts 25, 27, and 29 aircraft, yoke mounting of an EFB is not recommended and all of the yoke mounting components (e.g., mounts, brackets, clips, etc.) for the EFB must be incorporated into the aircraft type design. When the EFB mounting device is not intended for a specific EFB model, document the demonstrated performance parameters for the mounting device (e.g., weight parameters) in the airplane or rotorcraft flight manual (AFM/RFM), airplane or rotorcraft flight manual supplement (AFMS/RFMS), operating manual, or instructions for continued airworthiness (ICAs), as appropriate.
I read this to mean you cannot mount an EFB on a yoke unless it is type certificated.
[AC 20-173, ¶5.b.(5)] Mount Cabling. If cabling is installed to mate aircraft systems with an EFB, the cable should not hang loosely and provisions should be made to easily secure any exposed cables out of the way during aircraft operations (e.g., cable tether straps). Cables external to the mount should be of sufficient length to perform the intended tasks. Cables too long or short must not present an operational or safety hazard.
If you are going to have power or other cables connected to your EFB, you need to make sure they are out of the way so they do not impact movement of any flight controls, switches, levers, or other cockpit components. Additionally, these cables should not impede your ingress or egress from seats.
[AC 120-76D, ¶9] HARDWARE SUPPORTING EFB APPLICATIONS. In the context of this AC, EFB equipment components supporting EFB applications are “installed” when they are incorporated into aircraft type design under 14 CFR part 21, or as a proper alteration under 14 CFR part 43, § 43.3. All other components supporting EFB functionality are considered “portable,” regardless of how often they are removed from the aircraft. In order for portable EFB hardware to support EFB applications, installation of at least some EFB components may be required, depending on requirements for positional integrity (e.g., installed mounts), continuity of power (e.g., dedicated primary power port), and data connectivity (e.g., Wireless Fidelity (Wi-Fi®), and Ethernet). Airworthiness regulations do not apply to portable EFB components other than for specifications associated with the installed components (i.e., mounting (size and weight), power (maximum electrical load, voltage, and current frequency), and data connectivity (input/output (I/O) data specifications and security)). Regardless, this AC is applicable to any portable EFB components (e.g., mount, display, external Global Positioning System (GPS), cables/cords/adapters, and portable wireless transmitters) supporting an applicant’s authorization for use. Display of EFB applications on installed displays may require differentiation to enable the flightcrew member to distinguish between the installed avionics display and the supplemental or “secondary” EFB display. For guidance on the design of installed components supporting EFB functionality, refer to AC 20-173.
If you are operating under part 91K, 121, 125, or 135, this paragraph captures any portable EFB components, including external GPS receivers.
[AC 120-76D, ¶9.1.2] Portable EFB Hardware Components:
[AC 120-76D, ¶10.1] Portable EFB Electromagnetic Compatibility (EMC) Demonstration. The certificate holder/operator must demonstrate all portable EFB components, including cords/cables for data or power, are electromagnetically compatible with aircraft navigation and communication systems. One of the following three methods in paragraphs 10.1.1, 10.1.2, or 10.1.3 must be accomplished to demonstrate portable EFB EMC with aircraft for all phases of flight.
Advisory Circular 20-173, Installation of EFB Components, 9/27/11, U.S. Department of Transportation
Advisory Circular 120-76D, Authorization for Use of Electronic Flight Bags, 10/27/17, U.S. Department of Transportation
Copyright 2019. Code 7700 LLC. All Rights Reserved.