In the days before electronic flight bags, the duffels filled with the necessary performance, operational, and navigation paper were a weight and balance line item, especially with a full set of instrument approach plates. When formatted as electrons, all this necessary information weighs no more than the electronic device that stores and displays it.
As EFBs proved their reliability, many pilots reduced the redundant paper they carried on every flight, following the insuccinct guidance found in Advisory Circular 91-78, Use of Class 1 or Class 2 Electronic Flight Bags, which the FAA issued on July 20, 2007. For newcomers and those who might not remember, a Class 1 EFB is a portable electronic device, most commonly an Apple iPad. Class 2 EFB can also be an iPad, but a Class 2 device must be “attached or secured to a permanently installed aircraft mount during use.”
The new EFB guidance, Advisory Circular 91-78A, Use of Electronic Flight Bags, dated February 23, 2024, resolves the redundant paper question. “EFB systems may be used in conjunction with, or to replace, the paper reference material that pilots typically carry in the flight deck. EFBs can electronically store and retrieve information required for flight operations, such as the POH and supplements, minimum equipment lists (MEL), W&B calculations, aeronautical charts, and terminal procedures.”
In all phases of flight, an EFB can replace paper when the information it displays 1. does not replace any system or equipment (e.g., navigation, communication, or surveillance system) that is required by part 91; 2. displays only information which is functionally equivalent to the paper reference material which the information is replacing or is substituted for; 3. the interactive or precomposed information being used for navigation or performance planning is current, up to date, and valid, as verified by the pilot; and 4. the operator complies with requirements of §91.21 to ensure that the use of the EFB does not interfere with equipment or systems required for flight.
Curiously, AC 91-78A makes no reference to the EFB classes mentioned in the superseded AC. That’s because AC 120-76D, Authorization for Use of Electronic Flight Bags, dated October 27, 2017, “Eliminate[d] EFB Classes 1, 2, and 3, and introduce[d] a simpler concept of portable and installed equipment, to harmonize with the International Civil Aviation Organization (ICAO), and to accommodate increasingly complex systems integrating both installed and portable equipment.” It also includes the appendix lists of Type A and Type B EFB applications.
Portable EFBs do not depend on a dedicated aircraft power source or input from navigation equipment to provide display functionality, although they may connect to aircraft power through a certificated power source [but this is always a good idea]; they are not attached to an aircraft mounting device; and are not connected with or receiving data from any aircraft system.
Installed EFBs may receive power from the aircraft that is derived from an electrical bus source protected against short circuits with an appropriately rated circuit breaker or fuse; they may receive position reference from an onboard navigation system, provided such input is designed and integrated in such a manner as to not adversely affect the output of the navigation source to which they are connected; and they may be attached to a mounting device provided that such device is approved for installation into the aircraft (e.g., if intended for installation into a type-certificated aircraft, then such mounting device must meet the requirements of § 21.303.
Portable or installed, the tablet-based EFB is still a single point of failure, which suggests the need for some sort of backup. Many pilots say their smart phones meet this need nicely, and some go a step further by slipping a fully charged power bank and the necessary cables into their headset bag, Others still carry some redundant paper because essential information such as a navigation log and maps for the flight don’t require batteries or a working display to read them. Fire is their only real failure mode, and in that case a pilot has a more pressing problem. Forgetting to bring some sort of backup EFB is another form of failure, but this one is pilot error. — Scott Spangler, Editor