Electronic Flight Bags (EFB)

An electronic flight bag (EFB) is an electronic information system for the flight crew that replaces the paper once carried in a pilot's flight bag: the operations manual and aircraft manuals, charts, checklists, performance tables and the flight's paperwork. It may be a portable device, usually a tablet, or installed equipment that is part of the aircraft. Beyond displaying documents, its applications compute take-off and landing performance and mass and balance, and the results go into the flight management system and the load sheet.

EFBs are now standard in airline operations; the A320's standard operating procedures, for example, assume that both pilots use one. They bring current data and less paper, but also new risks: a wrong input produces a wrong answer with every appearance of authority, devices fail and batteries run down, and a screen draws eyes into the flight deck. Operators therefore assess each EFB system, obtain approval for the applications that matter and write procedures for each risk.

What an EFB is

An EFB has two parts: the host platform, meaning the hardware and its operating system, and the applications that run on it. What makes it an EFB rather than avionics is its role. It supports the crew with information and calculations, but it does not replace any system or display that the aircraft's certification or the operating rules require. A function whose failure could have more than a minor effect must be certified as part of the aircraft. Some functions are built into the aircraft by design: on the Boeing 787, for example, the electronic checklist is part of the aircraft's display system, called up from the multifunction keypads, and the Flight Standardization Board requires a current paper backup to be carried on board.

The FAA's guidance on EFBs is Advisory Circular 120-76, and an airline's authorisation to use them in place of paper documents and charts is operations specification A061. Under 14 CFR 121.549, for example, the pilot in command must ensure that appropriate aeronautical charts are aboard for each flight; with that authorisation they may be carried on an EFB. European operators follow EASA's Air Operations rules, under which the operator must ensure that an EFB does not adversely affect the aircraft's systems or the crew's ability to operate the aircraft and, in commercial air transport, must hold its authority's approval before using a Type B application, described below.

Portable and installed EFBs

A portable EFB is a device that is not part of the certified aircraft configuration: in practice a commercial tablet or laptop. It is a portable electronic device, so the operator must make sure that it does not interfere with the aircraft's systems in the phases of flight where it is used. It may simply be carried by the pilot, or it may use installed resources, such as a certified mount, a power outlet or a data connection, that belong to the aircraft even though the device does not. The A320's FlySmart with Airbus suite, for instance, runs on a portable electronic device, which the crew can plug into the 110 VAC, 60 Hz outlets on each lateral console; the 115 VAC, 400 Hz outlets at the rear of the cockpit are for maintenance use only.

An installed EFB is part of the aircraft, covered by its type design and airworthiness approval, with displays and computers built into the flight deck. On the 787 the touchpad cursor control devices can place the cursor on the EFB as well as on the left, right and lower displays, and the FAA's Flight Standardization Board report refers to the Boeing Class 3 EFB, a term from an older classification of EFB hardware into classes. The board makes the EFB a ground training special emphasis area, and its proper use is checked in initial and recurrent checks.

Types of EFB applications

The software, more than the hardware, decides how much scrutiny an EFB needs. EASA and the FAA both classify EFB applications by the effect that a malfunction or misuse could have:

• A Type A application is one whose malfunction or misuse would have no safety effect, such as a browser displaying the certificates and other documents that must be carried on board. In Europe the operator can introduce it under its own procedures, without a specific approval.
• A Type B application is one whose malfunction or misuse could have at most a minor effect, and which does not replace equipment that the rules require. Typical examples are performance calculation, mass and balance, electronic charts and the manuals required on board. In European commercial air transport the operator needs its authority's approval before using them; in the United States an airline's EFB programme is authorised through OpSpec A061, and since AC 120-76E the Type B applications no longer have to be listed in it.

Anything more critical than a Type B application is not an EFB function at all and must be certified as part of the aircraft.

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Typical uses

An airline EFB typically carries:

• Documents. The operations manual, aircraft manuals and the MEL. On the A320, Airbus's Operations Library application gives access to the FCOM, MEL, AFM, CDL and FCTM and to the airline's own manuals, and MEL and CDL items selected there pass automatically to the take-off and landing applications (see operations manual and flight crew documentation).
• Charts. En route, terminal and airport charts, which are subject to the same currency requirements as paper ones (see aeronautical charts). A moving map that shows the aircraft's own position depends on GNSS, and the FAA lists an inaccurate position on an EFB among the effects of GNSS jamming and spoofing (see GNSS interference).
• Performance. Take-off, landing and in-flight calculations, described below.
• Mass and balance. The A320's Loadsheet application checks the masses and centre of gravity against the loading envelope, handles last-minute changes and, depending on the authority's requirements, can produce the load and trim sheet itself (see load and trim sheet).
• Checklists. The A320's electronic QRH holds the normal checklists, some abnormal procedures and operational data such as the operations engineering bulletins (see standard operating procedures and checklists).
• Flight briefing. The operational flight plan, weather and NOTAMs, which many airlines now deliver electronically with graphical products. A graphical depiction helps, but the NOTAM text remains the authority.

Performance calculation

Performance calculation is the application with the greatest consequences. On the A320, the take-off application computes the maximum take-off mass, the take-off speeds and the flexible temperature from the aircraft configuration and the runway, obstacle and weather inputs; the landing application computes the maximum landing mass and the approach speed; and the in-flight application computes time, fuel, distance and altitude. The inputs are the actual mass, the runway and intersection, wind, temperature, pressure and runway condition, the flap setting, the air conditioning and anti-ice settings and any MEL or CDL items. The results are then entered in the flight management system, which the EFB does not replace (see take-off procedures).

Because a single mistyped figure can produce a convincing but dangerous answer, airline procedures make the calculation independent and redundant. Airbus's procedures assume that both pilots use an EFB, and Airbus recommends operating with two EFBs to reduce the risk of erroneous inputs. The two results are compared with each other, with the load sheet and with the FMS, and a gross error check confirms that the speeds are sensible for the mass. The need was shown at Melbourne on 20 March 2009, when an Airbus A340-500 struck its tail and overran the runway on take-off after a weight nearly 100 tonnes below the actual figure had been entered into the EFB, producing speeds far too low for the aeroplane.

A late change of runway or intersection invalidates the result. The procedure is a complete recalculation and a second cross-check, and a crew without time for that declines the change.

Operational approval and evaluation

Before an EFB replaces paper, the operator has to show that it works in its own operation. The detail differs between EASA's rules and the FAA's AC 120-76, but the elements are broadly the same. For a Type B application EASA asks for evidence of:

• a risk assessment of the device, the application and its functions: what happens if an application fails or gives a wrong answer, and how redundancy and procedures mitigate it;
• an assessment of the human-machine interface against human factors principles;
• suitability of the host platform, including, for portable devices, non-interference with aircraft systems;
• an EFB administration system, with procedures for operating the EFB, managing changes and data, maintenance and security, and training for the crews who use it;
• an operational evaluation, a period of use in service before the operator relies on the EFB.

At the centre stands the EFB administrator, the person the operator appoints to administer the EFB system and to act as its link with the system and software suppliers: managing the hardware and software configuration, making sure that no unauthorised software is installed and that only current versions of the applications and data are loaded, and supporting the crews who use it. On the A320, the Manager application updates the performance data and manuals used by the FlySmart applications on the tablet, and each application's My Flight page shows the versions of the installed applications and data, so the crew can check that they are current.

Risks and mitigations

Distraction is managed as on any flight deck. The EFB is for flight tasks only, and US airline rules forbid flight crew members to use personal wireless devices or laptops at their duty stations during flight time except for purposes such as operating the aircraft. Consumer devices also carry consumer limitations: a tablet can lose signal or power, has no integrity alerting for the position it displays, and can overheat. In general aviation, device overheating, battery failure and expired databases have all contributed to airspace infringements by pilots navigating on tablets.

Power, mounting and failures

Power. A portable EFB runs on its battery, recharged in flight where the aircraft provides outlets. Its lithium-ion battery can go into thermal runaway if it is damaged or faulty, so a device that overheats is a fire risk, dealt with under the operator's procedures (see aircraft batteries).

Mounting and stowage. Under EASA's material a portable EFB may be used in all phases of flight when it is secured to a certified mount or attached to a viewable stowage device that leaves the crew a clear view outside and does not impede any of their tasks. A device that is not secured in this way is stowed during critical phases of flight.

Failures. Redundancy is the main defence. With two EFBs a single failure leaves the other pilot's device, and the operator's procedures cover the loss of both, using paper backups, a third device or other sources such as runway tables for take-off performance. The two devices should not share a single point of failure, such as one charging source or one faulty data update.

Library articles are written for study and exam preparation. They do not replace your aircraft's approved documentation, your operator's procedures or the regulations themselves.