What is an avionics “load” on the E-Jet? Load 25 vs Load 27 explained

In short

• A load is the certified software package that runs the whole Primus Epic avionics suite, released as a numbered version.
• Load 27 brought the Next Generation FMS (NGFMS), certified in 2016, and needs a processor upgrade on older airplanes.
• Features such as LPV approaches, ECON speeds and integrated CPDLC are options on top of the load, so check what your fleet actually has.

If you are new to the E-Jet E1 family, you will hear it in your first week of ground school: “we’re on Load 27”, “that airplane is still on 25”, “that page only exists after the update”. It sounds like jargon, but it explains a lot of the differences you will meet on the line, in the simulator and in your manuals.

Start with your phone

Think of your phone. The phone model is the hardware. The operating system version (the iOS or Android number you see in Settings) is the software. Two people with the same phone model can see different menus and features just because one updated and the other didn’t.

An E-Jet works the same way. The airplane model and the avionics hardware are the “phone”. The load is the “operating system version”. There are two big differences from your phone, though:

• Nothing updates by itself. Every load is certified, and the airline decides when each airplane gets it, usually as a planned maintenance task.
• It is not one app at a time. The whole avionics suite is updated together, as one package.

A load is a software version for the whole airplane

The E170, E175, E190 and E195 use the Honeywell Primus Epic integrated avionics. Displays, flight management, autoflight interfaces, crew alerting and maintenance functions run as software on a set of shared computer modules. That software is not updated piece by piece. It is certified and installed as one package, and that package is called a load.

Loads have version numbers. A major load (25, 27) can have point releases such as 27.1, 27.2, 27.3, 27.4 and 27.4.0.1, each one with a part number and its own list of changes. Airplanes get a new load either from the factory or as a retrofit through a manufacturer service bulletin.

That is why the same airplane type can show different pages, messages and functions: the hardware in front of you is the same, but the software behind it is not.

What Load 27 changed

The big step was the Next Generation Flight Management System (NGFMS), which came with Load 27. According to Honeywell, the Load 27 NGFMS was certified in July 2016. On older airplanes it requires a hardware upgrade first: the main processing modules move from an Intel 486 to a Pentium M processor.

The basic NGFMS package includes, among other things:

• FMS-managed speeds from takeoff to landing, with a speed intervention feature;
• multiple secondary flight plans, with copy and swap and full performance predictions;
• support for all ARINC 424 leg types and a table-driven performance model;
• a closest-airports display with fuel predictions;
• RNP AR approaches down to RNP 0.3 on final and RNP 1 on the missed approach;
• automatic LNAV engagement on TOGA.

Options sit on top of the load

Here is the part that confuses many pilots: being “on Load 27” does not tell you everything. Several capabilities are separate options that an operator may or may not have bought:

• Cost Index and ECON speeds, optimized idle descents and automatic landing speed calculation;
• LPV approaches using WAAS in North America (and SBAS in Europe), which also need SBAS-capable GPS receivers;
• Advanced RNP, with RNP values below 0.3 on final;
• integrated CPDLC (FANS and ATN in the FMS);
• synthetic vision, INAV moving map and vertical situation display, which also need newer display units;
• advanced runway awareness with a stable approach monitor.

So two Load 27 airplanes at two different airlines can still look different. And during a retrofit campaign, one airline may have airplanes on different loads at the same time.

And Load 25?

Load 25 is the earlier baseline that many E-Jets flew with before the NGFMS retrofit. The features above that came with Load 27, such as the NGFMS speed management and the integrated CPDLC, are not there. Your company manuals will tell you exactly what applies to your fleet.

Why it matters for your training

• Study for the load you will fly. MCDU page layouts, available approaches and speed management depend on it. A video or app made for a different load can teach you pages that do not exist on your airplane.
• Read the effectivity. Operations manuals and the FMS pilot’s guide state which load and options they cover. When in doubt, the airline’s documents win.
• Ask in the simulator. The training device should match the fleet’s load. If it doesn’t, the instructor will brief the differences.
• Changing airlines? Even on the same type, budget time for load and option differences.

How do I find out which load my airplane has?

Don’t guess. Ask your training department or check your airline’s operations manuals: their effectivity pages say which software load and options they cover. The FMS pilot’s guide also states the load on its cover. When you study with outside material, compare it with what your airline documents say.

Words you will hear in ground school

Primus Epic

The integrated avionics suite of the E-Jet E1 family: displays, FMS, autoflight interfaces, alerting and maintenance functions.

FMS

Flight Management System: the computer that holds your flight plan, calculates performance and guides the airplane laterally and vertically.

MCDU

Multifunction Control Display Unit: the keyboard and screen you use to talk to the FMS.

NGFMS

Next Generation FMS, the FMS that came with Load 27.

Service bulletin

The manufacturer’s document that tells the airline how to modify an airplane, for example to install a new load.

Option

A capability the airline buys on top of the load, such as LPV approaches or CPDLC.

The E175 version of the TOGA Academy MCDU trainer is being built on the Load 27 NGFMS, following the Honeywell NG FMS Pilot’s Guide for the E170/175/190/195. While it is in development, you can try the free MCDU trainer today.

Sources

• Honeywell. “NGFMS Upgrade for E-Jets: Epic Load 27 Update” (brochure N61-2230-000-000).
• Honeywell. NG Flight Management System (FMS) Pilot’s Guide for the E170/175/190/195, Load 27 (27.1/27.2/27.3), pub. D201007000016, rev. 2, April 2018.
• Service Bulletin SB190-31-0077, Primus Epic Load 27.4.0.1 (Dec. 2021), published in FAA docket FAA-2022-1246.