![](/images/new-backgrounds/1223481/223481115x1.webp)
The Mark III CMU has also been designed to support a future upgrade for new Gatelink technology. With the advent of commercialized 2.4 GHz spread spectrum wireless communication, a new technology is emerging for the airline industry for providing the ability to transmit very large data packets from and to the aircraft when in the vicinity of a short range transceiver (commonly referred to as Gatelink). This new technology has significant potential advantages in the future due to the high transfer rates (between 1 and 11 Mbits/ second), and the fact that this technology uses an unlicensed frequency band. This technology is also being defined to interoperate with normal Intranet / Internet based systems, providing significant growth capability for seamless interoperability with an airlines existing computer network. Honeywell has recognized the potential of this new technology, and as such has designed into the Mark III CMU the ability to upgrade the unit in the future to support such capability on the aircraft. This includes the use of using one of the existing Ethernet ports within the Mark III CMU to communicate with the our wireless transceiver/antenna which would be added to the aircraft in the future to support the Gatelink transmissions.
Similar to the Mark III CMU hardware, the Mark III Software architecture within the unit has taken the next leap forward in technology. Honeywell, which first introduced and certified
degree of flexibility to airlines, allowing you to add or modify logical elements within the CMU. In contrast, other systems require such logical processing changes to be performed by the CMU manufacturer (within their AOC software). Thus such processing as determining flight phases (such as OUT, OFF, ON and IN events), various exceedance conditions, and other logical processing for sending downlink messages can be defined in a database, modifiable by either Honeywell or the airline. This flexibility to define logic conditioning within the Mark III CMU has been expanded to other areas of the system as well, such as allowing increased flexibility in controlling what is displayed on the MCDU; and conditional processing for determining what information to include in downlinks and printer based reports. All such capability is able to be performed without impacting the certification status of the unit. All of the Mark III CMU operational software and database are software loadable into the unit, allowing updates without removing the system from the aircraft. In addition, due to the size of the memory on the Mark III CMU, the Mark II CMU is capable of a single database across all of the aircraft in an airline’s fleet of aircraft. This will allow an airline to have not only the same software but also the same database (thus identical and single configuration) across the complete fleet.
The Mark III CMU also incorporates a certified database which is used to implement changes to certified components easily, versus requiring software modifications. As an example the ARINC 623 ATC messages are contained in this certified database, which would also be expanded in the future as other ATC messages become operational.
The Mark III CMU also has added in special software and hardware that supports Honeywell’s NZ FMS / CDU, used on many regional aircraft such as the Embraer 135/145 as well as other types of aircraft. These aircraft which do not use the traditional ARINC 739 protocol, can now have the latest in Datalink technology, through the use of the Mark III CMU’s special processing for such aircraft types.
HONEYWELL Aerospace Electronic Systems | Page 58 |
Use or disclosure of information on this page is subject to the restrictions on the title page of this document.