That Air Traffic Technical Company Limited (ATTECH), a subsidiary company of Vietnam Air Traffic Management Corporation, successfully studied Aeronautical Message Handling System (AMHS) with distinct advantages over Automatic Message Switching System (AMSS) has confirmed its right technology approach and demonstrated its competence and experience in the development process of Vietnam aeronautical industry under the leadership of the Prime Minister . 

Current status of AFTN network

Aeronautical Fixed Telecommunications Network (AFTN) with AMSS stations acting as its core is one of the most important telecommunications networks in the civil aviation industry to serve the exchange of information among aeronautical service providers, airport authorities and civil aviation authorities, and between domestic and international civil aviation authorities .

Until recently, all regional aviation administration agencies use AFTN network as the primary means to execute their professional duties.

The old-fashioned Automatic Message Switching System can only deliver simple text message (7-bit IA5 or 5-bit ITA-2), which is far below current requirements on aeronautical information exchange . On the other hand, numerical monitoring to avoid loss of messages is a complicated method and easy to make mistakes. In addition, AFTN network includes separate AMSS stations, therefore, the establishment of message channels and addresses among stations often come up with a lot of difficulties. With the low amount of channels (40 channels/1 AMSS station), the system cannot satisfy the demand for extension when there is an increase in the number of channels in future. Additionally, some disadvantages such as:  the limited length of messages (max. 1,800 characters), private line… require upgrading the system.

AMHS Group

Modern aeronautical message switching system requires the message sharing under various kinds of formats like: sound, image…not simply text. Hence, the old-fashioned AMSS has revealed many disadvantages, which would require a replacement by a more modern, effective and cohesive information exchange method.   

CAAV working group attended the official AMHS acceptance test performed by AC-B GmbH

To that end, ATTECH embarked on the research to create the premium product AMHS. Unlike other conventional products, AMHS is a highly complicated information technology  programme. With the resolution to fulfill the task to manufacture specialized air-ground products and provide ATM technical services assigned under Decision No.21/QĐ-TTg of Prime Minister on the development of aeronautical industry, ATTECH focused all its resources to develop the AMHS within 2 years, this product is expected to become the basis for ATN communications system.

The advantages of AMHS system

AMHS is an aeronautical automatic message handling system, it is capable of processing, storing, and handling messages in accordance with ITU-T recommendations and ICAO standards. It is developed on the basis of Message Handling System – MHS. MHS was constituted in accordance with ITU strict standards on message handling.

In accordance with ICAO Doc 9880 Part II, AMHS has 2 systems:

Basic system: is the most basic AMHS system, it is established on the basis of ITU-T X.400 recommendations and  is capable of connecting with AFTN and supporting AFTN message handling functions.

Extended system: is developed from basic AMHS system. Its message handling ability is enhanced to form a complete AMHS system with the following prominent features:

— – Use of File Transfer Body Parts (FTBP): allows the system to receive and deliver numeric files.

— Use of IPM Heading Extensions (IHE): allows the system to use standard message field instead of ATS message header as in Basic AMHS. Messages can have all types of format as described in X.400 standards.

— AMHS Security (SEC): supports AMHS safety policy, it provides message authentication and data content security among AMHS direct users

— Use of Directory (DIR): support the system to use ATN directory for channel distribution and message handling.

AC-B specialists and ATTECH AMHS development group members tested the AMHS

AMHS will completely solve AFTN limitations thanks to its outstanding advantages like: message handling speed and capacity, higher level of safety and reliability…,  it can satisfy future development demand of the civil aviation industry.

AMHS software is developed as an ATN service, it is completely compatible with VATM’s future ATN networks in terms of connectivity, safety and security.

AMHS can support 200 terminals, store 100,000 messages in queue; support the flow of 100 messages per second, mixed flow of 50 AFTN messages; 50 AMHS messages per second. AFTN/AMHS gateway supports the bidirectional transfer of 30 messages/second, each message has the medium capacity of 1,500 bytes, min: 100 bytes and max: 15,000 bytes.

AMHS is programmed to ensure the provision of basic AMHS services will comply with Asian Pacific requirements and and are able to support various kinds of AMHS addresses in accordance with ICAO standards  (XF and CAAS). Additionally, the system has many convenient, modern, safe and efficient functions when put into operation.

ATTECH is competent and experienced in developing automatic message handling systems. The successful trial connection with Singaporean AMHS has confirmed ATTECH’s technological solutions are completely appropriate and fully connected. At present, the basic AMHS software is being developed. AMHS products strictly comply with ICAO standards and recommendations, they satisfy requirements of VATM and are completely compatible with VATM’s hardware and transmission line.

The scene at AMHS test room

AMHS developed by ATTECH has the following main software: Central processing software (processes, manages, handles messages); CM software (supervises the system operations); Gateway software (bridges the format transfer of messages between AMHS and AMSS); Client software (operates the system terminals). These software have been checked, tested and edited through ATTECH internal testing system and overally accredited and certified as compliant with ICAO technical and operational standards on AMHS.

AMHS and requirements on aeronautical global connectivity

ATN/AMHS implementation is one of the most crucial objectives in Vietnam CNS/ATM development master plan (Aeronautical communications, navigation and surveillance/management) up to 2020 and further towards 2030 approved by the Minister of Transport.

Under the new CNS/ATM program, AMSS systems will be gradually replaced by AMHS systems which are much more superior in terms of aeronautical information exchange so that Vietnam can connect with other countries in the region and all over the world through AMHS.

At ATNIGC/8 Workshop taking place from 18 to 21 March 2013 in Indonesia, Asian Pacific countries agreed to complete all AMHS/ATN implementation and interconnections by 2015. With its successful development of AMHS, Vietnam planned its schedule to implement the interconnections with regional related countries such as Thailand, Laos, Singapore, Hong Kong by end of 2014 and beginning of 2015. This plan was approved by ICAO and related countries.

Hence, the development of basic AMHS system will help solve the current limitations of AFTN network, satisfy operational demands, fulfill integration commitments of Vietnam civil aviation industry and at the same time, create a specialized aviation equipment system of international quality with low operational costs.

Source: Transport Magazine – August 2014