WORLDWIDE implementation of the future air-navigation system (FANS) is still years away, but civil-aircraft manufacturers and operators are already adopting satellite-based avionics, for several near-term reasons.

These include the availability of fuel-saving routes for suitably equipped aircraft, the pending decommissioning of the Omega navigation system, and the approaching introduction of new US and European airspace regulations.

With the future environment for communication, navigation, surveillance and air-traffic management (CNS/ATM) being introduced incrementally, and regionally, aircraft and avionics manufacturers alike are tackling the problem of how to meet operators' near-term needs with solutions that will fulfil their long-term requirements - not an easy task when many of the CNS/ATM standards have yet to be agreed.



Boeing took the first step toward CNS/ATM in 1995 when it introduced the FANS-1 upgrade for its 747-400. So far, more than 120 aircraft have been equipped and the manufacturer has begun delivery of FANS-1 upgrades for the 777. Certification of a FANS-1 capability for the 757 and 767 is planned for December. Pioneered on South Pacific routes, FANS-1 operations have spread to the Russian Far East and, most recently, to the Bay of Bengal.

Airbus Industrie will move to CNS/ATM when it certificates its equivalent to FANS-1, called FANS-A, in April 1998 on its A340. The capability is planned to be common across its range of narrow- and widebody airliners.

Compliance with CNS/ATM requirements is a key feature of new flight-management systems (FMS) planned for the A319/A320/A321 and A330/A340. The consortium is to offer customers a choice of FMSs, from incumbent supplier Honeywell and a new Sextant Avionique/Smiths Industries team.

CNS/ATM compliance has become a watchword for the civil-avionics industry, for new-aircraft and retrofit applications - and including the regional-airliner and business-aircraft markets.

Compatibility with the future airspace system is a key feature of Rockwell-Collins' Pro Line 21 integrated avionics, selected for the Raytheon Premier I business jet and Bell-Boeing 609 civil tilt-rotor, and Honeywell's Primus Epic integrated avionics, selected for the Raytheon Hawker Horizon business jet. Sextant, meanwhile, is developing its IMS integrated-avionics system for the Bombardier de Havilland Dash 8-400 regional turboprop.

Manufacturers specifying systems for derivatives of their existing aircraft are insisting on CNS/ATM compliance. Collins will expand the capability of its Pro Line 4 avionics for the stretched Bombardier Canadair Regional JetSeries 700, while Honeywell's Primus 1000/2000 family is likely to be developed for planned derivatives of the Embraer EMB-145 and Fairchild Dornier 328 regional aircraft.

Honeywell, through its involvement on the 777 and McDonnell Douglas (MDC) MD-11 programmes, has built a commanding lead in the development of integrated avionics for airliners. The company's latest Versatile Integrated Avionics (VIA) system has been selected by MDC for its upgraded-cockpit DC-10 , dubbed the MD-10, as well as for the MD-95, while the system's large-format liquid-crystal displays (LCDs) are an option on the MD-90.

Collins plans to compete for future airliner programmes with advanced, integrated avionics which will share key features with its Pro Line 21 system now under development. In common with Honeywell's VIA system, these features include the use of large-format LCDs and a processor architecture in which avionics functions become software modules, with the aim of simplifying upgrades and growth to keep pace with CNS/ATM developments.

The first steps toward the future airspace system have brought with them a demand to retrofit existing aircraft. Examples include the US decision to decommission the Omega long-range navigation aid in 1997, in favour of the satellite-based global-positioning system (GPS), and Europe's plan to introduce new area-navigation requirements in January 1998. Both are generating a market for systems enabling airlines to continue to operate with, and gain the operational benefits for, existing aircraft.

extensive upgrades

The principal requirement is for a GPS-based FMS, but some operators are taking the opportunity to conduct more extensive upgrades. Leading the field is KLM's programme to equip its "classic" Boeing 747-300s with the equivalent of FANS-1 capability. This is centred on Canadian Marconi's (CMC's) CMA-900 FMS/GPS, but includes Litton's LTN-92 inertial-reference system (INS) and an electronic flight-instrument system (EFIS) using Smiths Industries' 5ATI-size LCDs which replace the conventional electromechanical instruments. Certification is scheduled to take place in the first quarter of 1998.

Lufthansa has completed a 747 FANS upgrade for an outside customer, using Honeywell equipment, while ARINC is planning a 747 FANS-upgrade programme. Other 747 operators are looking for less-ambitious upgrades. Tower Air has fitted its 747s with the LTN-92 INS, which Litton will upgrade with FMS/GPS capability under an agreement with Interstate Electronics. The upgraded LTN-92E is being offered to replace LTN-72, -92 and Delco Carousel INSs in older widebodies.

Airbus has selected Collins' GNLU-920 multi-mode receiver (MMR) with which to upgrade A300s. The unit, which houses a GPS receiver and an instrument landing-system (ILS), also has an FMS module developed by Smiths Industries.

MDC's MD-10 upgrade for the DC-10 mimics the layout and capabilities of the MD-11 two-crew cockpit, but uses the same large-format LCDs as Honeywell's 777 and new-generation Boeing 737 systems. Redelivery of upgraded DC-10s is scheduled to begin in mid-1999.



Narrowbodies account for most of the recent upgrade activity, with several fleet-wide FMS/GPS-retrofit programmes having been announced.

The first, and largest so far, of these is American Airlines' deal to upgrade more than 400 Boeing 727s and MDC MD-80s, as well as its DC-10s, with the Honeywell/Trimble HT9100 FMS/GPS as a replacement for Omega. The contract was the first major success for the Honeywell/Trimble team, formed to pursue upgrade business.

Honeywell and Trimble have subsequently entered the regional- and business-aircraft retrofit markets, with the HT9000, while its HT1000 has been selected as a standard option for new-build Aero International (Regional) ATR 42/72 regional turboprops.

Collins, meanwhile, has won the contract to upgrade Delta Air Lines 727s and 737s, with its GNLU-900 FMS/GPS/MMR as well as 5ATI-size LCD displays to replace the electromechanical flight instruments. United Airlines has decided against retrofitting its 727s, after conducting a competition amongst FMS/GPS vendors, but Northwest Airlines still seems intent on upgrading its DC-9s.

Internationally, retrofit activity is gathering pace. Alitalia is upgrading its McDonnell Douglas MD-82s with an all-weather landing system that includes Sextant's Topstar GPS receiver and Head-up Flight Display System, as well as a Honeywell FMS and EFIS. Swissair, with Austrian, is to install CMC's CMA-900 FMS/GPS in its MD-80s.

Some freighter operators are also upgrading their aircraft. Emery Air Freight is retrofitting is MDC DC-8s with Universal Avionics' UNS-1D FMS/GPS, while United Parcel Service is equipping its Boeing 727 freighters with Apollo 2101 GPS navigation-management systems produced by IIMorrow. Evergreen Airlines has installed Trimble TNL-8100s GPS navigators in its 747s.



Retrofit activity is also strong in the regional-airline market, prompted in part by the recent upgrading of US commuter operations to the same standards as are applied to major carriers.

In North America, US Airways Express is equipping its aircraft with the Magellan/ ARINC CNS-12 system that combines GPS navigation with the ACARS airline-datalink. AMR Eagle carrier Executive Airlines is already operating its ATRs with Universal's UNS-1C GPS navigation system. Horizon Air is using the UNS-1C in its Dash 8s. United Express carrier Atlantic Coast Airlines has fitted its Jetstream 31s and 41s with AlliedSignal Aerospace's GNS-XLS FMS/GPS.

In Europe, Austria's Tyrolean Airways selected the UNS-1C to meet impending European area-navigation regulations with its Dash 8-300s. Switzerland's Crossair is evaluating Interstate's GNLS-9001 in the Saab 2000 in ongoing trials of a differential-GPS landing system. British Aerospace has selected Collins' GNLU-910 FMS/GPS/MMR for forward-fit and retrofit to the BAe 146 and Avro RJ regional jet airliners.

AlliedSignal has launched development of the FANS-compatible GlobalStar 2100 FMS/GPS, which is to be available for forward-fit and retrofit in 1998. Bombardier has selected the system to be standard on the Dash 8-400, Regional Jet and Learjet 45, while the GlobalStar will be installed in Cessna's Citation Excel business jet - its FANS-upgradeable GNS-XL single-box FMS/GPS is already standard on the Citation Ultra.

Collins is certificating its Avsat 4000/5000/ 6000-series FMS/GPS units on a range of regional and business aircraft equipped with its Pro Line 4 integrated avionics, such as the Regional Jet, Saab 2000 and Raytheon Beechjet 400A. Honeywell is upgrading its FMZ-2000 FMS with GPS. The system is used in a wide range of commuter and corporate aircraft equipped with its Primus 1000/2000 and SPZ-8500 avionics systems. Recent examples include the EMB-145 and Gulfstream V.

Slower-than-expected development of the GPS-based landing system (GLS), has fuelled sales of the multi-mode receiver. The MMR was conceived as a way for airlines to make the transition from today's ILS to the GLS, a process which is now expected to last for another ten years.

Airlines operating into Europe must upgrade their ILS equipment to be immune to increasing radio interference, and the MMR has been developed as way to update their ILS units while providing an upgrade path to GLS, by way of the microwave landing-system (MLS) if necessary.

Collins already has secured MMR orders from British Airways, to equip some 300 aircraft, and United, for its Boeing fleet. United also placed the launch order for Sextant's MMR, to equip its Airbus A319s.

Southwest Airlines is among the first customers for AlliedSignal's MMR. Airbus has announced plans to offer both the Collins and Sextant units on new-build aircraft, while Boeing intends to certificate both the AlliedSignal and Collins MMRs. Eventually, all three systems are expected to be offered by both aircraft manufacturers.

Collins is developing both the GLU-900 MMR for forward-fit to aircraft with digital avionics, and the GNLU-900 for retrofit to analogue aircraft. The basic system combines ILS and GPS, with MLS and GLS as later options. FMS is an option in the GNLU.

The US manufacturer is developing the MMR with Daimler-Benz Aerospace, which is also working on the associated differential-GPS ground station. CMC will supply the MLS module. Certification at Airbus and Boeing is planned for the latter half of 1997.

Sextant is flight-testing its MMR in the A319, with certification planned for September in the initial ILS/GPS configuration. AlliedSignal's MMR will substitute for the ILS in the company's Quantum range of digital communication/navigation avionics.



While work continues towards the introduction of the GLS, some airlines are moving ahead with the installation of head-up displays (HUDs) to provide a reduced-visibility landing capability. Alaska Airlines led the field, with Flight Dynamics' Headup Guidance System (HGS) entering service on the carrier's 727s in 1988. Alaska has since upgraded to HGS-equipped 737s, and the system is also installed in regional subsidiary Horizon Air's Dash 8s.

Flight Dynamics still leads the commercial-aircraft HUD industry. Southwest is equipping almost 240 737s with the HGS and, in March, UPS ordered 60 units for its 727 freighters. The company's HUD is in service on regional jets operated by Brit Air, Lauda Air and Lufthansa City; Saab 2000s flown by Crossair, and the Dassault Falcon 2000 business jet.

Sextant has supplied its Headup Flight Display System for Aeropostale 737s and Alitalia MD-80s, and the French manufacturer's HUD will be a standard option on the Bombardier Global Express business jet. The HUD 2020, developed jointly by Honeywell and GEC-Marconi Avionics, was granted Category II certification in April on the Gulfstream IV-SP, and the manufacturer has orders for more than 50 systems for installation on GIVs and GVs.

Gulfstream is presently leading industry efforts to develop an enhanced-vision system (EVS) to give a Category IIIa landing capability using the HUD. Its programme is based on a forward-looking infra-red sensor.

Lear Astronics, meanwhile, is assessing airline interest in its Autonomous Landing Guidance (ALG) system, which uses a millimetre-wave radar to generate HUD images. The ALG has been flight-tested in a United 727. TRW, leading a team which includes Honeywell, plans to demonstrate a passive millimetre-wave camera which has potential application as an EVS sensor. Flight tests are planned to begin in September, in a USAir Force Boeing C-135.

Communications is a key component of CNS/ATM, and a critical element of the system is the planned aeronautical telecommunications network (ATN).

AlliedSignal has been selected by ATNSystems, a joint company formed by airlines and the US Federal Aviation Administration, to develop software for the ATN router - the ground and airborne system which will support routing and operation of data services over VHF, HF and satellite-communications (satcom) networks. The company's team includes Honeywell and Sextant.

AlliedSignal has also begun development of avionics for use with the Iridium satcom system. The company says the equipment will be smaller, lighter and cheaper than satcom systems using Inmarsat's Aero-H service. AlliedSignal plans to have a single-channel unit available by September 1998, when Iridium plans to begin aeronautical service. Multi-channel systems are planned to be available in 1999.

Iridium will compete with Inmarsat's new Aero-I service, which uses the spot-beam capability of its new Inmarsat-3 satellites to allow lower-gain antennas and smaller, lighter avionics. Aero-I systems will be cheaper to install and use than Aero-H equipment, and are expected to be fitted mostly to narrowbody, regional and corporate aircraft that will operate within the coverage areas of the satellite spot beams.


Development plans

Existing Aero-H equipment suppliers Collins and Honeywell/Racal have announced plans to develop Aero-I systems, as has Denmark's Thrane & Thrane, which now produces avionics for use with Inmarsat's low-cost Aero-C messaging service.

Collins is developing the SATCOM 6000, which will offer combined Aero-H and -I capability in a system one-third the size of its present SAT-906 multi-channel Aero-H unit. The SATCOM 5000 will be a lower-cost Aero-I unit.

The Honeywell/Racal team, meanwhile, is upgrading its MCS-3000/6000 Aero-H systems to Aero-I capability, the latter of which Inmarsat plans to introduce in March 1998.

Source: Flight International