The ubiquitous marshaller, complete with wands, has been a common sight at airports and remain so at many today. Major airports, faced with growing numbers of flights and logistic problems, have moved into the automated era and are extensively fitted with precision docking systems to ensure ramp integrity and accurate alignment with passenger airbridges, while conforming with ICAO’s Annex 14, which lays down the standards for aircraft docking guidance systems.
Although the term Visual Docking Guidance Systems (VDGS) is in common usage, the system s are also referred to as Nose-in Docking Guidance Systems or Stand Entry Guidance Systems (SEG), truly a rose by any other name. Typical VDGS currently in use, in the UK, include Azimuth Guidance for Nose-in Stands (AGNIS) and Parallax Aircraft Parking Aid (PAPA). Mirrors can be used to provide a pilot’s eye view of the nosewheel position. As technology evolved major airports have increasingly adopted Advanced Visual Docking Guidance Systems (AVDGS), offering electronically displayed information, such as the azimuth position of the aircraft and stopping distance. In some cases, the AVDGS can determine aircraft type automatically and sets the relevant guidance parameters accordingly. Inevitably, manufacturers have been keen to address this market.
ADB is a Siemens Company that develops and manufactures, a full range of Airfield Ground Lighting (AGL) products. It also produced the Video Docking System (VDOCKS), which became the first video-based docking system in the USA, when it was installed at the Delta Air Lines hub in Boston Logan International Airport.
VDOCKS is based on video sensors and image processing that locates and tracks aircraft approaching the stop position at the gate. Being a video-based system, apron surveillance is an integral part of VDOCKS, via the airport network, videos can also be made available to other users such as airlines and security. It is said to provide pilots with precise guidance information during the docking process and increases the airside efficiency and performance, especially in poor weather conditions such as snow, heavy rain, fog or low sunset.
More recently a cooperation agreement with Swedish FMT, a technological leader in docking guidance, has been agreed and it is noteworthy that at last year’s Dubai Air Show FMT provided guest speakers, at ADB’s invitation, to demonstrate their Visual Docking Guidance Systems (VDGS).
With more than 40 years experience of the technology, Sweden-based, FMT first produced an APIS – Aircraft Parking and Information System, based on azimuth guidance by range target, featuring two bars and ground sensors which detect position of the nosewheel to provide distance to go and where to stop.
The second stage of development, patented by FMT used Moiré (optic) technology for azimuth guidance and microwave technology for assessing distance. The third step was to use a laser to replace the microwave and this has since become the most common standard to measure distance to go and STOP information for aircraft in the stand. This system was named APIS++ and more than 1000 of these units have been delivered worldwide.
In another FMT patented technology, APIS++ may be integrated with the FMT Passenger Boarding Bridge to provide control and safety of the boarding bridge by passing coordinates to its computer, guiding it, semi-automatically, to the aircraft door. FMT’s automatic Passenger Boarding Bridges together with its own Aircraft Parking and Information System, APIS++, interfaced to ATLANTIS, Apron Management System provide a unique integrated system. This integration is said to be the key to safety, flexibility and speed for efficient turnaround of large aircraft.
By providing integrated and automatic boarding bridge system, including over-the-wing configuration, aircraft like the A380, can be turned around within 30 minutes, using three boarding bridges, of which one is upper deck, one to the front door and one over the wing.
The Company has also developed the FMT Airpark System, designed to be a robust and reliable aircraft parking aid, that is in full compliance with the ICAO Annex 14 regulations. Airpark is based on Moiré technology for real-time and unambiguous lateral aircraft guidance, in combination with a manually controlled stopping position indicator.
The system comprises different components that can be combined into several different configurations, as required by local, operational conditions. These elements are azimuth guidance unit, traffic lights, control panel and stand number sign.
Another video-based system is the Visual Docking Guidance System (VDGS) from Honeywell Airport Systems GmbH that guides the pilot providing continuous data, registering ONBLOCK/OFFBLOCK times and monitoring the gate area. This latter function can be crucial in day-to-day activity, as it is only too often demonstrated that “stray” equipment can be easily overlooked under the pressures of an operational arrival. This is achieved using a high dynamic range video sensor unit and an image processing system based on 3D aircraft models.
The computer-assisted VDGS calculates information on an aircraft’s location and transforms it into precise guidance information for both pilot and copilot. Its video sensor and 3D model-based processing system are able to recognise the outline of an approaching aircraft at distances of up to 100 metres.
In addition to specific docking guidance instructions, the Pilot Display Unit (PDU) can also provide information to ground crews before, during and after on blocks. The PDU can be integrated into the facade of a terminal gate or mounted independent of the terminal structure.
In the United States, J & B Aviation Services, has developed the JB1900 Gate Park System, a simple to-operate, fail-safe system to provide parking guidance, using both human and mechanical components for guidance.
The automatic element comprises aircraft alignment and a fail-safe feature to stop the aircraft in case of emergency. The human input allows the handling agent to control the parking of the aircraft via a hand held controller. Because the JB1900 signal can be quickly returned to red, by release of the hand-held controller, the handling agent can alert the pilot to any emergency that would require the aircraft to come to a rapid stop.
A single JB1900 hand-held controller can manage multiple aircraft parking via a selector switch. This is particularly effective at gate positions where many types of aircraft are positioned with different centrelines of cockpit viewing area.
Mirror Technology offers a low-cost, fail-safe method for the precision parking of aircraft that has been developed in conjunction with the UK’s Gatwick Airport. This approach represents the simpler approach to the problem providing accurate positional guidance with lower costs and less complexity, with the advantage of giving the pilot a true view of the aircraft nosewheel approaching the correct stop position.
Maintenance is straightforward with cleaning being required regularly depending on pollution levels. The only other check is alignment and this can be automatic. The Manufacturer likes to emphasise that a mirror system is failsafe. It cannot give a dangerous image; either the wheel is visible or not. Some airports have barriers around the mounting post to help prevent impact damage. Mirrors are made in a variety of sizes to accommodate differing aircraft types.
Generally the maximum size is the Airbus A300. Where a stand is used for a wide variety of aircraft, a two-high mirror set-up may be used, thus allowing both smaller types (lower mirror) and medium bodied aircraft (upper mirror) to be guided to the same stand.
Safegate International AB, is based in Malmö, Sweden and has supplied its Advanced – Visual Docking Guidance Systems (A-VDGS) Safedock systems to Dallas Fort Worth (DFW) and Beijing’s international airport.
During the last 30 years Safegate has developed the Safedock Docking Guidance System and the SafeControl Airfield Lighting Control and Monitoring System, aiming to maximise the number of aircraft an airport can handle whilst maintaining a high level of safety.
The Safedock System automatically guides an aircraft during its approach to the stand with a stopping precision of just 10 cm. The Type 1 will maintain the Safedock stopping accuracy of 10 cm whether the stopping position is two or 65 metres from the terminal. The Type 1 will dock all known and future aircraft types with the same precision, including the A380.
The laser scanner of the new model has a 30 per cent longer range than earlier models, which means enhanced detection capability in rain and fog. It has also, an increased scanning rate for safer measuring and identification of aircraft. A wider scanning area also offers the possibility to include more and curved centrelines in a single system.
The Gate Operating System (GOS) is complementary to the Safedock System, as it minimises delays and interruptions at the gates. However, an aircraft can be redirected, at short notice, due to technical problems or human error. With GOS the airport staff get a better overview and can monitor every event as well as carry out centralised maintenance of the docking system. Not only does the GOS information make gate allocation easier, the performance of the airport ground operations is enhanced, with gates utilised to maximum advantage.
Despite the technological advances, automation can still be compromised by human nature. Regulatory authorities emphasise certain basic concerns about the parking systems and their use. Typically, it is advised that a pilot should not assume that a stand is safe to enter simply because the VDGS is active or illuminated. An aircraft should not be taxied onto an VDGS equipped stand when the guidance system is switched off, except under the guidance of a marshaller. It is not permissible for ground staff to activate an VDGS until a thorough inspection of the stand and its immediate surrounds has been made, in order to ensure that all equipment is correctly parked and that the stand is safe for use by the type of aircraft being operated.
In these environmentally sensitive times it is also a marketing ploy to point out that efficient parking can contribute to carbon reduction. By not having to wait for marshallers decreases waiting time, reduces Ground Power Unit (GPU) and/or aircraft Auxiliary Power Unit (APU) usage, thereby reducing associated fuel consumption and permitting a more rapid shutdown of the aircraft engines.
