02 Jun 2014

TLD Aircraft Safe Docking System helps you make your ground ops safer

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Aircraft strike prevention has always been a critical item, and the arrival of the new composite aircraft is making this objective even more critical, as impacts on the fuselage currently detected during the aircraft check may not be evidenced any longer through a visual check. For this reason, prevention, detection and reporting of impacts during ground handling operations become more important, and significantly impacts the safety responsibility of the handling company in term of aircraft interface.

Increasing safety of ramp operations is a much broader challenge than it appears. As part of its innovative culture, TLD has decided to develop a new solution, bringing GSE to a higher level of safety during operations, with the ASD (Aircraft Safe Docking System).

As this safety challenge concerns the aircraft docking of any GSE, TLD has developed a solution adapted to belt loaders, passenger steps and loaders. The goal of the system is to prevent damage by GSE to the aircraft, and moreover to ensure that no aircraft should depart with unreported impact. The TLD ASD is a simple, reliable and easy to maintain solution.
An important objective of our R&D has been to develop a solution retrofittable on most existing equipment, from any manufacturer, as this safety improvement, once implemented, will most preferably need to be installed on the whole fleet of equivalent equipment. As a matter of fact, it would be dangerous for an operator already accustomed to this safety system, to be suddenly deprived of it when using the equipment from another brand.


How does the ASD work?

The ASD system prevents the equipment from approaching the aircraft too fast, thus avoiding a potential contact resulting in damage to the fuselage. With this view, we have defined 3 different areas in the airport for equipment speed control.
In the ramp area, the GSE can be driven without any speed limitation (up to 25km/h) and without specific supervision.
As the driver approaches the aircraft, he enters the safety area. The operator reduces his speed and presses the ASD button to activate the system. Immediately, a dedicated flashing beacon alerts the management and the other operators on the ramp that the equipment is now in safe mode. In this area, the GSE speed is limited to 5km/h, and the proximity sensor, associated to a sensitive bumper, are activated. The sensor is a 3D camera able to detect any obstacle in front of the GSE up to 7 meters (fuselage, engines, other GSE, other operators…). A buzzer warns the driver if he gets too close to the speed limit and in case of slow or no reaction from him, the system will automatically stop the equipment.
In the final phase of the docking, or approaching closer than few meters from an obstacle (mainly the fuselage), the ASD system automatically limits the speed of the vehicle to 0.7 km/h. At that speed, even in case of contact, the GSE’s kinetic energy can hardly cause any significant damage to the aircraft.
In case an impact with the aircraft occurs (or in case the operator does not activate the ASD system for instance) the impact strength will be measured and the GSE will be stopped until the responsible manager un-locks the vehicle after fuselage inspection. This procedure is comparable to the one existing on towbarless tractors in case of reported overtorque events.


Why is the ASD system safe?

ASD is not only a system, it is a combination between an operational process (systematic and easy to enforce and to control) and an electronic control supervising the speed of the GSE according to the area of operations.

The process is based on the fact that the driver is still in charge and responsible. So the ASD is initially not taking the lead on the driver but supervises his behavior. This supervision ensures that the driver operates in a safe manner, avoiding potential accidents with severe consequences. Within the aircraft area, the ASD is assisting the driver, and only acts on the equipment speed if the operator does not respond properly in time.
Being in charge and not relying on a fully automated system, the driver is much less exposed to possible system or equipment technological failure or adverse conditions. He must still ensure that he operates in a safe way,

This concept is also allowing us to design a system with a reasonable level of complexity. There is no 100% foolproof system and overly complex systems are difficult to maintain. If the driver totally relies on the system, technical failures can have disastrous consequences.


What makes the ASD unique to other systems?

The concept is simple, systematic and still largely relies on the operator supervised by the system, and not the other way around. In case of system failure (harsh meteorological conditions, electronic failure, etc…) the GSE remains just as safe as today.

The ASD is based on a single 3D camera instead of multiple sensors or radars. We believe that a solution based on a single sensor is a key advantage over solutions based on multiple radars. First, those radars are more sensitive than a camera to interference due to meteorological conditions. Second, when a large number of radars is deployed, the potential of technical failure is increased, and it is difficult to make the difference between a radar not detecting any obstacle and a radar not functioning. This creates a significant risk as operators may rely on a non-functioning system.

The 3D Camera requires very limited cabling, thus allowing an easy equipment retrofit, and maintains its own correct performance (the camera monitors itself every 150 millisecond that it is functioning properly). In case of malfunctioning or extreme operations conditions, the camera detects the problem and automatically defaults to the safest operation mode (eg. low speed).

The other critical ASD sensor is the Incident black box, measuring all excessive decelerations and logging the event, including the complete conditions of the unit (speed, gearbox status, brakes pedal status etc…) before, during and after the event. All data is then accessible by the management through a very simple, user friendly graphic interface. The existence of this black box will definitively induce a higher level of operator accountability.

Lastly, the system is retrofitable on most TLD equipment as well as machines from other manufacturers. The ASD can be installed not only on new GSE but also on existing GSE (with the exception of equipment mounted on commercial chassis). This is an important point, as this will allow to avoid managing a fleet of GSE with and without safety enhancement systems. The solution will be available on electric GSE, Diesel or Hydrostatic powered units.
At the cost of this ASD option, handling operations can bring significant value to their global fleets with increased ramp safety and the reduction of potential aircraft impacts.


Why is ASD reinforcing safety of ramp operations?

ASD, through its supervision, is making operators fully responsible while more controlled and managed.
More controlled, because in the aircraft area, the ASD is monitoring the environment and ensures that operators never drive too fast or too close to potential causes of impacts. ASD also acts as a black box, recording all events, including the conditions of the GSE during, before and after the event. So drivers know that ramp managers will know their operational behavior as well!
More managed, because through a beacon light, the GSE displays whether the operator is following the procedure or not.
Ultimately, ASD is increasing the operation’s safety. In case an impact should still occur, the GSE would stop and restart only after a manager comes and inspects the aircraft helping in eliminating unreported impacts.

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