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Current affairs

Within aircraft cabins, electrical and electronic systems are contributing to improving the passenger experience, thanks to technological advancements, as Mario Pierobon finds
 
Electrical systems generate electricity, which is an increasingly important commodity needed during flights. “We are seeing increasing demand for commercial technologies to be adapted and installed on our seating programmes. Everything from accent lighting, personal electronic device (PED) seating controls, connectivity to the internet during flight, wireless charging, seat heating and cooling, heated and cooled cup holders, occupant comfort detection and notification, locking boxes for personal valuables,” says Ashraf Sherif, Senior Technical Fellow at Collins Aerospace. “The list goes on and on. Simply put, if you have it in your daily life it is wanted on the aircraft. If it is in our cars, it is being requested on our seats.” 
 
PORTABLE ELECTRONIC DEVICES
 
In the last 10 years, an important development that has influenced electrical systems has been PEDs. More and more people have the necessity to use electricity to charge electronic devices during flights. Sherif explains: “The increase of portable electronics has created increased demand for additional recharging power on the seat. PC power, USB ports, and now wireless charging are all in high demand. From a seating perspective, this has resulted in additional wire routing, mounting of power conversion units and considerations for placement and location of the recharging unit itself. Each new device adds additional power wiring and more total power draw.”
 
The electrical power supply of aircraft is indeed in a constant state of change, and the focus is progressively on cabin applications. “In the past, a reading lamp was sufficient for the passenger, but it has become a fully digital entertainment application on own servers (audio/video on demand). Digitalchange is becoming the norm, and with it so is connectivity. In this context, a possibility for recharging PEDs was standard in long haul aircraft, now a USB port on each seat is getting increasingly popular on single aisle aircraft. A twin engine aircraft with a full PED power installation may even reach the limits for power generation,” say Viktor Daubner, Principal Design Engineer (Cabin Electronics) and Joachim Kienzler-Cleuvers, Principal Design Engineer (Avionics) at Lufthansa Technik. “Nowadays, more and more seats are equipped with USB or wireless charging modules.
 
However, standard USB ports require up to 10 Watts each, at 5 V/DC,” explains Lothar Trunk, Chief Engineer & Programme Manager of Innovation at Diehl Aviation. “So, assuming an aircraft has capacity for 300 seats, we need to ensure the supply of additional power up to 3000 Watts. Realistically, however, not all devices will need to be charged simultaneously. So, although we can expect the actual burden to be significantly lower, we must nevertheless cater to the maximum potential requirement.” According to Trunk, an important debate is open about “whether and how the classic seat-back in-flight entertainment will be replaced with handhelds such as smartphones or tablets.
 
Quite apart from the potential cost reduction, this would lead to a significant reduction in the aircraft’s weight, and its power requirements,” he says. “It is necessary nowadays to offer passengers USB connections to charge batteries. It means to install new dedicated wires to provide power to new ‘in-seat power’ systems. These wires are installed under the floor, respecting both safety and design requirements. Indeed, it is not always easy to make something smart and perform well. We try every day to solve this trade off by offering high tech systems in an attractive cabin,” says Cyril Brand, Design Manager at Air France Industries KLM Engineering & Maintenance.
 
“If we add the fact that wifi systems are also expected with this new way of travelling, it is clear that requirements have evolved and a lot more power is expected. Nowadays, electronic load analyses are much more difficult, as aircraft are charged a lot. It is also necessary to do more tests after a modification, to check electromagnetic interference (EMI) requirements. Wire segregation is also harder, and specific attention must be paid to this certification item. So, more constraint must be taken into account.”
 
WIRING AND LIGHTWEIGHT FIBRE OPTICS
 
According to Daubner and Kienzler-Cleuvers, PEDs are important for the demand of power management in aircraft: “Since the use of a user’s own PEDs is much more normal today than it was 5-10 years ago, the demand is the greater challenge. In the meantime, data is transmitted wirelessly, but energy still has to run over electrical cables. So wiring and LRUs required for PED power systems have a weight impact. LHT is generally supporting the operator’s vendor selection in order to source the best suitable and cost-effective solution for their fleet.” Lightweight fibre optics in networks and electronics systems and other new technologies is seen to provide solutions to the increasing demand for power in aircraft.
 
For now, lightweight fibre optics is mostly used by aircraft manufacturers to provide a complete network in the latest cabins. Daubner and Kienzler-Cleuvers affirm that peripheral equipment outside of enclosed systems like in-flight entertainment with fibre optics is still very rare on the market. “Fibre optics is a fixture in inflight entertainment systems that gets supplied to Collins by either partners or OEMS and are integrated into our systems,” says Sherif. “The use of fibre is increasing; however, there may be an inflection point where it gets refocused on high speed data busses and concentrators/multiplexors only as there will be a trend towards wireless communication for low speed/critical busses where large number of LRUs are required (seats, lighting, sensors, data collection).” >>
 

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