A conventional emergency lighting arrangement in an aircraft includes a number of emergency lights arranged distributed in the aircraft, as well as one or more emergency current supply units having rechargeable batteries that supply electrical current to the emergency lights in the event of a failure of the on-board electrical power supply network of the aircraft. Such emergency current supply units are conventionally known under the name Emergency Power Supply Units (EPSUs), for example from references and sources such as http://www.diehl-dle.com/en/frm.html or http://www.pageaerospace.com.
Depending on the storage capacity of the rechargeable batteries, such a conventional emergency current supply unit can supply electrical power to a certain limited number of the emergency lights. Typically, several or many emergency lights are connected to a single emergency current supply unit by suitable cabling. The rechargeable batteries must be regularly tested and occasionally replaced or exchanged due to their limited operating lifetime, which leads to a considerable inspection and maintenance effort and time expenditure. Also for this reason, the battery-powered emergency current supply units can only be installed at certain locations within the aircraft, namely locations that allow an easy access for the purpose of testing, inspection and replacement of the batteries, for example behind a maintenance panel or door.
A further disadvantage of the conventional arrangement is that the battery-powered emergency current units have a relatively high weight, for example because the batteries have a relatively high ratio of weight to storage capacity. Furthermore, when a plurality of emergency lights are to be connected to a single emergency current supply unit, this requires a complicated cabling arrangement that adds to the total system weight. Nonetheless, such a cabling arrangement is necessary to ensure a remaining adequate functionality of as much of the emergency lighting arrangement as possible, for example after the occurrence of an assumed cabin rupture that may break or interrupt at least some of the emergency current supply cables.
The US Patent Application Publication US 2003/0026092 A1 discloses a portable rechargeable blinking light, that is particularly adapted to be installed or mounted as a convenience light or lamp in a motor vehicle. A capacitor is provided as an independent current supply, whereby the supply of electrical current from the capacitor to the light emitting element can be switched on or off as desired by the user by means of a switch provided for this purpose.