Patent ID: 12195182

DETAILED DESCRIPTION

FIG.1shows part of an aircraft galley100. The galley100features an aircraft cabin equipment system2comprising a light fitting4in a ceiling of the galley100and three aircraft cabin devices: an oven6, a chiller8and a coffee maker10. In some other examples the aircraft cabin equipment system may include other galley devices and/or cabin devices located elsewhere in an aircraft.

Part of the aircraft cabin equipment system2is shown schematically inFIG.2. As illustrated inFIG.2, the light fitting4comprises an LED device12and a controller14. The controller14is connected to an external aircraft data management system102via an aircraft data network103. The aircraft data management system102maintains the aircraft time.

The oven6comprises a light detector16, a processor18, an internal clock20, a sensor22, a memory24, along with other standard oven components such as a heating element (not shown).

During operation (e.g. during a flight of the aircraft), the Light Emitting Diode (LED) device12of the light fitting4emits visible light to illuminate the galley100for normal cabin crew use. The light fitting4may be dimmed or switched off entirely in different phases of a flight. In other examples light sources other than LEDs may be used.

The controller14receives time information from the data management system102and generates a time signal that indicates the current time. The time signal is frequently updated (e.g. every second) so that it is up-to-date with the current time. The controller14broadcasts the time signal by modulating the intensity of light emitted by the LED device12at a high frequency (e.g. sufficiently high so as not to be visually discernible)). Because the light is modulated at a high frequency, this modulation is not perceptible to users of the galley100.

The controller14continuously broadcasts the time signal when the LED device12is used to illuminate the galley100. When the LED device12is dimmed or turned off, the broadcast is paused.

Light from the light fitting4is detected by the light detector16of the oven6. The light detector16detects the changing intensity of the incident light due to the modulation applied by the controller14. The processor18demodulates the detected changes in the incident light to determine the time signal.

The internal clock20maintains an estimate of the current time, i.e. based on an estimate of the time elapsed since a previous synchronization with an external time source. For instance, the internal clock20may comprise a crystal oscillator and associated circuitry arranged to measure elapsed time. Every time a new time-stamp signal is determined by the processor20, it updates the estimate maintained by the internal clock20(i.e. the internal clock20is synchronized using the time stamp signal). The internal clock20is thus kept in synchronization with the current time provided by the aircraft data management system102. In periods when the broadcast of the time stamp signal is paused but the oven6is still powered (e.g. when light fitting4is dimmed or switched off), the internal clock20maintains its estimate of the current time. The internal clock20is then synchronized when the broadcast of the time stamp signal resumes.

The sensor22detects operations of the oven6. For instance, the sensor22may detect the current operational state of the oven (e.g. switched on, actively heating, cooling down). The processor18uses information from the sensor22and the estimate of the current time from the internal clock20to produce a time-stamped event log of the operation of the oven6. This log is stored to the memory24. For instance, the log may record the times at which the oven6was used over the course of a flight. When the oven6is first switched on, it may wait to receive an initial time signal from the light fitting4before starting to record events.

Although not shown inFIG.2, the fridge8and the coffee machine10each also features a light detector16, a processor18, an internal clock20, a sensor22and a memory24arranged in a similar manner to those of the oven6. The fridge and the coffee machine also detect the light emitted by the light fitting4and use this to keep accurate time-stamped event logs of their operation during the flight.

Because the light fitting4provides a continuously updated time signal to the aircraft cabin devices4,6,8in the galley100, the devices4,6,8do not need to be manually updated every time the aircraft is started up to have an accurate estimate of the current time. They can simply wait to receive a time signal from the light fitting4. Furthermore, the time signal can be updated as the aircraft passes through or lands in different time zones, ensuring that the times in the event logs of all the devices4,6,8are accurate and useful.

While the disclosure has been described in detail in connection with only a limited number of examples, it should be readily understood that the disclosure is not limited to such disclosed examples. Rather, the disclosure can be modified to incorporate any number of variations, alterations, substitutions or equivalent arrangements not heretofore described, but which are commensurate with the scope of the disclosure. Additionally, while various examples of the disclosure have been described, it is to be understood that aspects of the disclosure may include only some of the described examples. Accordingly, the disclosure is not to be seen as limited by the foregoing description, but is only limited by the scope of the appended claims.