3
Operation
The steps that follow, describe the operation of the LDR:
3.1
Audio Acquisition
The audio signals received from the CAM and the pilots ACP are processed by a combination of hardware and
software resident in the LDR. The audio input is recorded as 16-Bit @ 48 kbps, with a bandwidth of 150 HZ to 20
kHz.
3.2
CSMU Data Recording
The data recording function is implemented in software as a task running on the LDR. The recording media is the
CSMU. The CSMU has 8 GB of flash memory that will provide non-volatile memory on the LDR.
3.3
ARINC 717 Flight Data
The LDR receives and processes the ARINC 717 flight data transmitted from the MAU and records this data on the
CSMU. The LDR can correlate the audio and flight data to within ± 1 second.
Files containing flight data are given timestamps based on the LDR's internal clock. The timestamps are in
Universal Time Coordinated (UTC) time (in seconds) and are included as part of the file name.
Flight Recorder Electronic Documentation (FRED) files are stored on the LDR to show incident investigators how
the recorded data is organised.
Flight data is recorded in a packetized 717 format. The LDR will place header and footer information for every 4
frames of 256 words each.
Flight data is stored in a Packed Binary Raw Data Output File Type. The packed flight data stores four 12-bit data
words in three 16-bit words. For ARINC 717 data, each consecutive 48 16-bit words form a subframe.
Each flight data .dat file will contain a maximum of one hour of data.
3.4
Status Monitoring and Fault Log Management
Built in test functionality and the management of the recorded Fault Log is implemented in a software task running
on the LDR. Fault Log information is recorded in the CSMU.
3.5
LDR Ground Support Interface
Access to the data stored in the CSMU is proved through a series of web pages hosted within the LDR. Known
as the LDR Ground Support Interface (LGSI), these web pages are used for the read-out of recorded data, system
configuration and maintenance.
3.6
LDR Setup
The LDR's operating and recording parameter setup can be accessed, and if necessary, altered. This is done from
the “Configure” page within the LGSI software loaded on a laptop, and with the laptop connected to the ethernet
RJ-45 port on the LDR through a CAT5E crossover cable, refer to AMM 12-B-31-30-01-00A-903A-A .
PC-12/47E AMM Doc No 02300, ISSUE 01 REVISION 26 MSN 545, 1001-1719,
1721-1999
12-B-AM-00-00-00-I
UNCLASSIFIED
Effectivity: All
12-B-31-30-01-00A-040A-A
UNCLASSIFIED
2021-12-04 Page 3
