Mar 2017
Page 39
© Penny & Giles Aerospace Ltd. No part of this work may be reproduced or distributed by any
means without prior permission in writing from the copyright owner.
DATA ACQUISITION FLIGHT RECORDER Type D51615-202-XXX or D51615-
202-XXX-090- with CCU Type D51616-XXXX and CAM Type D51623-XXXX
Installation and Operating Manual with Illustrated Parts
List
Commercial in Confidence
PIM434-I
4.3 SIGNAL
LEVELS
The CVR function of the DAFR utilises digital audio recording
techniques. These do not have the inherent ‘soft’ overload
characteristics, which analogue magnetic tape recorders had.
It is therefore particularly important that the input signal
levels are within the specification for the DAFR. Signal levels
at the recorder input should be verified with the use of an
oscilloscope.
When setting the Attenuation Links for the Cockpit Area
Microphone Preamplifier, it must be remembered that signal
levels encountered in flight will be higher than those
encountered on the ground and the attenuation therefore set
accordingly. Confirmation of optimum attenuation level
should be established by subjective evaluation of recordings
made during flight.
4.4 WIRING
The recommended minimum wiring sizes are shown in Table
2. These sizes are applicable for runs of up to 100 metres.
For variants with an Internal Preamplifier and remote Area
Microphone, the limit on cable length to the microphone will
be set by the electromagnetic environment.
The ground connection to the recorder should be within 30cm
of pins 4 and 5.
Power Ground must be connected on both a.c. and d.c.
installations.
The Area Microphone Record Level (attenuation) setting links
and Record On link are to be as short as possible.
The DAFR utilises a single connector, for the purposes of on
aircraft data recovery it is necessary to include a replay panel
comprising at least of a replay interface connector and audio
jack socket (if desired). The proposed wiring for the replay
panel is shown on the wiring installation diagrams included as
part of this manual. Connection from this panel to a portable
computer for the purpose of data recovery and status can be
achieved using Penny & Giles Replay Lead part number
SA109654.