Internal batteries provide transmitter operation for a
minimum of 48 hours.
b. Switches and Functions.
(1) ARM Establishes readiness state to
start automatic emergency signal transmissions, when
the force of impact exceeds a preset threshold.
(2) ON Turns set on initiating emergency
(3) OFF Turns set off.
Introduction. The Cockpit Voice Recorder
(CVR) system records all voice signals on a
continuous loop magnetic tape for a maximum period
of 30 minutes. Voice recordings in excess of 30
minutes are automatically erased. The voice inputs
may be either transmitted or received signals
originating from the aircraft's communications system
or the remotely mounted cockpit area microphone
mounted in the glareshield. The CVR system is a
modular system comprised of three modules, the
recorder, the control unit and a remote microphone.
The recorder is a vibrator mounted unit housed in an
international orange case located in the unpressurized
aft fuselage area. The recorder contains the recording
unit and associated electronics. An impact switch,
mounted in the aft avionics compartment, controls
power to the voice recorder. If the impact switch is
subjected to a 2.5 G shock, the recorder is electrically
disconnected to prevent further recording and erasure
of voice communications. A red light located on the
impact switch case, when illuminated, indicates the
switch has been actuated. Pressing the reset button,
located adjacent to the impact switch light, causes the
light to extinguish and restores power to the voice
recorder. The control unit is located on the extended
pedestal and houses the microphone preamplifier, test
switch, erase switch, and a meter. The remote
microphone module is located in the glareshield
outboard of the warning annunciator panel. The CVR
system receives 115 Vac power through a 1-ampere
circuit breaker, placarded RECORDER POWER
VOICE, located on the copilot's sidewall circuit breaker
Refer to Figure 3C-3.
(1) Go/No-Go Self-Test Meter Provides
visual indication of Go/No-Go during preflight self-test.
2. TEST Switch
3. ERASE Switch
4. HEADSET Jack
Figure 3C-3. Cockpit Voice Recorder
Control Unit OSA
recording mode. Meter indicates self-test Go/No-Go
indication and an aural tone is produced through
(3) ERASE Switch Permits erasure of
recording at end of flight. To prevent accidental
erasure, the switch must be held for 2 seconds with
the landing gear extended and the weight of the
aircraft on the landing gear and the parking brake set.
(4) HEADSET Jack Allows monitoring of
voice recordings, after a 2-second delay and an aural
tone during self-test.
3C-12. FLIGHT DATA RECORDER OSA .
The digital flight data recorder system
(referred to herein as a crash data recorder)
continuously records flight data inputs for the last
25 hours of flight. The flight data parameters recorded
are heading, altitude, vertical acceleration, and
airspeed. The data is recorded on a continuous loop,
1/4 inch, self-lubricating magnetic tape bundle. The
tape is drawn out of the hub and returned to the supply
reel at the outer periphery of the bundle after having
passed the write and read heads. The tape capsule is
protected by an inner aluminum casing, an isothermal
shield, outer stainless steel casing, and an outside
steel dust cover. The construction of the cases
provides survivability assurance while the isothermal
shield provides protection from temperatures. There
are no pilot accessible controls or switches associated
with recorder. Its operation is completely automatic.
An impact switch, mounted in the aft avionics
compartment, controls power to the recorder. If the
impact switch is subjected to a 2.5 G shock, the
recorder is electrically disconnected to prevent further
recording and erasure. A red light located on the