MD Helicopters 369-500, Maintenance Instructions Manual

Page: 151 / 722

CSP-HMI-3
MD Helicopters, Inc
.
MAINTENANCE MANUAL
[ Main Menu ]
[ HMI − 3 Book TOC ]
[ Chapter 95 TOC ]
95-10-30
Page 201
Revision 7
The information disclosed herein is proprietary to MD Helicopters, Inc.
Neither this document nor any part hereof may be reproduced or transferred to
other documents or used or disclosed to others for manufacturing or any other
purpose except as specifically authorized in writing by MD Helicopters, Inc.
Copyright
©
1999 − 2016 by MD Helicopters, Inc.
INSTANTANEOUS VERTICAL SPEED INDICATORS
MAINTENANCE PRACTICES
1. Instantaneous Vertical Speed Indicator
Description
(Ref. Figure 201 or Figure 202) The instanta­
neous vertical speed indicator (IVSI) is a
coupled inertial lead and barometric pressure
instrument that indicates the rate of change in
feet per minute due to climb or dive maneu­
vers. A pendulum mass within the instrument
provides an instantaneous reaction to change
that is sustained by barometric pressure.
Static line tubes and fittings are connected
between airspeed indicator, altimeter, IVSI
and static drain valve on canopy structure.
(Ref. Sec. 95-10-00 for general information on
the pitot-static system.)
The IVSI installations in R/H command
T-Panels also include a Grimes half-fixture
(eyebrow-type) post light. Installations in L/H
command T-Panels include a bolt light.
NOTE:
These instruments do not provide infor­
mation to the avionics systems. Gyros that
do interact with avionics equipment are cov­
ered in the avionics portion of this manual.
2. Instantaneous Vertical Speed Indicator
Operation
The IVSI presents helicopter climb and dive
information. Helicopter ascent is indicated by
clockwise rotation of the pointer from zero at
the 9 o'clock position. Descent is indicated by
counterclockwise rotation. Internal stops
prevent excessive pointer movement. Range of
indicator is 0-3,000 feet (0-915 meters) per
minute, ascent or descent. A small slotted
screw in the lower left face of the instrument
provides for zero adjustment.
A. Instantaneous Vertical Speed Indicator
Troubleshooting
(Ref. Figure 201 or Figure 202 and Table 201
for troubleshooting information on the
pitot-static system)
3. Instantaneous Vertical Speed Indicator
Replacement
A. Slim − Line Instrument Panels
(Ref. Figure 201)
(1). Check that all electrical power is OFF.
(2). Remove instrument panel hood and left
and right fairings (Ref. Sec. 95-00-00).
(3). (369H90044-BSC only) Remove
adapter, reducer and 0-ring from rear
of IVSI.
(4). (369H90044-501 only) Remove connec­
tor from rear of IVSI.
(5). (Primary location only) Remove clamp
assembly, mounting hardware and
IVSI.
(6). (Alternate locations only) Remove
mounting hardware and IVSI.
(7). (Primary location only) To replace,
install IVSI, mounting hardware and
clamp assembly to instrument panel.
(8). (Alternate locations only) To replace,
install IVSI and mounting hardware to
instrument panel.
(9). (369H90044-BSC only) Install O-ring,
reducer and adapter to rear of IVSI.
(10). (369H90044-501 only) Install connector
to rear of IVSI.
(11). Install instrument panel hood and left
and right fairings.
B. L/H Command T − Panels
(1). Check that all electrical power is OFF.
(2). (Ref. Figure 202) Disconnect static line
from rear of indicator.