MD Helicopters 369D - Inspection;Check; Fuel Quantity Gauge and Tank Sending Unit Operational Check; Instruments Inspection

CSP-HMI-3MD Helicopters, Inc.
MAINTENANCE MANUAL
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95-00-00
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Copyright © 1999−2016 by MD Helicopters, Inc.
INSTRUMENTS
INSPECTION/CHECK
1. Instruments Inspection
(1). Inspect instrument case for dents and
cover glass for slippage and cracks.
(2). Inspect fitting or electrical receptacle at
back of instrument for damaged
threads that might prevent proper
connection of the tube nut or electrical
plug.
(3). Inspect index markings and numerals
on dial face for discoloration and
legibility. Inspect pointers for cracked
or peeling paint.
(4). Inspect for presence of all required
range markings and white slippage
mark at bottom of glass (Ref. PFM).
2. Fuel Quantity Gauge and Tank Sending
Unit Operational Check
Perform following checks to determine that
fuel quantity gauge readings are within
tolerance. Checks are made at empty, 200
pounds and full fuel loads.
Consumable Materials
(Ref. Section 91−00−00)
Item
Nomenclature
N/A Plastic, thin clear sheet
Special Tools
(Ref. Section 91−00−00)
Item
Nomenclature
ST1010 Volt-ohmmeter
(1). Use following tolerances when checking
fuel quantity indications.
(a). For 3 pack gauges (early model):
E = +0, -2 degrees from centerline
marker
2 = ±4 degrees from centerline of
marker
F = ±4 degrees from centerline of
marker
(b). For 3 pack gauges (current model):
E = +1, -0 pointer width from
centerline of marker
2 = ±1 pointer width from centerline
of marker
F = ±1/2 pointer width from center
line of marker
(c). Tank sending unit circuit resistance
(gauge disconnected) is as follows
(Ref. Table 601):
Table 601. Tank Sending Unit Circuit
Resistance
Indication Early Unit Current Unit
E= 1 ohm 0.10 − 2.00 ohms
2 = 59 ohms 56.5 ohms
F= 88 ohms 88 − 95 ohms
(2). To check degrees of error, construct
template of thin clear plastic for 3 pack
gauge.
(a). Cut rectangular template to fit flat
on instrument glass, inside bezel and
covering fuel quantity gauge area.
(b). Tape template in position and scribe
lines on template from center of
pointer pivot shaft through center of
graduation marks at E, 2 and F.
(c). Scribe maximum tolerance (from list
of tolerances above) lines on each
side of centerlines.
(3). Defuel helicopter (Ref. Sec. 12-00-00).
NOTE: Helicopter should be as near level as
possible and external power should be 24 -
28.5 Vdc for accurate indications.
(4). Turn power ON. Gauge pointer must be
at E or below, with tolerance marked on
template.
NOTE: If indications are not within tolerances,
determine whether gauge or tank sending
unit is at fault by removing electrical power,
disconnecting gauge wiring and checking
tank sending unit circuit resistance (Ref.
Table 601).