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Communications
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Power supply system
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Equipment for overwater flights
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Fuel system
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Ice protection
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Flight data recording systems
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Warning and indication systems
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Lights
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Flight and navigation equipment
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APU
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Hoisting and transportation equipment
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Fuselage
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Tailplane
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Windows
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Rotor(s)
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Control system
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Powerplant
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Transmission
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putting out a fire
Because of an increase in power supply failures of electric energy receivers connected to battery with supply bus via cutout IP-50 on Mi-8MTV-1 helicopters, in accordance with the bulletin No. T3423-БУ-Г and No. T3241-БУ-Г, backup supply line for electric energy receivers is introduced and its electric diagram is modified.
In the process of operation of Mi-8MTV-1 helicopters, there was a number of incidents related to disconnection of DC consumers due to activation of cutouts IP-150 in power circuits feeding battery buses. In such case, flight and navigation equipment and avionics, assemblies of fuel, hydraulic, fire-prevention system become de-energized, that requires forced landing. In connection with this, it was decided to modify the power supply system and introduce backup supply line for electric energy receivers.
As a result of these works, the bulletin No. Т3241-БУ-Г “Introduction of backup supply line for electric energy receivers on Mi-8MTV-1 helicopters”was issued.
However, after implementation of this modification, the cases of false activation of warning panel “LINE ON BAT” took place due to failure of diode item 106/3.
To address this problem, additional modification was developed, which was executed in accordance with No. Т3423-БУ-Г «Modification of electric circuit of supply line for electric energy receivers by circuit of cutout IP-150 item 93/3», to be realized together or after fulfillment of the bulletin No. Т3241-БУ-Г.
For installation of backup supply line for power receivers and modification of electric circuit of supply line for electric energy receivers on Mi-8MTV-1 helicopters, according to this service bulletin, it’s required to perform electric installation works as follows:
- modification of distribution box of left instrument panel,
- installation of display board TS-5M-2,
- installation of resistor С5-36В-25 W-390 Ohm+0,5%,
- installation of relay ТКЕ21ПОДГ,
- installation of cutout IP-150,
- laying and crimping newly introduced bundles Л14, Л8,
- installation of diode 2Д220А1 with soldered wire.
After completion of the above works, it’s necessary to check serviceability of the system.
More detailed information is given in the bulletins:
- No. Т3241БУ-Г «Introduction of backup supply line for electric energy receivers on Mi-8MTV-1 helicopters»,
- No. Т3423-БУ-Г «Modification of electric circuit of supply line for electric energy receivers by circuit of cutout IP-150 item 93/3».