ELECTRICAL LOAD ANALYSIS G500H BELL 407

Transcription

1 ELECTRICAL LOAD ANALYSIS G500H BELL 407 Dwg. Number: Garmin Ltd. or its subsidiaries c/o Garmin International, Inc E. 151st Street Olathe, KS COMPANY PROPRIETARY

2 Company Proprietary Information This drawing and the specifications contained herein are the property of Garmin Ltd. or its subsidiaries and may not be reproduced or used in whole or in part as the basis for manufacture or sale of products without written permission. Copyright 2010 Garmin Ltd. or its subsidiaries. All rights reserved. Garmin Ltd. or its subsidiaries c/o Garmin International, Inc E. 151 st Street Olathe, Kansas U.S.A.

3 TABLE OF CONTENTS 1 INTRODUCTION Purpose of Document APPLICABLE DOCUMENTS Applicable Regulations SYSTEM DESCRIPTION Electrical Load Analysis Bell 407 with Existing Electrical Load Analysis Pass/Fail Criteria SUMMARY... 5 i

4 TABLE OF TABLES Table 3-1. G500H LRU Current Requirements... 2 Table 3-2. Replacement Electrical Load Analysis for Bell 407 Rotorcraft G500H Installation... 3 ii

5 1 INTRODUCTION 1.1 Purpose of Document The purpose of this electrical load analysis (ELA) is to document electrical loads for the G500H system as installed for this STC. This ELA will show the following: 1) The total change in power consumption after the alteration is negligible and does not exceed the capacity of the electrical power generation and distribution system of the aircraft under foreseeable operating conditions. 2) The aircraft systems can be supported by the generator during normal operation. 2 APPLICABLE DOCUMENTS Bell Helicopter, BHT-407-MM-10, Bell model 407 Maintenance Manual, Volume 10, Rev 25 dated 29 Sep 2008 Garmin International, Document No , G500H Installation Manual Garmin International, Document No. 005-C , G500H Flight Display System STC Installation Master Drawing List (MDL) 2.1 Applicable Regulations This analysis will show compliance to the following regulations: 1) 14 CFR (a) Amdt

6 3 SYSTEM DESCRIPTION The Bell 407 is equipped with a generator driven 28 VDC electrical system. The generator furnishes regulated power for all DC electrical circuits of the helicopter. Generator output is transferred to the main bus when a minimum of 24 VDC is achieved. The Starter-generator is located on the lower right side of the engine gearbox. This unit is used to start the engine, charge the battery, and supply power for operation of DC equipment. Power is stored in the 24 Volt battery. The DC generator power capacity at 30 VDC is as follows: 180 Amps continuous operation 300 Amps 2 minutes 400 Amps 5 seconds The generator is rated at 200 Amps, but is derated to 180 Amps to ensure adequate cooling. 3.1 Electrical Load Analysis An electrical load analysis (ELA) must be completed on the Bell 407 rotorcraft prior to installation to verify the rotorcraft electrical system is capable of supporting the additional load of the G500H system. The purpose of the ELA is to show compliance with FAR (a). As part of the G500H installation it must be shown that the maximum electrical system demand does not exceed the aircraft DC power generating system capacity. The results of the ELA must be recorded on FAA Form 337. Use the following values for computation: LRU 28 Volt Current Draw Typical Maximum GDU A 2.7 A GRS 77H/GMU ma 1.0 A [1] GDC 74H/GTP ma 235 ma [1] Maximum current draw occurs momentarily at startup or when the supply voltage drops to 9 VDC. Table 3-1. G500H LRU Current Requirements 3.2 Bell 407 with Existing Electrical Load Analysis The existing ELA for the rotorcraft must be updated to reflect the modification. It must show that the generator has adequate capacity to supply power to the modified systems in all anticipated conditions. Add the applicable loads outlined above to the existing analysis and ensure that the generator capacity is not exceeded under all anticipated operating conditions. The Bell 407 Maintenance manual contains an ELA which covers the basic rotorcraft electrical loads and the electrical kits and avionics equipment. The ELA is used to ensure that the DC power generating system will not exceed its designed capacity during all in-flight conditions. If additional electrical or avionics equipment is installed in the helicopter beyond what is covered in the maintenance manual, be sure to obtain appropriate electrical load data for the installed equipment and add it to the pre-existing ELA. Ensure the electrical load limits will not be exceeded with the installation of the G500H system. A simplified schematic of the electrical system of the Bell 407 is below. An ELA containing the addition of the G500H equipment is documented in Table 3-2. If there is additional equipment installed in the Bell 407 beyond what is documented in Table 3-2, be sure to add this equipment to the table in the additional equipment rows. Attach table 3-2 to FAA form 337 after completing the G500H installation. 2

7 EQUIPMENT PART DESIGNATION NOTES NO. OF UNITS AMPS PER UNITS OPERATING CONDITIONS START AND WARMUP TAKE-OFF CRUISE LANDING OPERATING TIME 5 SEC 2 MIN 15 MIN 5 SEC 2 MIN 15 MIN 5 SEC 2 MIN 15 MIN 5 SEC 2 MIN 15 MIN FLIGHT INTSTRUMENTS STBY ATTD IND JET CONT STBY ATTIND LT JET CONT TURN&SLIP IND CONT DIRECT GYRO CONT DG LIGHTING CONT HEATING AIR COND SYST AIR COMM 407EC CONT HEATER SYSTEM AIR COMM 407H CONT ENGINE CONTROLS PART SEPERATOR CONT MISCELLANEOUS CARGO HOOK KIT QUIET MODE KIT Q/M KIT SW LT CONT Q/M KIT RELAY M83536/6-025M CONT Q/M RPM SNSR CONT POWER BAT CHRG 28AH MARATHON CONT RADIO NAV AND COMM AUD PANEL KMA 24H CONT LIGHTING FOR KMA 24H CONT AVIONICS MODEL VHF NAV 1 KING KX VHF COMM1 RCV KING KX VHF COMM1 XMT KING KX VHF COMM1 KING KX CONT VHF COMM1 XMT KING KX VHF COMM1 RCV KING KX CONT WARNING AND EMERGENCY TOTAL POINTER CONT EMERG FLOATS DC BUS--KITS TOTAL BASIC + KITS Table 3-2. Replacement Electrical Load Analysis for Bell 407 Rotorcraft G500H Installation Sheet 1 of 2 3

8 Equipment Part Designation Notes No. of Units Amps per Units Operating Conditions Operating Time Start and Warmup Takeoff Cruise Landing 5 sec 2 min 15 min 5 sec 2 min 15 min 5 sec 2 min 15 min 5 sec 2 min 15 min Radio Nav & COMM OMNI/ILS IND KI CONT LIGHTING FOR KI CONT VHF COM RAD 1 VHF RECEIVE KING KY196A 1 1 CONT VHF XMIT KING KY196A ADF RCVR KR 87 KING CONT ADF IND LT KR 87 KING CONT ENCODING ALT CONT GPS SYSTEM 1 GPS RECEIVER KLN89B 1 3 CONT LIGHTING FOR KLN89B CONT COOLING BLOWER KA CONT COMPASS SYSTEM 1 DIR GYRO KCS-55A & KG CONT HSI KI CONT RADAR TRANSPONDER KING KT TRANSPONDER KING KT CONT G500H SYSTEM GDU 620 PFD/MFD GDU CONT GRS77H/GMU GRS 77H AHRS/GMU 44 GDC 74H ADC/GTP 59 ADDITIONAL EQUIPMENT CONT GDC 74H/GTP CONT TOTAL DC BUS- AVIONICS TOTAL BASIC+KITS+AVIONCS Table 3-2. Replacement Electrical Load Analysis for Bell 407 Rotorcraft G500H Installation Sheet 2 of 2 4

9 Notes and Assumptions: 1. Intermittent loads are not included in the total value as these loads are short duration loads and will be absorbed by the battery. 2. For worse-case loading conditions, the air conditioner and heater are assumed to be on at the same time, even though they are mutually exclusive. 3. Load values were taken from the Bell 407 Maintenance Manual. 4. Battery charge current is not considered in the analysis. 5. Additional equipment or differences between this ELA and the actual rotorcraft configuration must be accounted for in the final calculation. It is the responsibility of the installer to ensure correct electrical loading calculations in the final ELA. 3.3 Pass/Fail Criteria For a Bell 407 G500H installation, the following must be shown: 1. The electrical bus load must not exceed the generator capacity under continuous operating conditions. 2. The G500H system installation does not overload the generator capacity in any foreseeable operating conditions. If the limits outlined above are exceeded, alternate FAA approval is required for installation of the G500H equipment. 4 SUMMARY The analysis above demonstrates the following statements to be true: 1. The generator output is adequate for operation in accordance with FAR (a). 2. The total load on the generator during Start/Warmup, Takeoff, Cruise, and Landing phases of flight is below the rated 180 Amps for continuous operation. 3. The total load on the generator during Start/Warmup, Takeoff, Cruise, and Landing phases of flight is below the rated 300 Amps for 2 minutes. 4. The total load on the generator during Start/Warmup, Takeoff, Cruise, and Landing phases of flight is below the rated 400 Amps for 5 seconds. 5. This STC contributes no significant change to the existing electrical distribution or loading of the Bell 407 electrical system with the G500H equipment installation. 5