Module 12.8 Helicopter Electrical Power ATA 24 Planning

Module 12 is on Helicopter Aerodynamics, Structure and Systems and module 12.8 is on typical helicopter electrical system.

In preparation for the lessons to groups of students, the following will be the topics of the powerpoint presentation. I am not able to include the powerpoint without removing some of the photos which may attract copy right issues.

1. Syllabus

The syllabus is in according to EASA part 66. The Malaysian version is under AN1101. 

12.8 Electrical Power (ATA 24) Level 3 

Topics to be covered are...

- Batteries Installation and Operation; 

- DC power generation, AC power generation; 

- Emergency power generation; 

- Voltage regulation, Circuit protection. 

- Power distribution; 

- Inverters, transformers, rectifiers; 

- External/Ground power.

b. The fixed wing aircraft is similar and under the Module 11.6

- Batteries Installation and Operation; 

- DC power generation; 

- Voltage regulation; 

- Power distribution; 

- Circuit protection; 

- Inverters, transformers.

2. About Module 12.8 or 11.6

The electrical power system will always consists of 3 elements:

- Generation

- Distribution

- Utilization

3. Overview

To suit the adult learning preferences, I always give the students the overview. 

The traditional chalk and talk is used to suit the various levels of the students. Free white board drawing on the following topics.

- Brief Overview of parallel system

- Overview of DC System

- Main Components

- Generators – AC and

- CSD

- IDG

- RAT

- Voltage Regulator

- TRU

- Inverter

- Battery

- DC generator

- Circuit breaker

4. . Battery Installation and Operation

In module 3, we had covered the construction of batteries.

In this module, we cover on how the battery is installed in aircraft.

We are expected to know:

- Safety practices

- The practical installation and maintenance.

- The operation as intended for the aircraft.

- The circuit diagram

- Types of Batteries

       - Lead Acid

       - Nickel Cadmium

       - Lithium Ion

5. Battery Connector

A quick release connector with copper lockwire 26 AWG.

Contacts to be lubricated with  white petroleum jelly to prevent corrosion.

6. Temperature Monitoring - The importance of temperature monitoring. The description of thermal runaway.

7. Ventilation

- the various methods to ventilate, the importance of ventilation especially for lead acid battery.

8. Lead Acid Charging 

- Indications of fully charged cells

           - On charge – 2.7 volts => x12 = 32 volt.

           - SG maximum

           - Gassing

- Indication of fully discharged

          - Voltage 1.8v

          - SG minimum

9. Servicing – Lead Acid Battery

Lead Acid Battery

Nickel Cadmium

No servicing allowed.

Considered serviceable if the voltage (charger off) is above 24 volts.  

10 - Advantages/Disadvantage NiCd

 - The Advantages are Better power to weight ratio, Lower internal resistance, Longer life, Easy to replace cell, More robust and Higher Charging rate thus shorter charging time. Wider operating temperature

- Disadvantages are Higher cost, Prone to thermal runway and it Requires complex charging control circuit.  

11. Battery Capacity

Understand how capacity is measures and the effect of discharging rate on the capacity calculation.How the capacity is measured.