• Home
• About
• Privacy

Electricity Terms for PPL Theory

Electricity

Electricity is one of the topics students are required to know about and it is listed in the EASA PPL syllabus. The definitions of electricity that you need to know are described below and you will need to become familiar with them.

Electricity is a form of energy resulting from the movement of electrons through a conductive medium, such as wires or circuits. It is a fundamental force in modern society, powering various devices and systems.

Direct Current (DC)

Direct Current is the flow of electric charge in a single direction through a circuit. The voltage in a DC circuit remains constant with time. Batteries and solar cells are common sources of direct current.

Voltage (V)

Voltage, also known as electromotive force (EMF) or electric potential difference, is the driving force that pushes electric charges through a circuit. It is measured in volts (V). A higher voltage means that there is more potential energy available to move electric charges.

Current (I)

Electric current is the flow of electric charge (usually electrons) through a conductor. It is measured in amperes (A). Current represents the rate of flow of charge through a specific point in the circuit.

Resistance (R)

Resistance is a property of a material that opposes the flow of electric current through it. It is measured in ohms (Ω). Materials with high resistance impede the flow of electrons, while materials with low resistance allow current to flow more easily.

Conductivity

Conductivity is the inverse of resistance and measures how easily a material allows electric current to flow through it. Highly conductive materials have low resistance, while poorly conductive materials have high resistance.

Ohm’s Law

Ohm’s Law: Ohm’s Law is a fundamental principle in electrical circuits, named after the German physicist Georg Simon Ohm. It states that the current passing through a conductor between two points is directly proportional to the voltage across the two points, given constant temperature (for conductors that follow Ohm’s Law). The mathematical representation of Ohm’s Law is:

V = I x R

where:

• V = Voltage (in volts)
• I = Current (in amperes)
• R = Resistance (in ohms)

Power (P)

Power in an electrical circuit is the rate at which work is done or the rate at which energy is transferred or converted. It is measured in watts (W). The power consumed by an electrical device can be calculated using the following formula:

P = V x I

where:

• P = Power (in watts)
• V = Voltage (in volts)
• I = Current (in amperes)

Work

In the context of electricity, work refers to the energy transferred or expended by an electric current as it flows through a circuit and encounters resistance. The work done is related to the power consumed and the time during which the current flows.

The unit of work is the joule (J).

Alternating Current (AC)

Alternating current is a type of electrical current where the direction of the flow of electrons reverses periodically. In other words, the current alternates between positive and negative directions in a continuous manner.

AC is the most common type of electricity used in homes and businesses as it is more practical for long-distance transmission and can be easily transformed to different voltage levels.

Amplitude

In the context of AC, the amplitude refers to the maximum value of the current or voltage. Since AC changes its direction periodically, its current and voltage vary between positive and negative values. The amplitude represents the peak value of these fluctuations.

Phase

Phase refers to the timing relationship between two AC waveforms. When multiple AC waveforms exist in a circuit (e.g., in three-phase power systems), they are said to have a specific phase relationship.

The phase is measured in degrees and indicates the time difference between corresponding points on two waveforms.

Frequency

Frequency is the number of complete cycles of an AC waveform that occur per unit of time. It is measured in hertz (Hz), where one hertz represents one cycle per second. For example, if the AC frequency is 60 Hz, it means there are 60 complete cycles in one second.

Summary

Understanding these concepts is crucial for comprehending the behaviour of electrical systems and circuits, as well as for designing and troubleshooting electrical equipment.

Helicopter Checklists

Here are some helicopter checklists that will be useful for all pilots.

I have made these checklists in different sizes and one or both of these should be suitable for all helicopter pilots.

These checklists are available to purchase and download as a PDF file. You can then print them and if you wish, you can laminate them and bind them with a metal ring or other method. Or you can simply keep them attached to your knee-board.

The checklist for each helicopter complies with the current helicopter flight manual or pilot’s operating handbook but you should check for any amendments when you download the document.

Checklist

• Robinson R44 Emergency Checklist – click here
• Robinson R44 Quick-start Checklist – click here
• Robinson R44 Startup Checklist (size A5) – click here
• Robinson R44 Startup Checklist (size A6) – click here

Renewing an Expired EASA Type Rating

(Updated on 5th April 2021)

If you have let your helicopter type rating lapse – i.e. you forgot to do the annual License Proficiency Check (LPC) on time; then you will have to renew the rating before you can fly as PIC. Under EASA regulations this is quite practical and very straight forward.

The amount of training you will be required to do depends on three factors:

• Your experience.
• How long the type rating has lapsed
• The complexity of the aircraft

The requirements are all explained in EASA Document PART FCL Acceptable Means of Compliance AMC1 FCL.740(b)(1).

If the type rating has lapsed, you will have to do refresher training at an Approved Training Organisation (ATO). The objective of the training is to reach the proficiency necessary to safely operate the relevant type or class of aircraft.

To determine your experience, the ATO will evaluate your log book and , if necessary, conduct a test in a Flight Simulation Training Device (FSTD) or helicopter.

The amount of time lapsed since the expiry of the validity period of the rating is the most influential variable here for most people. The amount of training needed to reach the desired level of proficiency will increase with the time lapsed. In some cases, after evaluating the pilot, and when the time lapsed is very limited (less than 3 months) the ATO may even determine that no further refresther training is necessary. When determining the needs of the pilot, the following items will be taken into consideration:

• Expiry shorter than 3 months: no supplementary requirements
• Expiry longer than 3 months but less than 1 year: a minimum of 2 training sessions
• Expiry longer than 1 year but less than 3 years: a minimum of 3 training sessions in which the most important malfunctions in the available systems are covered
• Expiry longer than 3 years: the pilot should undergo the training required for the initial issue of the rating or, in case of helicopter, the training required for the ‘additional type issue’, according to other valid ratings held.

Once the ATO has determined the needs of the pilot, it will develop an individual training programme that should be based on the initial training for the issue of the rating and focus on the aspects where the applicant has shown the greatest needs.

After successful completion of the training, the ATO will issue a certificate or other document evidence that the training has been successfully achieved to the pilot. This will be submitted to the relevant Authority when applying for the type rating renewal. The certificate or other document evidence must contain a description of the training programme.

On successful completion of a License Skills Test (LST) the pilot must then wait for the  type rating to be renewed on their license before flying as PIC.

Helicopter Power Checks

(Updated on 5th April 2021)

When is the last time you had to do a confined area approach or take-off? Do you still remember how to do a helicopter power check? If not – you need to read this post.

Power Checks

There is no point in attempting to do a confined area approach without first doing a power check. The power check will tell you if you have sufficient power to do the approach or take-off.

During your training you will have been taught that the amount of power available will determine the type of approach you will use e.g. normal, running landing, zero speed etc. However I have a different view on this. If you do not have sufficient power to allow you to come to the hover Out of Ground Effect (OGE), you should not attempt the landing. My reasoning for this is as follows; if you are limited to a particular type of landing and you are also limited on power, then you will only have one attempt at it. If you mess it up then there are no options available to you. Always ensure that you have sufficient power available to come to a hover OGE.

R44 Raven II

Landing

1. Fly straight and level at 500′ above the landing site at Vy (best rate of climb speed) = 55kts. It does not matter if you are into wind or not. Just make sure you are flying at Vy. Take a note of the manifold pressure at this speed.
2. Find the pressure altitude by setting the sub-scale on the altimeter to 1013 mb and then reset to the QNH. Refer to the power table (mounted above the windscreen on the pilots side) and note the 5min power value.
3. Subtract the power you were using at Vy from the 5min power value to find the POWER MARGIN.
4. If the power margin is less than 7″ then you do not have enough power to hover OGE and you should not attempt the landing.

Take-off

1. Come to a hover approximately 2′ AGL and take note of the manifold pressure.
2. Find the pressure altitude by setting the sub-scale on the altimeter to 1013 mb and then reset to the QNH. Refer to the power table (mounted above the windscreen on the pilots side) and note the 5min power value.
3. Subtract the power you were using in the hover from the 5min power value to find the POWER MARGIN.
4. You will require a minimum of 2″ power margin to do a vertical take-off and climb OGE. 1.5″ will be required to do a normal take-off.

R22 (almost identical to R44)

Landing

1. Fly straight and level at 500′ above the landing site at Vy (best rate of climb speed) = 53kts. It does not matter if you are into wind or not. Just make sure you are flying at Vy. Take a note of the manifold pressure at this speed.
2. Take note of the maximum manifold pressure you are allowed to use (depends on model of aircraft).
3. Subtract the power you were using at Vy from the max. manifold pressure value to find the POWER MARGIN.
4. If the power margin is less than 7″ then you do not have enough power to hover OGE and you should not attempt the landing.

Take-off

1. Ensure carburetor heat is fully cold.
2. Come to a hover approximately 2′ AGL and take note of the manifold pressure.
3. Take note of the maximum manifold pressure you are allowed to use (depends on model of aircraft).
4. Subtract the power you were using in the hover from the max manifold pressure value to find the POWER MARGIN.
5. You will require a minimum of 2″ power margin to do a vertical take-off and climb OGE. 1.5″ will be required to do a normal take-off.

If you follow the power check procedure you will not have any power issues on take off and landing and you will definitely feel more comfortable knowing this. If you would like information on other types of helicopter power checks, just let me know and I will find the information for you.

The power checks described above are relevant to circuits and confined area operations (among other things). Circuit procedures can be found here Circuit Procedures.