When it comes to navigation in aircraft, a reliable compass is crucial. However, compasses are not perfect and can be affected by various errors. In this blog post, we will explore the different types of compass errors that occur in aircraft and how they can impact navigation.

1. Magnetic Deviation

One common compass error is magnetic deviation. This error is caused by the presence of magnetic fields within the aircraft, such as those generated by electrical systems or ferrous materials. These magnetic fields can interfere with the compass needle, causing it to deviate from the true magnetic north.

2. Magnetic Variation

Another important compass error to consider is magnetic variation. Magnetic variation refers to the angular difference between true north and magnetic north at a specific location. This error occurs due to the Earth's magnetic field not aligning perfectly with the geographic North Pole.

3. Oscillation

Oscillation is a type of compass error that causes the compass needle to swing back and forth rapidly, making it difficult to get an accurate reading. This error can be caused by turbulence or vibrations within the aircraft.

4. Dip Errors

Dip errors occur when the aircraft is flying at different altitudes. As the altitude changes, the Earth's magnetic field can have varying effects on the compass needle. For example, when flying at higher altitudes, the compass needle may tilt downwards, leading to incorrect readings.

5. Acceleration and Deceleration Errors

During acceleration or deceleration, compass errors can occur due to the inertia of the compass card. When the aircraft undergoes changes in speed, the compass card may not immediately adjust, resulting in temporary errors in the displayed heading.

6. Northerly Turning Error

The northerly turning error is a compass error that affects the accuracy of the compass when making turns in certain directions. When turning towards the north or south, the compass tends to indicate a shallower bank angle than the actual bank angle of the aircraft.

7. Magnetic Dip

Magnetic dip is an error caused by the inclination of the Earth's magnetic field. As the aircraft moves closer to the Earth's magnetic poles, the compass needle becomes more susceptible to dip errors. These errors can result in inaccurate readings, especially when flying near the magnetic poles.

8. Precession

Precession is a gradual drift of the compass needle over time. This error occurs due to various factors, such as friction and changes in temperature. It is important for pilots to regularly check and recalibrate their compasses to compensate for precession.

Conclusion: Navigating Compass Errors

Understanding the different types of compass errors that occur in aircraft is essential for pilots. By being aware of these errors and their potential impacts on navigation, pilots can take appropriate measures to compensate for them. Regular compass checks, proper calibration, and staying updated with magnetic variation charts are crucial for accurate navigation.

English learning advice from Aviation English Asia. Article written by Michael Egerton

In this article you are going to learn techniques to describe pictures in ICAO English tests.  As mentioned in a previous article, The ICAO English test - guidance and advice, describing a picture is a common part of many ICAO English tests.  Describing pictures isn't something that pilots and controllers tend to do as part of flight operations, but the AEROSTA Framework and ICAO Document 9835 does indicate "giving a visual impression" as a relevant linguistic task.

What language skills are required?

Quite often the pictures will be of unusual or unexpected events such as damage to an aircraft, a crash/collision or a malfunctioning piece of the aircraft's equipment.  You will need to develop your vocabulary so that you can easily explain these situations without being lost for words.  As a pilot or controller you will need vocabulary to describe

1. each part of an aircraft,
2. weather and time of day,
3. the physical layout of an airfield and
4. various types of damage that can occur.

You will also need a good command of verb tenses so that you can describe:

• what is happening now
• what has happened before
• what is likely to happen in the future

You should also learn the language skills needed to explain why these events have occurred.  This will involve (among others) modal verbs of possibility/probability, conjunctions and infinitives of purpose. You should also use prepositions to describe the physical location, or path of movement of the various objects in the picture.

Phrases for describing pictures

Start by giving a brief description of each picture.

• The incident involves ...
• This is a...
• I can see...
• This is an incident that happened...

There are different phrases you can refer to parts of each pictures. For example:

• on the left / on the right (hand side)
• in the background / in the foreground
• behind  x / in front of x

Depending on the picture you will need to use appropriate tenses.  For example:

• an aircraft is trying to land (present continuous because it is something happening at the moment the photo was taken)
• the aircraft in this picture has collided with a ground vehicle (present perfect because it is something that happened in the recent past with a result in the present)
• a ground vehicle is about to make a wrong turn that will surely cause a problem for aircraft that are landing.

The assessor might also ask you to give your opinion about the picture.

• In my opinion...
• I think that...
• It looks like...
• x seems to be...

Exercise

1. Take a look at the following picture for 30 seconds.
2. Describe it in as much detail as possible for 90 seconds
3. Explain how you think the situation occurred for 30 seconds.
4. Post your description as a comment.  We will review it and give you feedback.

Five tips for describing pictures in an ICAO English test

1.  Keep it simple Try to avoid complicated expressions or grammatical structures if you are not sure how to use them.   Don't waffle (speak unnecessarily about a topic), and if you have nothing to say it's better to wait for the assessor to prompt you.

2.  Ask the assessor for an explanation if you don't understand the task If you don't understand what you are supposed to do, ask the assessor to explain. For example, you could say:

• Could you repeat the question, please?
• I'm sorry, could you explain what the word.... means ?
• Could you please ask the question in another way?

3.  Use full sentences Avoid answers which are single words or answers that sound like a list of bullet points.  Demonstrate that you know how to form sentences correctly  and can use a range of structures to express yourself.

4.  Be aware of the time limits When you are asked to describe a photo and explain why something has happened, make sure that you leave some time for explaining your own opinion if that is a required part of the task.  You should also avoid rushing, as speaking slowly and clearly is an essential skill in aeronautical communications.  You will have better pronunciation if you slow down and don't swallow your words.

5.  Get feedback Before an ICAO English test, get expert advice from Aviation English Asia Ltd.  If you only practice with friends in a study group, you might copy their mistakes, and you will not be aware of your actual difficulties or proficiency.  Remember, it's not what you say to answer a question, it's a matter of how well you answer a question.   Students at Aviation English Asia are a friendly bunch who really make the effort to help each other.  Of course, all our English courses for ICAO compliance offer thorough practice of these skills in each unit.

What to do next

For feedback and more information about Aviation English Asia’s courses please visit http://aviationenglish.com. We can help you improve your English whether you are an experienced pilot, a cadet entry pilot, a controller, engineer or flight attendant, with custom courses designed specifically for your needs.  If you haven’t already please join the Aviation English mailing list for special offers and details of courses in your area.

We had a rather strange question recently.  Someone applying for a cadet pilot programme that had failed asked us if AEA "course content is going to be similar to the real test, like making a cabin announcement because otherwise it would be a waste of time and money".

There are many ICAO English tests, and though they vary in format, the language tasks assessed should be within a range of topics that have been identified in ICAO 9835 as being relevant.  However ICAO does not endorse or approve courses, tests and raters, and some language tasks might not be suitable for ab initio and low hour pilots.  Therefore the Aviation English Organisation was formed by an independent body of linguistic and aviation experts to assess the quality of rating organisations, teachers and courses.  The course and test assessment mechanism is called the AEROSTA Framework.  When you see that a course "conforms to the AEROSTA Framework" that is your guarantee that it is relevant and meaningful to you at your current experience level.

A test can change, and any decent test provider will have a question bank of at least 100 versions, so it's not really a matter of whether a course is focused on the content of a test, it's a matter of whether a test or a course conforms to the AEROSTA Framework and ICAO 9835.

Let's look at some examples of topics which were included in a recent ICAO English test conducted in Hong Kong.  

You can see that relevant topics are well covered on AVIATION ENGLISH ASIA LTD courses.  In fact, by coincidence all of those topics were offered within the previous 10 days. Cockpit to crew communication is included, as is every relevant communicative function of ICAO 9835.  

it's not what you answer, it's how well you answer

Of course, it's not just a matter of a course conforming - teachers must also surpass minimum requirements and have recognised teaching qualifications too.  

An English test should not be about knowledge, it should be about language proficiency.  AEROSTA based courses include specific activities to improve proficiency in relevant and valid language tasks.  For example, negotiating a level change or giving a visual impression of damage is relevant.  Describing a picture is not relevant.  Comprehension of an ATIS is relevant, comprehension of non-routine situations with strong interference might not be relevant to a student pilot.  The danger is that focusing on the test content could lead the candidate to neglect improving the actual language skills required. A test which rewards candidates for rote memorisation of answers is not valid or reliable, particularly so when test content is beyond the candidate's experience.

The ICAO English test is not necessarily the "real" ICAO test

ICAO tests designed for cadets are often just filters.  It's not fair to assess candidates on operational knowledge beyond their experience.  A pilot should expect to be tested again and again throughout their career.  For example, in a recent internal English test at Flight Training Adelaide 5/11 candidates failed a listening comprehension activity.  Two of those candidates had already scored level 6 in an ICAO English test conducted in Hong Kong.  

AEROSTA is the guarantee of excellence in Aviation English Teaching

For example a rating organisation which gives unreliable (inconsistent) ratings would not conform, similarly an English teacher who claims to be "ICAO approved" would not conform, and an English course which is only focused on replicating the content of the test without real life application would also not conform.

An Aviation English course which teaches a range of relevant language skills, and improves proficiency within those domains would conform.  Aviation English Asia Ltd is the only training provider in Hong Kong which wholly conforms to the AEROSTA Framework.  AEROSTA based tests and courses are used internally within a number of organisations, including Cathay Pacific Airways and Airport Authority Hong Kong.

Yes, Aviation English Asia Ltd can help you pass the real ICAO test

It is natural that you should want to pass a test, and of course Aviation English Asia Ltd can help with that. But you should be cautious of English teachers who try to manipulate gullible candidates saying that they can teach you to "pass the test" or teach "content similar to the real test".  The truth is that as a training provider to airlines and airports where genuine proficiency is important we see many problems facing high-stakes candidates that were caused by high test scores but low proficiency.  

There are no magic pills for proficiency but I can say that a fair and properly conducted test is not at all difficult to pass.  The vast majority of AEA students do well in tests but there are also factors such as low starting level (they need a longer course), or unreliable testing.  In fact, Aviation English Asia Ltd guarantee that if you follow our recommendations you will pass a test which conforms to the AEROSTA Framework.

#AEROSTA #AviationEnglishAsia