Magnetic compass 

Introduction

Being forced to rely on a magnetic compass and an OBS to shoot an approach while in IMC is not necessarily a pleasant experience.

It can be done however, assuming the pilot has an attitude indicator. But then, understanding the way a magnetic compass works is a big help. By the way, don't forget that magnetic compass use is required during IFR initial test.

A few simple rules 

Looking at a magnetic compass, if the numbers tell you to turn right, turn left!

In the example above, wishing to head toward east, turn to the left.

Apply standard rate of turn

Standard rate of turn means turning at a rate of 3° per second. (360° in 2 minutes). Therefore, wishing to change heading from 130° to 120°: start the turn and count "one and two and three" and get back to level flight. (10° are flown within 3 seconds at standard rate of turn).

Standard rate of turn means grossly 20° bank. To be specific we should say that flying 120 Kts, bank should be 18° (12+ 6). It might be easier to refer to the turn coordinator.

Verify

Wait a little bit for the compass to settle down and apply any necessary correction. It is often wise to apply corrections by 10°. To do that, apply banking quite precisely, (count 1-2-3) and level back precisely. In other words, avoid getting into the turn too softly  because if you do, when you start counting, you have already flown a couple of degrees.

Don't

You can only rely on compass indications when stopping a turn at 090° or 270° heading. The compass indication is true at those two headings. The more north or south, the larger the error.

Basic rule

Going toward North.

Stop turning before desired heading appears on compass. The closer to the north, the more one should anticipate leveling. 

For example, heading south, turning left and intending to stop the turn at 030° heading, one should get wings leveled when 050° appears on compas card. (20° before 030° heading).

Flying to the North

Flying toward South

Stop turning after desired heading appears on compass. The closer to the south heading, the more one should overshoot desired heading.

For example, heading north, turning left and intending to stop the turn at heading 210°, one should get wings leveled when heading 180° appears on the compas card. (30° after passing the 180°).

Southern american's pilot pretend that "South leads". Of course.

Flying toward south

Flying toward East or West

On East and West headings, compass indications are to be followed because they are right.

Flyting toward East

Download Magnetic Compass

BEFORE YOU START LEARNING

What is it all about ?

The course is divided into SECTIONS

Each section is concerned with a part of the flight : Before taxiing, Using flight instruments, Departure, En Route, Holds, Arrival, Approaches, unusual events and so on.

Each section is divided into Lessons.

For exemple, section "PLANNING FOR AN IFR FLIGHT" contains two lessons : planning weather wise and planning fuel wise.

Each lesson ends up with a Quiz.

The quiz is simple, it aims at getting things memorized, not tricking you. Read carefully and choose the most complete answer.

It is not tricky and it is not by any mean some sort of evaluation system. You can - and you should - take the quiz as many times as necessary, get back to the lesson as much as you want. But you have got to get a 100%.

So read the answers, some are obvious some are not so obvious. Some of them are right but incomplete. Once again, the quiz is a learning experience !

Note that you have the opportunity to have a look at your answers completed with eventual comments.

The length of each lesson depends on its content but every single one of them processes only one subject which has been brought to what really matters.

Do not go through as fast as you can

Don't get over the text as fast as you can to reach the quiz and proceed to the next lesson. Obviously you are already familiar with some material but keep in mind that the course is constructed as a whole and intended to be efficient as far as IFR flight is concerned. Attempting to cut through in order to gain time will end up lengthening the overall process.

If something appears that you do not know

Should you come through some concept that you don't understand, don't stuck on it, chances are that it does not matter so much at that stage or eventually - and it is generally the case - the explanation will follow rapidly. Should the explanation come up in a couple of pages, a note will let you know.

Logo's

Some PDF are available for downloading

  And above all:

Have fun, it is exciting !

It is up to you now !