# Questions tagged [magnetic-compass]

A device used to determine one's direction with respect to the Earth's magnetic field.

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### Calculating True Course, Magnetic Heading and Compass Heading when Wind, True Heading, Magnetic Course and Deviation is known

I came across another exercise while studying for my PPL(A) exam where I would need some help with some calculations. The question sounds like this: Given: WCA: -012°; TH: 125°; MC: 139°; DEV: 002°E ...
4k views

### Is this the correct sequence of steps to convert from true course to compass heading?

I wanted to confirm my understanding of VFR Flight Planning/Dead Reckoning with relation to heading and course calculation. Is the below correct? Using a plotter, draw a line from departure airport ...
4k views

### What aircraft is this compass from?

I have come into possession of some of my grandfather's things including some aircraft parts that he had. He was a naval pilot who flew single-engine fighters in WW2 and then at some point ...
1k views

### How does the GMU44 magnetometer differ from a magnetic compass?

In comments to Is the Garmin G1000's heading indicator based on a Magnetic compass?, it's claimed that the GMU44 magnetometer is not a magnetic compass. I don't understand this claim, as the device is ...
43k views

### How do I convert true heading to magnetic heading or the other way around?

Is there a method by which the conversions can be achieved on the fly by using a mathematical formulae and not using specific area charts?
4k views

### Is the Garmin G1000's heading indicator based on a Magnetic compass?

How does the heading indicator displayed on the PFD of the G1000 work? A conventional cockpit uses a magnetic compass to correct the heading indicator. However, I don't know if the heading indicator ...
4k views

### Understanding UNOS and exceptions from it

I'm studying for my EASA PPL(A) exam, and one thing that I came across are the following questions: Q: An aircraft in the northern hemisphere intends to turn on the shortest way from a heading of 270°...
1k views

### How were compasses in early interwar planes safeguarded against interference from flight?

I understand during the early days of flight that compasses were regarded as extremely unreliable and unfit for even basic navigation, but I'm unsure as to what caused this unreliability and what the ...
452 views

### How to know how much overshoot/undershoot the compass if you're flying close to one of the poles; is it even needed?

As far as I understand, the formula (1/2LAT + 15°) is not applicable when flying close to one of the poles or the equator.Therefore, when flying close to the poles, what happens? Does it have the same ...
190 views

### Why are there no magnetic compass errors during skidding turns?

Could someone break down why the magnetic compass reads accurate on all turns-to-headings, regardless of geographic position, when performing rudder-only turns with no bank?
528 views

### Do large cities contain enough iron to significantly affect an aircraft's magnetic compass?

In most areas of the world, the magnetic compass is the ultimate heading reference. Although pilots look to the directional gyro most of the time when flying (because the directional gyro's reading ...
484 views

### What can be done when the magnetic compass breaks during a cross country flight? [closed]

On United state a VFR cross country flight, after arriving you discover that the magnetic compass has leaked all of the fluid and is inoperative. The weather at airport shows a fast moving cold front ...
1 vote
349 views

### How to visualize compass deviation? [duplicate]

What will the magnetic compass which has an Easterly deviation of 10 read when the true heading is North Will it read 350W or 10E? I understand that the 10E East variation means that the underlying ...
223 views

### How to simulate magnetometer used on navigation system?

Magnetometer is used to measure yaw angle which will be used on AHRS system.When I simulate the magnetometer in matlab, I feel confused about what unit should be used for measurements magnetometer?...
1 vote
546 views

### What is pendulous suspension in magnetic compass?

I am not able to understand what is pendulous suspension and how centre of gravity and centre of suspension are related in magnets and their errors. Can someone explain this in layman language or ...
1k views

### Why don't the magnetic compass and direction indicator spin the same direction?

You set a direction indicator (DI) based on the magnetic compass in certain GA aircraft, e.g. Cessna 172. During training you're taught how to align the DI with the compass, the DI being the opposite ...
3k views

### Are magnetic compass acceleration errors due to the southern side of the compass being weighted?

When I was in college, I had an instructor who taught me that the acceleration errors in a magnetic compass were due to a counter-weight installed on the south-facing side of the compass that was ...
3k views

### Is the turning error of a magnetic compass greatest when tuning through South in the Southern Hemisphere?

Question: The turning error of a magnetic compass in the Southern Hemisphere is greatest when turning through South. Is the statement true or false? And why is this/isn't this the case?
572 views

### What is the most commonly occurring fault with this type of electrically driven gyro?

I have an examination tomorrow about advanced avionics systems (EASA module 13) and we are required to troubleshoot a fault with the compass system. What is the most commonly occurring fault with a ...
2k views

### When resetting the heading indicator to match the magnetic compass, do I need to use the compass deviation card?

At least every 15 minutes we set the Heading Indicator's number to match the number of the magnetic compass. In this situation, should I consider the deviation card below the compass card or not?
1 vote
39 views

### How does the runway number relates to Magnetic Heding/Course? [duplicate]

I know that runway numbers correspond to Magnetic North, how does it relate to Magnetic Course/heading? Can we say that the runway number is equivalent to Magnetic heading?
189 views

### Semi-circular rule for choosing a FL: Risk of head on collision with borderline headings (179, 359)?

If it happens that you fly a 179/359 heading in uncontrolled airspace, what's the risk of collision with aircraft flying in opposite direction?
2k views

### How would you use the mental clock code to solve this dead reckoning problem?

Can someone explain the question below in details? You plan to fly a cross country flight at 2 000 feet at a true airspeed of 120 knots. Your track is 270° (True) and the wind is from 225° (True) at ...
1 vote
996 views

### Does the movement of the magnetic poles affect aviation?

Recently I read that Earth's magnetic pole moves quite significantly, several kilometers. Do these changes affect aviation, i.e. for pilots landing their airplanes?
13k views

### How do you calibrate the compass of an aircraft on a compass rose?

A follow-up from this question; one of the answers mentioned that the compass rose in the picture was used to calibrate an aircraft's compass. But how does that actually work? Do you park the ...
5k views

### Why do we undershoot/overshoot with a compass turn?

In the southern hemisphere you would undershoot when turning towards a southerly heading and overshoot towards a northerly heading, and the opposite in the northern hemisphere. Why is this?
2k views

### At what distance from magnetic north do pilots start referencing true north for heading?

The Earth's magnetic poles are constantly shifting, resulting in a significant distance between the true and magnetic poles. This means that while using them as references for heading at lower ...
1 vote
4k views

### Do I use true or magnetic north in headwind component calculations? [duplicate]

For the landing performance calculations, I want to calculate the headwind component. I can do this with the runway heading and the reported wind direction and speed. But do I need to make any ...
1 vote
1k views

### Is there any instrument similar to a compass but which I can electrically drive?

I would like to build a home weather station with analog instruments showing for example temperature, wind speed and wind direction. I would like to use a salvaged flight instrument to show the wind ...