Taking Minibots on Airplanes

[David Brinza]

That 5 mGauss limit at 5 m might be an issue.

If you postition additional magnets to form a quadrupole arrangement, the field will drop off more rapidly with distance (1/r^4) than for a magnetic dipole.

You can also look into mu-metal shielding. You'll need to degauss the shield first.

You can use Boy Scout compass to test for excessive fields.

[Al Skierkiewicz]

Dale,
I would think the Tetrix battery would raise some eyebrows as well.

[Jeffy]

Originally Posted by Al Skierkiewicz

Dale,
I would think the Tetrix battery would raise some eyebrows as well.

Explain what it is, and you shouldn't have a problem as long as its checked. I have traveled with NiCad, NiMH, and Lithium-Polymer batteries.

[DavidGitz]

About 7 years ago, some students I know from my college were traveling by air to an IEEE Robotics competition. Their robot had a lot of exposed wires and circuit boards. Even though they were checking it in a container, TSA made them take their robot completely apart and they had to rebuild it at their competition. I think this was an extreme situation and there aren't as elements on the minibot that can be "scary" to TSA, but on the same hand I would do what it takes to not have it go through TSA.

[EricVanWyk]

Originally Posted by Al Skierkiewicz

Dale,
I would think the Tetrix battery would raise some eyebrows as well.

I recently traveled with comparable batteries. There is a limit of two "large" batteries per person, where "large" is really difficult to figure out from their web page. I played it safe and assumed that mine were large, and shipped the other 30 cells.

The rules are pretty wonky, so be sure to check out the TSA page.

[DonRotolo]

To emphasize what David Brinza wrote: Magnets can be put inside a magnetically-shielded* box to reduce external fields.

*Magnetic shielding is accomplished by using any material that conducts magnetism. Steel, iron,nickel can be used. Mu Metal is a special alloy that is hyper-conductive to magnetism. It's a bit costly and hard to find - you might get some from around the picture tube of an old CRT monitor or TV - but a small steel box, surrounded by a larger steel box, all put inside your checked bag, should have a negligible field at 7 feet (don't assume - check it. Your pilot depends on his instruments, and if your magnet is messing with that, it could be your life at stake).

Minibots can be checked. Just disconnect everything from everything as much as possible, and pack the batteries separately. I'd hesitate to bring them as carry on.

[MrForbes]

Do they still use magnetic compasses for navigating airliners? Hmmm....

(as I sit staring at a WWII vintage military aircraft compass)

[Dale]

It's just an FAA regulation. They do have them as backups, though.

[Al Skierkiewicz]

On another note...
Everyone has heard that the magnetic pole is drifting right? I think Miami recently had to renumber their runways since the declination has changed so much.

[MrForbes]

My wife mentioned it this morning. Really.

[flameout]

As someone interested in aviation (and flight simulation), I can answer this:

No, modern jet airliners do not depend on magnetic compasses, but rather have at least 2 Inertial Navigation Systems.

Inertial Navigation Systems find true north by detecting the earth's rotation during an alignment phase (while the aircraft is still stationary). They contain 3 axes of gyros (usually laser-ring gyros) and 3 axes of accelerometers. Using these, after alignment, they keep track of their current orientation and position.

Many airliners do have a magnetic compass as a backup -- but they're inaccurate if you are turning, accelerating, or changing altitude (not sure on the last one).

Other sensors, however, may internally use magnets. Also, a minibot could latch itself onto the aircraft's frame...

Of course, the only things that matter here are the regulations, but I just had to say this .

I hope your minibot makes it safely to your regional.

EDIT: Forgot to mention that since aviation still uses magnetic direction (that is how runways are numbered, and what any aircraft smaller than a jet airliner would use (an aviation-grade INS is probably way more expensive than a Cessna)), the Flight Management System has to use a database of magnetic variations to convert true north back into magnetic north. On at least some planes (the MD-11 at a minimum), the pilot has a switch for true/magnetic headings.

EDIT2: I should have known better. Aluminum isn't magnetic. Thanks to jgw for pointing that out. The minibot couldn't latch onto the aircraft's frame.

[Jim Wilks]

Originally Posted by flameout

Also, a minibot could latch itself onto the aircraft's frame...
.

Given that aircraft are predominantly made of aluminum, how is this possible?

[flameout]

Given that aircraft are predominantly made of aluminum, how is this possible?

Oops. Thanks for the correction.

I should have known better .

[wendymom]

If anyone coming to the Florida Regional wants to ship their minibot to my house just PM me. I only live 7 minutes from the venue and I would be happy to deliver it to them.

[11douglash]

Because airplanes arn't made out of ONLY aluminum. While it isn't much of a big problem in the big jets, there are steel components in the airplane. And the airplane's electronics. The big problem, in reality, is the magnet coming close to the magnetometer in airplanes, thus distorting the magnetic compass. IN reality, this isn't much of a problem on big jets, since the magnetic field from magnets drop off as 1/r^3. But for small planes, where the magnetometer may be close to the cabin, this is a problem. And since the FAA is a beaucracy, odds are they would have a problem with it.