Appreciate that.
I've got my head wrapped around fixed-card NDB and bearings with regard to how they work, although the idea of procedure to intercept a given bearing is still a little fuzzy - there's math involved in figuring out heading changes to get to a bearing, which means I shriek and run away. Want to focus more on that.
How they (NDBs) fit in the IFR system is a bit ahead of where I am in reading, I think. I know they're uncommon, but it's still something I want to know how to do.
Probably the last thing I would focus too much attention on, since it is the least likely thing you are ever going to encounter in 2014 in the US. I was lucky enough to learn this stuff back before GPS was common, and since then, I think I have seen an actual ADF with no GPS exactly twice. Mostly used it to listen to Cuban radio stations around here...
That said, it depends a bit on the type of ADF you have. The basic one has a needle that points to the station. It also has a dial that always has 0 degrees at the top. It gives you a "relative bearing," since it will show you that the station is, let's say, 30 degrees to the right. But we still need to know which heading we are flying to deduce what that bearing is to the station.
The "better" version of this has a compass card that we can rotate. We can set that to our heading, and like magic, the needle is now pointing to the magnetic bearing to the station. Which is way easier than adding relative bearing to magnetic in your head.
The last type is an RMI, where the compass card is actually a heading indicator. Works the same way, you just don't need to set the heading (as often).
Now, actually intercepting a bearing. When you are on that bearing, with the compass card set to your heading, the needle will point straight up. Assuming it isn't, we know how many degrees we are off that bearing. Let's say we want the 360 bearing to the station, and the needle shows 010. We are 10 degrees off to the left. Our intercept will be double that relative bearing, 20 degrees. So we fly 020, until the needle points to 360, and then we fly 360. Wind, of course, will complicate matters.
The big difference from a VOR - the ADF actually cares which way the the airplane is pointed (it is a direction antenna). If we rotate our airplane 360 degrees in place, the VOR needle won't budge (the TO/FROM flag will flip). The ADF? It will spin all the way around as we spin the aircraft. So any time we are talking about ADF's, our heading absolutely matters. You also don't need to worry about reverse sensing - the needle is always pointing at the station.
If you have a flight simulator, this is a great use of it.
**** Disclaimer: I am pretty sure that this is mostly correct, but I haven't actually flown an ADF without a GPS in about 6 years...
Right now, I pretty much get the concept of holds and protected airspace. What I don't understand is the rationale behind the various types of entries. (Tangentially, I was surprised to find out that hold entry types are guidelines and not regs, but that it can still cause a failed checkride. Which sucks.) I mean, I get that you want to be on a particular racetrack pattern, and it seems to me that you could approach it the same way you would a traffic pattern at any field, but this is not necessarily the case. I suppose terrain could be a factor but since the hold entry type is determined by your position relative to the fix, I'm not sure WHY things are recommended the way they are.
The gory details are spelled out here:
http://www.faa.gov/documentLibrary/media/Order/7130.3A.pdf
Key points though, are that you have protected area on the turning side of the hold, and the FAA assumes that you can make at most 25 degree bank turns. You can't just overfly the fix and then maneuver back to enter like an airport traffic pattern for two big reasons. First, you want to stay on the protected side at all times. Second, you don't have a visual reference to the hold racetrack, so all of your turns need to be referenced to the holding fix.
The easiest case is where you are already pointed roughly the right direction to the holding fix. In this case, you fly to the fix, then turn onto the racetrack pattern. This is called a Direct entry. Easy.
Now, let's assume we are flying exactly the wrong way to the fix. At somewhat less than a standard rate turn (25 degrees), you can't just turn onto the racetrack -- turning through over 180 degrees will take us over 2 minutes, and the hold legs are supposed to be 1 minute long. So instead, why not just fly the wrong way over the fix, continue for 1 minute, then turn back to the fix on the protected side and make a Direct entry? Well, that's exactly what you do, it is called a Parallel entry. I think that for a while, the Air Force only taught Direct and Parallel hold entries.
The last case is when you are approaching the holding fix the wrong way, and from the unprotected side. You could make a parallel entry, but the time it takes to turn onto the course will subject you to wind drift, and not give you much time to line up on it before needing to turn again. Instead of turning to go the wrong way on the inbound leg, and then turning again to make a direct entry, we can simplify things by just overflying the fix, then heading away 30 degrees to the protected side. One minute later, this should leave us on the protected side of the hold, and all we need to do is turn and fly inbound to the fix. After that that turn inbound, you are essentially flying a Direct entry. This is a Teardrop entry.
Fundamentally, all of the hold entries accomplish the same thing. They put you inbound to the fix, while remaining on the protected side for the entire maneuver, and minimizing the number of turns you need to make.