How do pattern and overflight altitudes work for airports underneath Class C airspace?

Question

Lowell City Airport (24C) has an elevation of 700 feet MSL. So normally, the pattern altitude is going to be 1,700 feet, and the altitude for overflying the pattern is going to be 2,200 feet.

However, 24C Lowell is located underneath Class C airspace which starts at 2,000 MSL, so you can't fly at 2,200 without talking to Grand Rapids.

What should I do if I'd like to fly over the field? I can think of a few options:

1. Maybe 24C Lowell has a non-standard pattern altitude, like 1,400, which would allow me to overfly at 1,900. (How could I find this out using official sources?)
2. Split the difference between pattern altitude and the Class C. If the pattern altitude is 1,700 and the Class C starts at 2,000, maybe I can overfly at 1,900.
3. Establish communications with Grand Rapids Approach, then go ahead and overfly at 2,200 while monitoring both Approach and CTAF at the same time.
4. Just avoid overflying the pattern, and fly around it instead.

When in doubt, I'm going with option 4. But what should I know about the other options?

I do have some particular questions about option 3. If I do choose to contact Grand Rapids Approach and climb to 2,200 to overfly, then I'll have to monitor both Approach and CTAF at the same time, right? Can most small airplanes even do that?

Answer 1

Just talk to the controllers. We live under a Class B with several underlying Class C or D fields. They'll talk to you. They'd rather know what you're planning to do than not, keeps everyone safer.

Answer 2

From the standpoint of the GR Class C airspace, your only choices are to go around Lowell or call GR Terminal for clearance into Class C to go over it, if you want to be legal overflight-wise.

Me, I generally avoid terminal airspace when at all possible when piddling around VFR, so it's a no brainer to just deke around it.

Answer 3

1. A non-standard pattern altitude would be in the Chart Supplement (formerly A/FD). Nothing is listed, so it's the expected 1700ft.

2. Overflight is 500ft above pattern altitude to maintain proper separation. Any closer than this (aside from formation flight) is unsafe and could get you violated. Don't do that.

3. There's no need to monitor CTAF while you're talking to ATC. They will tell you when to switch over. Have that freq preset on your other radio, though, since you'll probably be a lot closer than you're used to for making your first call and won't want to waste time fumbling with charts and knobs.

4. Going around doesn't seem to apply if your intent is to land there.

Overall, if you're operating in an area with Approach Control, use it! That isn't limited to the primary airport or even within class B/C airspace; they handle everything within a certain distance (at least 20nm in this case) from the primary, and they'd generally rather know what all those blips on their radar are going to do next than be surprised by sudden conflicts.

Rather than monitoring CTAF, I would monitor GRR's ASOS; it's only 9nm away, which should be close enough to decide Rwy 12 vs 30 at 24C. Once ATC does switch you to CTAF, just make your first call and if folks are using the other, they should pipe up quickly--and loudly!

If you're coming from the northeast and landing 30, I'd forget the pattern, turn south early and then do a long straght-in approach. If coming from the southwest and landing 12, turn north early for the same reason. If you really want to see the windsock or field condition, or you just don't like straight-in approaches, or there's traffic in the pattern, you can enter on upwind instead. Note that upwind is on the opposite side from downwind, not overflying the runway as some books incorrectly show it.

Many airports under shelves like this will have a right pattern on one runway specifically to allow entering 45 to downwind from the "outside" both ways. Unfortunately, that's not the case at 24C.