Short answer

But what about that shorter trip—a couple hundred miles or so—especially if you’re flying near large metropolitan areas? Knowing what cruise altitude works on those routes is a mystery.

I’m based at Muskegon County Airport (MKG) on the eastern shore of Lake Michigan. As you can imagine, the big majority of our trips head off in a southerly direction. Less than 100 nautical miles to the west is the Chicago metro area, one of the busiest parcels of airspace in the country. What cruise altitude is going to get us through the airspace surrounding Chicago with the least fuss?

You can see altitudes issued to other flights on flight planning services such as Fltplan.com. Those altitudes are accurate in that they were issued by center computer as an initial clearance. But did pilots actually get to fly those levels? No way to know.

A few years ago, my company acquired another on the north side of Cincinnati, creating the need for us to fly to Butler County frequently. The direct distance is 241 nm, and the preferred route only adds a couple miles. But what altitude would work to fly over southern Michigan and northern Indiana to get there?

We started filing FL250, a good altitude for the Beechcraft King Air 350i in terms of speed and fuel efficiency. As expected, we were cleared to that level. But as we flew south into the busy arrival and departure corridors for O’Hare, we were sent down. We usually ended up down at FL190, descending in steps. Annoying, and certainly not efficient.

Through trial and error, we found that FL210 would work almost every time, with an occasional descent to FL190 about halfway through the trip.

The other day we were going to Louisville Muhammad Ali International Airport (SDF) and Fltplan.com suggested FL260 for cruise. I never expected it to work, but since it was a slightly different route, we decided to try. As we were stepped up to FL190 there was a break on the frequency and I asked the controller if he thought FL260 was really going to work for us.

His response really jerked me up straight. He said, “Let me take a look at what’s going on with arrivals into Detroit, and I’ll let you know.” Wow. How unaware of me. Detroit is only about 110 nm to the east, so of course, arrivals needed to be descending through the 20s. I was so focused on Chicago that I didn’t think of the ATC issues for Detroit.

So, the question of why we can’t often get the altitudes we want on shorter trips isn’t a mystery at all. The airspace in many parts of the country is so complex, that an arriving or departing flight a hundred or more miles away matters. To find out what altitude works on a short flight, all I can suggest is trial and error, or maybe ask the controller if the frequency quiets down so you can plan for the next time.

J. Mac McClellan is a corporate pilot with more than 12,000 hours, and a retired aviation magazine editor living in Grand Haven, Michigan.