Determining Pattern Altitude

Figuring out the pattern altitude at an airport should be pretty simple, right?  But, in this day of helpful technology, most pilots actually get it wrong.  How can you always get it right?  Well, it just takes about an extra 15 seconds.  Here’s how.

As outlined in the Aeronautical Information Manual, section 4-3-3, “traffic pattern altitudes for propeller-driven aircraft generally extend from 600 feet to as high as 1,500 feet above the ground.”  Further, in the Pilot’s Handbook of Aeronautical Knowledge on page 13-10, it states:  “1,000 AGL is recommended pattern altitude unless established otherwise.”

Okay, so for piston driver’s, we’ve got it narrowed down to 1,000 AGL (Above Ground Level for those who don’t like acronyms).  But wait!  There’s that very important phrase at the end of the last quote:  “unless established otherwise.”  That means not all airports have traffic pattern altitudes of 1,000 AGL, or else they wouldn’t put that line in there!

How do you find out what the TPA (Traffic Pattern Altitude) is for a certain airport if it’s not 1,000 AGL?  Great question!  Your first guess is probably to look on Foreflight.  Though this is a good start, it is not the full answer.

Let’s use an example.  Look up KAQO, the Llano Airport on Foreflight.  At the top of the page, the airport elevation is stated as 1,101′ MSL and the pattern altitude is stated as 1,902′ MSL.  From what we just learned, 1,902′ MSL is not 1,000 AGL, so is 1,902′ MSL otherwise established?

On the Airports page with KAQO pulled up, tap the A/FD tab, second to last on the left.  Scroll down to Llano Muni.  Read the whole entry.  Does it state in the entry that pattern altitude is different than 1,000 AGL?  It sure doesn’t.  So, because it is not otherwise established, pattern altitude at KAQO is 2,102′ MSL not 1,902′ MSL.

Where did Foreflight get that?  I have no idea.  Too often, though, pilots look at the Foreflight pattern altitude and don’t actually check the Airport Facilities Directory (A/FD).  Then, they get the pattern altitude wrong.

What does it look like when pattern altitude is otherwise established?  Look up KSGR, Sugar Land Regional, on your Foreflight app.  Foreflight states the elevation as 82′ MSL and the Pattern Altitude as 1,000′ MSL.  Is this correct?  Well, tap that A/FD button again and let’s find out.

On the second line of the A/FD entry, it says TPA-See Remarks.  Down in the remarks section, we find the following:

TPA-1000 (918) single engine piston acft, TPA-1500 (1418) for twin and turbojet acft, TPA-500 (418) for helicopters within 2NM.

Foreflight got it right this time for single engine pistons, but if you are in a twin, the pattern altitude is different.  What’s the lesson here?  Always check the A/FD and don’t always go by what Foreflight says.  The A/FD is always right and usually has a little more detail to help set you straight.

One last thing.  Both the AIM and the Pilot’s Handbook of Aeronautical Knowledge, when talking about pattern altitude, state, “When operating at an airport, traffic pattern altitudes should be maintained unless otherwise required by the applicable distance from cloud criteria in…section 91.155.”  91.155 defines basic VFR weather minimums.  So, to fully interpret what the AIM is saying, we have to take into account the type of airspace we are in to determine if we can safely and legally operate at pattern altitude at a particular airport.

For example, let’s say we are at KCVB, the Castroville Airport.  Pattern altitude there is 1,602 feet, which is 829 AGL.  CVB is Class G airspace up to 700 AGL, then Class E above that.  Let’s say there is a 700 AGL broken cloud layer.  Pattern altitude is 829 AGL, so you won’t be able to get up that high with a broken ceiling.  What altitude can you do pattern work at to stay legal?

Class G VFR weather minimums during the day below 1,200 AGL is 1 SM visibility and clear of clouds.  So, legally, you could fly at 699 AGL (which at CVB would be 1,472 MSL) while in the pattern and be legal.  Safe?  Maybe, but probably not if you are skimming the base of the clouds.  Is 1300 MSL a safer pattern altitude in this example?  Well, that is 527 AGL, so probably not, since towers tend to stick up that high sometimes.

Let’s go back to KSGR and put a 1,000 AGL overcast ceiling there.  SGR is Class D airspace and we already determined pattern altitude there was 1,000 MSL for piston singles.  VFR visibility and cloud clearance requirements in Class D airspace are 1,000 feet above clouds, 500 feet below clouds, and 2,000 feet horizontally from the clouds with 3 SM visibility.  In order to stay 500 feet below the clouds, you would be flying a 582 MSL pattern.  Safe?  Probably not, though it is legal.

To summarize, don’t take Foreflight’s word for pattern altitude.  Cross reference the A/FD (it only takes 15 seconds at the most) to verify.  If it’s cloudy, it’s really best to stay on the ground, but if you want to find out your legal pattern altitude with a cloud deck, cross reference 91.155.  I don’t recommend flying below pattern altitude because it is there for a reason.