TPA - what to use?

Matthew

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Matthew
I use the TPA as published in the AF/D.

What about airports without a published TPA? I've been taught to use 1000 AGL. I have noticed in the AOPA Airport Directory listings that they will show 800 AGL as a pattern altitude when the AF/D does not indicate anything at all.

I think the AIM says something like 'enter at the TPA, usually 1000 AGL...'.

Is there a place where this is stated?
 
Matthew said:
I use the TPA as published in the AF/D.

I think the AIM says something like 'enter at the TPA, usually 1000 AGL...'.

Is there a place where this is stated?

At first I was tempted to just say yes it's in the AIM. But alas confirming it for myself is worth being the look up service:


AIM 4-3-3. Traffic Patterns

At most airports and military air bases, traffic pattern altitudes for propeller-driven aircraft generally extend from 600 feet to as high as 1,500 feet above the ground. Also, traffic pattern altitudes for military turbojet aircraft sometimes extend up to 2,500 feet above the ground.

..snip..

EXAMPLE-Key to traffic pattern operations
1. Enter pattern in level flight, abeam the midpoint of the runway, at pattern altitude. (1,000' AGL is recommended pattern altitude unless established otherwise. . .)

Joe
 
I've been rounding up to the nearest 100' at 1000' AGL above the airport elevation listed for the airport on the approach plates if there's no published TPA.

The 1000' AGL makes for a nice consistent pattern from airport to airport. The AF/D is one of the most under-rated publications.
 
JDW,

You and I are on the same page, both about TPA and AF/D.

I may have to ask on the AOPA web-site or help desk how they decided to publish 800' TPA for many airports that show no published altitudes in the AF/D.
 
Matthew said:
I may have to ask on the AOPA web-site or help desk how they decided to publish 800' TPA for many airports that show no published altitudes in the AF/D.

Around here in Mid to Northern Michigan most of the airports use 800 ft agl. More are going to 1000 ft. agl, I think it is because, with the dumbing down of math, people can't add 800 to another number, 1000 is easier.;) Really, though, I think it might be related to the 1000 ft above objects in a populated area rule. Rural areas use the 800 ft TPA more frequently.

Barb
 
When I started flying in the late 60's, the default TPA in the AIM was 800 AGL. That was changed in the 70's to 1000 AGL, and remains published that way today in the AIM note referenced (the "Key to traffic pattern operations" in section 4-3-3) as well as several AC's dealing with pattern ops at nontowered airports.

Why was the default value raised? I don't know for sure, but suspect mainly for noise abatement reasons.

Many airports which published "official" TPA's of 800 AGL never changed after the AIM change, probably out of inertia. We just got that done at Salisbury last fall after nearly four years of trying. No doubt those "rural" airports with published 800 AGL patterns find it easier to leave it be than to change it, which requires a bunch of paperwork, and don't have much pressure over noise issues due to a combination of smaller, quieter planes, lower traffic levels, and less residential congestion underneath the pattern.
 
I guess it gets down to this question - I print out the kneeboard PDF format airport guides from AOPA quite often. It's just a handy reference for planning. Some of the guides show a TPA. I am trying to determine just what a "published TPA" is. In the cases I have questions about, the airport guide as printed from AOPA show a TPA of 800', but the same airport listing in the AF/D does not show a TPA. My inclination is to use the AF/D as the final word and say that "if it isn't published in the AF/D, then it isn't a published TPA and I'll continue to use 1000' regardless of what the AOPA airport guides show". Or is there something the AOPA airport directories know that the AF/D doesn't?
 
Matthew said:
My inclination is to use the AF/D as the final word and say that "if it isn't published in the AF/D, then it isn't a published TPA and I'll continue to use 1000' regardless of what the AOPA airport guides show".
Your inclination is proper -- if it isn't in the A/FD, it isn't FAA-official. That said, if you discover a non-standard TPA in the AOPA guide that is not in the A/FD, do everyone a favor and bring this to the airport manager's attention so they can either get the change posted in the A/FD or fix the error in the AOPA directory.
 
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