TPA and Terrain Clearance

[C150J]

Hi guys,

I realize that a Part 77 deals a lot with obstructions and clearance in the terminal area, but does a traffic pattern altitude actually guarantee terrain clearance? Since it's obviously a visual maneuver, is it just assumed that you're going to avoid cumulo-granite with a set of Mark I eyeballs? Also, I'm trying to find prescribed distances from the field for downwind legs, as a lot of guidance just states "within safe gliding distance to the airport." We spend so much time focusing on TERPS in the airline world, so i'm just wondering how much is carried over these days to TPAs (this company seems to extend its knowledge to TPs - http://airspaceusa.com/index.htm).


Thanks!
J.

 

[tgrayson]

I realize that a Part 77 deals a lot with obstructions and clearance in the terminal area, but does a traffic pattern altitude actually guarantee terrain clearance?

The FAA doesn't establish traffic patterns in any regulatory fashion, except for the left turn thing. TERPS only applies to instrument procedures.

 

[SIUav8er]

The FAA doesn't establish traffic patterns in any regulatory fashion, except for the left turn thing. TERPS only applies to instrument procedures.

besides, traffic patterns are a visual maneuver used under VFR, so no terrain clearance would be gauranteed.

Check circling MDA (and radius) for the appropriate category if you want terrain/obstruction clearance.

 

[TwinCessnaDriver]

27R at Gillespee Field (KSEE) has a traffic pattern which goes around a hill. This hill reaches an altitude which is greater then the TPA; so when you turn downwind to base around the backside of the hill, you are out of sight of the control tower. I miss flying in San Diego, although I don't miss instructing.
:dunno:

 

[A150K]

besides, traffic patterns are a visual maneuver used under VFR, so no terrain clearance would be gauranteed.

Check circling MDA (and radius) for the appropriate category if you want terrain/obstruction clearance.

Here in NM the 7500 TPA at KGNT (Grants, some podunk town along I-40) gaurentees no terrain clearence on a normal left pattern. Most pilots fly the pattern at about 77-7800' .

 

[DHC6]

27R at Gillespee Field (KSEE) has a traffic pattern which goes around a hill. This hill reaches an altitude which is greater then the TPA; so when you turn downwind to base around the backside of the hill, you are out of sight of the control tower. I miss flying in San Diego, although I don't miss instructing.
:dunno:

Gotta love rattlesnake peak.... Have you ever been to KRNO? There's a huge peak to the SE of the airport that's probably at least 500 feet above tpa. Sorry for no contributing anything in writing but from experience there's no way tpa guarantees terrain clearance.

 

[TwinCessnaDriver]

Never went into Reno. But I have some great memories of landing a 340 at Catalina and Big Bear. Those are my favorite airports in SoCal. Oceano is nice too.