Bank Angle in the Pattern

[Jaybird180]

What do you use? 30deg? 15deg? 115deg?

 

[Jim Logajan]

What do you use? 30deg? 15deg? 115deg?

My CFI said there was not much to be gained by anything over 30 degrees in a normal landing. Anything more than that - such as in an engine out scenario - and he expected to see even more nose down if I needed to make steeper banks.

Generally he would bring my steeper turns to my attention by asking "Why the fighter plane maneuver?"

 

[Jim Logajan]

You should be able to fly the pattern without an airspeed indicator. Orville and Wilbur did not have an airspeed indicator. IMHO, many pilots are afraid of the low-speed end of the airspeed indicator and do almost everything too fast.

Bob Gardner

I believe that is a dangerous misrepresentation of history and current regulatory constraints. They had a very basic angle-of-attack indicator on their first airplane. In fact it was their only flight instrument. There should be no implication that they felt they could fly entirely by the seat of their pants. They did not trust their abilities that much, so it seems unwise for anyone else to be too trusting of their abilities except where exceptional circumstances require it.

Since the FAA regulations do not require an AoA indicator, but do require an airspeed indicator, the only alternative we later pilots seem to have is to use the airspeed indicator and keep the bank angle shallow so that the airspeed indicator can be used as a crude replacement for the AoA indicator.

With respect to the original bank angle question, here is a specific recommendation from an AOPA ASF stall/spin safety article:
"Don’t exceed 30 degrees of bank in the traffic pattern."
http://www.aopa.org/asf/publications/topics/stall_spin.pdf

From the FAA stall and spin AC:
"Excessively steep banks should be avoided because the airplane will stall at a much higher speed."
http://www.mccc.edu/~kuhlj/classpix/AVI 132/AC 61-67c stall spin.pdf

 

[Jim Logajan]

Too bad that's not true.

The conditions under which it isn't true for most pattern flying require descending flight - the more bank, the more nose down you have to be to avoid stalling. Anything else and the FAA AC is correct enough to save lives.

I know enough about physics to know when people are using conditions outside normal pattern maneuvers to score points on pedantry. Consider yourself a couple points up. If you actually read the two documents you'll find they say stalls can happen at any speed and any attitude (relative to the ground) but guess what - they still felt it appropriate to recommend low bank angles in the pattern.

Anyway - I've posted two presumably credible sources that recommend avoiding steep banks in the pattern. If all the net experts and CFIs who think differently wants to take them to task - fine. I've done what I thought was proper by bringing these sources to the discussion.

 

[Jim Logajan]

It is and I've been having fun for over 40 years now but some of this stuff we do naturally every day I guess I never really deeply pondered the actual physics behind it. It's interesting though.

Speaking of the physics of turns - the optimum bank angle is about 45 degrees when attempting a turn back to the runway after engine out or glider tow rope break. At least according to the author of these two papers:

http://jeremy.zawodny.com/flying/turnback.pdf

http://www.nar-associates.com/technical-flying/impossible/nonoptimalcost_screen.pdf