My fault, but did I take the right way out?
 

Some few years ago I got into a situation that earned me a stern ( and warranted ) reprimand, but have always wondered if someone else would have taken the same evasive action. Returning late one Friday afternoon to a field the club shared with a helicopter school, I called inbound to the private tower operated by the helicopter firm. No answer - (thinks)- "Friday afternoon, nearly 5 pm, they've gone home".

When the school was operating the field was shared with the N-S strip being the divider. I was coming in from the S expecting no traffic, but aware that sone club members might have left work early & be getting ready to fly. I therefor moved over the line to the E, helicopter, side of the dividing line, to have a good view of possible actvity on the strip. I was losing height and moving fairly quickly in a low-wing a/c, aiming for a tight and possibly a slightly low circuit. We all like to be noticed by other club members.

I was startled to see a helicopter climbing out of the ground background, straight ahead, climbing just below my level, as there had been no radio activity.

A quick decision, don't want to lose sight of him, I'm flying a low-wing, stick forward and go under him. Too close for comfort, and obviously a nasty shock for the helicopter student and instructor. The radio now burst into life with dire threats, and to cut the story short I got an official reprimand.

It was my fault for being in their airspace, but was my decision to go for a close but controlled pass under him, so I could keep him in sight, the right one? Opinions sought.

Overhead join not intended for this very purpose?

I'd turn away and open up some distance if there's room, but if you were that close that a banked wing might meet with a rotor, underneath might be the last ditch maneuver, as you did.
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Mind you, it's better for all sides to work things out before you get that close. Radio calls are not always received for all sorts of reasons. Lack of response to a radio call does not guarantee nobody else is up to something.

What was it like to fly close, under, a helicopter? I'd have thought the rotor turbulence would lead to loss of control.

Given the slightly low circuit planning and the strong helicopter rotor downwash on top of it, I think it it was not the optimal way out.
Head-on climbing traffic is better avoided by a climbing turn to the right, 45 degrees initially.

Granted,.the temptation is way to high to keep it in sight, but from energy point of view, the climbing traffic stops the climb easier, and a descending traffic stops the descent easier, than the way around.
Turning some excess speed into climb quickly ensures vertical separation while you lose sight momentarily. Then you can re-acquire visually after 45 degree turn.

That being said, I might have done like you, instinctively. But it's not the best solution. It is just a solution to survive with some luck, and in that sense, it worked for you.
The best solution is to avoid this situation by not trying to be noticed by club members! :D

I totally agree that I sould not have got into that position in the first place, I said I was in the wrong.

Interesting views as to the "correct" method of avoidance, the climbing turn to establish separation. I agree that would be better in most cases. I only noticed on re-reading my post that I hadn't mentioned I was behind him, he didn't see me until the game was over. I still think stick forward establishes seperation faster than bank and yank - you have to get some bank on before the yank actually changes your trajectory

And, no, I didn't notice the downwash, I was through it too quickly.

rnzoli, agree with your energy analysis,but if the climbing party, the helicopter stops his climb and I stop my descent it's lilely we'll be at the same level, - crunch....

Anyway, thanks for your opinions, and I learnt enough from it to avoid such a situation.

Radio calls (traffic) would have prevented this I am sure. Both parties would therefore be to blame on this part alone.

Point 1: You knew the SOP was to to stay out of the heli space. With no permission otherwise ("never assume - check"), you were asking for a raspberry even if no helicopter had got in your way. I cannot work out what blind R/T calls you would be making once you had got yourself so far out of place. Airfield apportionments are for a very good reason. My experience includes a field with powered and glider users which in its past had a nasty history of fatal tangles. Such dissimilar flying demands studious care from all involved.

Point 2. I am not surprised the radio burst into life - you must have frightened the life out of the heli crew. If you wanted to frighten them you could not have pulled a better manoeuvre. I discovered this in basic military flying training. Airborne solo one sunny day I sighted a fellow course member before he saw me and chased after him. I passed under him undetected from behind, as conscious of his long undercarriage (peculiar to our Piston Provosts) as of my quite tall fin. Thanks no doubt to the endless ground school we had both endured, I put my faith in the concept of momentum. I counted three from when I heard his prop passing just overhead and effectively pulled into a half-loop. It was disappointing when I picked him up again to see him still straight and level. Of course when we landed I received all the reaction I might have hoped for - he remained livid with me for about a fortnight