The first rule about ground loop is that we don't talk about ground loop. If we have never experienced one, we don't really know the exact tip point. If we have experienced one, we may fear loss of respect from peers.

If ground loop is defined as a violent, uncontrolled horizontal rotation of an aircraft while landing, taking off, or taxiing, reactive rudder movement will not either bring the fuselage back into alignment or even stop the rotation.

Before consideration of proactive solutions to the ground loop problem, let's address gaining experience of it. At slow speed taxi in an open field, we can push a rudder to the stop to experience a slow speed, non-destructive ground loop.

Two proactive ground loop avoidance techniques come to mind and have been discussed here before. The first involves avoiding bad wind and gust conditions and reacting quickly to any non-alignment with reactive rudder. The second emphasizes dynamic proactive rudder movement to bracket the taxi line, centerline, and centerline extended on final, or any target.

What tactical situations generally lead to ground loop? Instructing, first solo in tw airplanes, light crosswind, gust spread in crosswind, no wind and experienced pilot? Instruction in tw airplanes has seen more instructor oversight, I think, with the increase in hull value and rebuild price of airplanes. Dynamic proactive rudder movement oversight, instructor riding the rudder a bit, doesn't work well. Any riding will actually be reactive to longitudinal miss alignment. We used to let them ground loop at slow speed, continuously harp, "walk the rudder," and let them solo before plateau. First solo is the best confidence builder if performed while every day in every way things are getting better and better. Light crosswind seems to get more than its share. Using dynamic proactive rudder movement throughout final, touchdown, and roll out helps all landings but especially here. First, small coordinated turns to stay on the centerline extended will not be allowed to hide any crosswind. Second, dynamic proactive rudder movement will keep us ahead of the airplane. Gust spread in a crosswind is mostly a throttle management issue. Because poor control movement with one control can lead to lack of attention to another, gust spread can contribute to the ground loop problem. Finally, we come to a big one; no wind and experienced pilot.

Reaction to gyroscopic precession when the tail comes up can't be timed if we wait until relative wind brings it up and is difficult to time if we push the stick forward to bring it up smartly. Dynamic proactive rudder movement, if already there, makes it a nada. Reaction to p factor in most small airplanes is not problematic. With big engine, dynamic proactive rudder movement continuously could be much more effective. It is landing, however, that makes this tactical situation meaner than expected. Two things enter the equation here: landing often comes after a long flight, and touchdown often comes after a long power off hover in low ground effect. When tired, we may not walk the rudder on final, touchdown, and roll out. And if a round out and hold off are involved, they need not be, we are waiting until the wing finally decides to stall, or worse, forcing it on with flying speed.

More airspeed increases control effectiveness. More groundspeed increases damage in a ground loop. Regardless, we will eventually slow down. The sad thing about strong crosswind is that airplanes are torn up by excess groundspeed that could easily have been avoided in the strong headwind component of that crosswind.

I was told; once you realize you can’t stop the groundloop you should reverse the controls to get thru it with less chance of damage. Fighting it further creates a higher chance of digging a wingtip or folding a gear leg.

Any truth to that?

My tail wheel instructor pretty much had a single phrase. “Keep it f$#&ing straight”.

I think it was his timing that made it such good advice.

He did also occasionally say “Get of the f€£¥ing brakes”. This was actually not such good advice in the 170,
I use them occasionally.

In my experience, yes. I had some brackets installed wrong on the landing gear of an Ag Cat snap on landing, the left gear leg was moving 1 ft forward and backwards when I touched down, and ripped the brake line out of the caliper which I found out when I hit the brakes. Once it started coming around, I got off the controls and rode it out, ended up having no damage other than the pork chop and hardware being replaced that caused the whole thing.

Bagarre,

To answer can anything be done to save or mitigate a ground loop, the answer is no. There are two situations needing discussion. Ground loop by definition is "uncontrolled" ; it has gone beyond the tip point. No control, no mitigation.

The situation where your instructor wanted you to stop trying to get back on the centerline is different. With dynamic proactive rudder movement, we can bracket the centerline. By controlling error slightly left,right,etc, we are continuously moving our feet and continuously controlling. By reacting to error with a rudder jab in the other direction, we recover straight down the centerline again. The timing and amount with this jab method must be perfect or it becomes uneven dynamic reactive.

However we are controlling, using rudder continuously or occasionally, if we let the error become significant yet not tip point, we can only control the new straight line. Your instructor and myself will admonish: dynamically and proactively move the rudder to maintain that new line. Do not now attempt to return to the centerline. We are going off runway but in control. Big question here is would we do better to ground loop short of obstructions?

The really important thing is that using dynamic proactive rudder movement, a lot or a little, will keep us continuously in control of the direction of the longitudinal axis (between our legs) toward the target we choose, say the centerline. It is not as pretty, but neither is a bent airplane.

When training, the instructor who generally will take control at the significant error but not tip point , is now in control. It is he who must accept the new direction, dynamically and proactively keep this line, and go easy on the brakes.

My instructors comment wasnt about getting it back on centerline, it was about trying to mitigate damage in a grounloop.

Yes, it's uncontrollable and past the point of fixing and nothing is going to stop it from going around. No argument there.
But, once it's uncontrollable his point was, you might do less damage to the aircraft if you stop trying to fix it (becasue it's beyond fixing) and just help it go around (get off the brakes, put rudder into the loop) vs fighting it the whole way.

Nothing is a sure thing and im not expecting "this works every time" but I was wondering if there was any truth or opinion on this.
My guess is it varies greatly from plane to plane.

Bagarre wrote:My instructors comment wasnt about getting it back on centerline, it was about trying to mitigate damage in a grounloop.

Yes, it's uncontrollable and past the point of fixing and nothing is going to stop it from going around. No argument there.
But, once it's uncontrollable his point was, you might do less damage to the aircraft if you stop trying to fix it (becasue it's beyond fixing) and just help it go around (get off the brakes, put rudder into the loop) vs fighting it the whole way.

Nothing is a sure thing and im not expecting "this works every time" but I was wondering if there was any truth or opinion on this.
My guess is it varies greatly from plane to plane.

Seems like a completely moot point.

In my experience, anyone with the presence of mind and fast reflexes to throw in opposite controls when they realize the ground loop is inevitable, isn't going to have one in the first place. I really can't imagine making that transition, especially since you never get to practice it without damaging your airplane.

Bagarre,

I see your instructors point, but also Hammer's. It is a hard thing to shift from reactive to reactive in reverse. Dynamic proactive from the beginning of the approach works. Reaction to the actual tip comes as a startle wake up.

I could see going to rudder in the direction of the loop, after the fact, when the instructor allows student error to go all the way because groundspeed is below damage speed. I just never thought of following with rudder into the loop. Also I wanted to let the student see and understand his error.

I didn't ride the controls. I did, and do, use a stiff thumb to alert the pilot he should not use aileron (in a coordinated turn) on final and I jab a rudder briefly to effect/indicate longitudinal axis alignment between the legs. Yes, if between my legs the centerline will be between his legs. Optical thing. I also will dynamically and proactively move the elevator rapidly to help him see how to stay in low ground effect on takeoff.

Billy Howell, and I, used the ugliest dog available for tw training. When BCP pilots come to fly with me I thoroughly brief my disability and that I will not touch the controls on the ground. Airplanes are so well designed that even a mostly used up disabled guy can handle them in the air. Nosewheel helps, but none are designed to drive on the ground. Especially fast. Fly fast. Drive very slowly.

.

Only 3 kinds of taildragger pilots when it comes to ground loops:

There are those that will...
Those that have...
And those that have but are lying about it...

If you run out of rudder and you feel the yaw self energizing while you lose directional control, a FULL THROTTLE blast is the last thing you can do that will save your bacon and arrest the yaw.

Of course you better make sure you don’t run off the end of the runway into the fence or anything else.

Using the throttle after a rudder goes to the floor and brakes are ineffective has saved me more times than I can count.

After 30+ years, I’m still awaiting/anticipating my ground loop. It can happen on my next flight...you never know.

This video is an excellent learning tool for the importance of proper landing techniques to avoid a ground loop.

https://youtu.be/mukmCGDvFlQ

https://www.youtube.com/watch?v=iFvD7Ok0ghY


I guess I need a P-47 now...

Aryana,

There is a thread, 170 ground loop, on this one. Three serious things seem to set this up. Either he didn't realize he had a very slight (the one that gets most) crosswind. Regardless, he was using aileron turn to realign. Lastly, he or the instructor used left brake (and no rudder movement throughout) to try to stop the rotation.

Nastier than it looked because a quick reactive left rudder probably would have stopped rotation pointing the nose straight into hangers. Of course dynamic proactive rudder on final, round out, hold off, touchdown, and roll out would have first found the slight crosswind and the wing into the wind (used on short final) would have controlled the slight drift and life would have been good.

And the apparent brisk walk rate of closure or any slow power pitch approach would have made it possible to either turn off at the hanger or at least do no damage.

I’ve heard of intentional groundloops to avoid an obstacle, and even had an opportunity to contemplate one for a few seconds when my aircraft suddenly veered to the right after applying brakes during a night landing. It struck me that perhaps holding aileron into the loop would perhaps minimize wing damage and grind only the aileron, Unfortunately, it’s not a maneuver you can practice, unless you’ve got a lot of spare airframes!

Here’s the video of the infamous Red Bull T-6 groundloop, which appears to be holding right aileron into a left groundloop:

https://m.youtube.com/watch?v=Dz2_QJpfqXI

Ailerons CAN be somewhat helpful in an incipient ground loop. Ask any old time C-46 driver (the Curtiss have lousy brakes), and they'll tell you: "Drive it into the ditch". Full aileron INTO the swerve.

MTV

Big airplanes have two engines, land fast, and have big ailerons. MTV knows how to sail airplanes. I don't know, but I expect they sail about as good as they drive.

My favorite ground loop video:



Pilot basically just quits flying....

contactflying wrote:Aryana,

There is a thread, 170 ground loop, on this one. Three serious things seem to set this up. Either he didn't realize he had a very slight (the one that gets most) crosswind. Regardless, he was using aileron turn to realign. Lastly, he or the instructor used left brake (and no rudder movement throughout) to try to stop the rotation.

Nastier than it looked because a quick reactive left rudder probably would have stopped rotation pointing the nose straight into hangers. Of course dynamic proactive rudder on final, round out, hold off, touchdown, and roll out would have first found the slight crosswind and the wing into the wind (used on short final) would have controlled the slight drift and life would have been good.

And the apparent brisk walk rate of closure or any slow power pitch approach would have made it possible to either turn off at the hanger or at least do no damage.

No flaps deployed on approach and inputting some aileron into the wind would have solved a lot of problems for this incident.

He had some aileron in and got the right wing down a bit for the crosswind, but allowed a coordinated right turn. When he tried to drive the nose back down the centerline with a coordinated left turn, things went south. Aileron use is to lock the wing level or set a bank into the wind. Dynamic proactive rudder, rudder not aileron, rudder,rudder keeps the centerline between our legs. Aileron in no way keeps the centerline between our legs.

Flaps, full is most effective, slow groundspeed and allow the wing to fly at slower airspeed, and really, really help reduce groundspeed at touchdown. Slow touchdown and just a little ground roll, make a ground loop just embarrassing, not damaging.

This fast groundspeed ground loop was damaging.

Contact,

Okay, I beg to differ just a bit, when you state that aileron doesn't help straighten an airplane on the runway.

The "Drive it into the ditch" point is to help with precisely that. The DOWN aileron creates lift, hence it also creates DRAG. That drag, while not much help, DOES in fact help to turn the airplane. This is not what we think of as the "normal" effect of the ailerons, and I absolutely agree that rudder is THE primary directional control on the runway.
But, don't discount that the ailerons can assist. This was taught to me by a gent with several thousand hours in C-46 Curtiss Commandos, and demonstrated by him in my Cessna 170. It works.

MTV