TOW PLANE Accident

On Tuesday, March 12, 2019 at 1:17:43 PM UTC-4, Charlie M. (UH & 002 owner/pilot) wrote:
OK.....I am, "sorta among the oddballs in the US.....".
While I would like to mandate low tow......
First mandate that pilots pay attention. The kiting accidents and recreations indicate once kite acceleration starts the game is lost. Doesn't matter what tow position you start from. Tow position is a scapegoat for pilot inattention.

Name one case of kiting occouring from low tow. I can’t recall a single incident here, where we only use low tow.
It’s simple physics for goodness sake.

On Tuesday, March 12, 2019 at 7:10:12 PM UTC-4, Charlie Quebec wrote:
Name one case of kiting occouring from low tow. I can’t recall a single incident here, where we only use low tow.
It’s simple physics for goodness sake.

Somewhere (in this thread iirc) is a report on simulating kiting accidents at altitude and low tow being no better. As for citing a real world low tow tug upset I wouldn't be surprised if there aren't any. Not due to increased safety of low tow but due to how universal high tow is. And if there is one I'm sure the evangelical lowtowers would claim the pilot got high first. The lazy procedural golden bullet isn't the answer, the answer is paying attention for five minutes.

On Tuesday, March 12, 2019 at 7:10:12 PM UTC-4, Charlie Quebec wrote:
Name one case of kiting occouring from low tow. I can’t recall a single incident here, where we only use low tow.
It’s simple physics for goodness sake.

You've made it perfectly clear that you don't understand the physics.

It's all been covered.

READ.

T8

T8 You’ve made it perfectly clear you will stick to your view, regardless of the obvious extra risk you put your tow pilots in. Ive read plenty thanks and the facts are clear to me,
as are the physics. Let’s put it really simply for you, we don’t have kiting incidents from low tow. Even you should understand that..

Deep breath........

We all have our say and thoughts.

I can't say a dumb move on the glider end won't hurt/kill the tug pilot. Sorta regardless of what tow position you started in.
I am curious if any meaningful data exists that show a safer tow position.

Harsh choice of words, but as T8 stated, "out of control is out of control".

Soooo....let's attempt to keep this civil and "maybe" we learn something worthwhile.....

On Wednesday, March 13, 2019 at 8:15:43 PM UTC-4, Charlie Quebec wrote:
T8 You’ve made it perfectly clear you will stick to your view, regardless of the obvious extra risk you put your tow pilots in. Ive read plenty thanks and the facts are clear to me,
as are the physics. Let’s put it really simply for you, we don’t have kiting incidents from low tow. Even you should understand that..

T8 is a switched on pilot and very safety conscious. I find it funny when online pilot opinions differences devolve into accusations of the 'obviously wrong' pilot being an unsafe cowboy.
As for the original question does cracking a whip from a lower position give you more time to stop the resulting force? And wouldn't you end up with more total energy in a whip cracked from a lower position? Is it even possible to uncrack a whip once energy input has reached a certain level?

My takeaway from this mostly useful discussion is:

Low tow might provide an air "rumble strip" as the pilot is losing position, "wake him up" (pun intented) before he gets too far out of position.

I dont think these accidents are caused by a winch style rotation to the kite, but more a lack of attention that by the time it is detected, you are too far out of position (or control) to recover. A "stick shaker" at the very start of the event, might well prevent most of these accdents.


Well that and T8 is a cowboy, I have seen him in leather boots ;-)

RR

It's worth trying to understand these accidents and being ware of "solutions" that don't address the root cause. I think I've worked harder on this than many, so I'll share my summary. For those that don't know me, I've been instructing for 3 years and have about 2000 hours in gliders and towplanes since 1986. I am not timid (thanks Rick :-)).

The Skyline accident is an outlier. Video evidence shows that the glider deck angle never gets out of normal limits. It was not a kiting event. However, it's perfectly clear that the glider PIC lost situational awareness for several seconds and left the normal tow position at very low altitude (~200' iirc). The video + audio suggest that it is likely that the towplane's elevator authority was compromised before tow separation. Although this cannot be established with certainty, we do know that the tow line angle was unusually steep and that the tension became high enough to break the rope without a slack line event. I'll bet a year's worth of tow fees you can't break a rope in this manner without compromising the tug.

The similar accident I am aware of is the Sugarbush takeoff accident in 1999.

https://app.ntsb.gov/pdfgenerator/Re...Final&IType=FA

It's similar to the Skyline accident in that it involves a reasonably experienced pilot in a modern nose hook equipped glider giving in to a cockpit distraction on departure (open canopy) and allowing the glider to fly well outside normal positional limits. It's unclear to me if this became a kiting event or not, but it's clear that the towplane's elevator authority was badly compromised. Observers stated that the tow rope was "vertical" prior to separation. The towplane was forced into the ground and came to rest inverted.

We don't have an easy way to collect statistics on the gliders involved in upset accidents and incidents. The glider type is generally not mentioned in an accident report concerning a towplane, unless the glider is also wrecked. The anecdotes I know of suggest it's most often Schweizer iron, with the 2-33 figuring prominently. The anecdotes generally suggest a kiting event as described in the work of Rollings, et al.

It's easy to see why. The stick pressure on tow cannot be trimmed out in any 2-33 I've flown. The forward stick force required to maintain formation with the tug is substantial. The departure from normal tow position (high or low, doesn't matter), should you momentarily release forward pressure for any reason, will be extreme and potentially catastrophic for the tow pilot.