Re: [RAS_Prime] Tow releases for tow planes

[Kirk Stant]

In my opinion tow planes should all use Tost (or Tost-style) releases. Our club (St Louis Soaring Assn) has both of our Pawnees equipped with Tost reel systems, which include a backup external Tost release that can be used if the reel system is inop. Works perfectly. And cheaper than a dead tow pilot.

The reel system (retractable tow rope) is really nice - especially if you have a road or crops across the approach ends of your runways. More maintenance, a bit more training, and more procedures during tow (with chance to screw up) but overall the reels work really well and not dragging a rope around everywhere makes ground ops a lot easier and safer, IMO.

We have been using the reel systems for over 10 years now with only minor, easy to fix issues (mainly caused by rope tangles or knots that are not detected and towed on).

Kirk

66/tow pilot

On Tue, Jun 2, 2026 at 6:48 AM David S <david.s....@gmail.com> wrote:

Early in the conversation about the Adirondack Soaring accident there was speculation that a Schweizer tow release might have been involved.  I would have thought that most of these were long since replaced with Pacific Aerial / Javelin tow releases, which look very similar to the Schweizer but have modifications that make kiting jams less likely.

I have not been around gliding all that long, but I have only seen Schweizer releases on Schweizer gliders, never on a tow plane.

   ...david

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[Roy Bourgeois]

Kirk

I commend you for starting a new thread on what is a different subject. Below is a copy of an email that I sent you ( some 9 years ago) about the problems GBSC had with that system and why we got away from it.  Others may find it helpful.

Roy

We used the system for several years on our 2 Pawnees and finally got away from it.  I found that it was a useful system for situations of limited operations - particularly where the pilot wants to do a tow and then carry on to a new destination ( like a cross country retrieve) without landing to drop the rope. It also had all of the expected advantages of not landing with a rope hanging behind you. But - we also found a few very significant disadvantages: 

1) The system uses an electric motor that is operated by a manual switch. The tow pilot has a mirror that is focused on the tail cone so she or he can shut off the switch when the rope is fully retracted. The system depends on the tow pilot looking in the mirror at exactly the time & place where they need to be looking for traffic, checking cool down, etc. As a tow pilot I did not like that. 

2) The system is non compliant with FAR 91.309(a) since it uses only one weak link (the FAR requires 2: one at each end) and there is no way to use a weak link at the towplane end. In a towing accident that could be an issue. 

3) The system can't be used in cold weather.  If the rope gets wet it freezes on the reel.  If you switch over to use the manual Tost release you have to disconnect the guillotine cable and connect it to the Tost release. This is dangerous because if the reel is now used - the guillotine is disconnected. That happened to us twice and we had to tape over the housing to prevent a reoccurrence. 

4) It is possible for the reel to get tangled so that the rope stops close to the end - but the glider load is on the reel (and not on the airplane airframe). The reel is not designed to take that load. 

5)  Tangles are frequent - and a PITA. Checking the portion of the rope that is hidden behind the guillotine is also a PITA. Changing the rope is a PITA. 

6) The system is expensive and parts are expensive. We had lots of rope breaks (almost never at the Tost weak link) and that weak link unit is expensive, we lost several tail cones (also expensive) and had a motor burn out (really expensive and a long wait). 

7) We had incidents were the tow plane "slack out" process was interrupted and the tow pilot didn't realize that reel was not fully played out. Then when the tow started it whiplashed the glider. 

8) A&Ps are not familiar with the system and some were reluctant to work on it. 

Bottom line - it's a complex system that makes sense in an operation where cost is not important, the same people are using it, and obstacle clearance is important. But in a busy club or commercial environment a simple rope/release system works better  - I was happy to see it go. 

[Kirk Stant]

Hi Roy, it's been a while!

I appreciate your input and your experiences - I remember reading them when we were debating getting the reel system on our towplanes.

However, our experience does not match yours, and we much prefer the reel system for our operation. While the additional complexity does require more tow pilot attention, our two systems have proven reliable, and any problems we have do not cause excessive down time or problems. 

Yes it is expensive, and needs to be understood and used correctly - replacing the ropes annually is critical! Ground ops are definitely different (line crew need to be taught how to use the system) and tow pilots have more to worry about - but overall we feel its worth it and would not go back to a non-reel system.

As far as the mirror specifically - we only use that to confirm the rope is fully in when the switch clicks off and shows in - as a knot can stop retraction, as can a rope that is old and kinked and due for replacement. Then the tow pilot checks the mirror, and if the rope is not fully in, can try again or just land long and solve the problem. It no more takes pilot eyes away from lookout than checking engine Ts and Ps. Note that we are also in the process of installing PowerFLARM in all our gliders, already have ADS-B out in all our towplanes, and I fly with a PF Flex whenever I tow - so we take traffic awareness seriously!

As far as mirrors are concerned - the tiny external ones I see on most towplanes are really scary to me - we have a couple of huge custom made mirrors mounted on the instrument panel that let the tow pilot monitor the glider on tow without moving his head - and can detect glider movement out via peripheral vision immediately. Perhaps if more Pawnees had good mirror systems, upset problems would be detected earlier?

Cheers,

Kirk

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