TOST vs. Schweizer Hooks on Tow Planes.

On Wednesday, May 1, 2019 at 9:02:59 AM UTC-7, Paul Agnew wrote:
Does anyone know the limits on these STC'd hooks? They claim to be better than Schweizer hooks, but don't list any numbers to substantiate it. (I've emailed an inquiry to them.)

https://pacificaerialtowhooks.com/

Paul as I replied to your email,
The pacific Aerial Tow Hook is rated for a limit load of 1440 lbs. using AC 43.13-2B, 804(d) the glider can be 1200 lbs or a banner can be 720 lb, (although we recommend a banner limit of 600 lb.) The rope for glider towing is limited to 960 lbs breaking strength.

The geometry of the Schweizer hook has a load ratio on the release of .377 and the PATH tow hook has a load ratio of .265, so the release loads on the Schweizer are 42% more. Also the ring is held in one location and can't move around like the Schweizer hook.