TOST Weak Link Shackle

TOST Weak Link Application List

FAR Rules on Glider Towing

FAR 91.309 Towing: Gliders: (3) The towline used has breaking strength not less than 80 percent of the maximum certificated operating weight of the glider and not more than twice this operating weight. However, the towline used may have a breaking strength more than twice the maximum certificated operating weight of the glider if–

(i) A safety link is installed at the point of attachment of the towline to the glider or unpowered ultralight vehicle with a breaking strength not less than 80 percent of the maximum certificated operating weight of the glider and not greater than twice this operating weight;

(ii) A safety link is installed at the point of attachment of the towline to the towing aircraft with a breaking strength greater, but not more than 25 percent greater than that of the safety link at the towed glider end of the towline, and not greater than twice the maximum certificated operating weight of the glider.

TOST Weak Links

Tost weak links in their optimized format combine the following improvements:

• Longer service life
• Correct marking with load group and manufacturer’s name
• Made of high-quality certified aircraft steel
• Clear distinction from inferior copies
• Manufacturing tolerance only 5% (10 % are demanded in the requirements)

Like our type-approved products, our weak links are also manufactured according to
EASA approved production methods. Each batch is tested on computerized test equipment and the
results are documented. This guarantees consistent high quality and traceability. 

Important Notes

 Weak links protect your aircraft against overloading

• Use only the weak link stipulated in your aircraft TCDS or aircraft manual
• Checking the cable preamble is mandatory according to SBO (German Gliding Operation  Regulations); this includes the inspection of weak links
• Replace the weak link immediately in the case of a visible damage
• We recommend that the weak link inserts are replaced after 200 starts:
   an insert exchanged in time is always safer and cheaper than one single aborted launch
• Always use the protective steel sleeve
• Use only the correct shackles: they prevent the weak link and the steel sleeve from twisting,  leading to an undefi ned increase of the breaking load
• Never use two equal inserts, eg, both with round holes, in a reserve system, since this would double the breaking load

Warning
Using combinations of weak link inserts from diff erent manufacturers can double the breaking
load because of the elongation of inferior inserts! 

Custom Weak Links

Using combinations of weak link inserts from different manufacturers can double the breaking load because of the elongation of inferior inserts. Refer to our Weak Link Application List for choosing the right weak link.

We manufacture to your requirements custom-made weak links with defined breaking load in the load range of 10 daN to 50 kN. Testing on computerized test equipment. Material: plastic, stainless steel, steel. Application examples: bracing of antennas, retaining of flagpoles, Off–Shore–operation, testing of parachutes, test racks, food industry.

Connecting Ring Pair

Connecting ring pairs are vital for the safe connection and reliable separation of tow cable and tow release.

The type certification stipulates that every Tost tow release must be operated only with a ring pair meeting the Aeronautical Standard LN 65091 (in its respective current edition).

 These connecting ring pairs must be stamped with the manufacturer‘s name and the standard number.

Welded rings are categorically prohibited.

Their use voids the warranty of our releases. Welded rings cause damage to the releases. Moreover, undersized or deformed rings can cause the ring pair to jam the release and inhibit correct operation under load, a potential danger for the pilot.

Connecting ring pairs must be visually checked and measured at regular intervals.

Ring pairs that deviate from the standard dimensions must be replaced.