Also posted elsewhere:
Advisory Circular, AC 43.13-1B, 9-4 (a) states:
a. Old aircraft landing gear that employs a rubber shock (bungee) cord for shock absorption must be inspected for age, fraying of the braided sheath, narrowing, (necking) of the cord, and wear at points of contact with the structure and stretch. If the age of the shock cord is near 5 years or more, it is advisable to replace it with a new cord. A cord that shows other defects should be replaced, regardless of age.
Besides the inspection points above, at each annual inspection I grab a wing tip and rock the aircraft. It should rock on the tires only, with no movement at the pivot points where the gear attach to the fuselage. Such movement would indicate weak bungees. The gear should also have no visible sag or splay. The aircraft should not be leaning on its gear, with one wing drooping lower than the other. During normal taxi over small surface irregularities, the aircraft should be bouncing on its tires only, with no movement of the shock struts.
Here's all you need to know about shock cords. See what it has to say about longevity. I take this to mean that if the cords pass condition inspection and they've been protected from contaminants and UV, then they are good to go, regardless of age:
https://www.univair.com/content/Shock-Cords.pdf
Advisory Circular, AC 43.13-1B, 9-4 (a) states:
a. Old aircraft landing gear that employs a rubber shock (bungee) cord for shock absorption must be inspected for age, fraying of the braided sheath, narrowing, (necking) of the cord, and wear at points of contact with the structure and stretch. If the age of the shock cord is near 5 years or more, it is advisable to replace it with a new cord. A cord that shows other defects should be replaced, regardless of age.
Besides the inspection points above, at each annual inspection I grab a wing tip and rock the aircraft. It should rock on the tires only, with no movement at the pivot points where the gear attach to the fuselage. Such movement would indicate weak bungees. The gear should also have no visible sag or splay. The aircraft should not be leaning on its gear, with one wing drooping lower than the other. During normal taxi over small surface irregularities, the aircraft should be bouncing on its tires only, with no movement of the shock struts.
Here's all you need to know about shock cords. See what it has to say about longevity. I take this to mean that if the cords pass condition inspection and they've been protected from contaminants and UV, then they are good to go, regardless of age:
https://www.univair.com/content/Shock-Cords.pdf
