A chain is unserviceable when the elongation is:

1.   ?    20 %
2.   ?    0.2 %
3.   ?    2%

Axial movement check for bearings can be:

1.   ?    Rotate through 90 degrees very fast
2.   ?    Tapping with a light soft hammer and cooper drift
3.   ?    Lightly pulling and pushing

Aircraft construction will provide adequate protection against lightning if:

1.   ?    The total resistance with adequate bonding is more that 5 ohms
2.   ?    The skin is made with a copper insert
3.   ?    All the skin area has less than 0.05 ohms resistance