or even the wrong pins (eg A320 rated pins in an A321 bar, but hopefully not the other way round).
I thought this might be an issue!!.... Why then am I permitted to use the same towbar for A319, A320 and A321??
A319 positioning to BHX ) domestic ) rather than A321 full load to FUE, for example, same sheer pin, same load value for sheer rating...
surely sheer pins are for 'extreme' load protection...... Don't get me wrong.. I've had pins go for 'no' reason, simply coz they are old and corroded!!
737 towbar - used for enpty 737-500 and full 737-800.. slight difference in weight!!!
They should be changed regularly ( pins ).. but how regularly??? How often is a towbar used?? It doesn't have a counter on it!!
These days, a towbar 'should have an 'axial' and a torque' sheer pin, so as to cover all axis in loaded movement... But older towbars lack this!! One for both, or one for one and not the other....... You get me???
Not fool-proof, but there for a reason!! Headset cords are long and curly for a reason!!