Originally Posted by
ualboston1k
Hi folks, can you shed some light on why the A346 needs a unique towbar? What's so special about it?
When Airbus designed the ill fated A345 and 346 series (flopped against the B77L and B77W respectively) the specification for the towbar changed. So the towbar for 'regular' A330/340s cannot be used on A345/346.
Some insight from PPRune:
https://www.pprune.org/rumours-news/...ml#post9452612
An A330/A343 towbar cannot be used [...] due to the weight differential and the shear pin loading.
The A345/346 Manual says (page 320)
https://www.airbus.com/sites/g/files...40-500_600.pdf
A conventional type towbar is required which should be equipped with a damping system (to protect
the NLG against jerks) and with towing shear pins:
- A traction shear pin calibrated at 40 400 daN (90 823 lbf),
- A torsion pin calibrated at 4 800 m.daN (424 836 lbf.in).
The towing head is designed according to ISO 8267-1, cat. IV.
The A350 towbar has lower shear/torsion limits and a different head:
https://www.airbus.com/sites/g/files...0-900-1000.pdf
Same for the A330:
https://www.airbus.com/sites/g/files...ft-AC-A330.pdf
Section 5-8-0
A conventional type towbar is required which should be equipped with a damping system (to protect
the NLG against jerks) and with towing shear pins:
- A traction shear pin calibrated at 28 620 daN (64 340 lbf),
- A torsion pin calibrated at 3 130 m.daN (277 028 lbf.in).
The towing head is designed according to ISO 8267--1, cat. III.