How Close?

[SLF3]

Was on an A340 coming on stand at a third world airport. On the next stand was an A-330. The follow me truck cut the corner, and so did the A-340. From where I was sitting, alongside the wing root, it LOOKED as though the winglet of the A-340 was under the horizontal stabiliser of the A-330. Frantic baton waving and the pilot stood on the brakes (hard). The winglet dived and bounced up under the stabiliser. It looked very close. Recognising the answers can only be very approximate:
- How high is the top of the winglet above ground (when the fuel tanks are nearly empty)?
- How high is the outboard end of the horizontal stabiliser above ground?
- How much (roughly) would the wing tip move in an emergency stop from 5mph?

I'm not naming names or places, or saying the winglet was definitely under the stabiliser. I'm just curious as to whether what appeared to happen could have done!

[BigHitDH]

OK.

Clearances for the A330/A340


A330/A340 - Operating Weight Empty CG 26.8%/31.9%

Wingtip height from ground = 8.05m/7.91m
Horizontal Stab height from ground (outermost tip) = 8.33m/8.14m

A330/A340 - Max Ramp Weight CG 15.0%/20.7%

Wingtip height from ground = 7.70m/7.57m
Horizontal Stab height from ground (outermost tip) = 8.09m/7.96m

A330/A340 - Max Ramp Weight CG 36.5%/38.2%

Wingtip height from gound = 7.61m/7.53m
Horizontal Stab height from ground (outermost tip) = 7.88m/7.88m


So, considering that your A340 was probably low on fuel, and the A330 was fueled, the clearance would have been approx 1m - not much. I don't think the tips would move much under a 5mph stop, maybe half a meter, so that puts it 50cm(ish) away minimum.

Do bear in mind that with almost a 200ft wingspan, it can be difficult to judge distances from the cabin, so the horizontal sepration might have been more (or less!) than you think.

If it was enough to panick a wingwalker, I presume it was pretty close!

Hope that helps,

[SLF3]

It panicked me! I saw it coming and pushed the call button but by the time the stewardess arrived it was all over.

I agree it's almost impossible to judge how close it really was.

Thanks for taking the trouble to reply.