Compass Base?

[NineEighteen]

There used to be a taxiway block at LHR called 'Compass Base'. I just looked at the ICAO chart and it appears to be called block 136 now.

Can someone please explain what it is/was?

Thanks
918

[pilotwolf]

Theres one at the west end of taxiway Juliet, at LGW too.

I think they are magnetical and electrically 'quiet' areas designed for swinging compasses and calibrating instruments.

Might be wrong thou....

[Departures Beckham]

SNAP! We've got a compass base over at STN as well. Ours is a circular piece of concrete with one lead-n from the Juliet taxiway. I thought (and it is a very simplistic thought) that it was used to check/align the onboard compasses.

I'm quite possibly wrong on this one, we'll have to wait for it to be confirmed. Interestingly though this is where we tend to 'store' any hijacked aircraft that visit us, I think it's used as the area around it is raised and therefore good for hiding troops in, and it is away from the southside passenger aprons and the northside GA.

[BDiONU]

All RAF aerodromes have a compass base which is used for compass swinging on yea older style aircraft.

[ATCO Two]

Yep, Pilotwolf is spot on! The compass base at Heathrow was used for compass swings, whereby an aircraft was manoeuvred by a tug to point in various directions and its compass calibrated accordingly. I think there must have been ground markings to assist in this. There is still provision for compass swings to be carried out on Block 43 on Runway 23, but I haven't seen one for ages.

[BLK 33]

Yes quite a rare event at LHR these days, but BA did one 2-3 weeks back. The old compass base was the real thing with no light fittings through the centre (though, if memory serves, it did have blue edge lights), or reinforcement in the concrete, though the newer one in Blk 43 is not so but has been deemed suitable for the job (Class 2??) after being checked periodically by boffins from DERA or whatever they are now (Qinetiq?).