Black Circle on BA aircarft Nose

Gonzo, you of course are correct there and BA started flying trials of MLS @ LHR (27R)in the late 80’s. 757 IKK and 767 WND were both used at one point. I have had the pleasure of doing numerous MLS approaches in both aicraft and also in, if I recall, 1990 we did approaches for several hours overnight at LHR 27R in the FAA 727-100.

MLS is installed at LHR, and our Ops guys along with the CAA are currently working on procedures for its use.

The main benefit in our case is that the antennae on the ground need far less protection (i.e. CAT I bars rather than CATII/III bars) than an ILS, so our capacity in Low Visibility Procedures increases, as we need to provide the aircraft with less separation.

MLS proposed using 2 or 3 antennae, similar but smaller to the usual comms ones on top of and underneath the fuselage and possibly on the tail, it would not have used antennae in the nose. Not sure of MLS status now but it was suggested that CAT III approaches could be flown using GPS and ground repeater stations, in fact I think the FAA demonstrated this a few years back. Boeing did supply airplanes, including the earlier BA B767 fleet and also I believe the 747-400’s with rack positions, cabling and antennae for MLS.

You sir are a genius 🙂

Raymy

From another forum….

“I believe its part of the static-discharge system that protects the aircraft. All Boeing jets have it, some choose to paint over it with an static dissipating paint, but for some reason, it was left on the 757. Airbus have them hidden from view I think.

I believe also that they were designed to be apart of the MLS (Microwave Landing System) which were supposed to replace the ILS before 2000. The MLS was deemed more advantageous as it allowed pilots to fly curved precision approaches (when terrain was a problem). Pilots just have to fly non-precision approaches for the unconventional approaches. The idea was scraped – I don’t know why”.

Not my words, I hope he doesn’t mind me using it.

😉