ILS hopover

[Lunar Landing]

Is it possible for an aircraft on finals, on a LOC/ILS , to 'switch' to the parallel ILS, say at EGLL on ILS 27R, you have to switch to ILS 27L, or would they just tell you to rejoin and do some kind of missed approach?
Smooth skies,
Dan :)

[DJXL]

So you mean if an aircraft on final for 27R wanted to change over to 27L would it be able to? If you were 15 miles out you could probably make it but a go around is far more likely at the sort of distances we´re talking for most movements at Heathrow for example. In most cases I would imagine you´d have to go around and have another go.

Just a hunch. Any other input??

[eyeinthesky]

I understand that at LHR a visual switch from one runway to the other can sometimes be used if one aircraft catches up another on short final or one is slow to vacate or whatever. It is only a visual manoeuvre, I think. If you consider the need to ident the new ILS and DME and perform all the other checks then you will need to be quite a few miles out for it to work on instruments. Don't forget that many airlines' SOPs require the approach to be stable by a certain altitude and switching ILS will not comply with that.

I'm sure someone from LHR ATC will give the details on what the conditions are for a switch.

[sudden Winds]

also, in most modern airliners a safety feature will not allow you to switch ILS frequencies once below a certain height, measured by the radio altimeter, that usually coincides with the height at which the Land 3 mode is armed (for CATIII ILS), or the altitude at which the plane starts receiving information from both its Air Data computers.
In order to side step and fly the parallel ILS app. you would have to disengage the ap, re arm all the FD modes, go to heading select, choose an intercept hdg, identify the other ils freq... then arm the app mode again...it´s just not ok in my opinion.

Now side stepping to the parallel rwy is a diff thing. If the airport has 2 parallel rwys (1200 feet or less apart) then sidestep minimums can be published. They are higher than straight in minimums, but lower than circling minimums. If you´re cleared to the ILS 16L app sidestep rwy 16R, you´re supposed to initiate your sidestep maneuver as soon as you see the ldg rwy and only when/if you see the ldg rwy, which means that maneuver is 100% visual.
hope this helps.

[static]

In case of EGLL, as mentioned in the original post, it is no problem at all to switch to the other runway. In my company we are parked at Terminal 4 and we save a lot of taxitime if we can get 09R iso 09L. Sometimes ATC offers it by themselves, and as long as I`m visual and can be speed and power stabilized at 500` AGL, I will gladly accept it anytime.
Now in IMC it`s a little bit more complicated and I would accept it no later then at 8 NM final.