Night VFR flying in the UK

[alex90]

Hello!

I was wondering if anyone knew if there was a reason why all airfields I have flow to or from in the UK at night all seem to have unidirectional runway edge lighting.

I did some night flying in New Zealand recently, and they all seemed to have omnidirectional runway edge lighting which was incredibly easy to see when approaching the field, or even when in the circuit. The relative positioning was really easy and really accurate.

Last night I arrived back at Biggin from the west for the first time (normally come back from the east which I find easier), and without VOR/DME/GPS/SkyDemon/ATC I would have seriously struggled to position properly for the join. There isn't a beacon, and at least to me, no obvious lighted features for joining downwind for runway 21 in pitch black night (ie keeping parallel to the runway on downwind, rough heading checked, round xwind accounted for, M25 and Biggin Hill village are good features to look out for, but I found it hard to relate them to the exact runway heading and hence still no definite relative positioning). When coming back from the east you go over the runway, so you can check drift, relative position, more accurate headings etc...

Does anyone know why the runway edge lighting aren't always (or are they ever?) omni-directional in the UK? Is that the case in the rest of the EU too?

Does anyone have any tips other than "look for obvious lighted features", and "take up rough headings"? I am happy flying a DME arc to position to see the lights but surely it should be simpler than that?

Look forward to hearing from you all!

Best.
alex

[jollyrog]

What join were you given from the West?

I agree, it is hard to find from the West, but there's never a lot going on at night. You could request an overhead join at 2,400ft QNH then descend on the deadside for standard circuit join.

From the West, I normally aim for the VOR, then refer to the row of street lamps on Main Road, just outside the Tower, plus the apron flood lamps. The red beacon on the VOR is also a clue. New Addington is also helpful, but all of these are poo if you are given a straight in or left base for 03 from the West in the dark.

[chevvron]

Maybe that's the case at Biggin (never been there to see) but civil IFR where airfields where I have worked have edge lights which have bi-directional high intensity lenses in a 'dome' which gives a low intensity omni-directional element and VFR airfields have just low intensity omni-directional lights, both types of light being spaced at 60m intervals.
When the airfield where I worked still had a 'military' lighting system, the edge lights were high intensity uni-directional, back to back to serve both runway directions spaced every 30m with a low intensity omni directional light every 90m, the HI and LI lights being controlled separately so you could have the HIs set as per your lighting chart and the LIs on full blast for circling guidance.

[TheOddOne]

Have a look in CAP 168. You will see that the lamps are required to produce a certain intensity to a particular pattern. An Omni-directional lamp won't conform to this pattern. The requirement is so that on final, a slight misalignment of the approach will produce a slightly mis-matched intensity. When on the centreline, the intensities of each side will be equal.

We had a similar issue in the 1980s with taxiway lighting at CATIII aerodromes. Initially, these were Omni-directional fittings with switchable routes. For those of us who grubbed about on the ground, it was easy to see what routes had been selected and therefore we could avoid aircraft that had simply been instructed to 'follow the greens'. ICAO required that taxiway lights should produce a pattern viewed fore and aft, with a different spec for lamps on a curve. This made it impossible to see from a vehicle which route had been selected. I suggested drilling a hole in the side of the fitting but I think they thought I was taking the proverbial.

When I teach the night rating, I major on this difficulty in seeing the runway from an oblique angle. What I teach is to look out for other features, principally Apron lighting which usually stands out very well, even at a smaller aerodrome like Newquay. I say 'the runway is that dark linear hole in amongst all the lights'. It appears as if by magic as you turn final. BTW, the approach and PAPI lamps have similar narrow output patterns. Any Omni-directional runway lighting is probably non-ICAO compliant.

Makes for good bed-time reading, does CAP 168. Gets you off in no time!

TOO

[alex90]

What join were you given from the West?

I was given a downwind join for runway 21, nothing unusual about it. Only that I didn't see Main Road until I was right above it, which is when I became "visual" with Biggin's flood lit Southern Apron and positioned accordingly onto an estimated downwind for 21. (still of course couldn't see much of the runway lights). Had the runway edge lights been omni-directional (as where I flew in NZ) I would have been able to place myself for a normal downwind join as I would have been able to see the runway shape from quite a bit further out.

You could request an overhead join at 2,400ft QNH then descend on the deadside for standard circuit join.

- I thought about it after I realised how late I became "visual" with the field. I also considered taking up a 2mile DME arc until I became visual with the lights. I even considered doing the ILS (but then remembered that I'd be charged £50 for it...). But at uncontrolled airfields / aerodromes without VOR / DME / NDB / *proper* lighted beacon, it seems unnecessarily complex to just "see" where the runway is, don't you think? [have I just got too used to omni-directional pilot activated runway lighting with absolutely nobody around? perhaps...]

bi-directional high intensity lenses

Apologies - I assume that they are bi-directional, I meant that they were only useful from a particular angle. You say that there is a low intensity component which is omnidirectional but I am not sure I saw one. Jellyrog - you may have flown there more often than me at night, have you noticed one? When coming back from the East, I just track the VOR until I am overhead and then I can position myself accordingly by having seen the runway from above.

LIs on full blast for circling guidance

That sounds good! It'd make it easier for us few flying VFR at night.

The requirement is so that on final, a slight misalignment of the approach will produce a slightly mis-matched intensity.

Oh now... that makes a hell of a lot of sense! But then again - the military as chevvron stated seems to have the best of both worlds, visible in the circuit as well as mis-matched intensities! Clever thinking there.

I suggested drilling a hole in the side of the fitting but I think they thought I was taking the proverbial.

Haha good one! I guess that this was done in order to stop the possibility of having two vehicles / planes following the greens towards one another?

TOO - I also remember my instructor telling me the same thing when I learnt at Southend airport, although there, it was very easy to orientate oneself due to the fact that it really was "the dark bits amongst the lit" whilst at Biggin, at least from the West there are quite a few unlit bits that could very well hide a runway! haha! [although I was told a story about a student who flew a "perfect" approach, the instructor asked "do you have your features in sight?", the student replied that he did, the instructor then asked "is your DI and compass aligned?", student adjusted it a little but continued the approach, a moment later the controller asked "do you have the field in sight?", and the student replied "affirm" and continued down to 500ft when the instructor applied full throttle... He was perfectly aligned... With Southend Pier!]

I'll give CAP168 a go in a mo!

Thanks TOO, Chevvron & jollyrog - really appreciate the pointers and explanations! I think they will be invaluable in the future!