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I live in North London. It's not like we don't have a fair amount of noise pollution from the sky, with helicopters, and jets landing at LHR with a stupidly shallow glide path angle.

But in addition, quite often on a Sunday afternoon I hear this buzzing of a small propeller plane. It often seems to circle the area quite a few times before eventually going away. We had one today: I looked at it, and (this time) it was a small plane with two props, one on each wing. I have no idea what type of aircraft it might have been. It was flying low enough for the buzzing to be distinctly intrusive, and therefore affecting potentially tens of thousands of people.

It may not have been a flight simply for fun. I presume there's no way of finding out... but does anyone know what the rules are for just randomly deciding to fly over a built-up area like this for the fun of it?

PS I have friends in Cambridge and you often see small light planes overflying that town. They have a friend who owns a light aircraft, and once or twice my friends have said "oh, yes, that's Jim's plane", and have confirmed he does it for recreation.

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  • $\begingroup$ Thanks... that appears to be a site for tracking large jets landing at LHR. I'm aware of such information but my questions not about large jets. $\endgroup$ – mike rodent Oct 8 '17 at 14:13
  • $\begingroup$ @mins OK... thanks... well I had a look again. I haven't quite worked out how to "go back in time" with that map thing. Secondly, this aircraft I saw earlier circled around locally quite a few times, and I've no particular reason to think that its destination or origin was LHR, or even any big airport. But I'll give it a few more minutes trying to work out whether it's there... $\endgroup$ – mike rodent Oct 8 '17 at 15:32
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    $\begingroup$ Can you give a specific time when you heard this plane? And as to jets landing at LHR with a stupidly shallow glide path angle None of the glide path angles at LHR are less than the standard 3°. In fact some of them require an angle as high as 5.24°. The only one I’ve ever heard of that’s higher is 5.5° at LCY. $\endgroup$ – TomMcW Oct 8 '17 at 18:50
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    $\begingroup$ If it's a twin then it's very possibly a traffic spotting flight out of Stapleford, they overfly traffic hot-spots and report them to radio news stations. $\endgroup$ – GdD Oct 9 '17 at 6:40
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    $\begingroup$ @mins - your SERA comment is the correct answer, you should write it up $\endgroup$ – Dave Gremlin Oct 10 '17 at 8:32
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Does anyone know what the rules are for just randomly deciding to fly over a built-up area like this for the fun of it?

In UK, the master document for air regulations is The Rules of the Air Regulations (ROTAR). UK being still part of the EU, they refer to a common set of rules at the EU level, the Standardised European Rules of the Air aka SERA (qui sera sera...)

UK ROTAR state a minimum flyover height, one for VFR, one for IFR:

The minimum heights for VFR flights shall be those specified in SERA.5005(f) and minimum levels for IFR flights shall be those specified in SERA.5015(b)

and SERA says:

SERA.5005:

(f) Except when necessary for take-off or landing, or except by permission from the competent authority, a VFR flight shall not be flown:

  • (1) over the congested areas of cities, towns or settlements or over an open-air assembly of persons at a height less than 300 m (1 000 ft) above the highest obstacle within a radius of 600 m from the aircraft;

  • (2) elsewhere than as specified in (1), at a height less than 150 m (500 ft) above the ground or water, or 150 m (500 ft) above the highest obstacle within a radius of 150 m (500 ft) from the aircraft.

So for VFR: 150 m, but 300 m in populated areas.

SERA.5015:

  • (2) elsewhere than as specified in (1), at a level which is at least 300 m (1 000 ft) above the highest obstacle located within 8 km of the estimated position of the aircraft.

And for IFR: 300 m above obstacles.

As you see this is not very high. In addition, as you mentioned, aircraft landing or taking off will indeed fly below these minimums.

Jets landing at LHR with a stupidly shallow glide path angle

Landing cannot be done at high angle, the proper slope is the result of two elements:

  • Aircraft cannot afford a high descent speed, since the vertical rate determines how hard the landing gears will touch the runway and whether they will be damaged.

  • Aircraft cannot slow down under a given speed without losing their capability to create lift. This minimum speed and the previous maximum vertical speed determine a maximum slope.

This glide slope has been chosen so that it is compatible with all sorts of aircraft approach speeds and vertical rates.

A standardized value of 3° is common. But when the approach area is limited, or when this is desirable to maintain a higher altitude a longer time to reduce noise on the ground, then this angle can be increased to 3.5 or 4.5°, or even 5.5°, this is the case for some approaches at Heathrow as @TomMcW told us.

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Source

Alternatively, some airports have lower angles, down to 2.5°.

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  • $\begingroup$ Thanks, that's very interesting. I'm absolutely amazed that, seemingly, anyone can just choose to fly over an area like North London any time, and indeed I'm surprised there aren't more recreational flights if that's the case... are you sure there's nothing else to prevent this activity? Surely they can't do it at night, etc.? $\endgroup$ – mike rodent Oct 10 '17 at 18:37
  • $\begingroup$ Re glide paths to LHR. This is the bane of my life and I am not alone. I have learnt more than I need to about the murky politics of this and the point about me is that I live 15 miles ("as the plane lands") from touchdown at LHR. The sine of 3 deg is 0.0523 which therefore means planes should be 0.79 miles above my house minimum. I claim that this is NOT THE CASE. BAA and CAA have for decades indulged in this fiction according to which noise from jets landing at LHR only "significantly" affects a couple of miles around the airport. NONSENSE. $\endgroup$ – mike rodent Oct 10 '17 at 18:40
  • $\begingroup$ More on the politics: BAA/CAA cannot ever admit the reality about noise pollution from jets landing at LHR, because that would then mean there would have to be serious efforts and regulations to "share the misery" evenly over the whole of the "catchment" area for LHR. For this reason planes are still concentrated into "corridors" in arbitrary fashion, and moreover those corridors could be changed at any time. Only a Third World country would tolerate the amount of noise pollution which Londoners routinely take for granted. $\endgroup$ – mike rodent Oct 10 '17 at 18:44
  • $\begingroup$ @mikerodent: Yes this can be done at night, unless there is a curfew. But I believe curfews are for airport landing/takeoff, not for just flying around. This can even be done under "VFR at night" rules (no specific navigation instrument required). If you ask me, yes this is abusive. $\endgroup$ – mins Oct 10 '17 at 18:46
  • $\begingroup$ Yes, and it's not just the noise... VFR, in such a congested airspace as London, with innumerable helicopters, etc. As I say this appearance of a light plane is very infrequent currently, but if this ever changed I would be seriously concerned about the possible consequences of a crash in such a densely populated area. I'm pretty astonished. $\endgroup$ – mike rodent Oct 10 '17 at 19:01

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