LHR approach question
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LHR approach question
I live in Holloway North London and often hear and see aircraft overhead, sometimes turning west just over my house. Their altitude varies but sometimes seems very low indeed. How high would aircraft be around here and does the altitude vary with weather or anything else?
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Aircraft going into Heathrow runways 27L and 27R will make their base leg over the area that is approximately East / North London before turning for finals (or West as you say). They would at that stage be told to descend to 4,000ft or sometimes 3000ft. I'd say the aircraft flying over your way are at about 4,500-5,000 ft.
This isn't really dependant on weather.
This isn't really dependant on weather.
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As InTheAir says, Heathrow traffic will be descending to 4000ft and will not be descended lower until they are within 13 miles from touchdown on final approach - a little way to the west of you. The altitudes of the Heathrow inbounds are strictly controlled due to London City traffic and noise abatement.
Might you also have seen aircraft turning east towards London City, which is much closer and those aircraft will be much lower?
Might you also have seen aircraft turning east towards London City, which is much closer and those aircraft will be much lower?
We live almost alongside LCY. We notice that early morning heavy inbounds to Heathrow sometimes come overhead, heading south for a turn onto finals, lower and slower than at other times of the day, particularly on Sunday mornings, when LCY is closed of course. I am guessing they are bottoming out at 4,000 feet and putting the power back on. Is there a different procedure when departures from the City are not an issue ?
Just a question as to why we get woken up when so far from Heathrow (19 nm). Or why they have been descended so low so early. You notice it more in the current weather with the house windows open, of course !
Just a question as to why we get woken up when so far from Heathrow (19 nm). Or why they have been descended so low so early. You notice it more in the current weather with the house windows open, of course !
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WHBM - interesting. Guess you live north of the river. I live on the south a shade upriver from LCY. By the time the heavies get to me (Westcombe Park/Blackheath) they've usually made the turn you describe and are heading west on finals.
But it does vary a great deal. I don't think weather is a factor but stand to be corrected. We also get stuff coming from the south which seem to turn west as they approach Blackheath Common.
The first plane of the morning always wakes me up (anytime from 0430 local onwards, more usually circa 0500) but I'm a light sleeper and also the alarm is set for 0500 anyway!
On a previous thread I was told that the stuff that goes over us is at 4,000 feet because of the LCY restrictions.
But it does vary a great deal. I don't think weather is a factor but stand to be corrected. We also get stuff coming from the south which seem to turn west as they approach Blackheath Common.
The first plane of the morning always wakes me up (anytime from 0430 local onwards, more usually circa 0500) but I'm a light sleeper and also the alarm is set for 0500 anyway!
On a previous thread I was told that the stuff that goes over us is at 4,000 feet because of the LCY restrictions.
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Don't know where Holloway is, but traffic for LCY runway 10 is vectored onto a 5 mile final which usually means joining the localiser around Tower Bridge, altitude 2000'. Coming from the south, base leg usually takes the aircraft over the Houses of Parliament - spectacular view.
The normal from the south routing is direct Detling from about 10 miles out, to leave on a heading of around 300-320, then when a few miles south of the field, heading 270 and a base turn around 6 miles west of the field.
From the north its usually Lambourne, then a heading southish until a few miles north, thence a downwind to about 6 miles west.
They are very fussy about stopping the climb on departure at 3000' which I suppose ties in with LHR traffic at 4000'.
The normal from the south routing is direct Detling from about 10 miles out, to leave on a heading of around 300-320, then when a few miles south of the field, heading 270 and a base turn around 6 miles west of the field.
From the north its usually Lambourne, then a heading southish until a few miles north, thence a downwind to about 6 miles west.
They are very fussy about stopping the climb on departure at 3000' which I suppose ties in with LHR traffic at 4000'.
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<<low and slow thing in the early hours of the morning.....really slow.>>
Living that far out I'm not sure why you should be noticing a "lower" altitude because noise abatement restrictions are more stringent during the night (until 6am for where you live). What happens very early is that several flights from the far east come straight in from the Clacton direction, but they will descend initially to 6000ft, then to 4000 ft and then follow the ILS glidepath. By the time they're at 10 miles from touchdown they should be passing just over 3000 ft... but so should all other flights. The "slow" bit is puzzling too because with light traffic very early flights are usually given no speed restriction and most will keep up well over 200kts until they are past you, which is considerably faster than the approach speeds when it's busy (around 160 kts).. Any major reductions in speed would usually be because there is other traffic around.. Lastly, the first of the "curfew" flights, which mustn't land until 0601, might be slowed down so it doesn't land too early..
Living that far out I'm not sure why you should be noticing a "lower" altitude because noise abatement restrictions are more stringent during the night (until 6am for where you live). What happens very early is that several flights from the far east come straight in from the Clacton direction, but they will descend initially to 6000ft, then to 4000 ft and then follow the ILS glidepath. By the time they're at 10 miles from touchdown they should be passing just over 3000 ft... but so should all other flights. The "slow" bit is puzzling too because with light traffic very early flights are usually given no speed restriction and most will keep up well over 200kts until they are past you, which is considerably faster than the approach speeds when it's busy (around 160 kts).. Any major reductions in speed would usually be because there is other traffic around.. Lastly, the first of the "curfew" flights, which mustn't land until 0601, might be slowed down so it doesn't land too early..
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HD: I know I said it, but I didn't really mean "early hours of the morning" Sorry. It's more like 8-9am.
I've frequently seen Airbus's slowing down to near float speed on base.
I've frequently seen Airbus's slowing down to near float speed on base.
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<<I've frequently seen Airbus's slowing down to near float speed on base.>>
Not sure what you mean by "float" speed? The standard procedures call for a/c to be reduced to 180 kts airspeed on base leg, then somewhere around 160 kts airspeed on final approach (the exact speed is adjusted to determine the final approach spacing). Remember that wind has a dramatic effect on groundspeed - that's the same as the speed perceived by someone watching from the ground.
If there is a 30 kt wind from the west and an aircraft is flying downwind at 210kts airspeed, it's groundspeed will be 240kts, which will look pretty fast. If it then reduces to 180 kts as it turns north it will not suffer the same wind effect so the perceived speed will be much slower. Then when it turns on to final approach at 160kts the groundspeed will be only 130 kts, or a reduction in speed of over 100kts in just a few miles. (It's a thorough understanding of these effects, and the ability to control aircraft based upon that understanding which is the skill of a good radar controller).
Not sure what you mean by "float" speed? The standard procedures call for a/c to be reduced to 180 kts airspeed on base leg, then somewhere around 160 kts airspeed on final approach (the exact speed is adjusted to determine the final approach spacing). Remember that wind has a dramatic effect on groundspeed - that's the same as the speed perceived by someone watching from the ground.
If there is a 30 kt wind from the west and an aircraft is flying downwind at 210kts airspeed, it's groundspeed will be 240kts, which will look pretty fast. If it then reduces to 180 kts as it turns north it will not suffer the same wind effect so the perceived speed will be much slower. Then when it turns on to final approach at 160kts the groundspeed will be only 130 kts, or a reduction in speed of over 100kts in just a few miles. (It's a thorough understanding of these effects, and the ability to control aircraft based upon that understanding which is the skill of a good radar controller).
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Hi all
Reference the "low and slow" thing, as you may or may not have seen discussed in various places around here, LHR has a noise policy requiring inbound aircraft to make "continous descent" approaches, that both pilots and ATC must operate to.
I guess it can be simplified as such:
Cuts down on the noise so I'm told.
Reference the "low and slow" thing, as you may or may not have seen discussed in various places around here, LHR has a noise policy requiring inbound aircraft to make "continous descent" approaches, that both pilots and ATC must operate to.
I guess it can be simplified as such:
"... a descent will be deemed to be continuous provided that no segment of flight longer than 2.5nm occurs below 6000' and level flight is interpreted as any segment of flight having a height change of not more than 50ft over a track distance of 2nm or more."
Well, our experience, described above, is early, like about 06.00. And our location (Beckton, by LCY), has the traffic sometimes coming over notably different to the rest of the day, which of course we are used to. In fact as I write this (11.30 local) traffic is passing overhead nicely, higher and faster, and almost inaudibly.
So I wonder if Heathrow Director has identified the issue, that it is traffic which is being restricted to get in right after the 06.00 curfew. It must make for a distinct rush hour at that time, especially if there have been unexpected transatlantic tailwinds overnight, and I wonder if there are speed restrictions given just to make the timeslot. Certainly looking up at the 747s they seem to have visibly more flap out (hence why we feel correct about the "slow" comment) on right base compared to later in the day.
I also know that simultaneous parallel landings are done between 06.00 and 07.00, but don't know if this requires any accurate speed control so the approaching aircraft are staggered - another question for you guys who handle it.
So I wonder if Heathrow Director has identified the issue, that it is traffic which is being restricted to get in right after the 06.00 curfew. It must make for a distinct rush hour at that time, especially if there have been unexpected transatlantic tailwinds overnight, and I wonder if there are speed restrictions given just to make the timeslot. Certainly looking up at the 747s they seem to have visibly more flap out (hence why we feel correct about the "slow" comment) on right base compared to later in the day.
I also know that simultaneous parallel landings are done between 06.00 and 07.00, but don't know if this requires any accurate speed control so the approaching aircraft are staggered - another question for you guys who handle it.
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Came in on the BA18 from Singapore last week.
Left Lambourne at 6am for the approach into 27L. Must say i have never experienced an approach like it. The spoilers were fully applied until probably the point of hitting the GS, so i guess we must have been at a high speed all the way down. Also we seemed to turn onto final approach quite far West, just past Regents Park.
Whoever says flying is like driving a bus are seriously wrong as the whole operation seemed to require some serious skill.
Left Lambourne at 6am for the approach into 27L. Must say i have never experienced an approach like it. The spoilers were fully applied until probably the point of hitting the GS, so i guess we must have been at a high speed all the way down. Also we seemed to turn onto final approach quite far West, just past Regents Park.
Whoever says flying is like driving a bus are seriously wrong as the whole operation seemed to require some serious skill.
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Reference the parallel approaches, as the runways at Heathrow aren't far enough "apart", controllers are required to provide standard separation between aircraft making approaches to the different runways. Basically this equates to aircraft following on the same runway being 6 miles in trail (as opposed to the standard 4 miles required between heavies for wake turbulence), and the arrivals on the other runway spaced the same "in the gaps", giving 3 miles separation between the aircraft on the parallel. Increases the landing rate quite significantly.
This can be reduced if the drivers of one aircraft can see (and will be able to see for the whole approach) the aircraft they are "following" on the other runway. Used to be handy if required when Concorde came in (usually ot that time of the morning
) and as it was faster on final, it could "overtake" traffic on the other runway. Ideally when using both runways like that, T4 arrivals (BA, QANTAS etc...) are put on the south runway.
It is easier for the final director to have a long final at that time of the morning, as it alows for more flexibility in using vertical separation (1000 feet) to establish the jets on final, especially if there is an arrival coming from the south stacks to land on the north runway.
It can make for a "3, 2, 1 right start vectoring for approaches" situation. Aircraft that arrive before the curfew lifts do enter the hold, and it's not uncommon to have full stacks at 5:45. If the airport is in Low Visibility Procedures (fog etc), the curfew as such is suspended and aircraft can make approaches as they arrive.
This can be reduced if the drivers of one aircraft can see (and will be able to see for the whole approach) the aircraft they are "following" on the other runway. Used to be handy if required when Concorde came in (usually ot that time of the morning
) and as it was faster on final, it could "overtake" traffic on the other runway. Ideally when using both runways like that, T4 arrivals (BA, QANTAS etc...) are put on the south runway.It is easier for the final director to have a long final at that time of the morning, as it alows for more flexibility in using vertical separation (1000 feet) to establish the jets on final, especially if there is an arrival coming from the south stacks to land on the north runway.
It must make for a distinct rush hour at that time, especially if there have been unexpected transatlantic tailwinds overnight
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Hmmmm, I wonder how a heavyweight 744 handles a 160 kts approach speed when flaps 30 requires ~165 kts and flaps 25 is around 172 kts. If they are making them fly flaps 30 to keep them slow, the noise difference between flaps 30 and 25 is substantial. flaps 25 should always be the noise abatement approach flap. 
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<<So I wonder if Heathrow Director has identified the issue, that it is traffic which is being restricted to get in right after the 06.00 curfew. >>
OK.. what happens is that the vast majority of inbound traffic is descended to 4000ft - except those on a straight in approach will go down to 6000 ft outside 20 miles, then down to 4. Inside 13 miles, or inside a 10nm radius of the airfield they can go straight down to 3000 ft. Prior to 6am ALL traffic must join the final approach track no closer than 10nm from touchdown. The very early flights probably will not be speed restricted by ATC so they do their own thing - some will fly very fast and some will reduce speed quite quickly. Of course, if several arrive at once then speed control will be applied to separate them.
As my ex-colleague suggests, from 6am everything hits the fan and, because of the requirement for accurate spacing on final approach, ATC will apply speed control - usually around 160 kts - from the time the a/c is on final. Depending on traffic this can be anything from 8 to 20 miles from touchdown. The altitude of aircraft on the approach over your part of London should always be roughly the same - some may be a little higher, but none much below 4000 ft. Occasionally when LCY is closed Heathrow ATC will descend inbound traffic directly to 3000 ft, but this is usually only when that traffic will be joining final approach around 10 miles out. Beyond that they normally go down to 4 to start with.
During most of the rest of day aircraft on final approach will be flown at speeds specified by ATC as accurate spacing is essential a) for safety and b) to maintain the very high landing rate demanded by the airlines and airport authority.
OK.. what happens is that the vast majority of inbound traffic is descended to 4000ft - except those on a straight in approach will go down to 6000 ft outside 20 miles, then down to 4. Inside 13 miles, or inside a 10nm radius of the airfield they can go straight down to 3000 ft. Prior to 6am ALL traffic must join the final approach track no closer than 10nm from touchdown. The very early flights probably will not be speed restricted by ATC so they do their own thing - some will fly very fast and some will reduce speed quite quickly. Of course, if several arrive at once then speed control will be applied to separate them.
As my ex-colleague suggests, from 6am everything hits the fan and, because of the requirement for accurate spacing on final approach, ATC will apply speed control - usually around 160 kts - from the time the a/c is on final. Depending on traffic this can be anything from 8 to 20 miles from touchdown. The altitude of aircraft on the approach over your part of London should always be roughly the same - some may be a little higher, but none much below 4000 ft. Occasionally when LCY is closed Heathrow ATC will descend inbound traffic directly to 3000 ft, but this is usually only when that traffic will be joining final approach around 10 miles out. Beyond that they normally go down to 4 to start with.
During most of the rest of day aircraft on final approach will be flown at speeds specified by ATC as accurate spacing is essential a) for safety and b) to maintain the very high landing rate demanded by the airlines and airport authority.
Thanks for all the informed comments everybody. A last question - whereabouts does the 06.00 deadline apply ? Is it touchdown ? At some 20 nm track here we're about 7 minutes from touchdown which would make 05.53 a key time for someone who needs to just miss the curfew. Or are things not that tight ?
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<<whereabouts does the 06.00 deadline apply ? Is it touchdown ? At some 20 nm track here we're about 7 minutes from touchdown which would make 05.53 a key time for someone who needs to just miss the curfew. Or are things not that tight ?>>
Things are very tight as the airport authority penalises any airline breaking the rules. The deadline applies at touchdown. However, because of some quirk with the way time is measured by ATC and the airport authority, the earliest time for landing is 0601. The actual time the first lands is dependent on the skill of the radar controllers who have to take into account the wind and other factors to determine the speed of the a/c, etc. They don't often get it wrong!
Regarding height over Isleworth.. you appear to be just over 4 miles out so the height would be just under 1300 feet.... it's actually 318 feet per nautical mile so you can calculate it exactly!
Things are very tight as the airport authority penalises any airline breaking the rules. The deadline applies at touchdown. However, because of some quirk with the way time is measured by ATC and the airport authority, the earliest time for landing is 0601. The actual time the first lands is dependent on the skill of the radar controllers who have to take into account the wind and other factors to determine the speed of the a/c, etc. They don't often get it wrong!
Regarding height over Isleworth.. you appear to be just over 4 miles out so the height would be just under 1300 feet.... it's actually 318 feet per nautical mile so you can calculate it exactly!