On 8 June, 14:57, Bruce wrote:

Please don't ask any more stupid questions. *However, in the unlikely
event that you want to ask an intelligent question, go ahead.- Hide quoted text -

- Show quoted text -

I have a question, or several. Why was Heathrow designed like that,
with six runways crossing each other in a sort of Star of David
shape? They obviously wouldn't have been able to use all of them at
the same time, was it intended that they would use two parallel ones
at any one time depending on the direction of the wind? Why were only
three of these runways ever built? When, and why did the third runway
close? What are the numbers and letters at the ends of runways? The
letter always seems to be 'L' or 'R'; the only thing I can think of is
left and right, but that would depend on which direction you were
facing. Is there any significance to the numbers, or are they just
assigned the next free number? EWR seems to have similar numbers to
LGW and LHR, so I assume it must be an international thing.

Why do airports and ex airports often seem to have been built in
clusters fairly close together. Heston, Heathrow and Northolt for
example or Waddon and Beddington (originally separated by just a road
and later merged to form Croydon), Kenley, Redhill, Biggin Hill and
even Gatwick not too far away. Again, the same thing seems to have
been the case in and around New York, Floyd Bennett Field was only
just across the bay from JFK, and Flushing was right next to
LaGuardia. I would have thould that they'd want to keep airports well
out of each others way. Indeed, this was one of the reasons given for
not re-opening Flushing, along with the fact that the runway's sinking
into the swamp.

wrote in message

On 8 June, 14:57, Bruce wrote:

Please don't ask any more stupid questions. However, in the unlikely
event that you want to ask an intelligent question, go ahead.- Hide
quoted text -

- Show quoted text -

I have a question, or several. Why was Heathrow designed like that,
with six runways crossing each other in a sort of Star of David
shape? They obviously wouldn't have been able to use all of them at
the same time, was it intended that they would use two parallel ones
at any one time depending on the direction of the wind? Why were only
three of these runways ever built? When, and why did the third runway
close? What are the numbers and letters at the ends of runways? The
letter always seems to be 'L' or 'R'; the only thing I can think of is
left and right, but that would depend on which direction you were
facing. Is there any significance to the numbers, or are they just
assigned the next free number? EWR seems to have similar numbers to
LGW and LHR, so I assume it must be an international thing.

Slow piston-engined planes are much more affected by wind than jets,
hence the need to have short runways facing in three different
directions. That was the normal layout in the 1940s, when Heathrow was
designed.

All six runways were built, but when jets arrived, three were closed,
leaving space for a much larger central terminal complex. You can still
make out vestiges of the old runways in aerial shots of Heathrow (eg,
one ran under what is now terminal 3's remote pier).

The two east/west runways were lengthened for the jets, which have much
higher take-off and landing speeds. Runway 23 finally closed in 2005,
but was seldom used in the last few years before then. It was only used
when there were strong cross winds. It's now mainly used as a taxiway,
though the southern end is also used for T4 stands.

L and R do indeed mean the left and right-hand parallel runways of a
pair (the few triple parallel runways denote the central one with a C).

The number is the magnetic compass heading. Thus, 27L is also 09R, and
27R is also 09L. These are, of course, east-west runways, which are the
typical direction in the UK because of the prevailing winds (you rarely
see a north-south runway here). The numbers are occasionally revised as
the magnetic compass drifts.

wrote in message
...
On 8 June, 14:57, Bruce wrote:

Please don't ask any more stupid questions. However, in the unlikely
event that you want to ask an intelligent question, go ahead.- Hide
quoted text -

- Show quoted text -

I have a question, or several. Why was Heathrow designed like that,
with six runways crossing each other in a sort of Star of David
shape? They obviously wouldn't have been able to use all of them at
the same time, was it intended that they would use two parallel ones
at any one time depending on the direction of the wind?

I thinks it's to do with early aircraft only being to take off safely within
about 30 degrees of a headwind. I believe most wartime airfields started by
marking out three sides of a triangle, as buildings developed around about
the basic triangle would remain in position even if the runways were
extended for heavier aircraft.

As aircraft were developed the need to take off 'very nearly into the wind'
reduced, so the number of runway directions needed at any given site would
reduce, and IMO you can see this on aerial views of many RAF airfields,
where they now use only one main runway, and others have gone out of use.

Why were only
three of these runways ever built? When, and why did the third runway
close?

I took off from Heathrow in a NNE direction shortly before closure of the
third runway, about 2001 - but everyone reckons it was very rare to use it
by then. But I think there was a short period when Heathrow did have six
runways. Basically threee pairs though as you cannot feasibly use more than
a parallel pair together? As you'll know nowadays there are many airports
that operate with one runway (albeit to/from either direction).

What are the numbers and letters at the ends of runways? The
letter always seems to be 'L' or 'R'; the only thing I can think of is
left and right, but that would depend on which direction you were
facing. Is there any significance to the numbers, or are they just
assigned the next free number? EWR seems to have similar numbers to
LGW and LHR, so I assume it must be an international thing.

Compass direction, with the 3rd number left off. So Heathrow's current
runways are 09 L and R if approaching from the west, and 27 L and R if
approaching from the east.

Why do airports and ex airports often seem to have been built in
clusters fairly close together. Heston, Heathrow and Northolt for
example or Waddon and Beddington (originally separated by just a road
and later merged to form Croydon), Kenley, Redhill, Biggin Hill and
even Gatwick not too far away.

One airfield and a few satellites. You would have all the domestic and
maintenance done at the main airfield, but if you had more aircraft than you
could scramble from your single runway, you could disperse a squadron or two
a couple of fields away and then there'd be more room for take off en masse,
and also somewhere else to land if you came back and found your main base
bombed to bits.

Paul

On 11 June, 14:05, "Recliner" wrote:

All six runways were built, but when jets arrived, three were closed,
leaving space for a much larger central terminal complex. You can still
make out vestiges of the old runways in aerial shots of Heathrow (eg,
one ran under what is now terminal 3's remote pier).

The two east/west runways were lengthened for the jets, which have much
higher take-off and landing speeds. Runway 23 finally closed in 2005,
but was seldom used in the last few years before then. It was only used
when there were strong cross winds. It's now mainly used as a taxiway,
though the southern end is also used for T4 stands.

L and R do indeed mean the left and right-hand parallel runways of a
pair (the few triple parallel runways denote the central one with a C).

The number is the magnetic compass heading. Thus, 27L is also 09R, and
27R is also 09L. These are, of course, east-west runways, which are the
typical direction in the UK because of the prevailing winds (you rarely
see a north-south runway here). *The numbers are occasionally revised as
the magnetic compass drifts.

That all makes sense, but when I look at Gatwick something confuses
me. It seems to have a second runway, 08L and 26R, to the North of
the main one. I thought Gatwick only had one runway. This one is
rather short, and the markings on it are slightly different to those
on the main runway. What is this used for?

On Fri, 11 Jun 2010 07:33:32 -0700 (PDT),
wrote:
On 11 June, 14:05, "Recliner" wrote:

All six runways were built, but when jets arrived, three were closed,
leaving space for a much larger central terminal complex. You can still
make out vestiges of the old runways in aerial shots of Heathrow (eg,
one ran under what is now terminal 3's remote pier).

The two east/west runways were lengthened for the jets, which have much
higher take-off and landing speeds. Runway 23 finally closed in 2005,
but was seldom used in the last few years before then. It was only used
when there were strong cross winds. It's now mainly used as a taxiway,
though the southern end is also used for T4 stands.

L and R do indeed mean the left and right-hand parallel runways of a
pair (the few triple parallel runways denote the central one with a C).

The number is the magnetic compass heading. Thus, 27L is also 09R, and
27R is also 09L. These are, of course, east-west runways, which are the
typical direction in the UK because of the prevailing winds (you rarely
see a north-south runway here). *The numbers are occasionally revised as
the magnetic compass drifts.

That all makes sense, but when I look at Gatwick something confuses
me. It seems to have a second runway, 08L and 26R, to the North of
the main one. I thought Gatwick only had one runway. This one is
rather short, and the markings on it are slightly different to those
on the main runway. What is this used for?


Gatwick has a taxiway that is parallel to the main runway. However,
it can be used as an emergency runway if the main runway is out of
action for any reason. It is not used as a runway under any other
circumstances. In particular, it cannot be used as a second runway
because there would be no proper taxiways and stop bars and all the
other essential features an airport needs to support two runways.

It is constructed to full runway (rather than taxiway) standards
including width, pavement strength and lighting, and has its own sets
of approach lights and VASIs (visual approach slope indicators).

There is a remote possibility that Gatwick may one day build a second
runway. However there is a restrictive covenant that was attached to
the planning permission for the second terminal, and this prevents a
second runway being built until at least 2019.

Furthermore, the current coalition government unequivocally stated
(within hours of the government being formed) that there will be no
second runway at Gatwick. Of course, that doesn't prevent the
decision being reconsidered after 2015.

"tim...." wrote in message
...


All six were built. Only three of them survived (as runways) into the
70's but the others are still there as taxiways.

The third runway ceased to be used in about the late 70s, probably because
it wasn't long enough for modern planes

Not so, it might have been out of regular use but I took off from it in
about 2001 on a flight to Glasgow or Edinburgh, so it was long enough for a
757. I can date this because my job that required regular flights to
Scotland was from early 2000 to early 2003.

Since mentioning this in an earlier post I've done a bit of googling
and I now reckon the former runway 23/05 although regularly closed for long
periods by means of 'notices to airmen' (Notams); it was not reported
permanently closed by BAA until some time after 2003, possibly as late as
2005.

Paul

On Fri, 11 Jun 2010 17:17:45 +0100, Paul Scott
wrote:
"tim...." wrote in message
...
The third runway ceased to be used in about the late 70s, probably
because it wasn't long enough for modern planes

Not so, it might have been out of regular use but I took off from it in
about 2001 on a flight to Glasgow or Edinburgh, so it was long enough
for a 757. I can date this because my job that required regular flights
to
Scotland was from early 2000 to early 2003.

FSVO modern. If what I was once told about Oslo's old airport (Fornebu) is
true, 757s were able to operate from shorter runways than the Tridents
they replaced. So the 757s may have been one of relatively few jet types
that would fit on Heathrow's short runway, and Tridents may not have been.

Colin McKenzie

--
No-one has ever proved that cycle helmets make cycling any safer at the
population level, and anyway cycling is about as safe per mile as walking.
Make an informed choice - visit www.cyclehelmets.org.

On Fri, 11 Jun 2010 22:25:06 +0100, "Colin McKenzie"
wrote:
On Fri, 11 Jun 2010 17:17:45 +0100, Paul Scott
wrote:
"tim...." wrote in message
...
The third runway ceased to be used in about the late 70s, probably
because it wasn't long enough for modern planes

Not so, it might have been out of regular use but I took off from it in
about 2001 on a flight to Glasgow or Edinburgh, so it was long enough
for a 757. I can date this because my job that required regular flights
to
Scotland was from early 2000 to early 2003.

FSVO modern. If what I was once told about Oslo's old airport (Fornebu) is
true, 757s were able to operate from shorter runways than the Tridents
they replaced. So the 757s may have been one of relatively few jet types
that would fit on Heathrow's short runway, and Tridents may not have been.


The biggest problem with the short runway was that there was no
parallel runway. Not only did take-offs and landings have to use the
one runway, but they had to be in the same direction.

It is normal practice to both take off and land into the wind. This
reduces the length of runway needed, or increases the safety factor.

With the old third runway 05/23, take off had to be into the wind as
it is more safety-critical than landing; if a landing pilot realises
he is landing too fast, or touches down too far along the runway, he
can always take off again and go around. There are no such second
chances for take-offs. ;-)

The fact that 05/23 was only about half the length of the two 09/27
runways was also a very restricting factor:

09L/27R: 3902m x 50m
09R/27L: 3658m x 45m
23: 1962m x 45m

In its final years, 05/23 was only used in one direction in order to
spare the densely populated suburbs of Harlington, Hayes and Greenford
from take-off noise, so it became runway 23. When added to its very
short length, the fact that there was no parallel runway to allow
simultaneous take-offs and landings, and the inadequacy of the
taxiways to serve it properly, this was the final blow for the third
runway and it was taken out of use.

As Paul Scott correctly says, it was some years before this was
officially made permanent.

"Bruce" wrote in message

On Fri, 11 Jun 2010 07:33:32 -0700 (PDT),
wrote:
That all makes sense, but when I look at Gatwick something confuses
me. It seems to have a second runway, 08L and 26R, to the North of
the main one. I thought Gatwick only had one runway. This one is
rather short, and the markings on it are slightly different to those
on the main runway. What is this used for?


Gatwick has a taxiway that is parallel to the main runway. However,
it can be used as an emergency runway if the main runway is out of
action for any reason. It is not used as a runway under any other
circumstances. In particular, it cannot be used as a second runway
because there would be no proper taxiways and stop bars and all the
other essential features an airport needs to support two runways.

It is constructed to full runway (rather than taxiway) standards
including width, pavement strength and lighting, and has its own sets
of approach lights and VASIs (visual approach slope indicators).

Some years ago, I was on a BA 737 that was attempting to land at LGW 08L
on a stormy night, as 08R was closed for overnight maintenance. The
pilot warned that it didn't have the same level of guidance systems as
the normal runway, so he wasn't confident that he'd be able to land. I
assume it lacked ILS then, and perhaps still does.

And, indeed, when we emerged from the clouds, the plane wasn't lined up
properly, so he had to abort the landing, and decided that the clouds
were too low to make another attempt. He duly diverted to LHR, which
would have been good news for me except that my car was parked at LGW.
It took ages for the bus to get the pax back to Gatwick, and it must
have been about three hours after our Heathrow landing before I drove
past it again on my way home.

In contrast, I have landed on LGW 26L in very poor conditions -- once, I
didn't see the ground until we touched down, as the fog and rain were so
dense -- so I assume that it is fully equipped for autoland.

So, the emergency northern (taxiway) runway is just that -- it's no
substitute for the normal main runway.

On Sat, 12 Jun 2010 11:21:47 +0100, "Recliner"
wrote:

"Bruce" wrote in message

On Fri, 11 Jun 2010 07:33:32 -0700 (PDT),
wrote:
That all makes sense, but when I look at Gatwick something confuses
me. It seems to have a second runway, 08L and 26R, to the North of
the main one. I thought Gatwick only had one runway. This one is
rather short, and the markings on it are slightly different to those
on the main runway. What is this used for?


Gatwick has a taxiway that is parallel to the main runway. However,
it can be used as an emergency runway if the main runway is out of
action for any reason. It is not used as a runway under any other
circumstances. In particular, it cannot be used as a second runway
because there would be no proper taxiways and stop bars and all the
other essential features an airport needs to support two runways.

It is constructed to full runway (rather than taxiway) standards
including width, pavement strength and lighting, and has its own sets
of approach lights and VASIs (visual approach slope indicators).

Some years ago, I was on a BA 737 that was attempting to land at LGW 08L
on a stormy night, as 08R was closed for overnight maintenance. The
pilot warned that it didn't have the same level of guidance systems as
the normal runway, so he wasn't confident that he'd be able to land. I
assume it lacked ILS then, and perhaps still does.


That's why I mentioned approach lights and VASIs, but not ILS.


And, indeed, when we emerged from the clouds, the plane wasn't lined up
properly, so he had to abort the landing, and decided that the clouds
were too low to make another attempt. He duly diverted to LHR, which
would have been good news for me except that my car was parked at LGW.
It took ages for the bus to get the pax back to Gatwick, and it must
have been about three hours after our Heathrow landing before I drove
past it again on my way home.

In contrast, I have landed on LGW 26L in very poor conditions -- once, I
didn't see the ground until we touched down, as the fog and rain were so
dense -- so I assume that it is fully equipped for autoland.

So, the emergency northern (taxiway) runway is just that -- it's no
substitute for the normal main runway.


That's why I said: "However, it can be used as an emergency runway if
the main runway is out of action for any reason. It is not used as a
runway under any other circumstances."