"Bruce" wrote in message

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.

My experience was some years ago -- do you know if it's any better now?




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."

Yes, I was agreeimng with you.

On Sat, 12 Jun 2010 13:28:34 +0100, "Recliner"
wrote:
"Bruce" wrote

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

My experience was some years ago -- do you know if it's any better now?


It hasn't changed, except that the VASIs (visual approach slope
indicators) on both runways have been upgraded to PAPIs (precision
approach path indicators). Both are purely visual aids working on
similar optical principles using polarised light, and are sensitive to
cloud conditions. VASIs give an up/down indication of whether the
aircraft is on the correct glide path. PAPIs give up/down and also
left/right indications. But if you cannot see them because of thick
cloud, they are useless.

From Wikipedia:
"The main runway operates with a Category III Instrument Landing
System. The northern runway does not have an Instrument Landing System
and, when it is in use, arriving aircraft use a combination of
Distance Measuring Equipment and assistance from the approach
controller using surveillance radar, or where equipped and subject to
operator approval, an RNAV (GNSS) Approach, which is also available
for the main runway. On all runways, considerable use is made of
continuous descent approach to minimise environmental effects of
incoming aircraft, particularly at night."

RNAV (GNSS) is a navigation system, usually GPS based, that aims to
get the aircraft to a point where VASIs or PAPIs can be used for the
landing. It is very inferior to ILS which can put the plane on the
runway with a high degree of safety.

The last sentence refers to a higher altitude approach which means
pilots have to lose height rapidly to regain the traditional glide
path on final approach. The intention is to keep noise pollution to a
minimum in towns under the flight path. It is like the noise
abatement principle used for take-offs, but in reverse. It is used
routinely, and not just at night.

Bruce wrote on 12 June 2010 14:19:38 ...

From Wikipedia: [re Gatwick]
"The main runway operates with a Category III Instrument Landing
System. The northern runway does not have an Instrument Landing System
and, when it is in use, arriving aircraft use a combination of
Distance Measuring Equipment and assistance from the approach
controller using surveillance radar, or where equipped and subject to
operator approval, an RNAV (GNSS) Approach, which is also available
for the main runway. On all runways, considerable use is made of
continuous descent approach to minimise environmental effects of
incoming aircraft, particularly at night."
....

The last sentence refers to a higher altitude approach which means
pilots have to lose height rapidly to regain the traditional glide
path on final approach.

That's a misleading description, as a conventional approach in which an
aircraft is directed to fly successively at a number of different
altitudes in level flight is more likely to involve rapid descents from
one level to the next. With CDA, the aim is to allow an aircraft to
descend continuously at 3 degrees, with consequent benefits to fuel burn
and noise. For Heathrow and Gatwick, CDA applies from leaving the
holding stack at about 7000 ft and typically 25 miles from the airport.

See "Basic Principles of the Continuous Descent Approach (CDA) for the
Non-Aviation Community" at
http://www.caa.co.uk/docs/68/Basic_Principles_CDA.pdf
--
Richard J.
(to email me, swap 'uk' and 'yon' in address)

On Sat, 12 Jun 2010 16:40:22 +0100, "Richard J."
wrote:
Bruce wrote on 12 June 2010 14:19:38 ...
From Wikipedia: [re Gatwick]
"The main runway operates with a Category III Instrument Landing
System. The northern runway does not have an Instrument Landing System
and, when it is in use, arriving aircraft use a combination of
Distance Measuring Equipment and assistance from the approach
controller using surveillance radar, or where equipped and subject to
operator approval, an RNAV (GNSS) Approach, which is also available
for the main runway. On all runways, considerable use is made of
continuous descent approach to minimise environmental effects of
incoming aircraft, particularly at night."
....

The last sentence refers to a higher altitude approach which means
pilots have to lose height rapidly to regain the traditional glide
path on final approach.

That's a misleading description, as a conventional approach in which an
aircraft is directed to fly successively at a number of different
altitudes in level flight is more likely to involve rapid descents from
one level to the next. With CDA, the aim is to allow an aircraft to
descend continuously at 3 degrees, with consequent benefits to fuel burn
and noise. For Heathrow and Gatwick, CDA applies from leaving the
holding stack at about 7000 ft and typically 25 miles from the airport.

See "Basic Principles of the Continuous Descent Approach (CDA) for the
Non-Aviation Community" at
http://www.caa.co.uk/docs/68/Basic_Principles_CDA.pdf


Thanks, Richard.

It wasn't a misleading description, it was just plain wrong. So thank
you for being so polite. ;-)

On 9 June, 08:37, Roland Perry wrote:

London's Second airport, which just grew there by accident. Stansted,
being the official "Third airport" was the result of extensive public
enquiries etc, to satisfy the need for more capacity for London.

Just like the third runway at Heathrow is/was at the moment.

So what about Luton? It came to be known in the '70s and '80s as the
home of charter flights for cheap holidays in Spain etc., but what
were its origins?

I can't help wondering if the move from Gatwick to Heathrow by
Continental a couple of years ago was related to the forced sale of
Gatwick by BAA. Are BAA offering some sort of incentive to airlines
to move to the airports which it will continue to own? It would make
sense from their point of view to expand Heathrow as much as
possible. I've only flown once sine the move, and having to go to
Heathrow is a real pain for me.

I know that when the new terminal was built at Stanstead enough land
was available to allow it to be expanded to about twice its original
size. Is there scope to increase the capacity of that airport? If
two very short sections of railway hadn't closed then trains could
have run directly to Stanstead from both Luton, or at least the
airport parkway station, and Gatwick for those with connecting flights
from other airports. Luton would still be possible, but Gatwick
wouldn't.

Heathrow is still horrible to get to. The Underground takes ages, and
doesn't really have the space for luggage. The Express is expensive,
and only goes to Paddington, as do the Connect trains. Neither of
these services serve all terminals. The express Airbus routes from
central London no longer run, the X26 From Croydon does, but doesn't
serve 4 or 5, and the fare on the Underground from Hatton Cross to 4
is more than that on the bus all the way from Croydon. I'm not sure
which other bus/coach services still operate to Heathrow. Heathrow is
already too spread out, needing to take a train between termini rather
than the typical airport transit thing found elsewhere, but of course,
if you spread the flights out to other airports then you make this
even worse. I don't know what the answer is, other than to travel
less, as we used to.

In message
,
writes

So what about Luton? It came to be known in the '70s and '80s as the
home of charter flights for cheap holidays in Spain etc., but what
were its origins?

It was opened in 1938 and used as an RAF fighter base in WW2. Charter
flights started in the 1950s but only became big business in the 1970s,
when air travel became relatively cheaper.

I can't help wondering if the move from Gatwick to Heathrow by
Continental a couple of years ago was related to the forced sale of
Gatwick by BAA. Are BAA offering some sort of incentive to airlines
to move to the airports which it will continue to own?

No, Continental had always set its sights on Heathrow, but were
forbidden from using it by the Bermuda II agreement. As soon as that
agreement came to an end in 2008, and free open competition became
possible, they seized the opportunity to move to Heathrow.
--
Paul Terry

wrote in message
...
On 9 June, 08:37, Roland Perry wrote:

London's Second airport, which just grew there by accident. Stansted,
being the official "Third airport" was the result of extensive public
enquiries etc, to satisfy the need for more capacity for London.

Just like the third runway at Heathrow is/was at the moment.

So what about Luton? It came to be known in the '70s and '80s as the
home of charter flights for cheap holidays in Spain etc., but what
were its origins?

I can't help wondering if the move from Gatwick to Heathrow by
Continental a couple of years ago was related to the forced sale of
Gatwick by BAA. Are BAA offering some sort of incentive to airlines
to move to the airports which it will continue to own?

It's not allowed to

If an airport wants to make special offers (which will usually be for the
first xx months of a route's operation) it must make the same offer
available to any airline.

tim

In message
, at
02:56:27 on Sun, 13 Jun 2010, remarked:
I can't help wondering if the move from Gatwick to Heathrow by
Continental a couple of years ago was related to the forced sale of
Gatwick by BAA.

It's because the "Open Skies" policy plus continued retrenchment by BA
made everyone decide that Heathrow was "the" place to be for
transatlantic flights.
--
Roland Perry

In message , Bruce
wrote:
It hasn't changed, except that the VASIs (visual approach slope
indicators) on both runways have been upgraded to PAPIs (precision
approach path indicators). Both are purely visual aids working on
similar optical principles using polarised light, and are sensitive to
cloud conditions.

They aren't polarized; they simply involve lights shining above or below
an aligned plate.

VASIs give an up/down indication of whether the
aircraft is on the correct glide path. PAPIs give up/down and also
left/right indications.

I don't believe PAPIs give sideways indications; they just give a better
indication of the actual slope.

As I understand it, VASIs consist of two sets of lights which show red
below the glide path angle and white above it. So if you're on the
correct path, you see red over white. PAPIs, on the other hand, consist
of one set of four lights but each light is set at a different angle. So
the number of white lights indicates what angle you're at - the correct
angle is shown by two reds and two whites.

--
Clive D.W. Feather | Home:
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