"James Farrar" wrote in message

On Sat, 08 Sep 2007 10:50:00 -0700, Jon
wrote:

On 8 Sep, 10:35, "dB" wrote:
I once heard that a building either at or near Croydon Airport
has the word NO written on so as to advise pilots that they are
not approaching Gatwick.

There used to be a gasholder at South Harrow with NO painted on the
side to indicate that it was near Northolt airfield and not on the
approach to Heathrow.

That was done after someone tried to land a 747 at Northolt.

The gasholder still standing in Southall has an arrow and 'LH' marked
on it for the same reason. ISTR being told someone did land a 707 at
Northolt by mistake in the 1970's, and it had to be stripped of all
non-essential components to make it light enough to take off again
safely.

It was a PanAm 707 in October 1960. The racket must have startled the
residents of Harow-on-the-Hill and Harrow school, which is right under
the flight path.


http://www.abpic.co.uk/photo/1001607 and
http://www.thirdamendment.com/wrongway.html refer to this incident in
October 1960.

Wikipedia's page on [[RAF Northolt]] states "In days before such
navigational aides as instrument landing system (ILS) and the global
positioning system (GPS), the letters NO (for Northolt) and HR (for
Heathrow) were painted on two gasometers situated on the approach to
each airfield, one at Southall for the approach into Heathrow and one
at South Harrow for the approach to Northolt in an effort to prevent
recurrence of such errors." - this seems to imply that they're no
longer there, and certainly I cannot find any evidence from a quick
Google Maps search.

I don't know about Southall, but the Northolt gas holder is long gone,
to be replaced by a small retail park with three large stores:
http://maps.google.co.uk/maps?hl=en&...8476&z=17&om=1

Sadly, they don't have any helpful messages for passing pilots painted
on their roofs.

That's the Piccadilly line passing on the left, and you can still see
the remains of the old freight branch pointing at what is now a Waitrose
store.