Runway restrictions at LHR 27 July 2005

[BWBriscoe]

Quote BA flight ops news:

"Passengers are advised that due to runway restrictions at London Heathrow airport today, 27 July, British Airways has cancelled a number of services."

Can anybody shed any light on this?

Due to fly with BA this evening as PAX...should it all be cleared up by then?

BWB

[Gonzo]

Problems with the concrete put down overnight meant that up until 0805 local, 09R was only available for take off with a reduced distance of 1887m from the south at S6. That meant everything had to cross from the central area, or depart 09L if they needed more length.

An early mixed mode trial!

[Del Prado]

Any idea why the concrete wasn't dry?

Not because it was raining all night I hope?

[HEATHROW DIRECTOR]

Surely nothing new? Recall the days of runways re-surfacing... the end of the new surface would be feathered off to meet the old surface.. and within 10 minutes of ops starting the feathering would break up and the runway would be closed. Now did that ever happen just once or was it six million times?

[Dave Gittins]

Just to take up the point .. concrete doesn't dry (otherwise it would shrink like mad as there is maybe 50% -70% water to cement ratio) it is a chemical reaction and it sets (gaining max strength after 28 days). Being wet all night would do it a big favour.

Concreting in hot and dry weather is usually probematic becuase it does dry and that can cause cracking at worst and a lot of surface crazing at best (which means the top flakes off).

HD ... feathering out to an edge will always give a problem. The answer is you have to cut a vertical line down the "old" so that there is some thickness to the joint. bit like taking a wedge and cutting the pointed bit off. Some people never learn.

DGG

[helen-damnation]

Quite so.
Anyone buying in the sand pit, take note :hmm: :ooh: