Heathrow believes government 'mood music' in favour of third runway
0.2 degrees is not very much. Unless you are talking about the angle of descent an aircraft makes when approaching Heathrow.
Every 0.1 of a degree of elevation slightly reduces the noise for the hundreds of thousands of people who live directly under the flight path.
And that means the noise pollution they suffer is marginally lower.
At present, aircraft fly into Heathrow at a 3 degree angle - relatively shallow.
The airport is trialling a steeper 3.2 degrees, arguing that such a change is one of the many they can offer the government, which will shortly make an announcement on airport expansion and the toxic issue of a third runway at Heathrow.
Senior sources at the company that runs the airport tell me that the "mood music" around the decision is positive as far as those who want to see Heathrow expanded are concerned.
And certainly today's Daily Telegraph - Go-ahead for Heathrow expected in days - has done little to dampen expectations.
The Cabinet sub-committee set up to formulate the government response to Sir Howard Davies' recommendation that a third runway should be built meets tomorrow.
Prominent among its membership are George Osborne, the Chancellor, and Sajid Javid, the Secretary of State for Business.
Both are sympathetic to the case for Heathrow.
Whatever the decision of that committee - and I understand detailed discussions about the environmental impact assessments undertaken by Sir Howard's Airports Commission could delay any announcement - the final call will be made by the Prime Minister.
David Cameron knows that if he backs expansion, his 2009 statement "the third runway at Heathrow is not going ahead, no ifs, no buts" will be thrown back at him.
I understand his defence - if he needs it - will be two-fold.
First, that the third runway on the table at that time - a shorter option backed by the then Labour government - has been superseded by a better plan, a longer runway further to the west.
And second, that the pledge was made for the last Parliament, ie was only for the period 2010-2015.
Number 10 sources do agree, though, that Mr Cameron will face accusations that he is not a man of his word if he backs expansion.
Supporters of Heathrow believe that despite some possible political damage to the PM, the case for Heathrow is strong enough to carry the Cabinet.
The airport is also doing what a basketball coach would call a "full court press" to try and persuade those sceptical about Heathrow expansion on environmental and noise grounds.
Some opponents, like the Conservative mayoral candidate for London, Zac Goldsmith, and the present London mayor, Boris Johnson, will not move.
And Gatwick Airport, which also wants to expand, has made a strong case that Heathrow will simply not hit the environmental targets that have been set.
It also claims Sir Howard's methodology is flawed.
Rather than trying to persuade the unpersuadable, Heathrow has engaged directly with the Department for Transport (DfT) (which is running the Heathrow process), business groups and politicians who it believes are open to pro-Heathrow arguments, such as the Scottish Nationalist Party parliamentary party.
I am told it has made a number of pledges to the Director General of Major Projects at the DfT.
These include looking positively at the angle of decent issue; that the airport will hit environmental targets, on for example public transport, to enable Britain to meet its European Union (EU) obligations and backing an independent aviation noise authority to adjudicate on disputes.
John Holland-Kaye, the chief executive of Heathrow, has gone as far as meeting the head of the Australian equivalent, which I understand he believes "works well".
Newer, quieter planes, a £1bn compensation fund for local people affected by noise and an agreement to pay the market rate plus 25% for any houses lost to expansion completes the offer from Heathrow.
Mr Holland-Kaye knows that however much Heathrow puts on the table there will still be heavy-weight arguments against expansion.
And Heathrow has as yet not made any pledges on Sir Howard's recommendation that all night flights are banned between 11.30pm and 6am. At present the airport says it wants a "review" of the night flights issue.
Whenever the decision does come, before Christmas or early in the New Year, the airports expansion announcement will be controversial and, for David Cameron, there is political risk.
But Heathrow, at least, believes that the "mood music" is playing positively for a third runway.