The truth about yet another SMH scare story about noise at Sydney Airport is a tangled tale of political caution and  knee-jerk reactions.

Before last Friday, Airservices Australia intended to introduce straight line “glide in” lower noise approaches to Sydney Airport by the end of the year, in a procedure called RNP or required navigation performance.

But on that fateful day it briefed the Sydney Airport Community Forum — set up under the auspices of the Department of Infrastructure —  on its plans, everything went pear shaped.

The one-man band of the No Aircraft Noise movement, Allan Rees, persuaded Granny that RNP could put every suburb within 15 kilometres of the airport at risk of more noise. Premier Kristina Keneally, who has stonewalled the much-needed improvement of road access to Sydney Airport through her airport adjacent electorate, agreed, and the state member for Sydney, Clover Moore, took fright while various Labor MPs,  including Carmel Tebbutt, the wife of Federal Infrastructure Minister Anthony Albanese all took flight into “no comment” land.

The facts: RNP lowers noise by reducing engine power to near idle levels as a jet descends in the most direct path possible to an airport before increasing power to normal approach settings shortly before landing, or indeed aborting the landing and going around because of reduced visibility or conflicting traffic.

However, the major noise and power  reduction coming from RNP into Sydney would be within the consultative forum, because it exists to “share” noise and oversee the diversion of traffic away from busy skyways that come together close to the airport, and fly the jets when they are still low enough to be a noise nuisance over suburbs that would never otherwise hear them.

Thus, flying straight in and straight out is the last thing stakeholders in the airport noise debate want to hear about.

Anything that might make an airport work better is clearly a threat to the whole consultative process, and comes with risks of controversy in a federal election year, as well as state members who go to the polls next March 26.

Albanese this morning said he wanted to wait until he had proof RNP would produce a lower noise outcome at Sydney. Which means he wants to wait until after late March, because there is abundant proof already that it does lower engine noise.  The engines are running at lower thrust. They make less noise.  Talk about the bleeding obvious …

Which brings us to the short political history of airport noise at Sydney Airport. Whichever side is in power in Canberra has a very strong voice in deciding just who gets more loud jets in which electorates.

RNP could, if rigorously applied, ruin the fun, but reduce jet noise over the Sydney region in aggregate. It can’t increase it because airliner movements at Sydney Airport are capped at 80 per hour except during the curfew in perpetuity.

None of the benefits in lower noise and reduced emissions from RNP survive the use of twisted flight paths designed to link up opposition electorates, or avoid intruding on the tranquillity of Kirribilli House.

Those sorts of course changes involve changes to engine thrust and multiple changes in headings, and peg the jet to specific levels, as if climbing or descending a staircase, and add a political workload to the piloting of jet airliners, which is widespread around major cities in Europe, the US and Japan.

So the chance for greener, cleaner and in total quieter skies is being put off until a federal and a state election have taken place.