Missed Approach Track
A key part of our proposal hinges on the missed approach for the South Runway. The technical aspects of the missed approach paths is clouding the real issue. The net result of changing the approach path of the South Runway to allow the quieter departures from the North Runway. Residents will have no grievance, this will open the door for increased departures from the runway. Quality of life for the vast number of residents will be greatly improved. While it is a technical nerdy issue, it is the key to fixing the majority of the noise problem that changing the departure track has created.
So what is a Missed Approach?
The missed approach is just another track or flight path. When an aircraft is on approach to land on a runway there are some circumstances when they can’t complete the landing. This is call a go around or a missed approach. The most common reason is poor visibility during an instrument approach through cloud, fog, rain, etc. At the missed approach point (shown on the approach chart) the pilot must be able to see the runway clearly enough to land. If they can’t they must “go missed” and fly the published missed approach track.
Unexpectedly Overflown
The DAA accepts that the final regulatory safety review at the end of the design, planning, development and construction process was the point at which they discovered their intended departure track was going to need work. They had planned for all aricraft to climb straight-ahead for 5 nautical miles. All of the noise studies, measurement equipment and the original planning consultation was built around a straight ahead departure. In 2016, DAA did a consultation regarding a 15 degree turn off the North Runway to allow dual departure operations, but even then the 30 degree problem never came up.
Operating two parallel runways has some extra requirements compared to operating a single runway. One of those requirements is that simultaneously landing aircraft on one while departing them on the other is only allowed: if the departure course diverges immediately after take-off by at least 30 degrees from the missed approach track of the adjacent approach until other separation is applied.
In our case there must be 30 degree divergence between aircraft departing from (the north runway) 28R while aircraft are landing on 28L (the old runway). DAA appear to have read this quite literally and therefore they require all departing aircraft from 28R to turn 30 degrees to the north. This put them in breach of their planning permission for 100% of departures from the North Runway, they describe the 30,000 people in their way as “Unexpectedly Overflown”.
There is another way to create this divergence and that is of course to have the missed approach for 28L turn 30 degrees left (south) at the end of the runway. That way the original straight out departure would work fine for 28R.
Yeah but ...
“That says the departure course must turn.”
While it might seem that way, in practice that’s not correct. There are other international airports with exactly this scenario where the departures fly straight out and the parallel missed approach turns away at least 30 degrees. The closest of these to us you may have heard of: London Heathrow. In fact you don’t need to look that far. When the wind is from the east the aircraft take off the other way on the original south runway 10R. They climb straight ahead and don’t turn until over the Irish Sea. The missed approach for runway 10L turns 30 degrees left 1 mile after then end of the runway.
But aren’t you just pawning the problem off onto other “higher density” neighborhoods?
Dublin Airport averages upwards of 350 departures per day; most, although not all, depart the North Runway. It also averages 1 missed approach per day. Most missed approaches occur during bad weather when it is unlikely many people are in their garden trying to have a barbecue so the level of disturbance between the two is not comparable. They are already flying at least 130 knots at the start of the runway while already 200+ ft in the air so they get to altitude much quicker. They are also only climbing to 3000ft or 4000ft at which point they level off and reduce engine power which makes them much quieter.
There is already an established missed approach procedure from Dublin Airport Runway 10R that overflies the exact same residential area. The missed approach from Runway 16 flys straight out over South Dublin.
“Any decision on amended missed approach procedures from the South Runway would require multi-stakeholder discussion and agreement (daa, IAA, AirNav Ireland, ANCA, Irish Air Corps, Weston, GASU etc)”
In reality the missed approach change we propose does not enter Weston or Military airspace. Weston’s airspace stops at 2000ft and the Baldonnel military airspace R15, stops at 3000ft. Every aircraft that operates out of DUB can fly this missed approach using 50% of its capability; we know this because the proposed track has already been flown for every type by commercial pilots in the training simulators.