TL;DR – There are just no good reasons to disagree to the ILS.

Singapore will be using an Instrument Landing System (ILS) to guide planes to land in Seletar Airport. It’s a system that helps planes land safely and smoothly even in low visibility.

Malaysia disagrees with the use of the ILS. Malaysian Transport Minister Anthony Loke released a video explaining why. One of the claims is that the ILS will prevent Malaysia from constructing buildings taller than 54m at a distance of 3km away from Seletar Airport. That means the buildings in that area cannot be taller than 18 storeys.

When I saw that, I thought that Malaysia might have a point. After all, one of the main reasons for Singapore to relocate Paya Lebar Airbase is to allow us to build taller buildings in the Paya Lebar area, thereby unlocking greater value from the land. So if we are doing that, how can we stop other countries from doing something like that in their own country?

But hey, Minister Loke based height restrictions on the wrong thing…

It turns out, that the nice video released by Minister Loke is wrong.

The figures that appeared in the Malaysian video are derived on the basis that the area near Seletar airport is an “object limitation surface” (OLS). According to the International Civil Aviation Organisation (ICAO), this basis would be correct if the runways at Seletar airport are “non-instrument” runways, i.e. Seletar airport doesn’t use any instruments to guide the planes to land at the runways.

But once the ILS is implemented come January 2019; the runways at Seletar airport will no longer be “non-instrument” runways. Instead, because Seletar Airport uses the ILS, Pasir Gudang will no longer be considered an OLS, but an Obstacle Assessment Surface (OAS). The flight paths of planes in an OAS is different from that of an OLS, and is more like this:

The flight paths and resultant height restrictions in an OAS (via)

Why the difference? Because without instruments to guide them, planes have to fly lower so that the pilot can see the runways. The slope of approach needs to be gentler. But with guidance from an ILS, they can fly higher, because the pilots don’t need to see the runway from that far away, so the slope of approach can be steeper.

So, ironically, Minister Loke would be correct if Seletar Airport doesn’t use an ILS.

Or put in another way, if Minister Loke truly wants to allow taller buildings to be built in Pasir Gudang when Seletar Airport is fully operational, he should actually be advocating for Seletar Airport to use the ILS.

And he doesn’t understand international aviation standards

What’s more, Minister Loke is wrong that pilots would have no control over the planes and thus won’t be able to manoeuvre around obstacles. Just because pilots use ILS does not mean they do not have full control of the planes. They still do, meaning they can manually intervene should security concerns require it.

Furthermore, Minster Loke is wrong that because pilots can manoeuvre around obstacles and no height regulation is required around flight path area. Under international standards, it is also a requirement to mitigate the impact of tall buildings on aviation safety. This is regardless of whether or not pilots use the ILS or manual procedures.

And, as explained above, without the ILS, the height restrictions would be exactly what Minister Loke had said in his video.

Misguided understanding or deliberately misleading public?

Hi Malaysia, yes, Pasir Gudang, Johor, Malaysia, is yours, and Seletar Airport is ours. And the Instrument Landing System (ILS) is of international standards. Not only does it enhance operational flexibility, it also improves safety especially under poor visibility conditions. So please hear us out.

To Malaysians, please share this – there are no reasons why Malaysia has to oppose the ILS of the Seletar Airport which Singapore wants to implement from January 3, 2019.

Because if Malaysia wants to build taller buildings in the Pasir Gudang area than now, they should insist that we use the ILS in Seletar Airport. That is if they truly understand the ICAO regulations and how ILS actually work.