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Commentary: Singapore’s response against potential air threats – well-oiled machinery but task remains challenging

The Republic of Singapore Air Force scrambling of F-16 aircraft in response to a “potential air threat” on Saturday illustrates the airspace challenges facing the country, says Mike Yeo.

Commentary: Singapore’s response against potential air threats – well-oiled machinery but task remains challenging

File photo of a Republic of Singapore Air Force F-16 fighter jet. (AFP/Paul Crock)

MELBOURNE: The activation of Republic of Singapore Air Force (RSAF) fighter aircraft over the weekend was heard by many in the country.

Observers on the ground noted F-16s in the air on Saturday morning, circling over Singapore until around 11.30am.

Coming on the 20th anniversary of the 9-11 attacks, the incident raised questions over the safety of Singapore’s airspace and what could have sparked the RSAF response.

The Ministry of Defence (MINDEF) subsequently said in a statement that the RSAF scrambled F-16 aircraft at approximately 9.20am on Saturday morning “in response to a potential air threat”.

“After ensuring that our security was not compromised, we stood down our aircraft”, the short statement added.


While MINDEF did not divulge more details or identify the “potential air threat”, there have been earlier reports of a Royal Malaysia Police (RMP) helicopter flying into Singapore airspace that same day.

Open-source flight tracking websites including FlightAware, Flightradar24 and AirNav RadarBox showed a RMP Leonardo AW139 helicopter carrying the registration 9M-PMD in the vicinity on the same morning.

The helicopter’s onboard transponder was picked up soon after 9am on Saturday morning, taking off near a Federal Reserve Unit camp just north of the Causeway heading north and then east at about 170kmh at an altitude of 210m.

It then reached the Sungai Johor Bridge linking Senai with Desaru where it suddenly turned southeast, roughly 14km away from Singapore’s airspace north of Pulau Tekong, before making its way southwards towards the helipad at the Royal Malaysian Navy’s KD Sultan Ismail naval base at Pengerang.

The flight of an aircraft tracked on FlightRadar24 on Sep 11, 2021. (Screengrab: FlightRadar24)

In doing so, it flew through Singapore airspace for some 6km, clipping the northeast corner of Pulau Tekong. The helicopter then headed out to sea east of Peninsular Malaysia. 

At that speed, the helicopter would have only taken some 4 minutes to reach Singapore airspace from the start of its journey.

The RMP has confirmed that one of its helicopters was in the airspace near Singapore on that day on “official assignment” but did not enter Singapore airspace nor was it challenged by air traffic controllers.

While the RMP did not provide further details, photographs of a AW139 helicopter ferrying Rodzi Md Saad, the Director-General of Malaysia's National Security Council, to the Abu Bakar Maritime Base at Middle Rocks on that same day were subsequently posted on social media.

A picture of the Malaysian delegation to Abu Bakar Maritime Base at Middle Rocks. (Photo: Facebook/KP MKN)


Many countries have established protocols to follow when a suspicious aircraft or unidentified object is detected approaching their airspace.

This could be an aircraft that is not broadcasting information on its transponder, not filed a flightplan to enter the country’s airspace, not communicating or simply not flying where it was supposed to be. 

This usually first entails air traffic controllers attempting to contact the aircraft by radio, to request for identification and state its intentions.

Such was the case in June, when Malaysian air traffic controllers in East Malaysia attempted repeatedly to contact aircraft approaching Sarawak before sending up an air force jets to intercept what turned out to be 16 Chinese military aircraft.

If the suspicious aircraft responds to air traffic control queries and is assessed not to pose a threat to a country’s territory, they might not be pursued further.

However, if attempts to contact the aircraft fail with the plane continuing a route towards sovereign airspace, air traffic controllers will escalate the issue, for example, by asking nearby aircraft to attempt to contact or spot the aircraft visually – as was the case when Vietnamese air traffic control requested for nearby aircraft to contact MH370 shortly after it went missing in March 2014.

If these attempts are not successful or there are no nearby aircraft to assist, military interceptors already standing by for such contingencies will be activated, as was the case when the UK deployed two Royal Air Force Typhoon fights after a plane temporarily lost communications with controllers while over southeast England in December 2019.

These are poised to take off quickly, within five to ten minutes of being activated.

The interceptors will then attempt to identify, make contact with the suspicious aircraft and potentially direct it to land at a nearby airport or take further remedial action.

The RSAF themselves have done this before, with two F-16 jets intercepting a Cessna 208 plane and forcing it to land at Changi Airport back in 2008 after it failed to file an approved flight plan before approaching Singapore airspace.

In a worst-case scenario, the air force must be prepared to shoot down aerial threats. Such was the case on Sep 11, 2001, when US Air Force F-16s were poised to shoot down United Airlines Flight 93 as it sped towards Washington DC before it crashed into a field in Pennsylvania following an attempt by passengers to seize back the hijacked aircraft.

The RSAF should have in place a well-oiled response protocol, seeing how it investigates “more than 350 suspicious air threats on any given year in order to protect Singapore’s skies" - an average of almost one per day.

It was only in February this year when the RSAF sent F-15SGs into the air to investigate another unspecified potential air threat.


Singapore’s challenge is compounded by the busy airspace in and around the island and the proximity of a number of foreign airports nearby.

It is a challenge for air traffic controllers to decide whether an aircraft already so close to Singapore’s airspace could be left alone or warrant further investigation.

As the incident on Saturday demonstrates, any helicopter from Malaysia only requires 4 minutes before reaching Singapore airspace, meaning barely any time to ascertain its intentions, never mind take subsequent measures.

If the timepath from FlightAware is accurate, the 2 minutes the helicopter in question spent inside Singapore airspace before departing would also be barely enough time to warn the helicopter by radio, never mind getting any interceptors in a position to investigate.

RSAF's aerostat provides 24/7 low-level radar coverage over Singapore. (Photo: Jeremy Long)

Singapore’s tight reaction time is also compounded by the closeness of key infrastructure like Changi Airport to where Saturday’s incident occurred.

And yet, the seemingly obvious solution to ensure a future incursion is swiftly intercepted - like the maintenance of fighter jets overhead 24 hours, seven days a week, 365 days a year – is neither realistic nor sustainable due given the potentially astronomical costs and demands on the RSAF.

When cases of airspace intrusions are determined not to threaten national security, countries usually also choose to raise their concerns diplomatically so as not to escalate incidents on the ground – as was the case earlier this June when Malaysia summoned the Chinese ambassador to explain the intrusions of Chinese air force planes into East Malaysian airspace and issued a note of diplomatic protest.

Still, the RSAF does maintain air patrols overhead during key events of national sensitivity such as during National Day, while constantly maintaining a high level of vigilance at other times.

Mike Yeo is the Asia reporter for US-based defence publication Defense News.

Source: CNA/sl