In the past, the landside/airside boundary was the main line of defence for aviation security. We've focused on keeping the airside 'clean' to protect passengers, staff and the planes. 

To achieve this, we've deployed technology, searching and strict rules on access control. This trinity of measures proved useful in keeping people safe.

Then the terrorists switched, opting for landside attacks. Jinnah International Airport in 2014, Brussels and Atatürk Airports in 2016, are all examples. Granted we've seen airport landside attacks in the past -- the most notable being Lod 1972 that killed 26. Yet, recent incidents suggest a new phase.  

In response, we introduced landside patrols and other measures. Some airports are screening people entering the terminal. I'd opine this option is a stop-gap measure at best. Because, of course, the terrorists may then attack airport feeder infrastructure. A threat displaced hasn't gone away.

This all begs the question, are we going to push our security outwards? For instance, roadblocks and security control points on access routes? These may have a use at times of high-threat, but as permanent measures will prove costly and disruptive. 

Besides, the suicide bombers we've seen in landside attacks present a unique threat. The possibility of detection or dying is not a deterrent; the suicide bomber will press on because they're engaged in ritual sacrifice. Religious zeal or political dogma is the driver that barriers and checkpoints won't deter. 

Also, the suicide bomber who enters a checkpoint can meet his objectives. It's not the purpose here to discuss the range of options available to counter suicide bombers. I've flagged up the issue as a unique threat that's challenging to combat on the ground.

It appears to me that the impact of security measures is not always understood. When you extend them out from an airport, the wider community feels the effect. The knock-on effects can be severe. I'm sure communities can tolerate that disruption for a short time in the interests of public safety. Long term, the measures may prove less palatable. 

Returning to maintaining vigilance at airports, besides landslide patrols, ICAO recommends:

Recommended Practice 4.4.5:  Each contracting State should ensure that practices are established at airports and onboard aircraft to assist in the identification and resolution of suspicious activity that may pose a threat to civil aviation. 

To me a suspicious activity program fostering security awareness is essential. Moreover, to be effective, the plan must embed at all levels. That means the airport director to the terminal cleaner; all are responsible for security.  

Plus, successful implementation takes training and development. Airports also must have clear procedures and, most important of all, organisational commitment. A once a year statement of support by the people at the top is not enough. They need to drive the security culture and sustain it.

Defining suspicion activity helps and most airports have simple exemplars to teach staff. As an illustration, putting down a bag or other items and walking away or not wearing ID in an area where it's required. Checklists distributed on Apps or through email give any program a wide footprint. These can help prompt staff by keeping them current of events. Meanwhile, low-tech solutions can involve an on-shift briefing. 

Such programs must cover carpark staff, bus-drivers, porters and all ancillary workers. One airport is using plane-spotters. These guys are on site every day, watching, and are familiar with the routine and surroundings. Anything unusual soon comes to their attention. Engage them. Provide them with contact cards to security teams so they may report any unusual activity. These low-cost options could give a high return.

Less common is internal vigilance within organisations. Managers and supervisors must recognise the insider threat. They need to identify staff who are behaving strangely. People making radical statements or professing support for known terrorists need an intervention. The danger they pose needs consideration. Don't forget baggage handlers, loaders and others have ease of access to planes. What is more, these people are not supervised at all times.

I wish to stress that any program must have a 'no-blame' approach. If we reprimand or punish staff for making erroneous reports, then the program will fail. Word will soon get around. In fear of punishment and blame, people will remain silent. Without such a mature attitude you are wasting this critical resource. 

Staff and others must also see a pro-active response. Dismissed reports or no action will kill interest. Staff will ask "why bother?". 

As I discussed in my previous blogs, the threat to civil aviation is evolving. As we put in place or enhance security measures, so the terrorists adapt. In the end, we need systems that are agnostic of the attack method.

To me using technology is only a partial solution.  Vigilant and well-motivated people must be part of our response. Otherwise, the boundary of airport security will keep moving outward until it reaches our front door.