Evidence is mounting that a terrorist attack may have been responsible for the loss of an EgyptAir flight with 66 people on board. If that turns out to be the case, it will deepen concern about airport and airline security, particularly in North African and Middle Eastern countries. Authorities have linked at least two of three previous attacks in the region in the past year to airport employees who used their positions to exploit gaps in security.

This has prompted airports elsewhere including Asia to reflect on their own security. It is a reminder that ultimately any defence is only as secure as its weakest link. Recent incidents at Hong Kong International Airport did not amount to security threats. But they are wake-up calls that have brought security under fresh scrutiny. In the latest incident, the Airport Authority confirmed a breach involving two Indonesian passengers in transit to Beijing. They made their way to the departure area without passing through the transfer desk, immigration or required security checks simply by not getting off the airport’s internal train at the arrival area, but remaining on board as it proceeded to the departure area after picking up a fresh load of passengers.

Happily, the Airport Authority became aware of the breach and the passengers were eventually given the all-clear. This may indicate an efficient security back-up is in place. However, disclosure of the breach through a media leak by airport sources has prompted lawmakers to seek an explanation and security evaluation. Their concern is understandable, following a breach last month involving a young woman believed to suffer from a mental disability. Without a boarding pass or passport, she evaded normal checks and reached a far-flung boarding gate before being stopped.