MALAYSIA Airlines (MAS) has responded to the disappearance of Flight MH370 with new rules barring pilots from being alone in the cockpit to prevent them from wrong-doing.
Also, during meal times a cabin crew member must stand guard at the cockpit door so nobody can barge in as meals are delivered.
Malaysia's airport authority has also introduced new tighter screening of passengers.
However, industry experts said the various changes are unlikely to have a significant impact.
Assistant Professor Terence Fan, an aviation expert at the Singapore Management University, told The Straits Times: "Given the circumstances, they would rather be over- than under-cautious. To some extent, it's also about restoring public confidence."
Three weeks after Flight MH370 went missing en route from Kuala Lumpur to Beijing, MAS has issued a circular to all pilots on the new rules to boost cockpit security.
An MAS spokesman confirmed the tightening of onboard security and monitoring procedures but said that for security reasons, details cannot be disclosed.
On the ground, airport authorities now require all international travellers to walk through two metal detectors and undergo a body search before boarding, The Star newspaper reported.
It is unclear what the authority hopes to achieve with double metal detector screening, said Prof Fan.
"There is typically a rate of error with all such machines so it's possible the objective is to make sure that if something is not detected the first time, it will be on second screening."
Aviation and security experts also warned that body searches for all passengers could lead to delays and inconvenience.
The International Air Transport Association - the global voice of airlines - for example wants to see a tailored security approach based on actual risks.
In its view, security cannot have a one-size-fits-all approach.
The authorities should instead rely on technology, such as biometrics, intelligence gathering and other means to differentiate between less risky and more risky travellers.
Meanwhile, the mystery of Flight MH370 has also led to tighter security checks at other airports, including Changi.
Airport Police commander Sam Tee said: "Some of the enhanced security measures include increasing ground patrols to project a greater police presence, as well as more stringent checks on travellers."
A police spokesman told The Straits Times on Monday: "The security measures deployed at the pre-board screening include the walk-through metal detector, handheld metal detector, X-ray machine, explosive trace detection and physical body search. These measures are proactively reviewed and updated periodically along with the developments worldwide."
Checks also depend on information and intelligence received from counterparts, police said.
On cockpit rules, other airlines declined to comment for security reasons but Singapore pilots told The Straits Times that doors are typically locked from the inside.
In the cockpit, there is a camera so pilots can monitor what goes on in the area just outside and around the cockpit door.
Only cabin crew are allowed into the cockpit, to serve meals or if there is an emergency.
Before entering, they must press a call button.
The pilots then scan the area outside before they unlock the door.
A pilot who asked not to be named said: "I don't see the point of having a cabin crew in the cockpit when one of the pilots steps out for a toilet break for instance.
"If I'm really up to no good, there are switches and other systems I can mess with and the crew won't have the slightest idea what I'm doing."
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