In a statement, the ministry said an investigation found that the incident was caused by a trip at the Bukit Raja substation.

It said a 132kV gas insulated switchgear reserve at the substation tripped at around 4.54pm on Saturday, causing a voltage dip that led to a failure in the baggage handling system controller.

This, in turn, led to a major system shutdown affecting baggage processing for both departing and arriving passengers.

“Although supported by uninterruptible power supply (UPS) units, six UPS units were affected, exposing vulnerabilities in the system’s resilience,” said the ministry.

In response, Malaysia Airports Holdings Bhd (MAHB) and airlines implemented manual procedures and additional manpower. However, the ministry said there were key issues in coordination, response times, and system visibility, despite the activation of a business continuity plan.

Between 5pm and 10.30pm, the airport terminal processed 23,769 pieces of baggage, while 1,061 were accounted for but not loaded, and 120 were unaccounted for.

“MAHB and its ground handling partners have since delivered the vast majority of these items, with a small number of bags remaining in the final stages of clearance or collection.

“Notably, flight schedules remained unaffected, with no delays or cancellations reported due to the incident,” the ministry said.

It said a Cabinet note on the incident would be tabled to the Cabinet on Wednesday, while MAHB would provide weekly progress updates on the stabilisation of operations.

The Civil Aviation Authority of Malaysia is also investigating the incident.

“The transport ministry assures all stakeholders that proactive and decisive measures are being accelerated to prevent recurrence and ensure that KLIA continues to operate at the highest standards of efficiency and reliability,” the ministry said.