[Photo Credit: Reuters]

Several air traffic controllers on duty when two Qantas aircraft nearly collided at Sydney airport in July had been flagged as facing a high risk of fatigue, ​according to internal records and a call recording obtained by Reuters, a staffing situation one shift manager described as “a bit insane”.

The July 27 incident, in which a ‌landing Qantas (QAN.AX), opens new tab turboprop narrowly avoided a Qantas Boeing 737 that had been cleared to cross the runway, was the first of six near-misses at Sydney Airport in about a month, drawing further scrutiny of air traffic control staffing amid global shortages.

Of the 10 controllers on duty at the time, five were rated “H” for high fatigue risk under Australia’s fatigue-management system, according to an internal log reviewed by Reuters. One was rated “M” for medium risk and one was “L” for ​low risk. The other three were not ranked as at risk of fatigue.

Two of the three controllers directly involved in the incident were “high fatigued” and the third was “medium fatigued,” the shift manager said.

The ​fatigue-risk ratings and the internal call, neither of which has previously been reported, occurred as aviation authorities worldwide grapple with concerns about overstretched air traffic control workforces and the risk of accidents.

Airservices Australia, the government ​agency that employs the country’s air traffic controllers, declined to comment, citing the ongoing investigation into the incident. The Australian Transport Safety Bureau is investigating all six near-misses to determine whether they share common safety issues or contributing factors.

The fatigue management system does not measure whether a controller is actually fatigued. Instead, it uses an automated assessment of factors such as workload and scheduling to estimate the risk of fatigue.

Depending on the rating, controllers may be ​subject to mitigation measures approved by local shift managers or an air traffic management director, who may be based in another city. Those measures can include longer breaks, limits on traffic volumes ​handled by a controller, or ending a shift early.

Civil Air President Scott Nugent, whose union represents about 85% of Australian air traffic controllers, told Reuters that an increasing number of shifts in recent years had been assessed ‌as carrying ⁠elevated fatigue risk, reflecting controllers getting less rest and working longer hours.

If a controller believed they were highly fatigued, they should not work in accordance with safety regulations, Nugent said