David Kaminski-Morrow/London

Two low-approach incidents in three weeks sparked a dramatic decision to ground budget carrier Tiger Airways Australia, whose operations remain suspended until at least 1 August.

The grounding order from the Civil Aviation Safety Authority came almost immediately after the second incident, on 30 June, when a Tiger Airbus A320 descended below the published minimum altitude on approach to Avalon airport, Victoria, at night. Investigators from the Australian Transport Safety Bureau were already probing a similar incident on 7 June, when a Tiger A320 operating Brisbane-Melbourne descended to 2,000ft on approach despite the minimum safety altitude being 2,500ft.

Concerns were raised in March when CASA issued a show-cause notice to the airline, a subsidiary of Singapore's Tiger Airways, ordering it to tighten pilot training and fatigue management, improve maintenance control and reinforce its operational management structure. Despite this, Tiger Airways Australia failed to convince CASA it could conduct safe operations and CASA, insisting the carrier posed a "serious and imminent risk to air safety", suspended the airline on 2 July.

The crisis has cost the carrier's chief, Crawford Rix, his position. Rix will leave at the end of July. CASA said it took the grounding decision having already imposed conditions on the carrier's air operator's certificate.

"In the circumstances CASA no longer has confidence in the ability of Tiger Airways Australia to satisfactorily address the safety issues that have been identified," it said. Although the suspension was initially for five working days, the extent of the investigation led CASA to seek a prolonged grounding through the Federal Court in Melbourne.

CASA said concerns focused on "a number of areas" but particularly pilot proficiency, adding: "There have been a number of examples of pilots not performing to the standards we expect in Australia, which are very high standards. It's not as if they've been deliberately going out of their way to breach the rules. It's more about their systems failing them."

Tiger Airways had recently given evidence before an Australian Senate committee hearing on pilot proficiency, a hearing which also looked into a specific safety reporting oversight by Tiger. The airline, which has removed all tickets from sale, said it is taking internal steps to address CASA's concerns, stating: "We wish to reassure the Australian public that safety has, and will, underpin our operations at all times."

Services to Singapore are unaffected. "We are committed to resolving these [issues] quickly and resuming our [domestic Australian] services as soon as possible," Tiger said.

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Source: Flight International