Jakarta flights restart after Anak Krakatau ash grounds 2,961 services

Soekarno-Hatta International Airport resumed flights just after midnight on Tuesday after volcanic ash from Anak Krakatau closed Jakarta's airspace for two days. Transport Minister Dudy Purwagandhi said Halim Perdanakusuma, Husein Sastranegara in Bandung, and two smaller Banten airports also reopened. Three other fields, including Radin Inten II in Lampung, stayed closed until 10 a.m. local time. Atung Bungsu in Pagar Alam had already restarted on Monday morning.

The closures on Sunday and Monday disrupted 2,961 flights, 622 of them international, and affected about 341,000 passengers. Infrastructure minister Agus Harimurti Yudhoyono gave those figures while the ash was still over the capital. Early ministry tallies on Sunday had been lower, around 1,558 delayed flights and 170,000 stranded travellers. The count rose as the ban stretched through Monday evening to let crews sweep runways, taxiways and aprons and to give airlines time to recover aircraft.

Anak Krakatau sits in the Sunda Strait, about 150 kilometres from Jakarta. A continuous eruption began at 23:07 Western Indonesia Time on 4 September and produced lava fountains and an ash column that the Darwin Volcanic Ash Advisory Centre and Himawari-9 imagery tracked to 50,000 feet in places. Badan Geologi said that continuous episode ended at 00:04 on 6 September. Strombolian bursts continued. The agency recorded further eruptions at 05:08 and 05:34 on Tuesday morning. It kept the alert at Level III and told the public to stay three kilometres from the crater. Head of the agency Lana Saria said the chance of more eruptions remains high.

Ash on the runway, school on a screen

Ash is not smoke. It is glass and rock. It scores turbine blades and fills pitot tubes. That is why Angkasa Pura and the transport ministry would not reopen Soekarno-Hatta on a forecast. They waited for the airspace advisory to ease and for the paved surfaces to be cleaned. Some Tuesday morning departures were still retimed into the afternoon. At least one early flight out of Jakarta was cancelled after the official restart.

Jakarta shifted schools to remote learning so children would not walk through ash. Shipping in the strait was disrupted. Six provinces recorded ashfall: Lampung, Banten, Jakarta, West Java, Bengkulu and West Sumatra. Visibility at the main airport dropped to between four and seven miles while volcanic ash was in the METAR.

The last comparable shock from this volcano was the December 2018 sector collapse and tsunami. This week's event killed no one on land. It did stop a capital's airport, which is how a mid-size cone still sets the timetable for a country of 280 million. Purwagandhi now has to keep three Sumatra fields on a short leash while Badan Geologi watches the next plume. Airlines have to re-crew aircraft that sat for 48 hours. Passengers who slept in terminals get the first airborne slots. The mountain has not gone quiet. The timetable has only been allowed to move again.