Lower volcanic activity at Bali's Mount Agung and favourable wind conditions for the third day running allowed the airport on the neighbouring resort island of Lombok to continue operating for most of yesterday.
The airport, located just west of Bali, reopened yesterday morning after being closed on Thursday due to ash clouds from the volcano, which has been erupting intermittently since Nov 21.
Indonesia's airport operator, Angkasa Pura, said flights resumed because winds had blown the volcanic ash away from Lombok.
Favourable winds had also led the authorities to allow for the resumption of flights into Bali.
Reuters yesterday quoted meteorological officials as saying that a tropical cyclone south of Java had altered the wind direction in the area, but warned of heavy rain and strong winds until today. At least 27 people have been killed and thousands displaced by the heavy rain so far.
Many carriers, including Singapore Airlines, have resumed flights to and from Bali, but Reuters reported that budget airline Jetstar would cancel nine of 15 planned flights over fears that ash could hit the airport in the evening.
Reuters also said Malaysia's AirAsia would operate out of Bali only during the day.
Airlines avoid flying through volcanic ash clouds because they could damage aircraft engines, hamper pilot visibility and, in extreme circumstances, even cause engine failure.
Indonesia's National Disaster Mitigation Agency (BNPB), which maintains a separate alert status from the aviation authorities, has kept the highest alert level for Bali and has not lifted the 10km radius exclusion zone around Mount Agung.
Bali, which usually sees an influx of tourists during this time of the year, also remains in a state of emergency until Dec 10.
Data from the Volcanology and Disaster Mitigation Centre (PVMBG) yesterday showed no incandescent lava or major tremors at Mount Agung, but eruptions accompanied by heavy plumes of ash clouds were still detected.
PVMBG chief I Gede Suantika said the volcano remained in a "critical phase" with the potential for a major eruption.
"Although (volcanic activity at Mount Agung) is on a relative decline, we cannot determine that (it) has completely subsided," he said.
Bali is bracing itself for a major eruption, with BNPB spokesman Sutopo Nugroho disclosing that more than 55,700 villagers have been evacuated from the danger zone.
More than 1,500 people were killed when Mount Agung last had a major eruption in 1963.
Volcanologists say it is difficult to predict when the next large eruption will occur, pointing to Sumatra's Mount Sinabung, which is still at the highest alert level after roaring back to life four years ago. The volcano has in fact been erupting sporadically for even longer, since 2010.
