Philippines: Flight ban near restive Mayon Volcano declared

Manila: The Civil Aviation Authority of the Philippines (CAAP) has extended once more the flight ban in areas surrounding Mayon Volcano as volcanic activity continues to pose risks to aircraft.

In a Notice to Airmen (NOTAM) issued on Thursday, CAAP said flights are prohibited within the airspace around Mayon, in Bicol, about 600 km southeast of Manila, from the surface up to 11,000 feet until 9 am on Friday, December 19.

“Flight operators are advised to avoid flying close to the volcano, which remains under Alert Level 1 or low-level unrest,” CAAP said.

The extension follows a NOTAM first issued on December 10, after the Philippine Institute of Volcanology and Seismology (PHIVOLCS) reported lava flow activity at Mayon Volcano.

PHIVOLCS has since warned of an increased likelihood of volcanic hazards, including sudden steam-driven or phreatic explosions, rockfalls, and possible lahar flows during periods of heavy rainfall.

Why volcanic ash is hazardous to aircraft

Volcanic ash is extremely dangerous to aircraft because it is made up of tiny, sharp rock and glass particles — not soft ash like burned wood. When an aircraft flies through an ash cloud, the particles can damage jet engines by melting inside the engine and then re-solidifying, potentially causing engine failure or "flameout".

Ash can also scratch cockpit windows, reducing pilot visibility, clog air filters and sensors, and interfere with critical flight instruments such as airspeed and altitude indicators.

In addition, ash clouds are often difficult to detect by onboard radar, increasing the risk of accidental encounters.

Because of these risks, aviation authorities impose strict no-fly zones around active volcanoes to ensure passenger and crew safety.