VOLCANIC ASH Flashcards
How can Volcanic Ash be distinguished from normal clouds?
Volcanic Ash is generally brown and hazy in appearance?
How far way from a volcano should we plan to be?
120 nm on the upwind side
What is a VAA?
A “Volcanic Ash Advisory” issued by the responsible Volcanic Ash Advisory Center
What are the 4 alert levels for Volcanic Ash?
1 GREEN: Non eruptive stage
2 YELLOW: Potential activity increased
3 ORANGE: Ash below 25'000 ft
4 RED: Large eruption expected or confirmed. Ash likely
above 25'000 ftIs Volcanic Ash visible on a Weather Radar?
No
What are some of the indicators of Volcanic Ash?
S:t Elmos Fire Windshields severely pitted Bright glow around engine inlets Smokey or Acrid smells Haze/dust appearing on the flight deck Fluctuating engine or airspeed indications Engine stalls Increasing EGT
What is the procedure when experiencing Volcanic Ash?
- Exit area, most likely a 180 degree turn
- Retard thrust to idle power to lower EGT and improve
stall margins - Put Engine- and Wing Anti-ice ON to increase bleed extraction and further improve stall margins
- Do “Volcanic Ash Un-annunciated Checklist”
- File a PIREP
- Submit a VAR (Volcanic Ash Report) upon landing
- Set the re-circulation fans to off
What are some of the hazards associated with Volcanic Ash?
- Engine malfunctions. Stall leading to high EGT
- Blockage of Static and Pitot tubes. Unreliable airspeed
might occur - Contamination of cabin air. Oxygen use may be
required - Erosion of external components
- Windscreens can be damaged. Divert to airport with
autoland
What happens to the ash as it goes through the core of the engine?
Ash particles melt at 1’100 deg C. Engine temp is around 1’400 deg C so ash melts in the hot section and attaches to the HP turbine blades.
Why is reducing thrust a good idea in Volcanic Ash situations?
- Lowers EGT and improves the stall margin
- Lowers the core temperature to try to avoid the ash
particles melting
