Airspeed indications may fluctuate greatly or appear unusually high or low due to volcanic
dust blocking the pitot-static system. Establish the proper pitch and power settings required by
the Dash One or the NATOPS Flight Manual for flying with an unreliable airspeed indicator.
An acrid odor similar to electrical smoke may be present.
A rise in oil temperature could indicate dust-plugged oil cooler(s).
Torching (flames) from the engine tailpipe(s) may occur.
Volcanic ash/dust may be blown into the cockpit through the aircraft air conditioning
Windshields become severely pitted that results in translucence. In addition, the abrasive
cloud particles will sandblast the aircraft's leading edges.
7. St. Elmo's fire and static discharges around the windshield are often visible at night. A
bright orange glow in engine inlets frequently occurs.
At night or in dark clouds, landing lights cast dark distinct shadows in ash clouds (unlike
the fuzzy, indistinct shadows cast against moisture clouds).
Multiple engine malfunctions such as power surges, loss of thrust, high EGT, or
compressor stalls. These result from ash buildup and blockage of the high-pressure turbine guide
vanes and high-pressure turbine cooling ports.
10. More than one or all engines may flameout, since all engines are exposed to the same ash
If you encounter volcanic ash in flight, the best procedure is to perform a 180º turn immediately
and leave the area. Additionally, consider a reduction in altitude, as hot ash has most likely
ascended in convective currents before forming the cloud. Reduce thrust to the minimum
practical and monitor your engine instruments for indications of a possible flameout. If engines
flameout, continue attempting restart procedures, as exiting the ash cloud may improve the
probability of light off. Declare an in-flight emergency as soon as practicable, and land at the
nearest suitable airfield. Transmit PIREPs to military weather stations to report the location of
the volcanic ash cloud (to warn other aircrews). As soon as safely possible, record the altitude,
location, duration of exposure, and any related malfunctions observed, since special aircraft
cleanup procedures are required after flight through volcanic ash.
Weather Hazards of Turbulence, Icing, Ceilings, Visibility, and Ash Clouds