AIM 

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cabin may indicate the presence of SO

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 emitted by volcanic activity, but may or may not indicate the presence 

of volcanic ash. Every attempt should be made to remain on the upwind side of the volcano. 

c. 

It is recommended that pilots encountering an ash cloud should immediately reduce thrust to idle (altitude 

permitting), and reverse course in order to escape from the cloud. Ash clouds may extend for hundreds of miles 

and pilots should not attempt to fly through or climb out of the cloud. In addition, the following procedures are 

recommended: 

1. 

Disengage the autothrottle if engaged. This will prevent the autothrottle from increasing engine thrust; 

2. 

Turn on continuous ignition; 

3. 

Turn on all accessory airbleeds including all air conditioning packs, nacelles, and wing anti-ice. This will 

provide an additional engine stall margin by reducing engine pressure. 

d. 

The following has been reported by flightcrews who have experienced encounters with volcanic dust 

clouds: 

1. 

Smoke or dust appearing in the cockpit. 

2. 

An acrid odor similar to electrical smoke. 

3. 

Multiple engine malfunctions, such as compressor stalls, increasing EGT, torching from tailpipe, and 

flameouts. 

4. 

At night, St. Elmo’s fire or other static discharges accompanied by a bright orange glow in the engine 

inlets. 

5. 

A fire warning in the forward cargo area. 

e. 

It may become necessary to shut down and then restart engines to prevent exceeding EGT limits. Volcanic 

ash may block the pitot system and result in unreliable airspeed indications. 

f. 

If you see a volcanic eruption and have not been previously notified of it, you may have been the first person 

to observe it. In this case, immediately contact ATC and alert them to the existence of the eruption. If possible, 

use the Volcanic Activity Reporting form (VAR) depicted in Appendix 2 of this manual. Items 1 through 8 of 

the VAR should be transmitted immediately. The information requested in items 9 through 16 should be passed 

after landing. If a VAR form is not immediately available, relay enough information to identify the position and 

nature of the volcanic activity. Do not become unnecessarily alarmed if there is merely steam or very low-level 

eruptions of ash. 

g. 

When landing at airports where volcanic ash has been deposited on the runway, be aware that even a thin 

layer of dry ash can be detrimental to braking action. Wet ash on the runway may also reduce effectiveness of 

braking. It is recommended that reverse thrust be limited to minimum practical to reduce the possibility of 

reduced visibility and engine ingestion of airborne ash. 

h. 

When departing from airports where volcanic ash has been deposited, it is recommended that pilots avoid 

operating in visible airborne ash. Allow ash to settle before initiating takeoff roll. It is also recommended that 

flap extension be delayed until initiating the before takeoff checklist and that a rolling takeoff be executed to 

avoid blowing ash back into the air. 

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11.  Emergency Airborne Inspection of Other Aircraft 

a. 

Providing airborne assistance to another aircraft may involve flying in very close proximity to that aircraft. 

Most pilots receive little, if any, formal training or instruction in this type of flying activity. Close proximity 

flying without sufficient time to plan (i.e., in an emergency situation), coupled with the stress involved in a 

perceived emergency can be hazardous. 

b. 

The pilot in the best position to assess the situation should take the responsibility of coordinating the 

airborne intercept and inspection, and take into account the unique flight characteristics and differences of the 

category(s) of aircraft involved. 

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10 

Potential Flight Hazards