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AIM 

6/17/21 

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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10.  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 coordinat-
ing the airborne intercept and inspection, and take 
into account the unique flight characteristics and 
differences of the category(s) of aircraft involved. 

c. 

Some of the safety considerations are: 

1. 

Area, direction and speed of the intercept; 

2. 

Aerodynamic effects (i.e., rotorcraft down-

wash); 

3. 

Minimum safe separation distances; 

4. 

Communications requirements, lost commu-

nications procedures, coordination with ATC; 

5. 

Suitability of diverting the distressed aircraft 

to the nearest safe airport; and 

6. 

Emergency actions to terminate the intercept. 

d. 

Close proximity, inflight inspection of another 

aircraft is uniquely hazardous. The pilot

in

 

command of the aircraft experiencing the 
problem/emergency must not relinquish control of 
the situation and/or jeopardize the safety of their 
aircraft. The maneuver must be accomplished with 
minimum risk to both aircraft. 

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Potential Flight Hazards