Aeronautical Information Manual (AIM), page 536

Index   535 -- Page 536 -- 537

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

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

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.

7-5-10. 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

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-

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.

7-5-8 Potential Flight Hazards

Page 536 of the Aeronautical Information Manual (AIM.pdf)
AIM: Official Guide to Basic Flight Information and ATC Procedures

Index   535 -- Page 536 -- 537