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AIM

10/12/17

7−5−8

Potential Flight Hazards

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.

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

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.