(g)  
Examine leading edge flaps, leading edge slats, and mechanisms for evidence of volcanic ash.

(h)  
Examine aileron and elevator balance panels for evidence of volcanic ash.

(19)
Examine wing and engine nacelle thermal anti-icing system as follows:

(a)  
Remove wing anti-ice valves (Ref 30-11-11) and examine for evidence of volcanic ash.

(b)  
Remove engine and nacelle anti-ice control valves (Ref 75-11-11, 75-11-21) and examine for evidence of volcanic ash.

(20)
Examine airplane interior (if cabin and cockpit contamination is reported) as follows:

(a)  
Examine upper and main deck compartments, closets, seats, powered crew seats, floor coverings, lavatories, lavatory components, galleys, and galley components for evidence of volcanic ash.

(b)  
Examine refrigeration/chiller units (if installed) for evidence of volcanic ash.

(c)  
Examine baggage/cargo systems and electrical/electronic compartments for evidence of volcanic ash.

(d)  
On executive airplanes, examine powered window blinds for evidence of volcanic ash.

(e)  
Examine control cables and mechanisms for evidence of volcanic ash.

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BOEING PROPRIETARY - Copyright . - Unpublished Work - See title page for details.

DRAGGED TAIL CONDITION - MAINTENANCE PRACTICES (CONDITIONAL INSPECTION
1.  Dragged Tail Conditional Inspection
A.  Inspect lower fuselage skins from BS 747 to tail cone for scrapes, burns, holes, loose or missing fasteners and signs of cracks or buckling of the belly skin.
B.  If damage to exterior fuselage skin is detected, inspect internally in the area of the damage, for bent or cracked stringer, frames, or clips: buckled or wrinkled webs; loose or missing fasteners.
C.  If damage is detected, repair damage per Structural Repair Manual or other approved procedure.
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AIRFRAME VIBRATION CONDITION - MAINTENANCE PRACTICES (CONDITIONAL INSPECTION)
1.  General
A.  This procedure provides a check of items which may cause inflight airframe vibration. The vibration may be eliminated or reduced as a result of the check of these items.
B.  Vibration can be caused by many factors. Vibration similar to mach buffeting felt in the forward cabin can be induced by trailing edge flaps and usually occurs at high speed. Similar type vibration, at lower speeds on climb and in cruise, may be created by ground spoiler float, excessive slop in outboard aileron/tab, or loose doors and fairings.
2.  Conditional Inspection
A.  Vibration occurs with trailing edge flaps up and is most noticeable in aft and forward fuselage. Check the following:
(1)  
Check for excessive play in elevator tab pushrod, tab lockout mechanism, or tab hinges (Ref 27-31-0 T/S).

(2)  
Check for loose elevator hinge fitting bolts (Ref 27-31-0 T/S).

(3)  
Check for elevator balance panel hinge bolts (Ref 27-31-41).

(4)  
Check for loose or worn elevator output torque tube bolts which attach inner or outer torque tubes (Ref 27-31-0 T/S, 27-31-191).

(5)  
Check for loose or worn elevator output torque tube crank, control, pushrod or elevator mast fitting (Ref 27-31-0 T/S, 27-31-191).

(6)  
Check that all doors, panels, and fairings are in fair and attached securely.

(7)  
Check that nose and main gear doors are faired and all seals intact.

(8)  
Check nose gear doors for proper adjustment (Ref 32-22-0 A/T).

(9)  
Check for excessive play in horizontal stabilizer hinge bearing (Ref 27-41-31 I/C).

(10)
Check for separation or deterioration of elevator hinge seals or elevator nose seals (Ref 27-31-171).

(11)
Check for abnormal vibration in auxiliary power unit (APU) (Ref\49-00 T/S).

(12)
Check for loose or worn APU inlet door compartments (Ref\49-15-0\A/T).

(13)
Check for damaged or loose aft body vortex generators (Ref\53-31-21\R/I).

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B.  Vibration occurs with trailing edge flaps up and is most noticeable on the wing root area. Check the following:
(1)  
Check for misadjusted upper wing trailing edge panels (Ref 27-51-72 A/T).

(2)  
Check for loose or damaged outboard trailing edge flap track fairing (Ref 27-51-121).