100 Hour Inspection - Piper Navajo Chieftain PA-31-350 Service Manual

NAVAJO CHIEFTAIN SERVICE MANUAL
14-33. 100 HOUR INSPECTION.
a. Remove cowling in accordance with Removal of Engine Cowling, Section VIII.
b. Conduct 50 hour inspection.
c. Check for radio noise or radio compass interference by operating the engine at near take-off power and
with radio gear ON while turning deicer switch ON and OFF. If noise or interference occurs with deicer switch
ON, and disappears when switch is OFF, see troubleshooting chart.
d. Ascertain that all clamps, clips, mountings and electrical connections are tight. Check for loose,
broken or missing safety wire.
e. Deicers: Closely check deicers for wrinkled, loose or torn areas, particularly around the outboard end
and where the strap passes under the strap retainer. Look for abrasion or cuts, especially along the leading
edge and the flat or thrust face. If heater wires are exposed in damaged areas or if rubber is found to be tacky,
swollen or deteriorated (as from oil or solvent contact), replace the damaged deicer in accordance with
paragraphs 14-47 to 14-51.
NOTE
Check that strap restrainers are correctly located and secure.
Look for cracks or other damage. Operate propeller from full
low pitch to feathering and check that deicer lead straps do not
come under tension, or are pinched by propeller blade. (Refer to
Figures 14-21 and 14-22.)
f. Slip Rings: Check slip rings for gouges, roughened surface, cracks, burned or discolored areas and for
deposits of oil, grease or dirt.
1. Clean greasy or contaminated slip rings with CRC 2-26 solvent. (This solvent is available from
CRC Chemical Division Webb Inc., CJ10 Limekiln Pike, Dresher, Pa. 19025.)
2. If uneven wear is found or if wobble is noticed, set up dial indicator as shown in Figure 14-11 to
check alignment of slip rings to propeller shaft.
g. Brush Block - Brushes: Examine mounting brackets and housing for cracks, deformation or other
physical damage.
1. Test that each brush rides fully on its slip ring over 360
°
. Figure 14-12 shows wear pattern if this
condition is not corrected. If alignment is off, shim where brush block bracket attaches to engine back bone or
pivot at support arm which is attached to generator idler pulley bracket.
2. Check for proper clearance of brush block to slip rings as shown in Figure 14-15a. If not correct,
loosen mounting screws and move in elongated holes to correct block position before tightening securely.
NOTE
A brush alignment tool is available (Piper P/N 762 109) for
checking and adjusting brush alignment. (Refer to Figure 14-15b.)
3. Visually check brush block for approximately 2
°
angle of attack. (Refer to Figure 14-15a.) If not,
loosen mounting screws and twist block, but be sure to hold clearance limits shown when tightening.
h. System Wiring: With deicer system operating, have assistant observe ammeter while visually inspect-
ing and physically flexing wiring from brush blocks through fire wall, to timer, to ammeter, to switch and to
aircraft power supply. The ammeter will flicker as the timer switches approximately every 30 seconds in the
cycle. Jumps or flickers at other times indicates loose or broken wiring in the area under examination at that
moment. In such case, check continuity through affected harness, while flexing and prodding each wire in the
area that gave initial indication of trouble. Use the wiring diagram in Figure 14-13 to trace circuitry.
Revised: 3/31/94
ACCESSORIES AND UTILITIES
4E18