Complete failure of battery to operate.
a. Loose or broken lead.
b. Loose or disengaged terminals in battery.
c. Battery not charged.
d. Cell open internally.
e. Battery feeder fault.
Below normal battery output.
a. BATT switch left ON.
b. Generator control unit set too low.
c. Internal connection links loose.
d. External connector burned or pitted.
e. Defective or reversed cells.
f. Cell case current leakage.
External power fails to energize aircraft.
a. Defective or incorrectly polarized external power
b. Defective external power receptacle.
c. Defective external power relay.
d. Loose or wrong connection in external power cir-
e. Defective external power overvoltage monitor.
f. APU voltage too high.
g. APU defective.
h. Defective switch.
i. Circuit breaker tripped.
j. External power feeder fault.
k. Battery feeder fault.
Landing gear will not retract or extend.
a. LANDING GEAR RELAY circuit breaker (pilots