Gyro instrument preflight and taxi checks
Gyro preflight and taxi checks (PHAK ch.8):
| Instrument | When | Check |
|---|---|---|
| Turn coordinator | Before start | Inclinometer full of fluid, no air bubbles, ball at lowest point |
| Turn coordinator | Taxiing | Turn shown in correct direction; ball moves opposite the turn |
| Attitude / heading indicator (vacuum-driven) | Gyro spool-up | No abnormal sounds |
| Attitude / heading indicator (vacuum-driven) | Taxiing | Turns shown in correct direction; normal precession |
| Vacuum system | Before flight | Vacuum gauge (or low-vacuum warning light, if fitted) in specified normal range, not extra wobble on the ground (typical range in gyroscopic-instruments) |
Trap: faster-than-usual precession while taxiing at idle is normal, not a fault: vacuum gyros are below full operating speed at idle power (PHAK ch.8).
References
- PHAK ch.8 (FAA-H-8083-25), Instrument Check (Turn Coordinator; Heading Indicator/vacuum system)
- TP 1102, pre-take-off checks per the Aircraft Flight Manual