Engine warm-up: two phases and RPM
Warm-up brings a cold engine to operating range in two phases, at the AFM-recommended RPM.
| Phase | When | Goal |
|---|---|---|
| 1 | Before taxiing | Engine instruments begin registering somewhere in operating range |
| 2 | Before take-off | Temperatures and pressures within specified limits |
Phase 2 handling:
- RPM may be increased to hasten warm-up.
- Run headed into wind.
- Watch for overheating: engine closely cowled for in-flight cooling.
RPM:
| RPM | Effect |
|---|---|
| Too low | Inadequate distribution of still-sluggish oil |
| Too high | Wears parts that need to gradually acquire heat to reach operating clearances |
- No oil pressure indication after starting: shut engine down.
- RPM, temperature, and pressure limits come from AFM/POH, not TP 1102 (TP 1102 l.1275).
Trap: treating oil pressure showing as "warmed up." Skipping phase 2 leaves temperatures and pressures outside limits.
References
- TP 1102 (Aeroplane Flight Training Manual), ch.3 Engine Handling: Warm-up