Engine Limitations

The power plant limitations cover oil temperature, starter use, fuel types and temperatures, the propeller's ground-running band, and the idle gate. Several of them carry a reason worth knowing, and this lesson gives it with the number.

At a glance

• Minimum oil temperatureabove 45 °C
• Starter, continuous running60 s maximum
• Starter, three successive uses1 min 30 s cumulative
• Wait after three starter uses4 min
• Maximum fuel unbalance730 kg
• Minimum fuel temperature, Jet A / Jet A1 / RT, TS1-34 °C
• Minimum fuel temperature, JP5-26 °C
• Maximum fuel temperature57 °C
• Avoid static ground operation41.6 % to 62.5 % NP
• Avoid feather above66.6 % TQ

Oil and power

Oil temperature must be kept above 45 °C to protect the engine air inlet against ice accumulation. ENG OIL TEMP LO shows below 45 °C with the engine running.

MCT is the maximum power certified for continuous use, and it is used only for in-flight emergencies.

CAUTION — Flight with an engine running and its propeller feathered is not permitted.

Starter

The starter is running whenever the ENG START pushbutton is ON, whether CRANK or START is selected.

• Continuous running — the starter-generator must not run for more than 60 s.

• Successive uses — three, with a maximum cumulative running time of 1 min 30 s.

• Then — wait 4 min before using the starter again.

Fuel

• Acceptable fuels — Jet A, Jet A1, JP5 and RT, TS1.

• Prohibited — JP4 and Jet B.

• Maximum fuel unbalance — 730 kg.

Fuel temperature for flight preparation

• Minimum, Jet A, Jet A1 and RT, TS1: -34 °C

• Minimum, JP5: -26 °C

• Maximum: 57 °C (above 57 °C is acceptable before start and for 2 min after start)

Propellers

The aircraft has two Hamilton Sundstrand 568F-1 propellers.

• On the ground — avoid static operation between 41.6 % and 62.5 % NP.

• Feather — avoid use above 66.6 % TQ.

• Run-ups — perform them into the wind.

The idle gate

WARNING — The IDLE GATE protects against power levers below flight idle in flight. Any attempt to override it is prohibited: it may cause loss of control, or engine overspeed and loss of power.

Check yourself

• Why must oil temperature be kept above 45 °C?

• When is MCT used?

• What are the starter's continuous and successive-use limits, and how long must you wait afterwards?

• Which fuels are prohibited?

• Between which NP values should static ground operation be avoided?

Study aid — always fly your aircraft's current FCOM.