737 Engine Starts

Question 1

[1/3] Engine start sequence: (engine start level)

• Starting #2 Eng first is required.
• Single engine taxi is required with APU running.

Answer 1

• Call “STARTING ENGINE NO. 1 (or 2).
• PACK switches - OFF.
• ENGINE START switch - GRD.
• Start Timing.
• Verify increase in N2 RPM.
• Position engine start lever to IDLE detent when:
  • N1 rotation is observed and,
  • N2 RPM reaches 25%, or (if 25% N2 is not possible), at maximum motoring and minimum of 20% N2.
  [NOTE]: Maximum motoring occurs when N2 acceleration is less than 1% in approximately 5 seconds.

Question 2

[2/3] Engine start sequence: (Starter cutout)

Answer 2

• Verify fuel flow and EGT indications.
• At 56% N2 RPM check ENGINE START switch moves to OFF; [if not, position start switch to OFF.]
• Verify START VALVE OPEN alert extinguishes as the ENGINE START switch moves OFF and call “STARTER CUTOUT.”

Question 3

[3/3] Engine start sequence: (After starter cutout)

Answer 3

• Monitor N1, N2, EGT, fuel flow and oil pressure for normal indications as the engine accelerates and stabilizes at idle.
• ISOLATION VALVE switch - CLOSE.
• Right PACK switch - AUTO.
• Duct Pressure - Stable.

Question 4

Notes:

Answer 4

On a standard day at sea level, approximate stabilized idle indications are as follows:
• N1 - 20%
• N2 - 59%
• EGT - 410°C**
• Fuel Flow - 600 PPH
**Idle EGT may vary from 320°C - 520°C depending on OAT, bleed configuration, and engine conditions.

> Single Engine Taxi note: If there is an engine exhaust odor from the AC system, turn Left Pack OFF. (#2 Eng exhaust may be entering APU compressor).<

Question 5

Starter Duty Cycle

Answer 5

• Do not exceed 2 minutes during each start attempt

* A minimum of 10 seconds is required between start attempts

Question 6

Do the ABORTED ENGINE START when:

Answer 6

• The N1 or N2 does not increase or increase very slowly after the EGT increases
  
  • There is no oil pressure indication by the time that the engine is stable at idle
  • The EGT does not increase by 15 seconds after the engine start lever is moved to IDLE
  • The EGT quickly nears or exceeds the start limit (725°C)