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In the Boeing 737-700/800 Quick Reference Handbook (QRH), the section titled "Performance Inflight - QRH" provides Pitch Attitude and %N1 values for various weights and pressure altitudes during Flight with Unreliable Airspeed. These values are useful to be aware of for manual flight, as pitch and power datums, especially in simulator events.

However, I couldn't find any listed values specifically for single-engine flight in Boeing’s 737 reference materials. I am curious to know if Boeing includes Pitch Attitude and %N1 values for single-engine ops in their manuals?

Alternatively, do pilots have to rely solely on "rules of thumb”? For example:

For Single Engine add 15% N1 + 5% N1 in turns?

b737.org.uk

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  • $\begingroup$ @757toga thanks, definitely sounds reasonable. What would their “thinking” be regarding single engine ops - it seems a little strange to have no rough figures for N1% settings when AT not available. 🙈 $\endgroup$ Jun 22, 2023 at 15:47
  • $\begingroup$ @757toga 👍 thank you. $\endgroup$ Jun 22, 2023 at 16:32

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The FCOM/QRH for the B737-700/800 (my copy) also shows only data for both engines operating during "unreliable airspeed" operations. My guess is that because an unresolved "unreliable airspeed" event and an "engine failure" at the same time would be considered unlikely, engineering flight testing was not performed. So, you're left with "rules of thumb."

If you were without autothrottle (engine out) the expectation/thinking (I believe) would be that you adjust the power to give you the performance (airspeed, vertical speed, etc.) that you need for the circumstances. I've never had an inflight engine failure in a jet (except being simulated - thrust lever to idle - during training/testing), but we did it all the time (single-engine operations) in the simulator and it never posed a problem. Once you have the power set and observe the performance you are getting, you just make the necessary power adjustment to keep or change your state of flight. Some SOPs for normal operations have you turn off the autothrottle anytime the autopilot is not engaged - similar principle I think.

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