I would have no problem with being told we should try and use arm more. But based on my experience I still prefer all off or all on for the 737.
I can't see the problem. The Boeing 737 FCTM advice could not be more clear. My version states: "Autothrottle use is recommended during takeoff and climb in either automatic or manual flight. During all other phases of flight, autothrottle use is recommended only when the autopilot is engaged in CMD."
Forget the why's and wherefore's. if Boeing had to provide a technical reason for all recommendations in the FCTM, the manual would be double the size.
In addition, the FCTM has this to say under Autothrottle ARM mode.
"The autothrottle ARM mode is normally not recommended because its function can be confusing. The primary feature the autothrottle ARM mode provides is minimum speed protection in the event the airplane slows to minimum maneuver speed. Other features normally associated with the autothrottle, such as gust protection is not provided."
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Before the above advice was published, you can bet Boeing test pilots have conducted measured tests on the various autothrottle systems before final recommendations are published. Yet one wonders what causes pilots to think they know better than the experts at Boeing
