Quote from cosmo kramer (my emphasis):
In my company the response to e.g. "flaps XX" is to select flap XX and the call out " " (thank god). We don't have any incidents of flaps being wrongly selected. Both pilots know which gates are being used pr. SOP. No one moves the flap handle from flaps 1 to 40, because they think that is what they heard. They know the next step pr. SOP is flaps 5.
Response from Denti (my emphasis):
Same here, flaps/gear are asked for and the confirmation of that call is the action, after the PM silently checked that the conditions are within limits for that command. No further callous needed. If a non-standard flap setting (2, 10, 25) is used one says so when asking for that setting.
Yes, I agree with the parts I've highlighted. I'm out of touch with the current generation of Boeings, but I presume that - like the Airbuses - the PF can monitor the
selection and the results on EICAS/ECAM. As you say, any non-standard command for flap would (hopefully) be acknowledged as such by the PF when making the command.
BUT that's not the main problem my philosophy is addressing. When the PNF's workload is either very high or very low (perhaps mind-wandering), (s)he may interpret an unrelated command or mere comment/observation as a call for the next flap selection. In a noisey cockpit, for example, "Yeah, I'll try that too." could be misheard as "Yeah, I'll take flaps two." If the PNF responds with "Speed checked, Flaps two", there needs to be time for the PF to shout "NEGATIVE!"
before the selection is made. Flap calls, of course, are not the only ones that can be misinterpreted - as in "Cheer-up!"
We are all capable of hearing what we expect or want to hear. Most of you are too young to have been airframe drivers at the time of the Staines accident in 1972, when a BEA Trident deep-stalled into a reservoir after T/O from LHR. (I was on VC10s with another airline.) The PNF who retracted the leading-edge flaps ("droops") prematurely was very new, and knew that the next thing he would hear from the dour old captain would be his command for that. The captain was having a heart attack...
"Check Airman",
CRM is not about blind confidence in the infallibility of your workmate - least of all about expecting him/her to have blind faith in yours. To err is to be human, which is the main reason we still need to have two pilots in present-day, automated airliner cockpits. Otherwise, one would suffice 99% of the time.